[Senate Hearing 111-145]
[From the U.S. Government Publishing Office]
S. Hrg. 111-145
RANGE OF INNOVATIVE, NON-GEOLOGIC APPLICATIONS FOR THE BENEFICIAL REUSE
OF CARBON DIOXIDE FROM COAL AND OTHER FOSSIL FUEL FACILITIES
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HEARING
before a
SUBCOMMITTEE OF THE
COMMITTEE ON APPROPRIATIONS UNITED STATES SENATE
ONE HUNDRED ELEVENTH CONGRESS
FIRST SESSION
__________
SPECIAL HEARING
MAY 6, 2009--WASHINGTON, DC
__________
Printed for the use of the Committee on Appropriations
Available via the World Wide Web: http://www.gpoaccess.gov/congress/
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COMMITTEE ON APPROPRIATIONS
DANIEL K. INOUYE, Hawaii, Chairman
ROBERT C. BYRD, West Virginia THAD COCHRAN, Mississippi
PATRICK J. LEAHY, Vermont CHRISTOPHER S. BOND, Missouri
TOM HARKIN, Iowa MITCH McCONNELL, Kentucky
BARBARA A. MIKULSKI, Maryland RICHARD C. SHELBY, Alabama
HERB KOHL, Wisconsin JUDD GREGG, New Hampshire
PATTY MURRAY, Washington ROBERT F. BENNETT, Utah
BYRON L. DORGAN, North Dakota KAY BAILEY HUTCHISON, Texas
DIANNE FEINSTEIN, California SAM BROWNBACK, Kansas
RICHARD J. DURBIN, Illinois LAMAR ALEXANDER, Tennessee
TIM JOHNSON, South Dakota SUSAN COLLINS, Maine
MARY L. LANDRIEU, Louisiana GEORGE V. VOINOVICH, Ohio
JACK REED, Rhode Island LISA MURKOWSKI, Alaska
FRANK R. LAUTENBERG, New Jersey
BEN NELSON, Nebraska
MARK PRYOR, Arkansas
JON TESTER, Montana
ARLEN SPECTER, Pennsylvania
Charles J. Houy, Staff Director
Bruce Evans, Minority Staff Director
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Subcommittee on Energy and Water Development
BYRON L. DORGAN, North Dakota, Chairman
ROBERT C. BYRD, West Virginia ROBERT F. BENNETT, Utah
PATTY MURRAY, Washington THAD COCHRAN, Mississippi
DIANNE FEINSTEIN, California MITCH McCONNELL, Kentucky
TIM JOHNSON, South Dakota CHRISTOPHER S. BOND, Missouri
MARY L. LANDRIEU, Louisiana KAY BAILEY HUTCHISON, Texas
JACK REED, Rhode Island RICHARD C. SHELBY, Alabama
FRANK R. LAUTENBERG, New Jersey LAMAR ALEXANDER, Tennessee
TOM HARKIN, Iowa GEORGE V. VOINOVICH, Ohio
JON TESTER, Montana
DANIEL K. INOUYE, Hawaii (ex
officio)
Professional Staff
Doug Clapp
Roger Cockrell
Franz Wuerfmannsdobler
Scott O'Malia (Minority)
Brad Fuller (Minority)
Administrative Support
Michael Bain
C O N T E N T S
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Page
Opening Statement of Senator Byron L. Dorgan..................... 1
Statement of Senator Jon Tester.................................. 4
Statement of Scott M. Klara, Director, Strategic Center for Coal,
National Energy Technology Center, Department of Energy........ 5
Prepared Statement........................................... 7
Coal Research and Development Program............................ 7
Carbon Capture and Storage....................................... 7
CO2 Re-use Technologies............................... 8
The American Recovery and Reinvestment Act....................... 10
Statement of Jeff D. Muhs, Executive Director, Center for
Biofuels, USU Energy Laboratory, Utah State University......... 11
Prepared Statement........................................... 13
Statement of Brent R. Constantz, Ph.D., Chief Executive Officer,
Calera Corporation............................................. 14
Prepared Statement........................................... 16
Level the Playing Field for New Technologies..................... 17
The Calera Process: CMAP Technology and Low-voltage Base
Production..................................................... 17
Cost-efficiency.................................................. 19
Pollutant Removal................................................ 19
Demonstration Plants............................................. 19
Beyond Cement.................................................... 21
Recommendations.................................................. 22
Statement of Marjorie L. Tatro, Director of Fuel and Water
Systems, Sandia National Laboratories.......................... 22
Prepared Statement........................................... 24
Summary of Key Points............................................ 24
Thinking Differently About Energy, Carbon and Security........... 25
Algal Biofuels................................................... 27
Synthetic Fuels From CO2 and Water.................... 29
Extracting CO2 From Air............................... 30
Algae Biofuels and Carbon Recycling--A Summary of Opportunities,
Challenges, and Research Needs................................. 35
RANGE OF INNOVATIVE, NON-GEOLOGIC APPLICATIONS FOR THE BENEFICIAL REUSE
OF CARBON DIOXIDE FROM COAL AND OTHER FOSSIL FUEL FACILITIES
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WEDNESDAY, MAY 6, 2009
U.S. Senate,
Subcommittee on Energy and Water Development,
Committee on Appropriations,
Washington, DC.
The subcommittee met at 9:04 a.m., in room SD-192, Dirksen
Senate Office Building, Hon. Byron L. Dorgan (chairman)
presiding.
Present: Senators Dorgan, Tester, and Bennett.
opening statement of senator byron l. dorgan
Senator Dorgan. I am going to call the hearing to order.
This is a hearing of the Energy and Water Subcommittee on
Appropriations in the U.S. Senate. Today, we are going to hold
a hearing on the beneficial reuse of carbon dioxide,
CO2. The $3.4 billion for carbon capture and
sequestration funding that was put in the stimulus program, or
the economic recovery program, includes beneficial use in that
solicitation.
And one of the reasons that we wanted to have this hearing
is I am convinced that we will need to continue to use coal in
our future. Fifty percent of the electricity comes from coal.
The question isn't whether we use coal. The question is how.
And my belief is that we will continue to use coal, but in
a different way. We need to make a significant effort to
decarbonize coal, and the question is what do you do with that
carbon?
Perhaps some will be used for enhanced oil recovery.
Already that is the case with a project in North Dakota, and
that makes a lot of sense. Some will be sequestered somewhere,
and some will be used for, we hope, beneficial use. And that is
the purpose of this discussion.
We need to look at a wide range of options for sequestering
CO2 and using CO2. The issues that we
will discuss today increase those options.
We know that there are benefits that can come from storage
in soils of CO2. We have a project in North Dakota,
sponsored by the North Dakota Farmers Union, which has
established carbon credits on the Chicago Climate Exchange.
They are the largest aggregator of agricultural carbon credits
on the CCX, with more than 5 million acres enrolled in 31
States.
But there has been growing interest and need to support
carbon capture and storage on a very large scale, both in this
country and around the world. The Department of Energy
Technology Laboratory study shows that if the United States
emits about 2 gigatons of CO2 a year from coal-fired
power plants, then there could be more than 40 years worth of
storage for enhanced oil and gas recovery, more than 35 years
worth of storage in unminable coal seams, perhaps 500 to 1,600
years worth of storage in saline aquifers.
And North Dakota, as I said, has played a significant role
here with the Great Plains synthetic fuels plant. I was just
there a week and a half ago. They strip off 50 percent of the
CO2 from the facility. They compress it and put it
in a pipeline, shipping it to the Weyburn oil fields in Canada
for enhanced recovery. And they are sending about 3 million
tons a year for that purpose.
This leads us to the issue of beneficial reuse and the
primary focus of the hearing. When we talk about beneficial
reuse, it is important to make a distinction between the
terrestrial offsets that absorb CO2 from the
atmosphere and processes that directly capture CO2
from coal and other fossil-burning plant emissions and convert
it into usable products.
Well, algae biofuels are an example, I think, of beneficial
reuse. They have a chart, I think, that shows algae tanks.
Algae are the fastest-growing plants in the world. They can
double their bulk in very short period of time. They can grow
in wastewater and convert CO2 into a liquid fuel
that is compatible with our existing fuel structure.
This is an algae tank chart. We had stopped research on
algae for about 15 years, I believe. And we began in the
subcommittee to start that research once again. The
circumstance in this case should be to take a product, such as
CO2, and turn it into a usable product.
We have a project that I looked at in Arizona, where they
are taking the CO2 from the flue gas and growing
algae and then harvesting the algae for diesel fuel. Well, that
is a beneficial use.
There are other projects that have been described to me,
including patents that would turn CO2 into a
product, one product similar to concrete. Harder than concrete,
they say, with significant value. A beneficial use because that
would capture all of the CO2.
Another company came to me and described a process by which
they create chemically I believe it is nitrogen, hydrogen, and
baking soda. And the equivalent of baking soda contains all the
CO2.
There are a lot of interesting ideas out there. My hope is
that the funding that we are making available will allow us to
scale up a range of these ideas to find out what works at
scale? What is the silver bullet, if there is one? And let the
free market then beat a path to their door to say you have
demonstrated something that we are very interested in and want
to do.
This chart, by the way, shows that some folks came to my
office with a plate of cookies and said this comes from coal,
cookies from coal. But, in fact, it was a description of
storing CO2 in what is commonly called baking soda.
So beneficial use of CO2. What are the ideas out
there? What might or might not be the case? What will we find?
Will science and technology and research unlock the mystery of
how to do this at scale and in a way that perhaps reduces the
price of carbon that is limited by legislation, reduces that
price to near zero? Who knows?
And so, we will hear from four witnesses today.
Senator Tester?
statement of senator jon tester
Senator Tester. Thank you, Mr. Chairman.
Only in America could you make cookies out of coal.
Senator Dorgan. That is right. It is good.
Senator Tester. I don't want to repeat what you said, but I
fully agree with the fact that we are going to be burning coal
for a long, long time. Montana happens to be America's version
of the Saudi Arabia of coal, and we need to figure out ways to
deal with the CO2 issue. I think everybody
understands that.
I guess the only thing I will ask of you guys, and the
chairman alluded to it, is how close are we to
commercialization on each one of the things that you are going
to talk about? I think that is really what is critically
important as we try to address the CO2 issue.
And as I get people from the State of Montana coming into
my office every day saying, ``We can't do this. We can't deal
with the CO2 issue. We have got to keep doing
business in the same way.'' What that tells me is that there
are not a lot of known options out there, and we need to make
them known, the options that are real.
So, with that, thank you, Mr. Chairman. And I look forward
to the hearing.
Senator Dorgan. Senator Tester, thank you very much.
As you say, Montana has a lot of coal. So does North
Dakota. And as I have indicated before, I don't think we are
going to see a future without coal. I think we are going to see
a future in which we use coal differently, and that is
decarbonizing the use of coal. The question is can we do that
in a manner that provides benefits, or is it just a liability
to try to do that?
So we have witnesses today that come from a variety of
areas. Mr. Scott Klara is the National Energy Technology
Laboratory at the U.S. Department of Energy. Mr. Klara,
welcome.
Mr. Jeff Muhs, executive director of the Center for
Biofuels, USU Energy Laboratory at Utah State University. He
will be talking about algae fuels.
Dr. Brent Constantz, chief executive officer of Calera
Corporation, will be talking about mineralization and some
other issues.
And Ms. Marjorie Tatro the director of fuel and water
systems at Sandia National Laboratories in Albuquerque, New
Mexico is here.
Let me thank all of you for being here. We are going to
have a hearing that is a bit shorter this morning because the
Energy Department is beginning the markup of the energy bill,
and I am a member of that committee and will have to be there
in a while. But I am really appreciative of all of you coming.
Mr. Klara, why don't you proceed? And let me state that the
entire statements that you have will be made a part of the
permanent record, and you may summarize.
Mr. Klara.
STATEMENT OF SCOTT M. KLARA, DIRECTOR, STRATEGIC CENTER
FOR COAL, NATIONAL ENERGY TECHNOLOGY
CENTER, DEPARTMENT OF ENERGY
Mr. Klara. Thank you.
Mr. Chairman and members of the subcommittee, I appreciate
this opportunity to provide testimony on behalf of the U.S.
Department of Energy's carbon capture and storage research,
with particular emphasis today on CO2 reuse.
The Department has supported research on CO2
reuse for more than a decade. When the sequestration program
was initiated in the mid-1990s, it was recognized that
technologies such as mineralization, chemical conversion to
useful products, algae production, enhanced oil recovery, and
enhanced coalbed methane recovery could play an important role
in mitigating greenhouse gases.
Although the CO2 reduction potential of these
approaches is limited, due to factors such as cost and market
saturation of saleable byproducts, these approaches are logical
first-entry candidates for greenhouse gas mitigation due to
their ability to produce revenue from the use of CO2
to offset costs.
Enhanced oil recovery and enhanced coalbed methane recovery
represent attractive beneficial reuse options of CO2
that produce oil and natural gas while permanently storing the
CO2 in geologic formations. Current research
activities in these areas now focus on developing reservoir
management strategies to increase oil and gas production while
maximizing CO2 storage, ultimately leading to best
practices and protocols for using these approaches as a carbon
mitigation option.
Chemical conversion methods represent another approach that
can be used for CO2 reuse. CO2 can
provide the carbon source for many chemical reactions that
range from simply producing mineral carbonates to serving as
chemical building blocks to make chemicals such as methanol and
urea and, ultimately, making other organic products such as
plastics, composite materials, and rubber, which have useful
applications and represent long-term storage.
The key hurdle to these opportunities as potential
CO2 mitigation approaches relates primarily to cost
and volume. CO2 is a stable molecule. Hence,
chemical conversion to these useful end products often requires
expensive processes with high temperature and high pressure
that are typically not competitive with conventional methods.
Also, these potential applications are likely to utilize
relatively small volumes of CO2 compared to the
large volumes produced from power plants. However, even with
that, chemical conversion approaches could still offer
beneficial early market opportunities that provide a smoother
transition to geologic sequestration.
As the Senator stated, biological capture of carbon dioxide
through algae cultivation is another CO2 reuse
option that is gaining attention. Algae, the fastest-growing
plants on Earth, can double their size as frequently as every 2
hours while consuming carbon dioxide.
Algae can be grown in regions with desert climate so as not
to compete with farmlands and forests, and they do not require
fresh water to grow. They can often grow in brackish, salty
water.
Algae has the desirable feature of having a considerably
high oil content with yields of oil that are orders of
magnitude higher than those of traditional plant materials that
could be used to produce biofuels such as ethanol and
biodiesel.
While it is recognized that the greenhouse gases stored by
the algae will ultimately be released to the atmosphere, there
is a net carbon offset by more effectively utilizing the carbon
contained in the coal. The coal is used to produce power and
then again for algae production. Hence, a net carbon offset is
realized by an increase in the energy extracted from the coal
when compared to using that same coal for just power generation
only.
In conclusion, advanced CCS technology will undoubtedly
play a key role in mitigating CO2 emissions under
potential future carbon constraint scenarios. CO2
reuse technologies with saleable byproducts are logical first-
entry market candidates for greenhouse gas mitigation due to
their ability to produce revenue from the use of the
CO2.
These options will likely provide a technology bridge and
smoother transition to the deployment of large-scale geologic
sequestration that ultimately will be needed to stabilize
greenhouse gases. The Department's research programs are
critical to ensure the availability of all these enabling
technologies.
PREPARED STATEMENT
I applaud the efforts of this subcommittee and the members
for taking a leadership role on these significant issues. And
this completes my statement, and I would be happy to entertain
questions at the appropriate time.
Thank you.
[The statement follows:]
Prepared Statement of Scott M. Klara
Thank you, Mr. Chairman and members of the subcommittee. I
appreciate this opportunity to provide testimony on the United States
Department of Energy's (DOE's) research efforts in carbon capture and
storage (CCS), with a particular focus on carbon dioxide
(CO2) reuse technologies.
INTRODUCTION
Fossil fuel resources represent a tremendous national asset. An
abundance of fossil fuels in North America has contributed to our
Nation's economic prosperity. Based upon current rates of consumption,
the United States has approximately a 250-year supply of coal. Making
use of this domestic asset in a responsible manner will help the United
States to meet its energy requirements, minimize detrimental
environmental impacts, positively contribute to national energy and
economic security, and compete in the global marketplace.
Fossil fuels will play an important role in our Nation's future
energy strategy throughout the remainder of this century. A key
challenge to the continued use of fossil fuels, especially coal, will
be our ability to reduce greenhouse gas emissions from fossil fuel
processes. By developing technologies to mitigate the release of
CO2 into the atmosphere, we can continue to use our
extensive domestic coal resource, while reducing the potential impacts
on climate change. CCS can play a central role in fossil fuels
remaining a viable energy source for our Nation. CCS is the primary
pathway DOE is pursuing to allow continued use of fossil fuels in a
carbon-constrained future.
COAL RESEARCH AND DEVELOPMENT PROGRAM
The coal research and development program--administered by DOE's
Office of Fossil Energy and implemented by the National Energy
Technology Laboratory--is designed to address environmental concerns
over the future use of coal by developing a portfolio of revolutionary
CCS technologies. In partnership with the private sector, efforts are
focused on maximizing efficiency and environmental performance, while
minimizing the costs of these new technologies.
In recent years, the program has been restructured to focus the
urgent need on CCS technologies. The program is focused on two major
strategies:
--Capturing and long-term storing greenhouse gases; and
--Substantially improving the efficiency of fossil energy systems.
The first strategy will reduce emissions of CO2 from
fossil energy systems. The second strategy will improve the fuel-to-
energy efficiencies of fossil-fueled plants, thus reducing pollutant
emissions, water usage, and carbon emissions on a per unit of energy
basis. The improved efficiency strategy also provides a positive
efficiency impact to partially offset the efficiency penalty incurred
when CCS is added to a plant. Collectively, these two strategies
comprise the coal research and development program's approach to
develop technologies that will help current and future fossil energy
plants meet requirements for a safe and secure energy future.
Coal research has resulted in important developments and insights
regarding future technology innovations. New engineering concepts have
been developed to convert coal into gases that can be cleaned and then
used to generate power or produce fuels. New approaches to low-emission
power generation are emerging that hold promise for integration with
coal-based or combined coal-and-biomass energy plants. Technologies for
achieving CCS are stretching beyond basic research, defining pathways
in which greenhouse gas emissions can be permanently diverted from the
atmosphere. With these building blocks, a new breed of coal plant can
be created--one that generates power and produces high-value energy
with dramatically reduced environmental impact. The Department's
activities are focused on high-priority CCS enabling technologies, such
as advanced integrated gasification combined cycle, advanced hydrogen
turbines, carbon capture and storage, coal-to-hydrogen conversion, and
fuel cells. These research areas provide the supporting technology base
for all CCS development.
CARBON CAPTURE AND STORAGE
The coal research and development program is addressing the key
technology challenges that confront the wide-scale deployment of CCS
through research on cost-effective capture technologies; measuring,
monitoring, verification, and accounting technologies to ensure
permanent storage; permitting issues; liability issues; public
outreach; and infrastructure needs. As an example, it is estimated that
today's commercially available CCS technologies would add around 80
percent to the cost of electricity for a new pulverized coal plant, and
around 35 percent to the cost of electricity for a new advanced
gasification-based plant.\1\ The program is aggressively pursuing
developments to reduce these costs to less than a 10 percent increase
in the cost of electricity for new gasification-based energy plants,
and less than a 35 percent increase in the cost of electricity for
pulverized coal energy plants.
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\1\ Cost and Performance Baseline for Fossil Energy Plants, Volume
1: Bituminous Coal and Natural Gas to Electricity, U.S. Department of
Energy/National Energy Technology Laboratory, DOE/NETL-2007/128 1,
Final Report, May 2007.
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The coal research and development program has been performing CCS
field tests for many years. For example, the Regional Carbon
Sequestration Partnerships are drilling wells in potential storage
locations and injecting small quantities of CO2 to validate
the potential of key storage locations throughout the country, as well
as conducting large-scale carbon sequestration field tests. Geologic
sequestration projects at key locations across the country are being
pursued. Substantial progress has occurred in the area of monitoring,
verification, and accounting with the development and refinement of
technologies to better understand storage stability, permanence, and
the characteristics of CO2 migration.
Research is also focused on developing technology options that
lower the cost of capturing CO2 from fossil fuel energy
plants. This research can be categorized into three pathways: post-
combustion, pre-combustion, and oxy-combustion. Post-combustion refers
to capturing CO2 from the flue gas after a fuel has been
combusted in air. Pre-combustion is a process where a hydrocarbon fuel
is gasified to form a synthetic mixture of hydrogen and CO2,
and the CO2 is captured from the synthesis gas before it is
combusted. Oxy-combustion is where hydrocarbon fuel is combusted in
pure or nearly pure oxygen rather than air to produce a mixture of
CO2 and water that can easily be separated to produce
relatively pure CO2. This research includes a wide range of
approaches: membranes, oxy-combustion concepts, solid sorbents,
CO2 clathrates, and advanced gas/liquid scrubbing
technologies. These efforts will produce meaningful improvements to
state-of-the-art technologies and seek to develop revolutionary
concepts, such as metal organic frameworks, ionic liquids, and enzyme-
based systems.
A center piece of the program is DOE's field test program, carried
out by the Regional Carbon Sequestration Partnerships. Each Partnership
comprises State agencies, universities, and private companies, which
are a ``capacity building'' enterprise with the goal of developing the
knowledge base and infrastructure needed to support the wide-scale
deployment of CCS technologies. Each Partnership is focused on a
separate and specific region of the country with similar
characteristics relating to CCS opportunities.
Collectively, the seven Regional Partnerships represent more than
350 unique organizations in 42 States, three Native American
Organizations, and four Canadian Provinces. Collectively, these
Partnerships constitute a significant national asset in that they
represent regions encompassing 97 percent of coal-fired CO2
emissions, 97 percent of industrial CO2 emissions, 96
percent of the total land mass, and essentially all the geologic
storage sites in the country that can potentially be available for
carbon sequestration. The non-Federal cost share in the efforts being
pursued by the Partnerships is greater than 35 percent, which is a key
indicator of industry and technology vendor involvement that will help
to ensure that developments are ultimately deployed. Together, the
seven Partnerships form a network of capability, knowledge, and
infrastructure to enable carbon sequestration technology to play a
major role in a national strategy to mitigate CO2 emissions.
Over the course of these CCS activities, DOE will develop Best
Practice Manuals on topics such as site characterization, site
construction, operations, monitoring, mitigation, closure, and long-
term stewardship. These Manuals will serve as guidelines for a future
CCS industry, and help transfer the lessons learned from the
Department's program to current and future stakeholders.
CO2 RE-USE TECHNOLOGIES
The coal research and development program has supported research on
CO2 re-use technologies for more than a decade. When the
Sequestration Program was initiated in the mid-1990s, it was recognized
that technologies such as mineralization, chemical conversion to useful
products, algae production, enhanced oil recovery (EOR) and enhanced
coalbed methane recovery (ECBMR) could play an important role in
mitigating CO2 emissions. Although the CO2
reduction potential of these approaches is limited, due to factors such
as cost and market saturation of salable byproducts, these approaches
are logical ``first-market entry'' candidates for greenhouse gas
mitigation, due to their ability to produce revenue from use of the
CO2 that could be used to offset the costs for these ``early
adopters.'' Hence, these options provide a technology bridge and
smoother transition to the deployment of the large-scale, stand-alone
geologic sequestration operations that will ultimately be needed to
achieve the much larger reductions that would be required to approach
stabilizing greenhouse gas concentrations in the atmosphere.
EOR and ECBMR represent attractive beneficial re-use options for
CO2 that produce oil and natural gas while permanently
storing the CO2 in these geologic formations.
The Department has recognized the importance of CO2 EOR
for more than 40 years. As early as the 1970s, DOE-funded projects were
developing concepts to improve the effectiveness and applicability of
CO2 EOR. DOE also has a long history in conducting research
on the benefits of unconventional gas recovery with technologies such
as coalbed methane recovery. Due in part to research conducted by DOE,
coalbed methane production has increased for each of the last 15 years
due to advances in production methods and now accounts for roughly 8
percent of the United States' natural gas production.
More recently, the Department has been studying the technologies
needed to ensure permanence of CO2 storage in ``enhanced''
coal bed methane recovery, where natural gas production is ``enhanced''
by injecting CO2. The CO2 displaces the methane
on the coal surface and the CO2 remains stored in the
formation. Relative to CO2 storage, current research
activities in EOR and ECBMR now focus on developing reservoir
management strategies to maximize and ensure permanence of
CO2 storage, while increasing oil/gas production; along with
the development of technologies for measuring, monitoring,
verification, and accounting that will validate permanent
CO2 storage in these applications while providing best
practices and protocols for using these approaches as a carbon
mitigation option.
Chemical conversion methods represent another technology approach
that can be used for CO2 re-use. CO2 can provide
the carbon source for many chemical reactions that range from producing
mineral carbonates, to serving as chemical building blocks to make
chemicals like methanol and urea, and ultimately making other organic
chemicals, plastics, or composite materials that could have useful
applications and represent long-term storage opportunities. Some
industries that currently use relatively small quantities of
CO2 in their operations include metals; manufacturing and
construction; chemicals, pharmaceuticals, and petroleum; rubber and
plastics; and the food and beverage industries. Also, most of the
baking soda (sodium bicarbonate) produced in the United States is
manufactured by reacting soda ash with CO2 and water.
The key hurdles to these new opportunities as potential
CO2 mitigation approaches relate primarily to cost and
volume. CO2 is a stable molecule; hence, chemical conversion
to useful end products often requires expensive processes (high
temperature and/or high pressure) that are not competitive with
conventional manufacturing methods. These applications are also likely
to utilize relatively small volumes of CO2, as compared to
the large volumes produced from powerplants.
The Department had previously supported a working group for several
years that consisted of several Universities and National Laboratories
working on the science and economics of speeding the reaction of carbon
mineralization as a potential option to permanently sequester
CO2. Carbonation reactions were investigated that combined
CO2 with alkaline earth elements (predominantly magnesium,
but also calcium and other elements) derived from silicates to yield
thermodynamically stable solid mineral carbonates--essentially, rocks.
The team focused on conducting laboratory experiments and modeling the
complex chemical reactions associated with this process. It was
ultimately concluded that the process could not be cost effective as a
CO2 capture mechanism, and that numerous mining and storage
issues also existed as key barriers. However, the knowledge-base gained
from these efforts is proving valuable in pursuing applications where
mineralization can be used to produce salable byproducts that might
make this concept practical for a limited set of applications.
In the past few years, DOE has refocused research efforts on using
mineralization chemistry as a possible means of ``solidifying''
CO2 after it is stored in a geologic formation, thereby,
ensuring permanent storage. A category of geologic formations called
``Basalts'' have emerged as leading candidates where this approach may
someday have merit. Basalts are silica-rich volcanic rock that contains
key minerals--such as calcium and magnesium--that can combine with
CO2 to form carbonates.
The Department is supporting the Big Sky Regional Carbon
Sequestration Partnerships and Pacific Northwest National Laboratory in
conducting research focused on enhancing the mineralization process in
these formations. The Big Sky Partnership is conducting small-scale
CO2 injection in the Columbia River flood Basalts, with the
goal of confirming feasibility of safe permanent storage in these
formations. Successful research in Basalts could expand the viable
geologic options for CO2 sequestration in the continental
United States, and provide unexplored options for CO2
sequestration in developing countries that have extensive Basalt
formations, such as India.
Biological capture of CO2 through algae cultivation is
another CO2 re-use option that is gaining attention as a
possible means to achieve reductions in CO2 emissions from
fossil-fuel processes. Algae, the fastest growing plants on earth, can
double their size as frequently as every 2 hours while consuming
CO2. Algae can be grown in non-arable regions, such as
deserts, so as not to compete with farmland and forests, and they do
not require fresh water to grow. Algae will grow in brackish water,
plant-recycle water, or even in sewage streams, and, when cultivated
within closed systems, these waters can be recycled, thereby minimizing
further water use. Algae has the desirable feature of having a
considerably high oil content, with yields of oil per acre that are
orders of magnitude higher than those of traditional plant materials
used to produce biofuels, such as ethanol or biodiesel. The oils in
algae can be extracted and converted to liquid transportation fuel.
While it is recognized that the CO2 stored by the algae will
ultimately be released to the atmosphere, there is a net-CO2
emission decrease because the CO2 released from coal
combustion for algal growth reduces demand for petroleum without
increasing coal consumption The coal is used to produce power and then
again for algae production, hence, a net-carbon offset is realized by
an increase in the energy extracted from the coal, compared to that
same coal being used for power generation only.
A cost-effective, large-scale production system for growing algae
using CO2 from a powerplant has not yet been demonstrated.
DOE is sponsoring a project with Arizona Public Service (APS) to
develop and ultimately demonstrate a large-scale algae system coupled
with a powerplant. APS is examining the use of coal gasification for
the production of substitute natural gas. The utilization of algae for
carbon management and recycle is an integral part of the project. The
project has already proven the process at a small scale using a one-
third acre algae bioreactor that has been operating for weeks using
powerplant stack emissions to produce sustained algae growth.
Additionally, a prototype algae cultivation system is being evaluated
for continuous operation. The project will ultimately assemble a fully
integrated energy system for beneficial CO2 use, including
an algae farm of sufficient size to adequately evaluate effectiveness
and costs for commercial applications. To complement the engineered
system in Arizona, DOE has solicited Small Business Innovation Research
proposals to explore novel and efficient concepts for several
processing aspects of CO2 capture for algae growth. Projects
are addressing novel approaches for extracting oil from algae, and for
converting algae oil to transportation fuel, focusing on technology
consideration for integration with power or syngas production so as not
to duplicate biofuels work being conducted by DOE's Office of Energy
Efficiency and Renewable Energy. The results from these efforts should
prove useful to future algae farming applications at power and synfuel
plants.
THE AMERICAN RECOVERY AND REINVESTMENT ACT
The American Recovery and Reinvestment Act (Recovery Act)
appropriated $3.4 billion for the Fossil Energy Research and
Development (FER&D) Program. As reflected in the Joint Explanatory
Statement of the Committee of Conference leading to the act, these
Recovery Act funds will support activities targeted at expanding and
accelerating the commercial deployment of CCS technology, thus
providing a key thrust to the FER&D Program to accelerate, by many
years, the advances needed for future plants with CCS. Although
specific details are still being worked on by DOE, CO2 re-
use technologies will be addressed in the following activities of the
Recovery Act.
New CCS Initiative for Industrial Applications.--$1.52 billion is
to be used for a competitive solicitation for a range of industrial
carbon capture and energy efficiency improvement projects, including
innovative concepts for beneficial CO2 re-use.
CONCLUSIONS
Today, nearly three out of every four coal-burning powerplants in
this country are equipped with technologies that can trace their roots
back to DOE's advanced coal technology program. These efforts helped
accelerate production of cost-effective compliance options to address
legacy environmental issues associated with coal use. Advanced CCS
technologies will undoubtedly play a key role in mitigating
CO2 emissions under potential, future carbon stabilization
scenarios. CO2 re-use technologies with salable byproducts
are logical ``first market entry'' candidates for greenhouse gas
mitigation due to their ability to produce revenue from the use of
CO2. These re-use technologies, along with large-scale
geologic sequestration, will contribute to the suite of options for
reduction of anthropogenic CO2 emissions.
DOE's research programs are helping develop these enabling
technologies. The United States must continue to show leadership in
technology development and future deployment to bring economic rewards
and new business opportunities both here and abroad.
I applaud the efforts of this subcommittee and its members for
taking a leadership role in addressing these timely and significant
issues.
Senator Dorgan. Mr. Klara, thank you very much.
Next, we will go to Mr. Jeff Muhs, who is with Utah State
University, executive director of the Center for Biofuels at
USU's Energy Laboratory.
Mr. Muhs, welcome.
STATEMENT OF JEFF D. MUHS, EXECUTIVE DIRECTOR, CENTER
FOR BIOFUELS, USU ENERGY LABORATORY, UTAH
STATE UNIVERSITY
Mr. Muhs. Thank you, Mr. Chairman and members of the
subcommittee.
It is a pleasure to speak to you today on the beneficial
reuse of carbon dioxide. I will be summarizing findings from a
report that Utah State University is jointly issuing with a
number of other entities on the opportunities, challenges, and
research to each of our algae biofuels, particularly
emphasizing systems design for carbon recycling from point
source CO2 emitters.
America faces five interdependent challenges that threaten
our prosperity and quality of life--energy price spikes,
climate change, depletion of natural resources, high food
prices, and an addiction to foreign oil. Although there is no
single answer, algae energy systems represent a possible
partial solution to all five of these challenges.
Growing algae, the most productive of all photosynthetic
life on Earth, and converting it into fuels could help mitigate
carbon emissions, reduce oil imports and price shocks, reclaim
wastewater, and lower food prices. Fundamentally, algae use
solar energy and nutrients to transform CO2 into
organic matter. Due to their simple biological structure, they
capture carbon more rapidly than terrestrial plants and store
it in a form that can be processed into fuel such as biodiesel.
Some algae strains are capable of doubling their mass
several times a day, and unlike terrestrial plants, algae can
be cultivated on marginal desert land and using saline,
brackish, or wastewater. Since some species have a high
affinity for CO2, siting these algae systems near
point source CO2 emitters is a very attractive
option. Research has demonstrated that the yields can be
dramatically improved by enhanced concentrations of
CO2.
Because of its high lipid or oil content and growth rate,
algae can produce between 10 and 50 times more biodiesel per
acre than, for example, soybeans. To compare the two
feedstocks, if all the soybeans harvested in the United States
were converted into biodiesel, the resulting fuel supply would
accommodate less than 10 percent of our annual diesel fuel
needs.
Conversely, if an area roughly the size of one-tenth of
North Dakota or Utah were to be converted into algae systems,
it could provide all of our diesel fuel needs. So because of
that enhanced yield opportunity, there is a big opportunity.
The fundamentals of algae energy systems are sound. As a
recent article in National Geographic noted, there is no magic
bullet fuel crop that can solve our energy woes without harming
the environment says virtually every scientist studying the
issue, but most say that algae comes closer than any other
plant.
But many challenges lie ahead, and our analysis indicates
that the overall lifecycle cost of algae energy systems must be
reduced by at least a factor of two and probably much more.
Unlike traditional crops, the technology needed to grow and
harvest algae using industrial or agricultural processes is
still pre-commercial. In the field of plant biology, algae is
one of the least explored fields.
Recycling carbon is a new concept, and there are challenges
related to separating, compressing, and delivering
CO2 into these algae cultivation systems. To
cultivate algae in open ponds, land and water, which must be
replenished because of evaporative losses, are required. Energy
is needed to keep the algae stable, healthy, and growing.
Invasive species, which can kill algae, must be controlled.
In enclosed growth systems, capital costs for equipment
used to enclose, mix, and maintain cultures must be reduced. In
both scenarios, surface shading limits the amount of sunlight
that can be used constructively to produce biomass.
After cultivation, algae must be dewatered and dried prior
to oil extraction and fuel production, and each step along the
way, energy and other resources are required. But by harnessing
the same biology, chemistry, and genetics that led to the
doubling of yields in traditional crops, we should be able to
do the same with algae. And advances in optics, mechanical
engineering, and other disciplines are leading to scalable
cultivation systems that better utilize sunlight and have the
potential to meet cost targets.
Indeed, algae has the unique potential to produce renewable
fuels and recycle carbon sustainably without interfering with
food supplies. To succeed, however, private and public
cooperation is critical. Without it, the algae industry will
struggle to reduce cost and integrate subsystems. Without
regulations limiting carbon emissions, utilities and, in
particular, small CO2 emitters will have little
motivation to explore these reuse options.
Therefore, a robust and well-integrated RD&D program will
only occur with Government involvement, both in sponsorship of
research and development and enactment of policies in future
energy and climate change legislation that help to accelerate
commercial deployment.
We recommend that Congress authorize and appropriate funds
for an algae-related RD&D program at the Department of Energy.
It should include research on lifecycle analysis, leverage
strengths of existing Department programs, and be coordinated
at a systems level. It should take advantage of new program to
management tools and include a portfolio of activities from
foundational research to integrated demonstration.
PREPARED STATEMENT
And deployment projects should demonstrate the viability of
technologies at a scale large enough to overcome infrastructure
challenges and include regional partnerships similar to the
Department's programs in geologic sequestration.
Thank you very much.
[The statement follows:]
Prepared Statement of Jeff D. Muhs
Chairman Dorgan, Ranking Member Bennett and other members of the
subcommittee, it is a pleasure to speak to you today on the subject of
beneficial reuse of carbon dioxide. I will be summarizing findings from
a report Utah State University is jointly issuing with a number of
other entities on opportunities, challenges, and research needs for
algae biofuel production--emphasizing systems designed for carbon
recycling from point-source CO2 emitters.
America faces five interdependent challenges that threaten our
prosperity and quality of life:
--energy price spikes;
--climate change;
--depletion of natural resources;
--high food prices; and
--an addiction to foreign oil
Although there is no single answer, algae energy systems represent
a possible partial solution to all five challenges. Growing algae, the
most productive of all photosynthetic life on earth, and converting it
into fuels could help mitigate carbon emissions, reduce oil imports and
price shocks, reclaim wastewater, and lower food prices.
Fundamentally, algae use solar energy and nutrients to transform
CO2 into organic material. Due to their simple biological
structure, they capture carbon more rapidly than terrestrial plants and
store it in a form that can be processed into fuels such as biodiesel.
Some algal strains are capable of doubling their mass several times a
day, and unlike terrestrial plants, algae can be cultivated on marginal
or desert land using saltwater, brackish-water, or wastewater. Since
some species have a high affinity for CO2, siting algae
energy systems near point-source CO2 emitters is an
attractive option. Research has demonstrated that algal yields can be
improved dramatically using enhanced concentrations of CO2.
Because of its high lipid (or oil) content and growth rate, algae
can produce 10 to 50 times more biodiesel per acre than, for example,
soybeans. To compare the two feedstocks, if all the soybeans harvested
in the United States were converted into biodiesel, the resultant fuel
supply would accommodate less than 10 percent of our annual diesel fuel
needs. Conversely, if an area roughly equating to one-tenth the area of
either North Dakota or Utah were developed into algae energy systems,
it would supply all of America's diesel fuel needs.
There is growing consensus that the fundamentals of algae energy
systems are sound. As a recent article in National Geographic noted:
``there is no magic bullet fuel crop that can solve our energy woes
without harming the environment, says virtually every scientist
studying the issue. But most say that algae . . . comes closer than any
other plant.''
But many challenges lie ahead and our analysis indicates that the
overall lifecycle cost of algae energy systems must be reduced by at
least a factor of two and probably more.
Unlike traditional crops, the technology needed to grow and harvest
algae using industrial or agricultural processes is in its infancy. In
the field of plant biotechnology, algae is one of the least explored
areas. Recycling carbon is a new concept and there are challenges
related to separating, compressing, and delivering CO2 into
algae cultivation systems.
To cultivate algae in open ponds, land and water (which must be
replenished because of evaporative losses) are required. Energy is
needed to keep algae cultures stable, healthy and growing. Invasive
species, which can kill oil-rich algae, must be controlled. In enclosed
growth systems, capital costs for equipment used to enclose, mix, and
maintain cultures must fall. In both scenarios, surface shading limits
the amount of sunlight that can be used constructively to produce
biomass. After cultivation, algae must be dewatered and dried prior to
oil extraction and fuel production. In each step along the way, energy
and other resources are required.
But by harnessing the same biology, chemistry, and genetics that
led to a doubling of yields in traditional crops, we should be able to
do the same with algae. And advances in optics, mechanical engineering,
and other disciplines are leading to scalable cultivation systems that
better utilize sunlight and have the potential to reach cost targets.
Algae has the unique potential to produce renewable fuels and
recycle carbon sustainably and without interfering with food supplies.
To succeed, however, private and public cooperation is critical.
Without it, the algae industry will struggle to reduce costs and
integrate subsystems. Without regulations limiting carbon emissions,
utilities, and in particular, small CO2 emitters will have
little motivation to explore reuse options.
Therefore, a robust and well-integrated RD&D program will only
occur with Government involvement both in sponsorship of R&D and
enactment of policies in future energy and climate change legislation
that accelerate commercial deployment.
We recommend that Congress authorize and appropriate funds for an
algae-related RD&D program at the Department of Energy. It should
include research on lifecycle analyses, leverage strengths of existing
Department programs, and be coordinated from a Department-wide
perspective. The program should take advantage of new program
management tools and include a portfolio of activities ranging from
foundational research to integrated demonstrations. Deployment projects
should demonstrate the viability of technologies at a scale large
enough to overcome infrastructure challenges and include regional
partnerships similar to the Department's programs for geologic
sequestration.
Thank you. I look forward to answering any questions.
Senator Dorgan. Mr. Muhs, thank you very much. We
appreciate your testimony.
Next, we are going to hear from Dr. Brent Constantz, chief
executive officer and founder of Calera. And from his
biography, specializes in high-performance and novel cements.
Is that the case, Mr. Constantz?
Dr. Constantz. Yes.
Senator Dorgan. And is the inventor on over 60 issued U.S.
patents on the subject.
You may proceed. Thank you for being with us.
STATEMENT OF BRENT R. CONSTANTZ, Ph.D., CHIEF EXECUTIVE
OFFICER, CALERA CORPORATION
Dr. Constantz. Thanks. We really admire the Senate's vision
in appreciating the beneficial reuse of CO2 and
turning it into a profit center for a CO2 emitter
instead of a huge liability for them.
Just looking at the mass balance of carbon on Earth, if we
look at the Kyoto Protocol, we are calling for 5 billion tons
of mitigation. And to put that in perspective, powerplants and
cement plants put out about 11 billion tons of CO2 a
year into the Earth's atmosphere.
We could put 16 billion tons of CO2 a year into
cement and aggregate. So we could more than triple the Kyoto
requirement putting CO2 into cement and aggregate.
Calera has developed breakthrough technology that allows us
to handle the flue gas streams such as from coal, which are
only about 15 percent CO2, which is a major
challenge. Otherwise, it needs to be separated via very
expensive techniques. It can also be taken from natural gas in
cement plants, which are also dilute streams of CO2,
unlike what has been used in EOR.
This technology also has multi-pollutant control features,
especially with SO2 and NO as well as mercury and
other toxics. The absorption technology is an absolute
breakthrough and has allowed us to have very high absorption of
the raw flue gas with no separation step.
We have developed a revolutionary low-voltage base
technology, which allows us to produce base at one-fifth the
voltage of traditional base generation and have accelerated
mineral dissolution technologies to produce. Then we utilize
the waste heat from the power plant to dry the powders to make
cement.
Our chief operating officer joined us from NRG, the largest
nonregulated power company, where he held the same role. Our
head of emissions came from 30 years' experience with General
Electric. His Ph.D. was on the burning of coal. Our head of
process technology came from Exxon, where he spent 20 years
building their process plants.
We are producing green building materials. Our first
product, which we launched already, is a replacement for
portland cement, a supplementary cementitious material that has
been tested against ASTM C1157, and we have a 15,000 square
foot lab where we do concrete and cement testing. It was
launched at the World of Concrete, which is an 80,000-person
convention. It has been well addressed by the entire portland
cement industry and the ready-mixed industry as well as the
asphalt industry.
In addition, we are producing aggregate. I have an example
of the aggregate. At Stanford, I teach carbonate sedimentology.
And if I were to put this piece of aggregate on my final exam,
unless they had a microscope, none of the students could tell
you that this wasn't natural limestone, which is what two-
thirds of all natural aggregates are.
These mix designs are carbon negative. So they are not just
carbon neutral, but we are actually sequestering CO2
from the powerplant into the solid material. And we can
sequester, as I said, 16 billion tons of CO2 a year
this way on an ongoing basis for centuries to come. This is a
profitable option, both for a cement plant that has to deal
with their CO2, as well as a coal plant.
The aggregates provide the possibility of specialty
products such as lightweight aggregates, which are very
important, or aggregate for pervious concrete.
One byproduct of our process is fresher water because we
take all of the hardness out of the water to combine with the
carbonate, and this fresher water can be desalinated via
reverse osmosis for less than 50 percent the regular energy
intensivity. So the water aspect of the profit is important. In
fact, in Moss Landing, where we have 200-acre pilot plant, we
already have a contract with the local water district to
produce fresh water in addition to everything else we are
producing.
Other revenue sources are the carbon tipping fees and
allocations where we are working in Victoria, Australia,
already doing this. We have the ability to use off-peak
electricity consumption. So this can be done with almost no
energy footprint.
And the important point I would like to point out is this
is the permanent removal of CO2. It is not
temporary. We convert the CO2 to carbonate. Just
like the white cliffs of Dover, it is going to stay there for
millions of years. It is never coming back.
I would like to urge the Senate to consider leveling the
playing field because there is currently a monomaniacal focus
on geologic sequestration in all of the language. We believe a
more inclusive approach to look at all of the ways of dealing
with carbon would be better for everybody and focus on the
outcome of sequestering CO2 as opposed to one
specific method, which is geologic sequestration.
PREPARED STATEMENT
And I think the United States needs to provide
international leadership in this area, showing the broad
variety of solutions for removal of CO2.
Thank you.
[The statement follows:]
Prepared Statement of Brent R. Constantz
INTRODUCTION
Chairman Dorgan and members of the subcommittee, first, I would
like to thank this subcommittee for their important work in advancing
solutions to climate change. I would also like to thank you for
inviting me to testify on a carbon-mitigation sector that I believe
holds tremendous promise: the conversion of carbon dioxide
(CO2) to mineral form for beneficial reuse.
This hearing comes at a critical time: Congress is debating climate
change legislation; the President has promised a green energy policy
that helps not hurts our economy; and almost 200 countries are
preparing for the Copenhagen international climate discussions. As
these and other political decisions unfold against the backdrop of a
global economic crisis, we must develop a broad array of cost-effective
methods to mitigate the release of CO2 into the atmosphere.
My name is Brent Constantz, and I am the CEO of Calera Corporation,
based in Los Gatos, California. Over the past 20 years, I have built
three successful Silicon Valley companies based on innovative
specialty-cement technologies, covered by approximately 70 issued U.S.
patents I hold in this area. Additionally, I am a professor at Stanford
University where my teaching and research are focused on carbonate
mineral formation and oceanic carbon balance.
My goal today is to urge Congress to think broadly in terms of the
carbon capture and sequestration (CCS) technologies it supports, and
the current budget language that needs to be carefully crafted to take
full advantage of the opportunities these technologies can offer.
Additionally, my testimony will give you an overview of our
CO2-conversion technology; how it is possible to
beneficially reuse CO2 when it is converted to a mineral
form; how our technology compares with other CO2-capture
options; and the commercial potential of beneficial CO2
reuse.
Finally, I will conclude with recommendations that not only align
with this subcommittee's demonstrated commitment to CCS, but also help
move beneficial CO2-reuse technologies such as Calera's from
pilot-scale to global innovation, thereby fostering other technologies
that may be alternative or complementary to CO2 separation
and geologic sequestration.
Calera has developed a transformational technology that converts
CO2 into green building materials. The process captures
CO2 emissions from power-plant flue gas and cement
manufacturing, and chemically combines it with a variety of natural
minerals, water and solid waste materials to produce cementitious
materials, aggregate and other related building materials. Thus the
process is more than CO2 sequestration--it represents
permanent CO2 conversion.
Calera is backed by Khosla Ventures, a well-regarded venture
capital firm specializing in ``green'' technology. With Mr. Vinod
Khosla as a partner in this effort, Calera has been able to engage a
formidable team of scientists and engineers to move beyond the
laboratory and bench-scale research. We currently operate a pilot
facility adjacent to a 1,000 MW powerplant in Moss Landing, California
that allows us to test our technology with a goal of scaling the
process up to full production levels. In less than a year Calera has
grown from 12 to more than 70 employees, including 18 PhDs and senior
executives with more than 200 years of combined experience in power,
water and concrete.
But we have many milestones ahead to reach commercial scale,
particularly in this difficult economic climate. Government support is
necessary at this stage of development for demonstration facilities and
early deployment in commercial plants. Government support, along with
commercial partner investment will make the financial hurdle of
financing these first scaled plants possible. Government policies that
are directed toward mitigating carbon and stimulating the economy by
the best available approaches will enable substantial progress for the
profitable, beneficial reuse of CO2.
LEVEL THE PLAYING FIELD FOR NEW TECHNOLOGIES
I would like to underscore that CO2 mitigation
technologies are evolving rapidly. Calera is one of several companies
focused on CO2 conversion technologies with the potential
for beneficial reuse. Yet, despite the promise of these technologies,
carbon mitigation funding has been narrowly focused on CO2
separation and purification for geologic sequestration. This focus is
proscriptive to one method, assuring that carbon reduction dollars will
be directed only towards this method's narrowly defined pool of
projects in hopes of making geologic CO2-sequestration a
viable option. This is especially vexing, considering that the Calera
process and comparable CO2-capture technologies largely
avoid the economic burden, carbon balance, risk and permitting
constraints that accompany geologic CO2-sequestration.
We submit that taxpayer support and funding should be based on
carbon reduction outcomes and seek to advance the most effective
technologies. While CO2 separation and purification for
geologic sequestration is one important potential method in the carbon-
capture toolbox, we need to consider all of the potential solutions to
address the volume of CO2 at issue. Broad statutory language
is needed that encourages innovation and rewards breakthrough
technologies consistent with our goals as a free-market nation. The
methods we implement should be selected by how we best arrive at the
desired outcome, and not constrained to any one particular method for
CO2 mitigation.
I will come back to the crucial point of how the Federal Government
can level the playing field for other technologies after providing you
with an overview of Calera's CO2-conversion technology.
the calera process--cmap technology and low-voltage base production
Calera's technology is called Carbonate Mineralization by Aqueous
Precipitation (CMAP). The Calera process is unique in how it
essentially mimics the natural carbonate mineralization of corals when
making their external skeleton. This technology captures CO2
emissions by converting CO2 to CO3 (carbonate)
and effectively storing it in a stable mineral form. This mineral can
then be used to replace or supplement traditional portland cement,
offsetting emissions that would otherwise result from the
CO2-intensive manufacture of conventional cement.
The biggest hurdle to the mineralization concepts studied has been
high-energy demand or extremely slow rates of reaction occurring over
geologic timeframes. Calera's CMAP bypasses the limitations of previous
mineralization approaches, but it has not been broadly pursued in the
past due to the requirement for sustainable, unlimited chemical-base
sources. Amongst the many technologies now possible are novel base-
production methods that are low in cost, energy, and carbon footprint.
These Calera innovations--fully described in USPTO patent
applications--revolutionize the technical feasibility, carbon-mass
balance and economics of carbonate mineralization for CO2
capture and conversion via aqueous mineralization.
Calera's mineralization process utilizes break-through, low-voltage
chemical base-production technology that makes the conversion from
CO2 to carbonate cost-effective and sustainable. Using
approximately one-fifth the voltage of conventional base-production
processes, Calera's base production has a very low carbon-footprint and
is an alternative to natural or waste sources of chemical base.
Therefore, the process can occur irrespective of any specific site
location.
The technology uses aqueous minerals and CO2 from power
plant flue gas. The CO2 in the flue gas is dissolved in a
reactor, where it becomes carbonic acid converted to carbonate ions
that forms a slurry containing the suspended mineral carbonates. A
solid-liquid separation and dewatering step results in a pumpable
suspension. Calera employs spray dryers that utilize the heat in the
flue gas to dry the pumpable suspension. Once dried, the Calera cement
looks like white chalk and can be blended with rock and other material
to make concrete. A graphic illustration of this process is attached.
Once it is hydrated, Calera's carbonate mineral cement behaves like
traditional portland cement, and it can be used as a supplementary
cementitious material to replace portland cement at various levels. A
20 percent-50 percent replacement has been tested extensively against
ASTM C 1157 concrete specifications. Based on worldwide production
estimates, approximately 1.5 billion tons of portland cement could be
substituted with carbonate cement, and another 30 billion tons of
aggregate used in concrete, asphalt, and road base could be
substituted--each ton of carbonate aggregate and cement containing one-
half ton of CO2. Thus, some 16 billion tons of
CO2 could be permanently converted to CO3 per
year on an ongoing basis at a profit. This product would be stable for
centuries.
The Department of Energy, the National Energy Technology Labs, and
several academic institutions in the United States and other countries
have evaluated several methods for accelerating the natural chemical
weathering of minerals to produce carbonate minerals. Research has
focused both on aboveground conversion of CO2 to carbonate
minerals, and the potential for carbonate conversion belowground in
brine reservoirs, or at geologic sequestration injection sites. These
investigations began in the mid-1980s with Reddy's investigation of
techniques to accelerate the natural mineral carbonation process.
Since then, there have been many well known scientists working in
this study area: Herzog at MIT, Halevy and Schrag at Harvard, O'Connor,
researchers at the National Energy Technology Laboratory in Albany, and
others, active in mineralization research. The focus of this research
was testing of various base materials, reducing the massive energy
consumption in the processing of these materials, and acceleration of
the reaction rates. Current research has moved toward carbonation of
coal-combustion fly ash and accelerated dissolution techniques of
magnesium- and iron-rich silicates (so-called mafic minerals) used in
carbonation processes.
COST-EFFICIENCY
Every carbon-capture technology struggles with the issue of cost.
The economic viability of our carbonate mineralization business model
is significantly enhanced by the ability to sell captured-and-
converted-CO2 building materials into large end-markets. For
each ton of CO2 captured, about two tons of building
material can be produced. This process provides the opportunity to
transform an environmental liability into a profit center. The market
for these newly created materials can be significant. Based on USGS
data showing worldwide annual cement consumption of 2.9 billion tons,
approximately 12.5 billion tons of concrete are used yearly. Additional
aggregate usage for asphalt and road base almost triples the potential
for storing this captured CO2.
Test data has shown that we can capture and convert CO2
at 70 percent to 90 percent + efficiency with our current absorption
configuration on flue gas typical of coal fired utility boilers (about
10 percent-15 percent CO2). We have higher capture
efficiencies for other industrial combustion sources, with higher
concentrations of CO2 such as cement kilns (about 20
percent-40 percent CO2) and refinery operations (about 95
percent-100 percent CO2). In addition to our high-capture
efficiencies, we produce materials that offset other products that have
large carbon emissions such as cement. When we include the ``avoided''
CO2 of our capture and conversion into materials, this
results in CO2 efficiency greater than 100 percent.
We believe our CMAP technology can be cost-competitive.
Particularly advantageous as compared to traditional CCS methods, our
conversion technology does not require CO2 separation, which
can be more energy, cost and carbon-intensive as the CO2 gas
becomes more dilute or compressed. Separating CO2 emission
from dilute streams, such as a coal-fired plant or a cement plant, is
far more difficult than from a refinery that is almost pure
CO2. In addition, our process does not require
transportation, injection, storage or monitoring. Finally, it is
important to keep in mind that as our plants grow and scale, we believe
our costs will be lower than revenues, enabling a more rapid and
extensive scale-up to address large-scale CO2 mitigation.
POLLUTANT REMOVAL
Unlike other carbon-mitigation technologies, CMAP removes sulfur
compounds and other pollutants. We are developing a multi-pollutant
control option using the same basic absorption and conversion
techniques we are using for CO2. The basis of our process
for SO2 (sulphur dioxide) control is similar to seawater
scrubbers that have been used in the world's largest power plants. We
are still in the process of generating data, but our initial analysis
indicates that we will be able to readily achieve SO2
capture efficiencies greater than 90 percent.
We are also working on new systems that will control NOX
compounds by converting NO (nitrogen monoxide) to NO2
(nitrous oxide), serious greenhouse gases that are water-soluble and
can be stabilized in our mineral product. A significant advantage of
our carbonate mineralization technology is that scrubbing
SO2, NOX, particulate matter and other regulated
air pollutants is not required in order for the process to capture
CO2. This robust feature is in sharp contrast to other
CO2-capture technologies such as those based on amine (MEA)
and chilled ammonia, which require stringent control of SO2
because it interferes with the absorption process. Therefore, to
adequately compare carbonate mineral CO2-reduction to
conventional CO2-reduction methods would require that the
cost and energy consumption of the additional SO2 control be
included with the conventional method for comparison sake.
DEMONSTRATION PLANTS
Calera's business model is focused on the global potential of our
technology with a milestone-driven plan to demonstrate capture rate and
scalability. Our plan calls for building one or more demonstration
plants that capture and convert flue gas CO2. These projects
will benefit the socioeconomic status of the local communities by
creating new jobs and business opportunities. Each plant will create
200-300 construction jobs over a 2-year construction phase. Job types
required include pipe fitters, electricians, operators, carpenters,
laborers, steel workers, ironworkers, mechanics, bookkeepers, and
clerical staff, among others. The completed facility will also provide
new permanent jobs.
We have completed a substantial amount of laboratory and scaled
batch-process development and have recently commissioned a continuous
pilot plant at Moss Landing, California, producing an average of one
ton of material per day (a photo of this site is attached). From there
we can quickly scale up the process to 20-80 MW for demonstration at
coal-fired, electricity-generating units and cement manufacturing
plants. Though the capital expenditures on these demonstration
facilities are lower than many other CO2 mitigation
technologies, they require investments in the tens to hundreds of
millions of dollars--hence, my testimony today in support of a more
balanced legislative language to foster the commercial development and
scale-up of innovative technologies such as ours.
Our process converts CO2 into carbonate minerals, thus
permanently converting CO2 into a stable mineral form. When
compared to traditional CCS methods, this conversion technology does
not require costly CO2 separation or compression. Like any
other manufacturer, energy is required to produce this product. Unlike
other processes, our technology has the flexibility to capture
CO2 and produce products continuously, while shifting a
large fraction of the electrical power consumption to off-peak hours.
The shifting of power consumption is accomplished through energy
storage in chemical intermediates specific to the mineral sequestration
chemistry. By producing and storing these intermediates during periods
of low power demand, this process not only avoids straining the grid,
but also better utilizes off-peak sources of power such as solar and
wind.
Calera's technology also reduces energy consumption and carbon
footprint by utilizing power plant waste-heat for product processing.
The use of waste heat is enabled by the process chemistry, which
requires only low temperatures--in contrast to the very high
temperature processes employed in the manufacture of other building
materials. As a further means of reducing environmental impact,
advanced versions of the process employ recirculation of process water.
Although recirculation of process water may be desirable in arid
regions, other process options under development may exploit synergies
between the mineralization process and desalination technologies,
resulting in improved economics for freshwater production.
Another key breakthrough of our technology is the capacity to
incorporate solid waste normally bound for landfills into useful
products. Waste (such as fly ash) or aluminum smelter by-products (such
as red mud and other waste products) can be incorporated into this
process.
BEYOND CEMENT
Calera will be important and valuable to States producing and/or
consuming coal as they attempt to meet future carbon capture and
trading requirements. Calera projects will bring long-term benefits to
the coal industry by allowing existing coal plants to continue their
operations under new air compliance regulations and avoid shutting down
plants producing electricity at the lowest cost. This will save jobs at
coal plants, mining sites and in transportation. The low cost of
implementing Calera's technology compared to other CCS technologies
reduces the impact of new CO2 regulations on the cost of
energy and avoids leakage of U.S. operations oversees to countries that
don't have CO2 regulations.
By shifting the treatment of CO2 from a pollutant that
needs to be disposed at a high price, to a potential raw material for
clean manufacturing, our process enables a sustainable and cost-
effective capture of a significant portion of the anthropogenic
CO2. In fact, when factoring the long-term potential
revenues, revenues from building materials, carbon incentives and water
treatment using a carbonate mineral process will be offset by the cost
of capturing a ton of CO2.
Based on our current estimates for construction and operating
costs, and our forecasts for the building material markets, we expect a
payback period of less than 10 years. Furthermore, based on our
experience we believe our costs will go down as we learn to build and
operate our plants, to the extent that our payback period could be
reduced to 7 years. In our 2 years of operation we have made
significant progress in understanding the scientific and engineering
tasks of building a full-scale plant. From a small one-liter batch
process to a 1-ton per day continuous pilot plant, we have learned how
to optimize our capture rates and reduce our footprint and costs. Our
progress is supported enthusiastically by the scientific community,
environmental groups, potential business partners and the public.
However, as for any industrial large-scale process, the next step
requires a large investment to build a full-scale plant confirming our
commercial scalability. Furthermore, the urgency of the climate
challenge calls for an accelerated development path that demands
special investments and support.
RECOMMENDATIONS
Congress is working hard to address CCS and to rethink product
manufacturing. We commend the Committee for acknowledging the
importance of CCS and funding innovations in this area. However,
current legislative language and Government funding consistently
targets geological sequestration, which disadvantages other CCS
options. While we acknowledge the potential value of geologic
CO2 sequestration, we recommend placing other viable
CO2-sequestering technologies on an equal playing field with
geological sequestration.
It is our hope that your subcommittee will also consider supporting
an independent assessment by the National Academy of Sciences that
reviews the opportunities and challenges of beneficial reuse and carbon
conversion as part of the larger national CO2-reduction
strategy.
Calera is one of many breakthrough clean technologies that are
evolving rapidly. Companies like ours need Government funding to help
move this process towards commercialization. It is in the best economic
interest of our country to advance the most effective technologies over
time by providing grants, loan guarantees, tax incentives and other
sources of financial support. For this reason, I urge Congress to
preserve our ability to move beyond existing carbon-sequestration
technologies through broad statutory language that encourages
innovation and rewards breakthrough technologies that are not yet, but
may soon be, household names.
Finally, we seek Federal Government support because--despite the
promise of technologies such as ours, the capital requirements are high
in an extremely challenging macroeconomic environment and the risk of
any new business venture is significant. The market for CO2-
reduction solutions such as ours is tremendous, but our product will
take time and considerable capital to develop sufficiently in order to
offset our development costs. Thus we need to scale up rapidly.
On behalf of Calera Corp. and our stakeholders, I respectfully
thank Chairman Dorgan, Ranking Member Bennett, and subcommittee members
for your time and consideration. We see an important new option with
the recovery funding, and we thank the Energy and Water Subcommittee
for providing us with this opportunity to explore with you the
beneficial reuse of CO2. The funding we seek could be both
stimulating and transformative to energy policy, climate change, and
the future of our economy. We look forward to working with the U.S.
Congress and the appropriate subcommittees of jurisdiction (i.e.,
Senate Energy, Senate Finance, and others) to ensure equitable policies
are in place that provide Federal support of CO2-beneficial
reuse technology.
Senator Dorgan. Dr. Constantz, thank you very much.
And finally, we will hear from Ms. Tatro. Marjorie Tatro is
the director of fuel and water systems at the Sandia National
Laboratories.
So, Ms. Tatro, thank you for being with us. You may
proceed.
STATEMENT OF MARJORIE L. TATRO, DIRECTOR OF FUEL AND
WATER SYSTEMS, SANDIA NATIONAL LABORATORIES
Ms. Tatro. Great. Thank you, Mr. Chairman, Senator Bennett,
and distinguished members of the subcommittee.
As you know, we are faced as a Nation with two challenges
that actually inspire us as well to think about the reuse of
carbon dioxide not only to enable this use of the coal reserves
that we have, but we believe that carbon dioxide as a fabulous
feedstock for creating liquid fuels that could be inserted into
our existing infrastructure is really a fabulous and innovative
idea.
You mentioned algae-based biofuels, which do have
tremendous promise, and we agree that those need to be
developed in a way that allow us to scale them up to the kind
of quantities to make them commercially and technically viable.
And I wanted to talk to you about another technology today that
offers some of the same benefits.
We have done a little work at Sandia National Laboratories
in taking concentrated sunlight, high-temperature solar energy,
and putting it into a heat engine. This heat engine takes
carbon dioxide in one side, takes water in the other side, and
splits those molecules apart to then thermochemically
recombining those together to create a liquid fuel. In this
case, it is methanol. And there are commercial processes that
can convert methanol into gasoline, jet fuel, and diesel.
This is another way to use carbon dioxide as a feedstock.
Just like it is a nutrient for algae, it is a feedstock for a
liquid fuel that can be compatible with our existing
transportation infrastructure.
Another area I wanted to mention that we ultimately have to
look at is being able to extract carbon dioxide from the air.
Because if we are going to have progress in reducing the
overall emissions from our energy enterprise into the
atmosphere, it is important that we think about scalable,
affordable technologies that can capture that CO2
ultimately from the air and reintroduce it or recycle it into
some of these fuel feedstock options.
I agree that our first steps are using carbon dioxide from
our coal enterprise as a fabulous feedstock for these
transportation fuels, and ultimately, we need to make progress
in pulling carbon dioxide from the atmosphere as well.
These are just a few ideas that are out there. We believe
that this Nation is ready to step up to this innovative area of
recycling and reuse of carbon dioxide. And I believe there are
many ideas out there that none of us have even thought of, and
it is worth an investment by this country to stimulate those
ideas and bring them forward.
I think the United States has a chance to be a leader in
these areas, but right now, let me tell you other countries are
also investing in these areas. And my fear is not only that we
might be left behind in this area, but perhaps we could end up
importing both these technologies or the fuels they create from
foreign sources, which would not help our energy security
situation.
So we have talked about algae. We have talked about
synthetic fuels that could come from renewable sources like
solar energy. We have talked about the idea of extracting
CO2 from the air, and there are many more details in
my written testimony that I believe you have been provided.
PREPARED STATEMENT
But we are excited. We think this is a great innovative
area for the country. We appreciate and applaud the
subcommittee's leadership in looking at this area, and we stand
ready to support this area with innovation from a number of
different collaborative teams all across the country.
With that, I would like to conclude and look forward to
your questions.
[The statement follows:]
Prepared Statement of Marjorie L. Tatro
INTRODUCTION
Mr. Chairman, Senator Bennett, and distinguished members of the
subcommittee, thank you for the opportunity to testify this morning. I
am Margie Tatro, Director of Fuel and Water Systems at Sandia National
Laboratories. Sandia is a multi-program national security laboratory
owned by the United States Government and operated by Sandia
Corporation \1\ for the National Nuclear Security Administration
(NNSA). I am a Mechanical Engineer by training and I have worked in
energy technologies for over 20 years.
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\1\ Sandia Corporation is a subsidiary of the Lockheed Martin
Corporation under Department of Energy prime contract number DE-AC04-
94AL85000.
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Sandia has roles in the design, development, qualification, and
certification of non-nuclear subsystems of nuclear warheads, nuclear
nonproliferation, energy security, intelligence, defense, and homeland
security. Sandia is proud of the considerable expertise it has achieved
in the area of energy security, especially in understanding the
relationship between national security and the energy enterprise.
Sandia is widely published in the energy and fuels research
category. In fact, according to Science Watch,\2\ among institutions
ranked by total citations of papers published between 1998 and 2008,
none surpasses Sandia National Laboratories, with more than 4,100
citations to its 395 papers. In addition, Sandia ranks in the top 10
institutions when measured by citation impact. The area most widely
cited during this 10-year period was combustion science followed by
strong contributions in battery science and solar energy. Sandia is
fortunate to have a talented multidisciplinary team of scientists and
engineers who are dedicated to delivering ``exceptional service in the
national interest.''
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\2\ Science Watch (2008), Nov/Dec Featured Analysis, http://
sciencewatch.com/ana/fea/08novdecFea/ (Note that citation impact is
measured by average number of citations per published paper.)
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SUMMARY OF KEY POINTS
My statement today is summarized in four key points:
--The U.S. economy and environment would benefit from investments in
scalable technologies and processes for recycling of carbon
dioxide (CO2) as one option for addressing two
critical, yet interrelated, challenges facing our Nation and
the world--stabilizing the concentration of CO2 in
our atmosphere and producing new supplies of liquid hydrocarbon
fuels that help reduce our dependence on petroleum. Though I
will describe efforts at Sandia focused on CO2
recycling to address these challenges, an organized and focused
national effort including the establishment of a number of
collaborative teams to explore these and other approaches would
be prudent investments in the long-term interest of the Nation.
--Algae-based biofuels and synthetic fuels from solar energy are
attractive because of the possibility of converting solar
energy into liquid hydrocarbon fuels which are compatible with
the existing infrastructure and at scales and efficiencies
sufficient to meet large demands. Lifecycle efficiencies are
important because they are indicators of the relative ``size of
the enterprise'' necessary for large volume production. As
important as efficiency, both options can recycle
CO2 back into fuel at rates faster than the
biosphere takes up CO2. Lastly, if CO2 is
extracted directly from the atmosphere, then we can produce
high-efficiency, carbon-neutral fuels.
--With the support of the Department of Energy (DOE) and others,
Sandia is developing and applying science-based algae growth
models and techno-economic tools to examine the best options
for scaling up the production of algal biofuels. Sandia has
also built a prototype ``chemical heat engine'' to split water
and CO2 using concentrating solar energy. This
prototype is a critical step towards demonstrating the
feasibility of making solar-based fuels without first making
electricity. We are equally excited about a number of ideas for
extracting CO2 from the atmosphere. As excited as we
are, we know of many others with similar enthusiasm and ready
to make major contributions.
--Other countries are exploring reuse and recycling of CO2
and it would be unfortunate if the United States became
dependent on imported technology in this critical area. This
``grand challenge'' has excited our team; indeed, I believe
this, and sustainable energy research in general, is exciting
to the next generation of engineers and scientists all across
the Nation.
THINKING DIFFERENTLY ABOUT ENERGY, CARBON AND SECURITY
Taking today's energy system in the United States as a whole, there
are six major problems: (1) over 50 percent of primary energy resources
are lost as waste heat and emissions during energy transformations and
transport; (2) diverse and intermittent resources, such as wind, solar,
and distributed generation, are difficult to accommodate; (3) the
system relies on nature to close the cycle on waste by-products such as
used nuclear fuel, CO2, and heat; (4) the infrastructure is
limited in capacity, flexibility, reliability, and resiliency; (5)
increased competition for finite petroleum and natural gas resources
limits our foreign policy options and puts pressure on our economic and
military resources; and (6) unpredictable energy prices create
uncertainty and risk for all stakeholders (producers, suppliers, end-
users, and policy makers).
As we strive to transition today's energy system to one that
alleviates the problems mentioned above, we should keep the following
requirements in mind:
--Safety.--Safely supplies energy services to the end user;
--Security.--Resists malevolently caused and weather or aging
infrastructure-related disruptions and recovers quickly from
any disruptions;
--Reliability.--Maintains delivery of energy services when and where
needed;
--Sustainability.--Matches resources and delivery with needs for
energy services for the entire duration of those needs with
minimal waste; and
--Affordability.--Delivers energy services at the lowest predictable
cost.
To meet the needs of future generations--and assuming a desire to
stabilize CO2 concentrations in the atmosphere and a
continued demand for portable energy for transportation--the
transformed energy system will be one that likely has five key
elements: (1) its primary energy supply comes from persistent
(preferably domestic) low-net-carbon energy resources; (2) its energy
carrier conversion, as well as distribution and use, involves processes
that are as efficient as practical; (3) it reuses or recycles resources
in waste streams, particularly ones that have some inherent value such
as residual energy or useful mass; (4) it uses liquid hydrocarbons \3\
made from abundant and accessible carbon and hydrogen resources; and
finally, (5) it has inherent storage to accommodate disruptions and
makes maximum use of the existing energy infrastructure. The current
national dialog focuses mostly on the first element and, unfortunately,
very little on the other four.
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\3\ Liquid hydrocarbons are easily distributed and used in the
existing infrastructure, including the hundreds of millions of vehicles
currently on the road with mean age of 8-9 years and median lifetimes
of >17 years. Hydrocarbons can also provide inherent portable storage
for intermittent sources such as solar and wind, especially in
circumstances when those resources are not readily connected to the
grid.
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We find making liquid hydrocarbon fuels from ``recycled''
CO2 an intriguing prospect for enabling the above envisioned
energy system as it would preserve the positive attributes of petroleum
while eliminating most of the negatives, and at the same time using an
abundant waste stream. Indeed, developing solar, wind, geothermal (and
maybe nuclear) driven processes that can efficiently, cost-effectively,
and sustainably take the products of combustion, CO2 and
water, and recreate liquid hydrocarbon fuels would be an unparalleled
achievement. Surmounting this challenge would go a long way toward
solving the problem of finding domestic substitutes for petroleum which
do not add more carbon to the atmosphere. Later in my statement, I will
talk more about our ultimate vision of ``recycling'' CO2 by
extracting it directly from the atmosphere, thereby slowing the
increases in the concentration of CO2 in the atmosphere. We
envision using the atmosphere as an efficient means for transporting
the CO2 from any source to the ``recycle sink.'' But before
doing this, a summary of the CO2 ``situation'' is in order.
Carbon Management Options
Carbon dioxide is a by-product of energy conversion processes; it
is emitted when fuel is combusted. In 2006, worldwide CO2
emissions were 29.2 GtCO2 (metric Gigatons of
CO2) with the U.S. being one of the largest contributors,
adding 5.9 Gt in 2006.\4\ The United States consumed 20.7 million
barrels of oil per day in 2007. Note that a typical barrel of crude oil
will produce 0.42 metric tons of CO2 if combusted.\5\ Of
petroleum use in the United States, 69 percent goes to transportation.
The transportation sector in the United States contributed almost 2 Gt
of CO2 emissions to the atmosphere in 2006.\6\ Since pre-
industrial times the concentration of CO2 has increased from
roughly 280 parts per million by volume (ppmv) to approximately 385
ppmv.\7\
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\4\ DOE Energy Information Administration (2006).
\5\ NETL (2008), ``Storing CO2 with Enhanced Oil
Recovery,'' DOE/NETL-402/1312/02-07-08, 35.
\6\ DOE Energy Information Administration (2006).
\7\ http://www.noaanews.noaa.gov/stories2008/20080423_methane.html.
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We now explore how recycling of CO2 fits into carbon
management options with the goal of reducing the growth of atmospheric
CO2 concentrations more broadly. We think of carbon
management in terms of rebalancing the sources and sinks to and from
the atmosphere--currently sources exceed sinks and this is why the
concentration of CO2 in the atmosphere is increasing. There
are five elements in a carbon management tool box: (1) reduce; (2)
extract; (3) reuse; (4) recycle; or (5) bury. There are three avenues
to reduce: (i) reduce the demand for energy services (e.g., drive fewer
miles); (ii) increase the efficiency in the energy conversion and
transport processes; and (iii) reduce the carbon intensity or
CO2 emitted per unit of primary energy. Extract comes into
play as we begin to seriously think about active carbon management by
capturing at the source, usually large stationary sources, such as
coal-burning power plants. However, we can also conceive of extracting
directly from the atmosphere, surface waters, or heavily distributed
emitters. The reuse category presents several options, including
enhanced oil recovery (EOR) as well as using the CO2 as a
``green'' solvent in chemical processing, for dry ice in food
processing, and for carbonation. The recycle category has received very
little attention to date except indirectly through the production of
bio-energy from biomass. Recycle is the category that is the principle
focus of my statement today. The bury category is equivalent to
sequestration--or the storage part of carbon capture and storage.
At present, industry has a variety of uses for CO2, but
the quantities are small. Some example uses are: neutralizing alkaline
effluents in the chemical sector; making salicylic acid and aspirin in
the pharmaceutical sector; chilling and carbonation in the food and
beverage sector; balancing the pH in the pulp and paper sector; cooling
and cleaning in the electronics sector; and as the fire suppression
material in fire extinguishers.\8\ \9\ The annual use of CO2
for EOR in the United States is estimated at 0.04 Gt.\10\ While
``recycling'' CO2 as a feedstock for chemical production is
an important use, the United States only consumed on the order of 0.11
Gt \11\ of CO2 in the 2003 timeframe; the largest use was to
make urea. Furthermore, even if the top three U.S. produced chemicals
(ethylene, propylene, and ethylene di-chloride) used CO2 as
the carbon source, they would only consume another 0.14 Gt.\12\ The one
``chemical'' product that does scale to large quantities is fuels. If
we were to use CO2 as the carbon source to generate the
equivalent of our petroleum consumption, 3.0 Gt of CO2 would
be consumed or recycled.\13\
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\8\ Gobina, E. (2004), ``Carbon Dioxide Utilization and Recovery,''
BCC Report E-131, Business Communications Co., Norwalk, CT.
\9\ ``Carbon Management: Implications for R&D in the Chemical
Sciences and Technology'' (A Workshop Report to the Chemical Sciences
Roundtable), http://www.nap.edu/catalog/10153.html.
\10\ DOE/NETL-402/1312/02-07-08, ``Storing CO2 with
Enhanced Oil Recovery,'' February 2008, pp 45.
\11\ Beckman, E.J. (2003), ``Green Chemical Processing Using
CO2,'' Ind. Eng. Chem. Res., 42 (8), pp 1598-1602.
\12\ Chemical & Engineering News, July 2, 2007.
\13\ For this conversion, we assumed 20.7 million barrels/day, 136
kg/barrel, and 83 percent carbon in petroleum by weight.
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Technologies that can recycle CO2 into liquid
hydrocarbons are attractive propositions. Liquid hydrocarbon fuels are
ideal energy carriers and exceptionally convenient to store, transport,
and transfer due to their liquid form and high energy-density by mass
and volume. While greater electrification of the transportation fleet
will almost certainly be an important element of a transformed energy
system, routes to creating liquid hydrocarbons which have properties
equivalent to gasoline, diesel, and jet fuel should not be ignored.
Efficiency Matters
We are reminded that petroleum, coal, natural gas, and
unconventional oil are in fact ``stored sunlight'' and ``sequestered
carbon''.\14\ We tend to categorize fossil fuels as primary energy
resources when, in fact, they are energy carriers, which are the result
of an inefficient set of conversions of energy and mass fluxes
integrated over a very long time. The process began many millions of
years ago with a biological organism capturing sunlight (solar flux)
and storing the sun's energy by using it to drive chemical reactions of
CO2 and H2O to higher energy hydrocarbons and
oxygen (photosynthesis). A small fraction of the plant matter was then
converted over time by heat and pressure to coal, oil, and natural gas.
The overall efficiency in this naturally occurring process was quite
low.
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\14\ Dukes, J.S. (2003), ``Burning Buried Sunshine: Human
Consumption of Ancient Solar Energy.'' Climatic Change, 61, 31.
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Efficiencies are important because they provide an indicator of the
``scale of the enterprise'' needed to convert solar energy into fuels,
and are therefore one indicator of relative costs. For oil, the
sunlight-to-stored energy can be estimated \14\ to be only about 0.0002
percent efficient, with large error bars on that estimate. Another way
to look at this efficiency is to estimate energy and carbon fluxes.
This estimate reveals possible efficiencies of algal biofuels of nearly
3 percent and solar synthetic fuels of 5 percent-10 percent (though
large uncertainties exist because neither technology has been proven at
large scale). Assuming an average lifecycle efficiency of 5 percent
(and average solar energy of 200 watts per square meter), producing the
equivalent of the U.S. petroleum usage of 20.7 million barrels of oil
equivalent per day using solar energy would require approximately 28
million acres of land. In contrast, total U.S. land is roughly 2
billion acres and paved highways in the United States cover
approximately 19 million acres.
Bio-energy from biomass or biofuels can be thought of as a modern-
day approach to improve upon nature's inefficient process to create
petroleum. As with fossil fuels, the starting point is the
photosynthetic conversion of CO2 and H2O to
hydrocarbons in the form of carbohydrates and lipids. The efficiency of
this process is significantly better than that for petroleum and is
estimated in our energy flux analysis to be approximately 3 percent.
Additional chemical or biological steps are then undertaken to produce
a liquid hydrocarbon fuel. Algae are attractive as a fuel feedstock
because their production can potentially avoid competition with
agricultural lands for food and feed production and can use nonfresh
water resources. CO2 is added to the water as a nutrient to
achieve high productivity from algae.
Taking another step further towards increasing the efficiency and
directly recycling CO2 into synthetic fuels can be thought
of as emulating the effectiveness of nature's choice to store solar
energy by converting CO2 and H2O into high
energy-density hydrocarbons.\15\ Synthetic processes bypass the
biological steps that lead to low energy and carbon fluxes and low
efficiencies. A worthy target for synthetic routes would be to achieve
lifecycle efficiencies of approximately 10 percent.
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\15\ Nature's preferred energy storage means is fat or oil, both
which have an energy density of approximately 39 MJ/kg, fairly close to
that of gasoline, diesel, and jet fuels at approximately 45 MJ/kg.
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A known option would be to assemble a system based on solar
photovoltaics using electrolysis of water to make hydrogen
(H2), then reacting the H2 with CO2.
Such a system could be assembled from commercially available components
(though none is currently economically viable) and could achieve
approximately 5 percent efficiency, with a limiting factor being the
initial step of converting solar energy to electricity.
It is these relatively high efficiencies and minimal land
requirements that generate our excitement about the prospects for
recycling CO2 into algae-based fuels and solar-based fuels.
Creating technologies that are capable of extracting CO2
from the atmosphere is also important to make these fuels ``carbon
neutral.'' In the remainder of this document, we delve more deeply into
the three types of technologies that are key enablers for the recycling
of CO2: (1) algae-based fuels; (2) direct synthesis of fuels
from CO2 and water including ``Sunshine-to-Petrol''; and (3)
extraction of CO2 from the air. For each technology, we will
present a few activities both domestically and abroad, efforts at
Sandia that that indicate the promise of such options, and current
technological and economic challenges with possible timelines.
ALGAL BIOFUELS
Current Activities
From 1978 to 1996, the Department of Energy's (DOE) Aquatic Species
Program represented the most comprehensive research effort to date on
fuels from algae. Headed by National Renewable Energy Laboratory
(NREL), the program also supported fundamental research at many
academic institutions.\16\ Since 2007, Sandia has partnered with NREL
to develop an algal technology roadmap for DOE's Office of Energy
Efficiency and Renewable Energy and Office of Biomass Program. The
roadmap will identify and prioritize key biological and engineering
hurdles that must be overcome to achieve cost-effective production of
algal-based biofuels and coproducts. It will also suggest research
strategies to address these barriers. The DOE's National Energy
Technology Laboratory has partnerships in place with coal-fired power
plant operators to explore the option of growing algae in cooling-water
ponds.
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\16\ Sheehan, J., T. Dunahay, J. Benemann and P. Roessler (1998),
``A look back at the U.S. Department of Energy's Aquatic Species
Program-Biodiesel from Algae,'' https://www.nrel.gov/docs/legosti/fy98/
24190.pdf.
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The prospective value of biofuels from algae has been recognized
internationally not only by the global research community, but also a
range of commercial sectors including transportation energy,
agriculture, and biotechnology, and the venture capital community. A
large cadre of venture-backed start-ups working on algal biofuels has
emerged over the last few years and larger companies are also getting
involved in algae. Meanwhile, the global research community has moved
quickly to embrace the challenges presented by producing algal biofuels
at scale as witnessed by the dramatic acceleration in conferences on
algal biofuels and the formation of public-private partnerships and
consortia. This is occurring in the United States, Israel, China,
India, France, the Netherlands, and Denmark.
It is estimated that the production of 2.4 million barrels of
gasoline with algal oil would consume 1.5 billion tons of
CO2, or 43 percent of total 2008 U.S. emissions from
stationary sources.\17\
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\17\ National Carbon Explorer 2008 CO2 Stationary Source
Atlas, http://www.natcarb.org.
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Sandia's Efforts
The algal biofuels program at Sandia National Laboratories
leverages technical strengths in analytical chemistry and applied
biology, computational fluid dynamics, and integrated systems
analysis--including developing and applying biofuels supply chain
models aimed at identifying barriers to cost-effective production of
algal biofuels. Sandia's efforts include developing and applying
analytical tools to characterize algae gene and protein networks and to
monitor algae health. In applied biology, Sandia develops fundamental
understanding of algal physiology through genetic engineering, enzyme
engineering, and identifying biomarkers and strategies for monitoring
biomarkers relevant to biomass cultivation and fuel production.
In the area of computational fluid dynamics, Sandia has developed
an algae growth kinetic model in a computational fluid mechanics
framework as an engineering tool to develop cultivation strategies for
algae--both open ponds as well as photobioreactors.\18\ Sandia also
owns and operates a facility with algal growth tanks that are equipped
with sensors that can be used for validating production models. Systems
dynamics models also help us understand the relationship between water
supplies, evaporation, and algae production.
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\18\ Boriah, V. and S.C. James, ``Optimizing Algae Growth in an
Open-Channel Raceway,'' Algae Biomass Summit, 2008.
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In related efforts, Sandia is an active member of the Joint
Bioenergy Institute and contributes towards biomass deconstruction and
pretreatment for cellulosic biofuels. Our world-class Combustion
Research Facility and Center for Integrated Nanotechnologies provide
fundamental science understanding in areas of alternative
transportation fuels.
Techno-Economic Challenges
Scientific discovery must be complemented by engineering and
techno-economic evaluations to enable affordable, scalable algal
biofuels. Open literature has reported algal-derived crude oil at a
cost spanning over three orders of magnitude ($1 to $1,000 per gallon
of triglyceride), with the greatest uncertainties in estimates of
facility and operating costs.\19\ Investment in every step of the
supply chain, from understanding algal biology, strain selection and
optimization, cultivation at scale, harvesting, dewatering, and
extraction of the hydrocarbons from the algal biomass is needed. As
such, both the DOE and the U.S. Department of Agriculture have called
for algal biomass funding opportunities to accelerate the R&D cycle.
---------------------------------------------------------------------------
\19\ Pienkos, P., ``Historical Overview of Algal Biofuel
Technoeconomic Analyses,'' National Algal Biofuels Technology Roadmap,
December 9-10, 2008.
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The DOE has commissioned Sandia and NREL to jointly create a
systems dynamics model for carrying out techno-economic analyses of
algal fuel development strategies. To be cost competitive, the process
must be able to tolerate solar energy variability and energy and water
consumption must be lowered. In evaluating resource constraints, it is
clear that the availability of water and CO2 use will limit
the locality of sustainable algal biofuel production.\20\
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\20\ Pate, R., ``Algal Biofuels Techno-Economic Modeling &
Assessment: Taking a Broad Systems Perspective,'' National Algal
Biofuels Technology Roadmap, December 9-10, 2008.
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While algal biofuels present an opportunity that will require some
time (roughly 10 years) to realize, they are a key component in the
U.S. biofuels strategy. Transportation fuels produced from algal
biomass are compatible with our existing transportation fuel
infrastructure, can recycle CO2 waste streams, and can be
produced on nonarable land with impaired water sources.
SYNTHETIC FUELS FROM CO2 AND WATER
Current Activities
Work on alternative fuels has been ongoing for much of the last
century; the chemistry and technology for converting fossil-energy
resources such as coal is well established and has been practiced
commercially in parts of the world for many decades. In contrast, the
science and technology for producing hydrocarbon fuels from persistent
energy sources (e.g., solar, wind, geothermal, and nuclear power) in a
sustainable fashion, is relatively immature. Investments and advances
in biofuels and H2 are ongoing. Because H2 is a
critical feedstock for making liquid fuels, research efforts aimed at
the renewable production of H2 also further the vision of
recycling CO2 into fuels.
Work on CO2 reuse and recycling has been less visible,
but nonetheless efforts are underway around the world. Many of these
efforts have been directed towards applications that could consume only
a very small fraction of the CO2 produced through the
combustion of fossil fuels, for example supercritical solvents and
production of higher-value chemicals.
The primary challenge to recycling CO2 as a chemical
feedstock for either fuels or chemicals and pharmaceuticals is the
energy cost and efficiency for splitting (activating) the very stable,
CO2 molecule; furthermore, that energy source must itself
have a very low carbon intensity. Achieving such a technology would
open the door to using CO2 as a feedstock for liquid fuels
as well as for polymers, plastics, carbonates, and numerous other
valuable chemicals and materials (i.e., light-weight carbon composites
and carbon-nanotube-based materials).
One basic approach for re-energizing the CO2 molecule
into a useful product has been to react it with another energetic
molecule such as H2. Both Korea and Japan have sponsored
work in this area. For example, Japan's Mitsui Chemicals recently
announced their intent to make methanol from captured CO2
and H2. Additionally, efforts have been initiated in Iceland
to commercialize the production of methanol from CO2 and
H2 from geothermal-powered electrolysis of water.
An alternative means is to use electricity to directly re-energize
CO2. This is analogous to splitting water by electrolysis to
make H2. Hybrid biological and electrical approaches are
showing progress. Examples include work at Princeton and announcements
from the private sector, such as Carbon Sciences. However, we emphasize
that unlike splitting water and making H2, there are no
commercialized technologies that have been developed to directly
activate CO2 and only few research efforts around the world
are underway.
Finally the greatest amount of work has been carried out on
approaches that can broadly be categorized as artificial
photosynthesis. These most closely emulate the process of
photosynthesis in harvesting the energy from sunlight to generate
electrons and protons to reduce the CO2. The work ranges
from efforts to engineer new devices using the tools of nanotechnology
to efforts to replicate natural systems removed from a living organism.
Genetic engineering of living organisms is a related approach.
Sandia's Efforts
At Sandia, we have assembled a multi-disciplinary team of
scientists and engineers, including a number of university partners to
explore a promising new approach to directly activating CO2
using concentrated solar energy. A novel new ``heat engine'' concept
\21\ breaks a carbon-oxygen bond in the CO2 to form carbon
monoxide and oxygen in two distinct steps at two different
temperatures. Energy for the high-temperature step comes from the sun.
This thermochemical approach appears suited to the production of both
H2 from water and carbon monoxide from CO2. This
process, which we call ``Sunshine-to-Petrol,'' avoids converting the
principal energy source (e.g., solar energy) to electricity thereby
providing an avenue to potentially higher efficiency than the
alternatives. The Sandia team built a thermochemical ``heat engine''
and named it the Counter-Rotating Ring Receiver Reactor Recuperator or
``CR5.'' The CR5 is a solar receiver which converts concentrated solar
energy into thermal energy. The rings counter-rotate. It is a reactor,
actually two reactors--thermal reduction and oxygen extracting. Lastly,
it is a recuperator--to minimize heat losses and maximize efficiency.
If suitable materials can be developed and the design challenges can be
met, the CR5 heat engine concept appears to provide an integrated
approach for potentially efficient and affordable solar-activated
CO2 and water. However, this system imposes unique
requirements on materials.
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\21\ Diver, R.B., J.E. Miller, M.E. Allendorf, N.P. Siegel, R.E.
Hogan (2008), ``Solar Thermochemical Water-Splitting Ferrite-Cycle Heat
Engines,'' Journal of Solar Energy Engineering, November 2008, vol.
130, issue 4041001.
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Techno-Economic Challenges (for ``Sunshine-to-Petrol'')
The CR5 involves numerous design issues and tradeoffs. It places
extraordinary demands on materials and involves high-temperature moving
parts. Ensuring we have suitable materials will require a substantial
degree of fundamental understanding of the chemical and cycle
thermodynamics. To establish the practicality of the CR5 concept, we
are experimentally evaluating materials, exploring the thermodynamics
and kinetics of the materials, evaluating heat and mass flows within
the device, and assessing a number of integrated system designs. We
expect a focused effort to have a reasonable probability of success. We
envision a series of improved engine and system designs. Successful
progress would consist of continuously improved generations of
prototypes and Sunshine-to-Petrol systems resulting in a new generation
every 3 years with significant improvements in performance, durability,
and cost. The system would produce gasoline or diesel or jet fuel as
the end product. Our targets are efficiency: 10 percent system and
lifecycle efficiency,\22\ durability: 5 years of operation for the
reactive rings and 20 years for the mirrors and the rest of the engine,
and of course cost: competitive with all low-carbon alternatives to
petroleum, but perhaps no more than $5.00/gallon of gasoline. With that
schedule of improvements, the technology should be market-ready in less
than two decades. For a concept as new as the CR5 and Sunshine-to-
Petrol, we believe that this would be an aggressive schedule.
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\22\ Lifecycle efficiency includes solar energy to gasoline
conversion and takes into account the energy required to manufacture
the components of the system. Some refer to this as ``rays-to-tank''
efficiency.
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EXTRACTING CO2 FROM AIR
Current Activities
To achieve the promise of recycling CO2 into renewable
and sustainable liquid hydrocarbons through either algae-based or
solar-based fuels requires extraction of CO2 directly from
the air. The extraction of CO2 from air has received
relatively little attention. However, with the announcement of the
Earth Challenge Prize,\23\ by Richard Branson of Virgin Atlantic, a
number of small start-up companies are taking on this challenge. Small-
scale CO2 capture within submarines and spacecraft is well
known. In these applications however, the CO2 was generally
not used for further purposes and release from the capture agent had
not been a deliberate design parameter. Klaus Lackner of Columbia
University authored several studies on CO2 capture, with
many compelling arguments and has been awarded a patent, with Allen
Wright from Global Research Technologies for their novel concept. A
project initiated at Carnegie Melon \24\ demonstrated the general
feasibility of CO2 capture from air using an aqueous NaOH
spray. Lab-scale units have been built by teams at the University of
Calgary in Alberta, Canada and at the Swiss Federal Institute of
Technology in Zurich. ``Green Freedom'' efforts at Los Alamos National
Laboratory are addressing the capture of CO2 from air flows
of cooling towers, such as those at nuclear power plants.
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\23\ Sponsors are seeking method that will remove at least one
billion tons of CO2 per year from the atmosphere, and the
winner will receive $25 million.
\24\ Stolaroff, J.K., D.W. Kieth, and G.V. Lowry (2008), ``Carbon
Dioxide Capture from Atmospheric Air Using Sodium Hydroxide Spray,''
Environmental Science and Technology, 42, 2728-2735.
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While conversion of atmospheric CO2 into a pure
feedstock for hydrocarbon fuels synthesis is unquestionably feasible at
the bench scale, estimations suggest prohibitively high costs and very
low efficiencies relative to what is theoretically possible. Hence,
proven methods needed to concentrate large amounts of CO2 at
affordable costs and high efficiency do not exist. CO2
capture in a specially designed material is analogous to H2
storage, where the design consideration is to be able to grab it tight
enough, but not so tight that it cannot be released at the appropriate
time. Most materials identified have a large energetic cost penalty to
remove the CO2 or very slow kinetics at the uptake. What is
needed is fast kinetics at the uptake and low energy for release, but
not too low. Industrial-scale capture will also entail the processing
of large volumes of air through the capture media.
Sandia's Efforts
At Sandia, we have explored the plausibility of large-scale capture
from air and a number of new solid sorbents. Our investigations
indicate, among other things, that at 4.5 meters/second wind speeds,
the cross-sectional area needed to collect enough CO2 to
produce 20.7 millions barrels of oil is between 14,000-36,000 acres,
corresponding to capture efficiencies \25\ of 50 percent and 20
percent, respectively. Sandia has been collaborating with researchers
at the National Energy Technology Laboratory to explore the feasibility
of a number of ideas for capturing CO2 from the atmosphere.
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\25\ Capture efficiency is the percent of CO2 extracted.
For example, 50 percent at 400 ppmv in the air stream would leave 200
ppmv in the air stream after passing through the collection media.
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Techno-Economic Challenges
Our analysis suggests the following technical challenges must be
met before capture of atmospheric CO2 for conversion to
hydrocarbon fuels or for other re-use options can be considered
plausible at the industrial scale: (1) low-energy air processing
approaches to assure effective air flows through CO2 sorbent
media to ensure high production rates; (2) durable and easily
manufactured materials that readily capture as well as release
CO2 from air at industrial scales; (3) less expensive solid
or liquid CO2 sorbents that have high capacities and are
stable over very many catch-and-release cycles; and (4) bench-scale
testing and later, pilot-scale demonstrations of atmospheric
CO2 capture approaches.
We expect a focused effort for a decade would have a good
probability for success, depending on what cost the market can bear.
Note that a capture cost of $50-$75 per metric ton of CO2
would add only $0.44-$0.66 to the cost of a gallon of gasoline. This
seems achievable.
CONCLUSION
The possibility of making liquid fuels from domestic resources that
are compatible with our existing transportation energy infrastructure
while recycling CO2 is exciting and real. Because so much of
today's CO2 emissions come from the burning of fossil fuels,
it seems natural for us to use this waste stream to produce alternative
fuels for future generations. Ideas including those described in this
document--algal-based biofuels, solar or other renewable-based fuels,
and extraction of CO2 from air--require investments to prove
their technical and economic viability at large scale.
Collaborative teams from across the Nation, and the world, are
already developing ideas worth pursuing, but the efforts are currently
splintered; we must act now to stimulate this area of research and
development. Other countries are exploring the re-use and recycling of
CO2 and it would be unfortunate if the United States became
dependent on imported technology or imported alternative fuels in this
critical area.
Let me conclude by noting a caution from the technology-policy
interface perspective. Carbon management policies that might
inadvertently create disincentives for those who pursue the idea of
CO2 recycling could be detrimental to innovation and
commercialization of technologies in this area. Policy experts may want
to explore the implications of currently proposed actions from this
perspective.
Senator Dorgan. Ms. Tatro, thank you very much.
First, we are working on this issue of carbon capture, and
most people say carbon capture and sequestration, CCS, they
call it. And the sequestration side of it really describes a
mindset. ``Here is what we have to do. We have to figure out a
way to grab the carbon, separate it, and put it someplace deep
underground forever.'' I mean, that is kind of the mindset of
what CCS means.
The purpose of this hearing is to say I think there is
another mindset out there that I am much more interested in. It
is not that I am not interested in sequestration. I am much
more interested in finding is there a way to take this carbon
and provide from it beneficial use, which might well allow us
to cap carbon emissions and actually have very little cost if
you could find the right kind of beneficial use.
So the question for all of you is as you watch the Federal
Government invest in all these things, do you think there is
largely a bias in favor of sequestration or in geologic issues
as opposed to other alternatives?
Because, Ms. Tatro, you just suggested that we are moving
along here, but other countries are moving perhaps, in some
cases, faster. Is there a circumstance where you have more
difficulty in this whole collegiate discussion about carbon
capture with your approach as opposed to sequestration, Ms.
Tatro?
Ms. Tatro. Well, I believe there is a lot of activity being
looked at now for carbon capture and sequestration, and it is a
step forward we need to take. I don't believe that the country
has organized around this idea of recycling carbon dioxide.
There has been no organized, concerted effort to bring
innovation, ideas to the table beyond the capture and
sequestration.
But I think the science and technology and innovation
community and the industry and universities have ideas in their
mind and have talked about them. There is just no concentrated
way for those ideas to come forward at this point.
Senator Dorgan. But with the new Secretary of Energy coming
from a science lab, one would think that this is the time.
So tell me, Mr. Muhs, what do you think of Dr. Constantz's
testimony? You are working on a range of things at Utah, but
you heard Dr. Constantz testify on something I thought was very
novel and unique.
Mr. Muhs. My assessment is there is no silver bullet and
that we should look at biologic approaches as well as chemical
approaches to sort of, in his case, reuse for in the use of
cementitious material. So, in my mind, we have to look at all
of those things. And sort of to follow on with what Ms. Tatro
said, I think the whole idea of recycling is a mindset, and it
is one that sort of requires a certain level of osmosis into
one's mind.
Obviously, you think about recycling in a very general
sense, the European countries have done a lot on that in the
past and just in general sense in things like recycling
aluminum, things of that nature. So I believe that it takes a
little time, but I do think we are to that point, and I think
you are right.
Senator Dorgan. Mr. Klara, my understanding about algae is
that some strains of algae--there are many, many, many
different strains of algae.
Mr. Klara. Right.
Senator Dorgan. And so, some would be very productive with
respect to this and some not. Tell me how we go about
identifying which would be the productive candidates.
Mr. Klara. Well, absolutely that is a correct statement.
And a lot of the algae work that is ongoing right now is
looking at literally dozens and dozens of different strains to
find the most robust strain that could have the optimum
performance under flue gas conditions where they are getting
the CO2.
And there are also a lot of nifty approaches coming forward
with algae as well. One of the issues you have is there is so
much algae produced, you have to cultivate and remove it to
keep the algae growing. And so, there is all kind of schemes
being looked at right now to try to get past that issue so that
you can have the truly continuous process.
Senator Dorgan. Where do you think the most successful work
is going on in algae at the moment on a trial basis? I am
talking about growing algae and then harvesting the diesel fuel
and so on.
Mr. Klara. Well, I think, by far, relative to using carbon
dioxide from an energy facility and a coal plant, Arizona
Public Service is showing themselves to be a true leader in
this area.
Senator Dorgan. Yes, and I have been out to take a look at
that. We need to do a lot of everything to find out what works
and what scales up.
But Dr. Constantz--yours sounds like a silver bullet. But
you can take the carbon and with your process turn it into
concrete, and you have captured all of the carbon, which
probably has a significant value. You are talking about how
much you could produce worldwide and so on. When will you be
able to scale up your process so we understand if this works at
scale?
Mr. Muhs says there is no silver bullet, but is yours close
to a silver bullet?
Dr. Constantz. Where we are at is we have a 200-acre
facility next to a 1,000-megawatt powerplant in Moss Landing,
California. We also have a coal-fired boiler simulator there.
So we are burning both coal and gas, and we are making cement
every day. In a batch process, we have been making 5 tons a day
for several months.
We have just commissioned a plant, which is a continuous
process, which runs 24-7 solely on coal, which is producing 1
ton a day. The large EPC firms working with us say the
parameters that they are getting from this continuous plant
will allow them to design and construct a plant of any size.
Senator Dorgan. And you think this approach is going to
demonstrate at scale your capability?
Dr. Constantz. Yes, I mean, I think we are doing that right
now. And all the----
Senator Dorgan. Well, if that----
Dr. Constantz [continuing]. Energy balances look very good.
Senator Dorgan. I don't mean to interrupt you, but if you
are doing it right now and it was demonstrated at scale that
you can produce a product of substantial value and sequester
virtually all of the CO2 at the same time, it seems
to me there would be a traffic jam leading right to your office
of everybody in the world that says, ``You know what? You found
the silver bullet. We need to do that.''
Dr. Constantz. In fact, the materials I am pointing out to
you are highly sought after by the entire construction
industry, and they are beating a path to our door. I mean, we
are talking to every major producer of portland cement and
aggregate in the world.
And we are talking about the whole fabric of the
infrastructure here. It is not just a power problem. If you are
a hammer, everything looks like a nail. And just what you said,
the goal is not to purify CO2 so you can inject into
the ground. The goal is to lower the amount of carbon in the
atmosphere.
And you need to understand the whole construction industry
has a huge problem, too. The cement industry, for every ton of
cement produced, produces a ton of CO2. They are
under the same problem that the power guys are under. And so,
they are looking for ways to mitigate their CO2, and
they see the opportunity to turn this liability into a profit.
Sixty percent of the aggregate used in northern California
is imported from British Columbia on barges, and it is all
limestone. It looks just like this. We can produce it locally
with the carbon. We are producing in a profitable way.
And it links in with the water. At our plant in Monterey,
we have a contract with the local water district because they
have big problems, and we can lower the energy intensivity of
their reverse osmosis by 50 percent. So we are actually doing
it.
Senator Dorgan. Ms. Tatro, what do you think? I mean, you
are looking at a lot of different things. Give me your
assessment of Dr. Constantz's presentation.
Ms. Tatro. Sir, I think there is tremendous merit to taking
CO2 and permanently sequestering it in these
construction materials. I think that is a fabulous idea. I
think it can be complemented nicely by using CO2 to
create liquid transportation fuels.
This is my point in my testimony. I think there are a lot
of good ideas out there that have not come to the forefront
because there has not been an organized effort to call for
these ideas. I think it is a fabulous idea. It would complement
making transportation fuels very nicely.
Senator Dorgan. Now you have worked since 1985 for Sandia,
and you have got a couple hundred people working with you. You
lead a couple hundred people working on these issues. So you
have spent a lot of time and a lot of public funding working on
these issues. Let us fast forward 5 and 10 years.
Ms. Tatro. Okay.
Senator Dorgan. And let us say that we really begin to
focus on all the aspects of carbon capture and also start to
emphasize beneficial use. Do you think in 5 to 10 years we
would make significant progress on the beneficial use side?
Ms. Tatro. I believe we can. I think the 10-year
timeframe--to answer your question earlier about when the
maturity of these technologies is going to vary. But a 10-year
timeframe is a very reasonable timeframe for a target of doing
some of these concepts in a way that is both affordable and
technologically feasible.
I will offer this one caution. Those who are expert in this
area of policy, such as yourselves ought to be looking at the
current policies that are being discussed to make sure they do
not disincentivize the recycling of carbon dioxide as an
option. That will significantly affect the timeframe in which
these technologies can be viable.
Senator Dorgan. Well, this subcommittee is going to try to
have an impact on that, and we tried to have an impact on that
in the stimulus bill as well to make sure that most of these
things tend to move toward the geologic side of things because
of CCS. So we intend to try to have a significant impact on
that.
Senator Bennett?
Senator Bennett. Thank you very much, Mr. Chairman. And
thank you for the hearing.
Thank you to all the witnesses, and a special welcome to my
fellow alumnus from Utah State University. I became a graduate
as of last Saturday. They gave me an honorary degree.
Senator Dorgan. How were your grades?
Senator Bennett. I, what is the--you pencil-whipped them
through.
I would ask that the algae report be part of the record, if
that has not been done already.
Senator Dorgan. Without objection.
[The information follows:]
Algae Biofuels and Carbon Recycling--A Summary of Opportunities,
Challenges, and Research Needs
SUMMARY OF RECOMMENDATIONS
Congress should support and strengthen policies inclusive of algae
energy system development in future energy and climate change
legislation and loan guarantees for commercial demonstrations (EPACT
2005; title 17).
Congress should authorize and appropriate funds for a comprehensive
research, development, and demonstration program administered by the
U.S. Department of Energy specifically focused on algae energy systems.
--The program should include a balanced and distributed portfolio of
foundational, translational, and transformational research,
development, and scalable demonstrations.
--Fundamental research should provide new knowledge discovery in
several areas.
--Applied R&D should involve laboratory and pilot-scale R&D on all
three sub-systems (upstream, cultivation and downstream
systems) and interdisciplinary activities that bridge between
them.
--Crosscutting R&D should be included on topics such as advanced
materials, instrumentation and controls, systems engineering,
and economic modeling.
--Demonstration and deployment elements of the program should be
designed to demonstrate the viability of algae energy system
technologies at a scale large enough to overcome real and
perceived infrastructure challenges.
--The largest component of the demonstration and deployment program
should be regional partnerships similar to the Department's
Fossil Energy ongoing regional programs for geologic
sequestration.
--The program should include initial supporting research on lifecycle
analyses.
--The program should leverage strengths from existing Department
programs, establish programmatic roles, and coordinate from a
Department-wide perspective.
--The program should include development of education programs.
Contributors:
Jeff Muhs, Utah State University
Sridhar Viamajala, Utah State University
Barbara Heydorn, SRI International
Mark Edwards, Arizona State University
Quiang Hu, Arizona State University
Ray Hobbs, Arizona Public Service
Mark Allen, Algal Biomass Organization
D. Barton Smith, Oak Ridge National Laboratory
Tim Zink, Sapphire Energy
Dave Bayless, Ohio University
Keith Cooksey, Montana State University
Tanya Kuritz, Oak Ridge National Laboratory
Mark Crocker, University of Kentucky
Sam Morton, University of Kentucky
Jim Sears, A2BE Carbon Capture
Dave Daggett, Boeing
Dave Hazlebeck, General Atomics
Jeff Hassenia, Diversified Energy Corporation
Disclaimer: The views and opinions expressed in this concept paper
do not necessarily state or reflect those of the contributing
organizations and may not be used for advertising, endorsement, or
other purposes.
EXECUTIVE SUMMARY
The United States of America faces five interdependent challenges
(described below) that threaten the prosperity and quality of life of
its citizens. Central to these challenges is the need for domestically-
produced renewable transportation fuels and carbon mitigation
strategies that are affordable, environmentally-sustainable, and avoid
interfering with food supplies. This report summarizes opportunities,
challenges, and research needs for sustainable algae-based biofuel
production with an emphasis on systems designed for carbon recycling
from point-source CO2 emitters. It reviews the limitations
of other biofuel and carbon mitigation options and summarizes how algae
energy systems can fill a unique niche in both cases. Recommendations
for a national-scale RD&D program and critical steps leading to robust
pilot demonstrations by 2015 and integrated systems demonstrations by
2020 are also provided.
INTRODUCTION
In response to increasing pressure to reduce carbon emissions,
fossil-fired utilities are pursuing deep geological sequestration as
the preferred option for handling the enormous quantities of
CO2 being introduced to the atmosphere (Figure 1). Recent
analyses indicate that additional options for risk mitigation may be
necessary, as liability issues for deep sequestration are unknown and
potentially significant. Industries and utilities face increasing
difficulty in financing new fossil-fired boilers and electric power
generators because of uncertainty over CO2 abatement.
Figure 1.--World CO2 Emission by Region as Published in the
DOE Carbon Sequestration Technology Roadmap and Program Plan 2007
Industrial operations, in particular, face serious risk with
respect to CO2 control. Flue gas separation is expensive and
access to geological sequestration for smaller emitters is limited and
costly. Given EPA's new rules for assuring ground water quality, the
long-term risk to small operations is even more stifling. The lack of
other options has driven these operations toward natural gas, with
little possibility of future CO2 control. Natural gas
boilers emit less CO2 than coal per Btu, but without
control, long-term CO2 release will continue unabated.
Natural gas, which has higher value uses in the production of
fertilizer and in home heating, will continue to rise in price as
demands increase, resulting in higher food, home heating and
electricity prices. Without options to mitigate CO2
emissions, the ultimate loser will be the consumer.
Compounding the climate change challenge is the worldwide
dependence on fossil fuels for transportation and home heating. Unlike
concentrated CO2 sources, homes and vehicles are highly
dispersed, and it is difficult to visualize viable ways to collect,
separate, and sequester carbon dioxide from such locations. Instead,
options that are more viable are sought including replacement of fossil
fuels with biofuels.
The U.S. biofuel producers, however, are in the process of shifting
to new feedstocks because of increasing concerns over the environmental
and economical impacts of 1st-generation biofuels. Corn and soy-based
biofuel industries experienced rapid growth from 2002 to 2007, but
rising corn and soybean prices, volatile petroleum markets, and new
studies on their carbon footprints have slowed investments. The
cultivation and harvesting of traditional biofuel crops, long viewed as
part of the solution to climate change, may actually increase
greenhouse gas emissions.\1\ Further, the energy density of both corn-
and cellulosic-based ethanol is considerably lower than gasoline and
diesel making their widespread use in ground freight and air-
transportation markets highly unlikely.
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\1\ Searchinger T, Heimlich R, Houghton RA, Dong F, Elobeid A,
Fabiosa J, Tokgoz S, Hayes D, Yu T. Use of U.S. Croplands for Biofuels
Increases Greenhouse Gases Through Emissions from Land-Use Change.
Science AAAS [Internet]. 2008 [cited April 2009]. Available from:
http://www.sciencemag.org/cgi/content/abstract/1151861.
2008;319(5867):1238-1240.
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Thus, we are entering an era where several factors are aligning to
promote the use of algae for photosynthetic mitigation of greenhouse
gas emissions and production of next-generation biofuels. Algae and
cyanobacteria offer an alternative and sustainable solution via two
fundamental routes: (1) value-added sequestration of CO2
through conversion to stable biopolymers; and (2) displacement of
fossil fuel use by producing renewable fuels (biodiesel and/or biogas)
in areas with little plant life. Reported values of algal growth-rates
and yields indicate a near-term potential for using algal energy
systems for biodiesel production and carbon recycling from smaller
CO2 generators such as industrial boilers or fuel-ethanol
plants.
Algae energy systems will likely be part of a national/global
energy security portfolio, resulting in distributed energy systems not
disadvantaged by CO2 transportation costs to distant
geological locations, an option not likely viable for smaller-scale
producers.
Fundamentally, algae and cyanobacteria use solar energy to
transform atmospheric CO2 to organic cellular material via
photosynthesis. Due to their simple biological structure, they convert
and capture carbon more rapidly than terrestrial plants and store a
significant amount of carbon as material that can be converted into
biodiesel, bioplastics, feedstock for gasification, or numerous other
products. Some algal strains are capable of doubling their mass several
times a day. Algae can be cultivated on marginal land (and on ocean
surfaces) using low-quality and or saline waters. In contrast,
terrestrial sequestration and biofuel production requires fresh water,
is slower and restricted by the availability of fertile land;
eventually reaching steady state, with no additional sequestration or
biofuel production possible.
While algal products offer the potential to provide sustainable
solutions for both liquid transportation fuels and CO2
mitigation, important challenges must be overcome to make them cost-
effective. Unlike terrestrial crops that have been cultivated and
harvested for centuries, the infrastructure and knowledge needed to
cultivate and harvest algae using industrial processes is in a pre-
commercial stage of development. For example, within the field of plant
biotechnology, algal research is one of the least explored fields and
industrial-scale algal energy systems will benefit greatly from intense
R&D efforts.
For these reasons, clearly-defined goals and significant, well-
managed and coordinated Federal investments are needed in areas such as
CO2 delivery and conditioning; integration and systems
engineering; energy and water use; algal areal and volumetric
productivity; cultivation system design; strain optimization; synthetic
biology; downstream processing; value-added co-product development; and
carbon life-cycle analysis.
LIMITATIONS OF OTHER CARBON SEQUESTRATION PATHWAYS
Figure 2 illustrates the three primary pathways to carbon
sequestration. Though significant investments and progress in
developing geologic and chemical carbon mitigation pathways has been
made, significant hurdles remain.
Figure 2.--Primary Pathways to Carbon Sequestration
Challenges of Underground Geologic Sequestration
The problems associated with geological sequestration of
supercritical CO2 are well documented and reasonably well
understood; however, there is a significant difference between
sequestration of CO2 as a gas phase compared a supercritical
fluid. Gas phase CO2 can be stored in geological formations.
Large natural CO2 deposits can be found worldwide, much like
there are large natural gas formations. Gaseous CO2 has been
successfully used over decades for enhanced oil and gas recovery by
injection into gas and oil reservoirs, and there is strong evidence
supporting the ability to store gas phase CO2 for
significant lengths of time.\2\-\9\&
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\2\ Marchetti C. On Geoengineering and the CO2 Problem.
Climatic Change, 1977;1: 59-68.
\3\ Baes CF, Beall SE, Lee DW, Marland G. The collection, disposal
and storage of carbon dioxide. In Bach W, Pankrath J, William J,
editors. Interaction of Energy and Climate: D. Reidel Publishing, CO;
1980. p. 495-519.
\4\ Kaarstad O. Emission-free fossil energy from Norway. Energy
Conversion and Management. 1992;33(5-8):619-626.
\5\ Koide HG, Tazaki Y, Noguchi Y, Nakayama S, Iijima M, Ito K,
Shindo Y. Subterranean containment and long-term storage of carbon
dioxide in unused aquifers and in depleted natural gas reservoirs.
Energy Conversion and Management. 1992;33(5-8:, 619-626.
\6\ Van der meer LGH. Investigation regarding the storage of carbon
dioxide in aquifers in the Netherlands. Energy Conversion and
Management, 1992;33(5-8): 611-618.
\7\ Holloway S, Savage D. The potential for aquifer disposal of
carbon dioxide in the UK. In: P.W.F. pierce (Ed.), Proceedings of the
International Energy Agency carbon dioxide symposium, Oxford March
1993. Energy Conversion and Management. 1993;34(9-11):925-932.
\8\ Bachu S, Gunter WD, Perkins EH. Aquifer disposal of
CO2: hydrodynamic and mineral trapping, Energy Conversion
and Management. 1994;35(4):269-279.
\9\ Korbol R, Kaddour A. Sleipner West CO2
disposal:injection of removed CO2 into the Utsira formation.
Energy Conversion and Management. 1994;36(6-9):509-512.
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There are two concerns with gas phase storage of CO2:
First, at low gas pressures, the capacity of all geologic storage is
estimated to be only decades of fossil fuel use; Second, CO2
will remain in the gas phase and ready for release should an accidental
penetration occur in the formation or a cap rock be compromised. While
intense management of geological formations should limit this,
accidental release is a non-trivial possibility.\10\ \11\
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\10\ Gunter WD, Bachu S, Benson S. The role of hydrogeological and
geochemical trapping in sedimentary basins for secure geological
storage for carbon dioxide. In: S. Baines and R.H. Worden editors.
Geological Storage of Carbon Dioxide. Technology. Special Publication
of Geological Society, London, UK. Special Publication; 2004. 233: p.
129-145.
\11\ Kaarstad O. Geological storage including costs and risks, in
saline aquifers, Proceedings of workshop on Carbon Dioxide Capture and
Storage: Regina Canada; 2002.
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Supercritical CO2, or storage of CO2 at
pressures exceeding the critical point (7.38 MPa), is highly favored
over gas phase storage because the higher pressure significantly
increases the holding capacity of the geological formation. Gas
pressures as high as 80 MPa are being considered for sequestration.\12\
Further, supercritical CO2 is more reactive than gas phase
CO2 and has the ability to chemically join with metals in
the aquifer (e.g., calcium and magnesium) to form solid carbonates,
which would be permanently sequestered within the Earth with no chance
of accidental release.\13\ \14\
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\12\ Benson S, Cook P. Underground Geological Storage. In: Metz B,
Davidson O, de Coninck, Loos HM, Meyer L, editors. Carbon Dioxide
Capture and Storage (Intergovernmental Panel on Climate Change):
Washington, DC; 2005. p. 197-278.
\13\ Perkins E, Czernichowski-Lauriol I, Azaroual M, Durst P. Long
term predictions of CO2 storage by mineral and solubility
trapping in the Weyburn Midale Reservoir. Proceedings of the 7th
International Conference on Greenhouse Gas Control Technologies (GHGT-
7), September 5-9, 2004, Vancouver, Canada. 2005;II:2093-2096.
\14\ Van der meer LGH. Computer modeling of underground
CO2 storage. Energy Conversion and Management. 1996;37:6-
8(1155-1160). 14.
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Unfortunately, supercritical CO2 is far more problematic
for storage than gas-phase CO2. Supercritical CO2
is an extreme solvent and attacks concrete, which is the material of
choice for capping wells: And, while the time-scales for dissolution of
the concrete seals may be decades, the supercritical CO2
will be present for time-scales of centuries to millennia because
geochemical reactions that form carbonates are very slow. As a result,
the possibility of leakage through capped wells is potentially high,
and given the hundreds of thousands of wells that must be drilled, it
is very likely that leaks will occur.\11\ \15\
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\15\ Duguid A, Radonjic M, Bruant R, Mandecki T, Scherer G, Celia
M. The effect of CO2 Sequestration on oil well cements.
Presented at 7th international conference on greenhouse gas control
technologies, Vancouver, Canada, 5-9 September 2004; Paper 123.
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Whether the leaks are slow and manageable or rapid and catastrophic
are key questions. A scenario where a sudden and major leak occurs in
an area of high population could be catastrophic because CO2
has a higher molecular weight than air and presents a significant risk
of asphyxia at very high release rates. Therefore, deep geological
sequestration will require widespread monitoring over entire
formations, leading to significant cost.\12\ Further, liability issues
(should a significant leak occur) must be resolved by legislation,
because few companies will risk exposure to expensive lawsuits in the
event of a catastrophe.
Aquifer poisoning is another significant concern. Supercritical
CO2 is mobile, and should an underground fissure lead to
migration of the CO2 from its proposed storage formation to
a potable aquifer, the potential exists for formation of significant
quantities of carbonic acid in potable water sources.\12\ \16\ This
could make the contaminated aquifer unusable until suitable treatment
technology was applied to neutralize the acid. Neutralizing technology
is non-trivial, would be very costly, and would take months to
implement. Populations dependent on that aquifer could be without
drinkable water for the duration; businesses and organizations that are
equally dependent on the aquifer for their operation and livelihood
could be faced with significant revenue losses.
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\16\ Strutt, MH, Beaubien SE, Beabron JC, Brach M, Cardellini C,
Granieri R, Jones DG, Lombardi S, Penner L, Quattrocchi F, Voltatorni
N. 2003: Soil gas as a monitoring tool of deep geological sequestration
of carbon dioxide: preliminary results from the EnCana EOR project in
Weyburn, Saskatchewan (Canada). Proceedings of the 6th International
Conference on Greenhouse Gas Control Technologies (GHGT-6). Gale J,
Kaya Y (editors), 1-4 October 2002, Kyoto, Japan, Pergamon, Amsterdam.
2003;I: 391-396.
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Another significant issue for supercritical CO2 storage
in deep geological formations is corrosion. By injecting supercritical
CO2 in a saline aquifer, a mixture of corrosive carbonic
acid and salts would be present in the region of down-hole well
pipes.\12\ When the supply of injected CO2 is stopped, high
pressures in the region of the aquifer near the pipe could force that
corrosive mixture back, which would create the possibility of rapid
pipe failure. What exactly would happen when a down-hole well pipe
fails is unknown, but it could range from having to replace more than a
mile of down-hole well piping to a catastrophic failure of the entire
injection system.\17\
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\17\ Nesic S, Choi Y, Bayless D. Determining the Corrosive
Potential of Transporting CO2 with Impurities and
Development of Mitigation Strategies. OCRC-AY07-08;B2-Q3:2008.
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Unfortunately, today's carbon capture and sequestration methods are
also expensive. The Intergovernmental Panel on Climate Change's report,
Carbon Dioxide Capture and Storage, reports that CO2 capture
is expected to increase the cost of electricity production by 35-70
percent for a Natural Gas Combined Cycle (NGCC) plant, 40-80 percent
for a supercritical PC plant, and 20-55 percent for an NGCC plant. The
costs of retrofitting existing power plants may be even more expensive
and carbon dioxide transportation and storage further add to costs.\18\
\19\
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\18\ iEA GHG, Leading options for the capture of CO2
emissions at power stations, report PH3/14, IEA Greenhouse Gas R&D
Programme. Available From: Cheltenham, UK, Feb. 2000.
\19\ Thambimuthu K, Soltanieh M, Abanades J, Capture of
CO2. In: Metz B, Davidson O, de Coninck, Loos HM, Meyer L,
editors. Carbon Dioxide Capture and Storage (Intergovernmental Panel on
Climate Change). Washington, DC. 107-p. 178.
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As much as we must make deep geological sequestration work, the
potential problems, liabilities, and costs are not minor and it is
clear that other alternatives must be pursued to mitigate risk.
Challenges of CO2 Transport & Sequestration in Oceans
Several concepts have also been proposed for CO2 storage
in oceans. One option considered is injecting CO2 by ship or
pipeline into the water column at depths of 1,000 meters or more so
that the CO2 subsequently dissolves. Another option is to
create underwater lakes where CO2 is piped directly onto the
sea floor at depths greater than 3,000 meters where CO2 is
denser than water (and forms a natural lake). In both cases, no one is
quite sure how to cost-effectively collect, transport, or inject
CO2, or if the injected CO2 will actually remain
sequestered. Deep saline aquifer storage depends on supercritical
CO2 staying in the aquifer for enough time to form stable
mineral species. Unfortunately, the timescale for that transformation
is hundreds or thousands of years, and the chance that supercritical
CO2 will not find a way out without converting to carbonates
is probably less than is optimistically predicted.
Other environmental effects of oceanic storage are generally
negative and poorly understood. Concentrated CO2 kills ocean
organisms. As CO2 reacts with the water to form carbonic
acid, H2CO3, the acidity of the ocean water
increases, which will dissolve the shells of shellfish and corals and
cause reproductive problems for sea creatures. Consequently, ocean
storage of CO2 is likely to have several unintended
consequences.
Challenges of Chemical CO2 Separation and Sequestrations
Before CO2 can be sequestered in geological or other
storage sites, it must be purified or enriched beyond the 5-15 percent
concentration typically found in the products of combustion. The
concentration of CO2 in combustion gases is relatively low
because the high concentration of nitrogen in the air used to burn the
fuel (typically coal or natural gas) remains relatively unchanged
during the combustion process. Because there is limited space for
CO2 sequestration and the cost of compression and storage is
significant, it is not desirable to sequester large volumes of other
gases with CO2.\12\
The two primary approaches to purify CO2 for
sequestration are absorption-desorption separation and oxygen-based
combustion. Absorption-desorption separation removes CO2
from the nitrogen and water (the other major constituents in the
combustion gases). Oxygen-based combustion removes the nitrogen from
the combustion air before reacting with the coal or natural gas,
leaving mostly CO2 and water in the combustion products and
eliminating the need to remove nitrogen, which is not reactive and
difficult to separate from CO2.\20\
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\20\ Kohl, A.O, Nielsen RB. Gas purification, Gulf. Houston: TX;
1997.
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Absorption-desorption based separation of CO2 is a well-
known process. The most commonly employed method in industry uses
monoethylamine (MEA or amine) to absorb the CO2 from
combustion gases and, in a separated and heated chamber, strip
CO2 from the amine as a relatively pure gas. While numerous
amines have been developed, the energy requirement (primarily for
stripping) is enormous: DOE has estimated that about one-third of the
output of a power plant would be necessary to run an amine scrubbing
system for CO2 separation. This would not only lead to
significant increase in the cost of electricity, but also of the amount
of coal needed to produce an equivalent amount of electrical power.\21\
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\21\ Alstom Power Inc., ABB Lummus Global Inc. Alstom Power
Environmental Systems and American Electric Power. Engineering
feasibility and economics of CO2 capture on an existing
coal-fired power plant. Report no. PPL-01-CT-09 to Ohio Department of
Development, Columbus, OH and U.S. Department of Energy/NETL,
Pittsburgh, PA. 2001.
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Oxygen-based combustion is also being considered for implementation
to produce a sequestration ready CO2 stream.\22\
Theoretically, it is much easier to remove water vapor (the other major
constituent found in combustion gases) than nitrogen. However, even in
the most optimistic evaluations of implementing oxy-fuel combustion,
there will be significant amounts of nitrogen found in the combustion
gases. Unfortunately, power plants are difficult to seal completely
from air infiltration (need for oxy-fuel combustion) and the retrofit
costs of such a system, especially the air separation unit required to
remove the nitrogen from the air, will be non-trivial.\23\
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\22\ Babcock Energy Ltd, Air Products Ltd, University of Naples and
University of Ulster. Pulverized coal combustion system for
CO2 capture. Final report 2.1.1. Available from: European
Commission JOULE II Clean Coal Technology Programme--Powdered Coal
Combustion Project. 1995.
\23\ Wilkinson MB, Simmonds M, Allam RJ, and White V. 2003a: Oxy-
fuel conversion of heaters and boilers for CO2 capture, 2nd
Annual Conf on Carbon Sequestration, Virginia (USA), May 2003.
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Challenges of Other Biological Sequestration Pathways
Figure 3 illustrates the three primary pathways for biological
sequestration. Though there has been much discussion and limited
research on terrestrial and ocean algal carbon sequestration,
significant hurdles remain.
Figure 3.--Primary Pathways to Biological Carbon Sequestration
Carbon Capture by Forests
Forests are natural carbon dioxide sinks and sequester carbon in
the cellulosic structure of trees and humus soil. In 2004, forests
sequestered 10.6 percent (637 teragrams or 637 megatons) of the carbon
dioxide released in the United States by the combustion of fossil fuels
(coal, oil and natural gas; 5,657 teragrams or 5.6 gigatons) while
urban trees sequestered another 1.5 percent (88 teragrams) EPA
2008.\24\
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\24\ Malhi Y, Meir P, Brown S, Forests, carbon and global climate.
Philos Transact A Math Phys Eng Sci. 2002 Aug 15;360(1797):156.
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An average coal-fired power plant produces about 4 million tons of
CO2 annually (there are about 600 plants in the United
States): It would require planting 161 million trees to offset each
plant.\25\ The land, cost and energy required to plant trees to
sequester significant amounts of CO2 make the approach
infeasible.
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\25\ Union of Concerned Scientists, Clean energy [Internet]. 2008
[cited April 2009]. Available from: http://www.ucsusa.org/clean_energy/
coalvswind/c01.html.
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Typically, carbon stored in soils oxidizes rapidly and reenters the
atmosphere or water. Carbon captured by forests is typically temporary
(decades in duration) because many forests burn or are harvested and
release their stored carbon. Other forests are uprooted by fierce
storms and the carbon oxidizes. In 2004, Hurricane Katrina killed or
severely damaged 320 million large trees in Gulf Coast forests.\26\
Tropical forests are also poor at retaining carbon long term because
they tend to have very thin organic mulch on the forest floor; heavy
rains leach out the carbon and carry it to waterways. Conversely,
carbon stored in soils as humic acids can sequester carbon for long
periods and increase the carbon uptake vitality of all types of
vascular plants.\27\
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\26\ NASA, Forests Damaged by Hurricane Katrina Become Major Carbon
Source [Internet]. 15 Nov 07 [cited April 2009]. Available from: http:/
/www.nasa.gov/mission_pages/hurricanes/archives/2007/
katrina_carbon.html.
\27\ Wigley TML, Schimel DS. The Carbon Cycle. Cambridge University
Press: Cambridge; 2000.
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Regenerative Agriculture Carbon Capture
The Rodale Institute reported that regenerative (organic)
agriculture may sequester up to 40 percent of current CO2
emissions by plowing organic carbon in green manure (plant biomass)
back into the soil.\28\ The authors believe that agricultural carbon
sequestration has the potential to mitigate climate change. They
believe that organic farming practices can be accomplished with no
decrease in yields or farmer profits and that organically managed soils
can convert carbon dioxide from a greenhouse gas into a food-producing
asset.
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\28\ LaSalle T, Hepperly P. Regenerative 21st Century Farming:
solution to global warming. Rodale Institute, 2008.
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Some midwestern soils that, in the 1950s, were composed of up to 20
percent carbon are now between 1 and 2 percent carbon. This carbon loss
contributes to soil erosion by degrading soil structure, increasing
vulnerability to drought, by greatly reducing the level of water-
holding carbon in the soil, and by the loss of soil's native nutrient
value. Organic farming builds carbon back into the soil, which improves
the soil as it sequesters the carbon.
In 2006, U.S. carbon dioxide emissions from fossil fuel combustion
were estimated at nearly 6.5 billion tons. If a 2,000 lb/ac/year
sequestration rate was achieved on all 434 million acres of cropland in
the United States, nearly 1.6 billion tons of carbon dioxide would be
sequestered per year. This would mitigate about one-quarter of U.S.
fossil fuel emissions.
Critics note that the cropland required to grow enough green manure
for organic fertilizer would take 10 times more cropland than is
available in North America; which makes large-scale organic farming
impractical unless an organic fertilizer source can be found that
requires no cropland and minimal fresh water and fossil fuels. Farmers
would have to use no-till farming, which is currently used by less than
5 percent of farmers, in order to ensure the soil is not disturbed and
the carbon is not oxidized and released as CO2.
Marine Algae Sequestration
Even though algae represent only 0.5 percent of total global
biomass by weight, algae produce about 60 percent of the net global
production of oxygen, which is more than all the forests and fields
combined.\29\ Algae's ability to sequester CO2 and produce
massive amounts of O2 has prompted scientists to theorize
that propagating algae in large ocean dead zones may be a way of
sequestering millions of tons of CO2 and adding to
atmospheric oxygen.
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\29\ Hall J. Earthworks & Systems: the most important organism?.
Ecology Global Network [Internet]. 2008 [cited April 2009]. Available
from: http://www.ecology.com/dr-jacks-natural-world/most-important-
organism/index.html.
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English biologist Joseph Hart theorized in the 1930s that the
ocean's great desolate zones were rich in nutrients but lacking in
plankton activity or other sea life because they were iron
deficient.\30\ Decades later, a series of studies proved the iron
thesis.
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\30\ Jones ISF, Young HE. Engineering a large sustainable world,
fishery. Environmental Conservation 1997;24: 99-104.
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Ocean iron fertilization (OIF) seeds iron in open oceans with
micrometer-sized iron particles in the form of either hematite (iron
oxide) or melanterite (iron sulfate). The iron feeds phytoplanktons
that are in iron deficient blue ocean water. Phytoplanktons grow
quickly in algae blooms and consume massive amounts of CO2
that they convert into plant biomass that sinks to the ocean floor.
Since 1993, 10 international research teams have completed small-
scale ocean trials demonstrating the capability of ocean iron
fertilization. Ken Buesseler, a scientist of marine geochemistry at
Woods Hole Oceanographic Institution in Massachusetts, along with other
scientists, is trying to get approvals and funding for more
research.\31\
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\31\ Buesseler, Ken. et. al. Ocean Iron Fertilization--Moving
Forward in a Sea of Uncertainty, Science. 2008;319(5860):162.
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The Southern Ocean test in 2002 near Antarctica reported that
between 10,000 and 100,000 carbon atoms are sequestered for each iron
atom added to the water. Recent work suggests that biomass carbon in
the oceans, whether exported to depth or recycled in the euphotic zone
(depth with sufficient sunlight for photosynthesis), results in long-
term carbon storage. Therefore, the application of iron nutrients in
select parts of the oceans, at appropriate scales, could have the
combined effect of restoring ocean productivity while concurrently
mitigating the effects of human caused emissions of CO2 to
the atmosphere.
Support for the iron deficiency theory occurred with the 1991
eruption of Mount Pinatubo in the Philippines. Andrew Watson analyzed
global data from that eruption and calculated that the eruption
deposited approximately 40,000 tons of iron dust in the oceans. This
ocean fertilization event generated a significant global decline in
atmospheric CO2 and a parallel increase in oxygen
levels.\32\
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\32\ Watson AJ. Volcanic iron, CO2, ocean productivity
and climate. Nature. 1997;385: 587-588.
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Critics worry that seeding the ocean with large volumes of iron
might have unintended consequences. In a special report, the
Intergovernmental Panel on Climate Change called ocean iron
fertilization ``speculative and unproven and with the risk of unknown
side effects''.
LIMITATIONS OF OTHER BIOFUEL FEEDSTOCKS
Biofuels have been identified as one of the key pathways for
transforming our energy supply away from fossil fuels. The recent
cultivation of large quantities of biomass for biofuels has led to a
growing debate over the feasibility and sustainability of biofuels as a
renewable energy source. Figure 4 shows three primary feedstock options
for producing renewable liquid transportation fuels. Significant
investment and technological progress in both food/feed and cellulosic-
based bio-feedstocks have occurred in recent years; however,
substantial hurdles in certain niche markets remain.
Figure 4.--Primary Feedstock Options for Producing Renewable Liquid
Transportation Fuels
Traditional sources of biomass are abundant and include field crops
such as soybeans and corn; perennial grasses such as switchgrass; woody
crops such as trees; and other agricultural and forestry residuals.
Corn and soybeans are examples of so-called first-generation
terrestrial biofuels because of their use in both food and fuel
production. Clean-burning ethanol is derived from corn and most
biodiesel from soybeans. In 2006, close to 5 billion gallons of ethanol
were produced in the United States, which is 3.6 percent of our annual
gasoline demand (per volume) and 2.4 percent (per energy).\33\
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\33\ Yacobucci BD, Ethanol Imports and the Caribbean Basin
Initiative. Available from: United States CRS Report for Congress
(Order Code RS21930); 2007. Available from: http://www.docstoc.com/
docs/779532/CRS-Report-on-Ethanol-Imports.
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Limitations of corn ethanol include a considerably lower energy
density compared to petroleum both on a per volume and per weight
basis. Thus, ethanol requires more fuel to propel vehicles comparable
distances. Further, though the growth of corn and soybeans for biofuels
absorbs as much carbon as biofuel-powered vehicles emit, it does not
absorb the significant carbon emissions associated with planting,
fertilizing, harvesting, transporting, processing, and converting
biomass into fuel. One analysis concluded that it would take over 150
years for such crops to achieve carbon neutrality.\1\
These challenges are compounded by our need to both feed and fuel a
growing global population (projected to be 9 billion by 2050). In
comparison to less-complex organisms, food crops like corn and soybeans
grow much slower, and thus, require large quantities of fertile land
and water, which, in turn, increases food, and water prices. For
example, the food price index of the Food and Agriculture organization
of the United Nations rose 36 percent in 2007 after a 14 percent
increase in 2006 because of--among other things--biofuel production.
Because of these and other concerns, interest in producing
cellulosic ethanol from fibrous residue from plants (forestation
byproducts, corn stalks, wheat straw, and grasses) has grown in recent
years. The production of cellulosic ethanol, considered a second-
generation terrestrial biofuel because it uses only nonfood feedstocks,
is still a maturing industry. Though technologies for breaking down
fibrous material into fuel are still under development, the United
States could produce 60 billion gallons of ethanol per year by 2030
through a combination of grain and cellulosic feedstocks, which is
enough to replace 30 percent of projected U.S. gasoline demand.\34\
Further, perennial crops such as switchgrass would hold soil and
nutrients in place and require lower fertilizer and pesticide inputs,
thus reducing water quality impacts compared to first-generation
biofuels.
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\34\ Sheehan J. A look back at the U.S. Department of Energy's
Aquatic Species Program: Biodiesel from Algae. National Renewable
Energy Laboratory, 1998, Golden, CO.
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There are, however, limitations and uncertainties that accompany
the production of cellulosic ethanol. Anticipated cellulosic crops also
grow relatively slow in comparison to less complex plants (such as
algae) and have little history of use in large-scale cultivation. Like
first-generation biofuels, considerable land, water, and energy is
required to plant, harvest, transport, process, and convert cellulosic
biomass into usable fuels. Data on water, nitrogen and other nutrient
needs, herbicide use, soil erosion, and overall yields are still being
collected and synthesized. As second-generation biofuels expand into
regions that do not support high agriculture yields, they could
dramatically affect water use and damage irrigation introductions.
Many believe ethanol will become the bridge from petroleum to
electric-based commuter surface transportation in the coming decades.
However, because of its relatively low-energy density (compared to
diesel and jet fuel), ethanol is not likely to emerge as the preferred
energy carrier in air transportation, ocean shipping or long-haul
freight movement. For these markets, biofuels derived from oilseeds
such as soybeans are the preferred alternative because their energy
densities are comparable to petroleum fuels. Unfortunately, even if all
of the U.S.'s soybean crop were diverted to the production of
biodiesel, less than 10 percent of the U.S. diesel fuel needs would be
met. Clearly, new feedstocks that efficiently produce biofuels that
have energy densities rivaling petroleum-based products are needed and
current pathways are falling short.
THE PROMISE OF ALGAE ENERGY SYSTEMS
Aquatic (algae) energy systems have the unique potential to address
all five of the interdependent challenges facing the United States
today. They can domestically-produce renewable transportation fuels and
recycle carbon and do so in a way that is potentially affordable,
environmentally-sustainable, and does not interfere with food supplies.
Although there is no single answer to reduce atmospheric carbon
levels or end our dependence on foreign oil, aquatic-based algal energy
systems represent a possible partial solution to both challenges.
Growing algae, the most productive of all photosynthetic life, and
converting it into plastics, fuels and or secondary feedstocks, could
significantly help mitigate greenhouse gas emissions, reduce energy
price shocks, reclaim wastewater, conserve fresh water (in some
scenarios), lower food prices, reduce the transfer of U.S. wealth to
other nations, and spur regional economic development (Figure 5).
Figure 5.--Algae: A Partial Solution to Interdependent Challenges
Because of its high lipid (i.e., oil) content, affinity for and
tolerance of high concentrations of CO2, and photosynthetic
efficiency, algae cultivation results in higher areal yields and liquid
fuels with a higher energy density than alternatives, see Table 1 and
Figure 6, respectively.
TABLE 1.--COMPARISON OF OIL YIELDS FROM VARIOUS FEEDSTOCKS
------------------------------------------------------------------------
Oil yield
Crop Gallons/Acre
------------------------------------------------------------------------
Corn.................................................... 18
Cotton.................................................. 35
Soybean................................................. 48
Mustard Seed............................................ 61
Sunflower............................................... 102
Rapeseed/Canola......................................... 127
Jatropha................................................ 202
Oil Palm................................................ 635
Algae (10g/m \2\/day at 15 percent TAG)................. 1,200
Algae (50g/m \2\/day at 50 percent TAG)................. 10,000
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Figure 6.--Energy Density of Current and Future Transportation Fuels
For example, Figure 7 shows the extent to which soybeans are
planted each year across the United States. If all the soybeans grown
and harvested in the United States each year were converted into
biodiesel, the resultant fuel supply would accommodate less than 10
percent of our annual diesel fuel consumption. Conversely, if an area
roughly equating to one-tenth the land area of Utah were developed into
algal energy systems, algae could supply all of America's diesel fuel
needs. Thus, algae are an ideal feedstock for replacing petroleum-based
diesel and jet-fuel, which have a combined U.S. market approaching 100
billion gallons per year.
Likewise, because algal cultivation systems do not need fertile
soil or rainfall, they can be sited virtually anywhere that five
fundamental inputs (Figure 8) are present or can be transported. Since
some algae and cyanobacteria species have a high affinity for
CO2, siting algal energy systems near centralized
CO2 emitters is a very attractive option. Research has
demonstrated that algal yields can be improved dramatically using
enhanced concentrations of CO2.
Figure 8.--Algae Energy System Inputs
Prior Research
Algal energy systems is not a new research topic. In the 1940s and
1950s, SRI International and MIT conducted some of the first research
on algae mass culture, cultivation, and biofuel production. Soon after,
research at U.C. Berkeley targeted the use of algae for wastewater
treatment and methane production. In the 1980s, researchers in the
Soviet Union developed large photobioreactors to grow algae for animal
feed.
From 1991-1998, the U.S. Department of Energy supported a
comprehensive study of algae as a potential biodiesel feedstock through
its Aquatic Species Program (ASP).\34\ Though the chemistry of algal
oils was adequate for biodiesel production at the time \34\ \35\ \36\
major problems remained with growing and harvesting algal biomass.\34\
ASP feasibility studies of large-scale algae production proved the
concept of long-term, sustainable production of algae, together with
the twin environmental benefits of (1) extremely efficient utilization
of CO2 \34\ \36\ and (2) efficient wastewater treatment.\36\
---------------------------------------------------------------------------
\35\ Chisti Y. Biodiesel from microalgae. Biotechnol Adv
2007;25:294-306.
\36\ Benemann JR. Biofixation of CO2 and greenhouse gas
abatement with microalgae--technology roadmap. NREL Subcontract report
701000426. 2003.
---------------------------------------------------------------------------
The ASP studied a specific aspect of algae: their ability to
produce natural oils or triglycerides. Researchers not only concerned
themselves with finding algae that produced a lot of oil, but also
species that could grow under severe conditions (i.e., extremes of
temperature, pH and salinity). At the outset of the program, no
collections existed that either emphasized or characterized algae in
terms of these constraints. ASP researchers set out to build such a
collection. Algae were collected from sites in the west, the northwest
and the southeastern regions of the continental United States, as well
as Hawaii. At its peak, the collection contained over 3,000 strains of
organisms that were screened using the Nile Red method.\37\
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\37\ Cooksey KE, Guckert JB, Williams SA, Callis PR. Fluorometric
determination of the neutral lipid content of microalgal cells using
Nile Red. J.Microbiological Methods. 1987; 6:333-345.
---------------------------------------------------------------------------
After screening, isolation and characterization, the collection was
reduced to approximately 300 species (mostly green algae and diatoms)
based on algal yield and Nile Red response. The collection, housed at
the University of Hawaii, is still available to researchers and remains
an untapped resource, both in terms of the unique organisms available
and the genetic resources they represent.
Prior to the ASP, minimal research had been performed to improve
oil production in algal organisms. Much of the program's research
focused on finding the elusive ``lipid trigger''. This trigger refers
to the observation that, under environmental stress, many microalgae
appeared to ``flip a switch'' to turn on production of triacylglycerol
compounds (algal oil or TAG). Nutrient deficiency was the major factor
studied (along with studies of silicon deficiency in diatoms) but the
work did not expose overwhelming evidence in support of this trigger
theory. In fact, some of the ASP research suggested that the trigger
did not exist.
The common thread among ASP studies was a trend showing increased
oil production under stress concurrent with the cessation or slowing of
cell division. One study reported that preventing cell division by
inhibiting the tricarboxylic acid cycle increased TAG yield ten-
fold.\38\ \39\ \40\ This led to the hypothesis that TAG accumulation
was the result of synthesis minus utilization. Algae with a nutrient
starvation controlled cell-cycle did not show an increase in overall
production of oil. In fact, overall rates of oil production were shown
to be lower during periods of nutrient deficiency.
---------------------------------------------------------------------------
\38\ Thomas RM, Triglyceride accumulation and the cell cycle in
Chlorella [Thesis]. Montana State University; 1990.
\39\ Guckert JB, Cooksey KE, Jackson LL. Lipid solvent Systems are
not equivalent for analysis of lipid classes in the microeukaryotic
green alga, Chlorella. J. of Microbiological Methods. 1989;8:139-149.
\40\ Cooksey, KE. Acetae metabolism by whole cells of Phaeodactylum
tricornutum Bohlin. J. Phucol. 1974;10:253-257.
---------------------------------------------------------------------------
Another focus of the ASP included initial breakthroughs in
molecular biology and genetics engineering.\34\
The program was the first to isolate the enzyme Acetyl CoA
Carboxylase (ACCase) from a diatom. This enzyme catalyzes a key
metabolic step in the synthesis of oils in algae. The gene that encodes
for the production of ACCase was eventually isolated and cloned. This
was the first report of the cloning of the full sequence of the ACCase
gene in any photosynthetic organism. Researchers went on to develop and
patent the first successful transformation system for diatoms--the
tools and genetic components for expressing a foreign gene.\34\
In later years, ASP researchers initiated the first experiments in
metabolic engineering as a means of increasing oil production. They
demonstrated an ability to make algae over-express the ACCase gene with
the hope that increasing the level of ACCase activity in the cells
would lead to higher oil production. These early experiments, however,
did not demonstrate increased oil production.\34\
Efforts were also made to demonstrate feasibility of large-scale
algae production in open ponds. In studies conducted in California,
Hawaii and New Mexico, the ASP demonstrated the long term, reliable
production of algae.\33\ Based on results from 6 years of tests run in
parallel in California and Hawaii, 1,000-m \2\ pond systems were built
and tested in Roswell, New Mexico. The Roswell tests proved that
outdoor ponds could operate with extremely high efficacy of
CO2 utilization. Careful control of pH and other physical
conditions for introducing CO2 into the ponds allowed
greater than 90 percent utilization of injected CO2. The
Roswell test site successfully completed a full year of operation with
reasonable control of the algae species grown. Single day
productivities reported over the course of 1 year were as high as 50 g/
m \2\/day. Attempts to achieve consistently high productivities were
hampered by low temperatures encountered at the site. Desert conditions
of New Mexico provided ample sunlight, but temperatures regularly
reached low levels at night. If such locations will be considered, some
form of temperature control with enclosure of the ponds may be
required.
In Japan, a nation-wide algae-based carbon sequestration R&D effort
was also launched during the 1990s. The program was organized by
Research for Innovative Technologies of the Earth (RITE) under the
Ministry of Economy, Trade and Industry (METI). It involved more than
30 major industrial partners and several major public universities with
a total funding of over $250 million. The RITE program partially
addressed a number of R&D challenges including: (1) algae strain
selection and characterization, (2) photobioreactor design and
optimization, (3) mass cultivation of algae supplied with
CO2-rich synthetic or real flue gases from power plants, and
(4) the development of value-added co-by-products from the algal carbon
recycling processes. Unfortunately, the research focused heavily on one
particular photobioreactor design that ultimately proved infeasible.
Recent Research
In the United States, algae-based research related to carbon
recycling restarted in 2000 when Ohio University researchers developed
a technique to control the emissions of CO2 from fossil-
fired power plants by growing organisms on reactor-enclosed biofilms: A
thermophilic mesophilic organism was examined with respect to its
ability to recycle CO2 from scrubbed stack gases and
cyanobacteria was grown on fixed surfaces to facilitate algal stability
and improve light distribution.\41\ Growth-rates of 50 g/m \2\/day were
reported, but the lipid content was lower than the rates reported by
eukaryote algae grown in aqueous solutions.
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\41\ Bayless DJ, Kremer G, Vis M, Stuart B, Prudich M, Cooksey K,
Muhs J. Enhanced Practical Photosynthetic CO2 Mitigation.
Third Annual Conf on Carbon Capture & Sequestration. 2004:173.
Available from: http://www.netl.doe.gov/publications/proceedings/04/
carbon-seq/173.pdf.
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In 2003, a roadmap outlining short- and mid-term R&D needs for
carbon dioxide abatement using microalgae was prepared and issued by
John Benemann on behalf of the International Network for Biofixation of
CO2 and Greenhouse Gas Abatement with Microalgae, a group
formed under the auspices of the International Energy Agency (IEA).\42\
---------------------------------------------------------------------------
\42\ Benemann J, Pedroni PM, Davison J, Beckert H, Bergman P.
Technology Roadmap for Biofixation of CO2 and Greenhouse Gas
Abatement with Microalgae. Second Annual Conf on Carbon Capture &
Sequestration. 2003. Available from: http://www.netl.doe.gov/
publications/proceedings/03/carbon-seq/PDFs/017.pdf.
---------------------------------------------------------------------------
The roadmap emphasized the use of open pond algae production in
combination with municipal- and agricultural-waste treatment
facilities. In such combined systems, algae would be used to accomplish
wastewater treatment to help subsidize the cost of carbon utilization
and algae growth. It also emphasized the need for generation of co-
products including fuel, fertilizer and animal feed to add value to
algal energy systems and provide outlets that could partially displace
use of fossil sources for these commodities. The use of enclosed
photobioreactors was considered as a viable option only for small-scale
growth (e.g., for the production of inoculum for larger-scale open
systems).
More recently, research and development has begun at several dozen
universities and private companies with total Federal, State, and
private investments in excess of $300 million in 2008-2009. In
industry, for example, Arizona Public Service began a DOE/NETL-funded
project to demonstrate CO2 capture by algae using a scalable
bioreactor integrated with a power plant.
APS's planned an algal biofuel production system that will use
modular photobioreactors, algae harvesting systems for dewatering and
oil extraction, inoculation systems, water/nutrient management, flue
gas/CO2 management, and instrumentation and controls.
In academia, for example, the State of Utah is investing over $6.5
million over 5 years in research at Utah State University on algal
energy systems.
Likewise, the Department of Defense has accelerated investment in
algal RD&D. The Defense Advanced Research Projects Agency (DARPA)
recently awarded two large contracts aimed at developing and fielding
large-scale production facilities with aggressive biofuel production
price targets by 2011. The Defense Energy Support Center recently
certified an algal oil-based biodiesel and demonstrated a Ford F450
driven solely from algal feedstock. Boeing Corporation has teamed with
multiple engine suppliers on similar lab and flight tests using algae-
derived jet fuel.
Clearly, the promise of algal energy systems is becoming evident
with growing energy, land, water, and carbon concerns over first- and
second-generation biofuels; aggressive renewable fuel standards;
growing acceptance of peak oil; and the oil price shocks of 2008. These
factors have moved algae energy systems to the forefront of energy
research.
Nevertheless, as noted by National Geographic: ``[T]here is no
magic bullet fuel crop that can solve our energy woes without harming
the environment, says virtually every scientist studying the issue. But
most say that algae . . . comes closer than any other plant . .
.''.\43\
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\43\ Feature Article: Biofuels. National Geographic. April 2009.
Available from: http://ngm.nationalgeographic.com/2007/10/biofuels/
biofuels-text/6.
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ALGAE ENERGY SYSTEMS--CHALLENGES AND R&D NEEDS
Though intermittent investments and progress has been made in
recent decades, the potential of algal energy systems has yet to be
fully realized. Unlike terrestrial crops cultivated and harvested for
centuries, recycling carbon through industrial or agricultural algal
energy systems that simultaneously produce biofuels is a relatively new
concept.
In open algal cultivation systems, a large quantity of land and a
large volume of water (that must be replenished) are required. Energy
from outside sources is needed to keep algae cultures stable, healthy
and suspended in their solution and invasive species, which often
infiltrate cultivation raceways and lower or destroy the desired
cultures, must be controlled.
In most enclosed cultivation topologies, capital costs for
materials and equipment associated with containing, mixing,
controlling, and maintaining cultures are prohibitive. In both open and
closed systems, nutrients and CO2 must be delivered and
introduced into the growth environment. Likewise, photosynthetic
saturation and surface shading limit the amount of sunlight that can be
used constructively to produce biomass.
After cultivation, the algae must be dewatered and dried prior to
oil extraction and fuel production. In each step along the way,
significant energy is required for processing. There are also remaining
questions regarding the emission of certain criteria pollutants and the
compatibility of resultant fuels with existing energy distribution/
storage infrastructure, engine systems, and extreme operating
environments. Generally, the challenges and R&D pathways associated
with algal energy systems can be divided into three subsystems each
having a number of issues that must be addressed before commercial-
viability is realized (Figure 9).
Figure 9.--Three Rationales for Algae Energy Systems
Upstream Challenges & R&D Needs
To overcome upstream challenges, there are a number of
CO2 and nutrient-related issues that must be addressed.
CO2 Quality and Delivery
For microalgal processes to be considered as practical methods for
CO2 mitigation, the costs of separating, compressing,
treating and delivering the CO2 must be reduced. Ideally,
CO2 could be used directly from an emissions source.
Unfortunately, that may be impractical. CO2 from a
combustion source is usually delivered at extremely low pressures and
cannot be sparged through any depth of water without compression.
Further, combustion flue gas contains numerous pollutants that would
not be permitted for wide-spread direct contact and dispersion at
ground level, including but not limited to mercury, particulate, sulfur
dioxide, nitrogen-oxides, and heavy metals (notably arsenic and
selenium).
The vast majority of CO2 in enhanced gas streams
(typically >4 percent by volume) is found in combustion sources. It is
also potentially the lowest cost source of CO2, even lower
than air, as future carbon restrictions may give non-trivial value to
removing CO2 from combustion gases. However, unless low-
pressure drop bioreactors are used that can return the remaining flue
gas and products of photosynthesis to the stack for atmospheric
dispersion; the options for using direct flue gas become limited. Such
options include using separated enhanced mass transfer reactors in the
flue gas train to put carbon species in the aqueous phase for transport
to a microalgal growth facility.
Separated and pressurized CO2 from combustion sources
may or may not be available at low-cost in the distant future, as plans
are being considered for a supercritical CO2 pipeline
network. This pipeline is being proposed to facilitate large-scale
geological sequestration of CO2 though such a network would
not be ready for operation until 2020. We envision the same
CO2 piping and distribution schemes could assist the
deployment of distributed rural algae farms far from urban sources of
CO2.
Further, the current cost of CO2 liquefaction would make
its use cost prohibitive under almost any circumstance. Making such
sources viable for interfacing with microalgal growth facilities will
require new research focused on gas cleanup, enhanced aqueous phase
mass transfer, and/or development of low-pressure drop growth chambers
where CO2 gases could be easily recovered and dispersed from
stacks.
CO2 Sources
Since CO2 is a major contributor to the cost of algal
mass cultivation, the CO2 from flue gas is being explored as
a viable option to reduce cost and achieve economic-viability. In
addition to CO2 utilization, algae can utilize
NOX and SOX, reducing overall plant costs by
bypassing scrubber requirements. A syngas-fed open pond can result in a
4- to 10-fold increase of algal biomass yields.
Though commercially-viable biofuels can be produced while recycling
CO2, NOX and SOX from flue gas,
several research challenges remain. For example, pipelines have been
negatively influenced by the interaction of SOX with
industrial-grade steel joints and pipes. Further, a mismatch of volumes
and rates of CO2 exhaust exists between large industrial
coal-powered operations and gas fixation through slower, lower
throughput processes involving algae. To address flue gas integration
issues, R&D is needed to address mass transfer limitations (balancing
CO2 supply with algae growth at minimum system pH
disruption), CO2 purity requirements for algae growth, and
analysis of the viability (technical and regulatory) of ground-level
sparging of CO2 or flue gas into the algal growth media
(whether for pond-raceway or bioreactor application).
Another source of CO2 is biorefineries used to convert
sugars into ethanol and other commodity products: A process made less
cost-effective because of the release of fixed carbon in form of
CO2 (e.g., for C6 sugar, carbon losses are 30 percent).
Thus, recycling and utilizing carbon released via CO2 will
increase process efficacy. Capturing and recycling of the
CO2 off-gas has been discussed in scientific literature, but
practical solutions are still applied on a limited scale and often
involve collection of CO2 by chemical absorption for pulp
and paper, and food and beverage manufacturing (e.g., low-value
product).
Fortunately, the volumes and rates of CO2 production by
the biological process of fermentation at biorefineries are more
closely matched to the rates of biomass production by algae. But
integrating algae energy systems with biorefineries is limited by site-
specific spatial and climate constraints. For example, past use of
circular ponds resulted in adequate biomass productivity and captured
up to 90 percent of the CO2, but required more space and was
susceptible to contamination and loss of productivity due to overgrowth
and harvesting problems. Closed bioreactors required less space, were
well suited for the growth of uncontaminated cultures, and allowed
easier harvesting; however, light limitations and temperature
fluctuations effected their productivity.
Analysis of these data and application of conventional agricultural
practices to biotechnological processes led the ASP to believe that
cultivation productivity could be optimized regionally through rotation
of cultures because algae differ in their illumination and temperature
requirements. For example, cyanobacterial productivity is higher at
2000-3000 lux and 30 C, whereas productivity of green algae are
optimal at 200-300 lux and 26 C. Therefore, R&D on proper selection of
cultivation system design and optimal crop rotation schemes are needed
to optimize the productivity of each system.
Nutrient Sources
Algae, like any other living organism, require nutrients to
sustain, grow and thrive. They require the same nutrients as
terrestrial plants (e.g., nitrogen, phosphorus, potassium and trace
amounts of iron and other metals, and other fertilizers). In nature,
these nutrients are readily available via biomass decomposition and are
stored in aqueous form in bodies of water. However, large-scale, land-
or ocean-surface based algal production facilities will likely need to
replenish these nutrients at rates exceeding the naturally occurring
levels. As man-made fertilizers are increasingly used for large-scale
algal production, the need for low-cost nutrient supplies will drive
further research.
Agricultural wastes provide a readily available source for low-cost
nutrients. By processing nutrient-rich retention ponds and waste
lagoons at concentrated animal feed operations, algae can be grown at
rates needed to achieve economic viability with the benefit of
significantly reducing water contamination from animal waste.
Similarly, other agricultural and lawn-based fertilizer runoff into
wetlands and streams also provides a source for algal nutrients, which,
if used, could minimize the uncontrolled algal blooms that have damaged
ecosystems in such places as the Gulf of Mexico and the Chesapeake Bay.
Therefore, significant research must be conducted to provide stable,
conditioned, and low-cost nutrient supplies to future algal production
facilities. Site-specific controls must be developed and implemented to
monitor and control key inputs to cultivation systems. Establishing
reliable nutrient sources for mass-algae production will require R&D
for the development and production of other lower-value phototrophs as
a feed source, which supports wastewater treatment, and the cultivation
of strains requiring lower nutrient input.
Cultivation Challenges & R&D Needs
In addition to overcoming upstream subsystem challenges, there are
a number of biological, geographical, environmental, and site-specific
issues that influence algae cultivation.
Organism Selection
With over 40,000 species, algae and cyanobacteria exist in many
forms that can be optimized to grow under specific conditions to yield
desired products. These organisms evolve naturally and can be
engineered to meet specific goals. Harnessing the power of these
organisms to convert CO2 into useful products is
commercially practiced for the production of neutraceuticals and other
valuable goods. The production of transportation fuel, which is a
relatively high-volume, low-value product, will require additional
research and development to identify or create robust organisms that
grow and accumulate lipids rapidly under diverse environmental
conditions. It is unlikely that the ideal production organism has been
identitified, thus bio-prospecting is still a valuable approach.
The creation of modified microorganisms that produce valuable
commercial products previously derived from petroleum is well
established. For example, Genencor and DuPont received the U.S.
Environmental Protection Agency's 2003 Presidential Green Chemistry
Award for the development of a process to make 1,3 propanediol (PDO)
from renewable resources instead of petrochemicals. The process uses a
strain of Escherichia coli that was engineered to produce (PDO) from
glucose.
Despite some commercial successes, basic research is still needed
to improve the process of creating synthetic microorganisms. Genetic
modifications are inherently unstable due to the metabolic costs and
toxicities associated with the products produced as a result of the
modifications. Many engineered microbes lose their ability to generate
product within 1 day of growth unless the modifications are maintained
with expensive antibiotics. Research to develop general methods and
principles for stabilizing genetic modifications is critical to
advancing the practice of metabolic engineering and using this tool to
capture carbon more effectively. Further, the production of materials
by microbial biotechnology requires a deeper understanding of the
biochemistry involved at both the physiological and/or genetic levels.
It is most important to understand the associated regulatory
constraints.
The production of triacylglycerides (TAG) as a precursor of
biodiesel or biojet fuel will be no different. There is a paucity of
information on algae in general and almost none on algae poised to be
considered as production organisms. Thus, further research is needed to
strengthen our understanding of algae.
Growth Systems
Although a discussion of all algae cultivation techniques is beyond
the scope of this document, two primary architectures for cultivating
algae exist: open ponds and enclosed reactors.
Open ponds most closely resemble microalgae's natural environment
and are relatively inexpensive to build and operate (Figure 10). These
ponds, however, possess significant drawbacks, including low algae
production on surface areas, inability to strictly control the algae
environment, water evaporation, low volumetric cell densities, and the
risk of contamination by predator strains.
Figure 10.--Open Algal Cultivation System
In open raceways, algae are typically suspended at cell densities
of less than 2 grams per liter of aqueous solution. Unfortunately, low-
cell density cultures require extensive energy to keep algae properly
suspended, healthy, and well-mixed. Some estimates report that over
one-half of the energy needed during the cultivation process in open
ponds can be attributed to mixing and maintaining algae in
suspension.\37\
For these reasons, considerable research is now aimed at devising
low-cost enclosed systems (Figure 11). Relative to open ponds,
photobioreactors possess a lower risk of contamination, the ability to
better control and regulate nearly all of the important process
parameters, a reduced risk of losing CO2 or water to
evaporation, higher reproducibility, greater productivity (which
reduces land requirement), and reduced harvesting costs (due to the
higher cell densities achieved).
Figure 11.--Closed Algal Cultivation System
Conversely, the capital and operating costs associated with
photobioreactor-based cultivation systems are significantly greater
than those for open ponds. When operating at higher cell densities,
costs associated with the following become issues: thermal management
requirements, oxygen accumulation, mixing, and CO2
management. Biofouling and deterioration of optical materials occur
over time. Moreover, cell damage due to shear stress from rigorous
mixing remains a concern.
Regardless of the cultivation system approach, there are 10
published essential operational imperatives for successful deployment
of algae energy systems (Table 2).
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Table 2.--The Ten Essentials for Algae Energy Systems--A2BC Carbon
Capture
ALGAE ENERGY SYSTEMS HAVE THE POTENTIAL TO BECOME ONE OF THE PLANET'S
LARGEST INDUSTRIES. FOR THIS INDUSTRY TO BE SUCCESSFUL, CORE
TECHNOLOGIES MUST FULFILL 10 ESSENTIAL REQUIREMENTS
Flexibility in Cultivation and Harvesting.--High algal product
value requires precise control of cultivation parameters to support
diverse crop species and varying harvesting protocols. Advanced algae
variety development will be paralleled by the evolution of process
pathogens and consumptive invaders. Control and flexibility in the
growth environment and harvesting is critical.
Long Term Biologic Stability.--High productivity, profitability,
and industrial relevance require uninterrupted PBR operation over
periods of 1 year or more. Threats of bacteriological infection, virus
infection, weed algae invasion, and rotifer population explosions must
be sustainably managed in order to provide industrial reliability
energy and food source technology.
Efficient Temperature Control.--Broad global deployment requires
high efficiency utilization of water and energy to control algae farm
temperatures. Algal photosynthesis captures at most only 5 percent to
10 percent of the solar energy spectrum. Accordingly, all energy and
water expended in heating or cooling PBRs will greatly impact the
overall energy and water balance.
Functionally Unlimited Scalability.--Algae industry infrastructure
construction and operations must be viable at any scale using only
sustainable and abundant global resources. Once the algae industry is
set in motion via the engine of commerce it will be difficult to stop,
making it essential that this growth expansion occurs in a planet-
healthy and sustainable fashion.
High Areal Light Productivity.--High algal biomass productivity per
square meter of sunlight is required to minimize land area thereby
controlling high technology infrastructure costs. High technology
infrastructure elements are required to maximize the productive growing
season, crop value, and industrial reliability that will be required
for algae farms to propagate.
Frequent Cellular Re-Suspension.--During cultivation the entire
algal cell population must be kept in fluid suspension to provide each
cell sufficient access to nutrients and light so that a state of
generalized maximum productive health is maintained. Periodic re-
suspension of settled pockets of stranded cells is required to prevent
cell death, bacterial growth and PBR crashes.
Frequent Biofilm Management.--Biofilms are readily deposited on the
light transmission and containment surfaces of all PBRs. Sustainable
management of biofilms is required to maximize light transmission
efficiency and minimize deleterious bacteriological infections.
Biofilms can provide synergistic benefits and extra biomass
productivity when well managed.
Efficient Gas and Nutrient Management.--Every kg of algal biomass
produced will require more than two kg of CO2 and plant
nutrients to be fed into the algae PBRs. Energy consumption must be
minimized in handling these quantities of CO2; and
especially using flue gas. Sustainable sources and process recycling
strategies for the vast quantities of nutrients are mandatory.
Industrial Reliability.--The algae industry must work in tandem
with upstream and downstream industry partners to convert constant
process flows of CO2 into feedstocks, refine them into
products and distribute them to waiting markets. There is no room for
unreliability or disruption due to weather, infection, regulation,
terrorism, or scalability challenges.
Politically Deployable.--There is no more fundamental requirement
for an algae technology than to be politically deployable on a massive
industrial scale providing broad local benefits. Deployment and
operational plans must withstand the muster of planning boards,
regulatory agencies, funding agencies, lending banks, and environmental
interests.
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Water Use Issues During Cultivation
Of all the issues facing aquatic algae cultivation, adequately
addressing water issues may represent the biggest challenge of all in
open cultivation systems. Simply put, aquatic species need water to
grow. While the consumption of water by phototropic organisms is
essential for growth, it is usually less than the amount of water lost
through evaporation in open raceway cultivation systems.
This problem is exacerbated by the fact that phototrophic organisms
need sunlight for photosynthesis. Generally speaking, the more sunlight
available, the more algae produced. However, as the average solar
insolation increases, so does evaporative losses in open systems.
Unfortunately, areas with high solar insolation (e.g., southwestern
United States) are typically plagued by a shortage of fresh water.
The lack of fresh water can be overcome by growing algae which is
native to salt water, brackish, or wastewater. For example, transported
ocean water could provide the basis for large-scale algal ponds in the
American West. However, because the rates of water evaporation are
significant, a supply of fresh (or very low salinity) water remains
critical. Because salt remains in the ponds as water evaporates,
addition of more saline water would lead to an increase in salinity
levels, endangering algae, or reducing their productivity. Further,
salt-water intrusion could lead to adverse effects on the quality of
surface and ground water. While these problems are surmountable, they
represent an engineering and biological challenge for future large-
scale algal production. Solutions could come from development of algae
strains capable of living in hyper saline waters (note, research has
already begun) or through the development of low-cost partial
desalination processes (e.g., membrane filtration).
Most experts also believe that early algal production facilities
will depend heavily on wastewater reuse both for nutrients and to
conserve/reclaim fresh water (discussed earlier). Regions with less
solar insolation and more fresh water could find economically
competitive niches in algae production alongside regions with abundant
sunlight and limited fresh water. Ultimately, the issue of water will
force developers to evaluate trade-offs between:
--The cost of supplying of suitable water vs. the availability of
other cultivation inputs (e.g., nutrients, CO2, and
sunlight); and
--Low-cost open cultivation systems that rely on passive thermal
management through evaporative cooling vs. more expensive
closed bioreactors that conserve water but require, for
example, active thermal management.
While no one knows how these issues will be resolved, the
development of regional strategies leading to a national network of
distributed algal production facilities seems likely. To reduce water
consumption, it is also imperative that research continue on pathways
to improve volumetric yield (i.e., grams of algae harvested per liter
of aqueous solution). As volumetric yield increases, the amount of
water needed to produce the same amount of biomass decreases.
Unfortunately, surface-shading increases as cell density increases so
inexpensive methods to dilute sunlight spatially over a larger surface
area also must be developed.
Figure 12.--Technical Challenges on R&D Pathways for Cost-effective
Algae Energy Systems
Land Use Issues
The amount of land available for siting algae energy system
projects represents a significant challenge. Though algae grow
extremely fast in comparison to higher plants and, therefore, require
far less area to grow an equivalent amount of biomass, to overall
conversion efficiency of sunlight to biomass remains relatively low
(typically less than 4 percent).
Table 3 provides a first-order estimate of the amount of surface
area required to recycle carbon from various point source and
distributed carbon emitters. The data does not take into consideration
externalities such as the area needed for roads and processing
equipment and assumes optimistic algae yields of 40 g/m2/day (dry
weight) and 50 percent of the biomass as carbon.
TABLE 3.--SURFACE AREA EQUIVALENT REQUIRED TO RECYCLE CARBON FROM
VARIOUS POINT SOURCE AND DESTRIBUTED CARBON EMITTERS
------------------------------------------------------------------------
Approximate Area Rough Area
Carbon Emitter Required Equivalent
------------------------------------------------------------------------
Ethanol plant (50 million gal/ 100 acres......... \1/3\ of the
yr). National Mall
Typical industry boiler......... 800 acres......... 2 National Malls
Power plant (500 MWe)........... 35,000 acres...... Washington, DC
U.S. diesel vehicle fleet....... 5,000,000 acres... \1/10\ of North
Dakota or Utah
U.S. coal power plants.......... 22,000,000 acres.. Indiana or Maine
(\1/100\ of the
U.S.)
------------------------------------------------------------------------
From these estimates, it is clear that large-scale algal energy
systems, though dramatically less area-intensive than oilseed crops
such as soybeans (Figure 7), will require significant amounts of land.
When sited near point source emitters (e.g., ethanol plants or
industrial boilers), nearby land must be relatively flat (less than a 2
percent slope) to avoid cost-prohibitive site preparation. Large areas
covered with open ponds or enclosed photobioreactors will inevitably
disrupt the natural habitat of native wildlife (discussed in section
V.B.5). For these reasons, significant research is needed to develop
both biological and engineering pathways to improve area yield.
In coastal regions of the United States and Europe, land use issues
have driven some of the research community to contemplate ocean-
deployed enclosed cultivation systems where unused areas of ocean are
readily available, seawater is both abundant and provides thermal
stability, and natural wave action that can be used to aid in mixing.
Though the challenges differ from land-based architectures, ocean-based
systems have a host of biological, engineering and environmental
challenges that must be addressed (e.g., new problems related to ocean
wildlife impacts, cultivation, harvesting, and processing
infrastructure, access, shipping, durability, and control).
Wildlife Impact Issues
In recent years, there has been increasing interest in siting
large, industrial-scale renewable electric generation facilities
similar in size and scope to those envisioned in the western United
States for algal energy systems. As a result, the Western Governors'
Association (WGA) and U.S. Department of Energy initiated the Western
Renewable Energy Zones (WREZ) initiative in 2008. The WREZ initiative
is designed to identify areas in the West with significant renewable
resources to accelerate the development of renewable energy. One of the
renewable technologies included in the study is large-scale solar
thermal electric generation systems. Though there are several
differences, this technology has many of the same needs as algal energy
systems requiring large-tracts of accessible flat land with significant
solar insolation.
In parallel to the WREZ process, WGA also established the Western
Governors' Wildlife Council (WGWC) to manage the implementation of the
WGA Wildlife Corridors report. The mission of the WGWC is to ``identify
key wildlife corridors and crucial habitats in the West and coordinate
implementation of needed policy options and tools to conserve those
landscapes.''
As the WREZ process unfolds, resolving inherent conflicts between
wildlife corridors and renewable energy zones has emerged as arguably
the biggest hurdle to Western U.S. renewable energy development. The
same series of issues will need to be addressed in early deployment of
algal energy systems.
Other Permitting, Policy and Acceptance Issues
Another major obstacle for algal growth systems, especially at
large-scales, will be permitting issues. In addition to the
environmental impact of the footprint needed for significant
CO2 mitigation and biofuel development, the issues of water
quality, gaseous discharge, contamination of regional waterways by salt
water, and invasive or genetically altered species, are all non-trivial
considerations.
Efforts must be made to work with local, State and Federal
officials to develop streamlined environmental impact assessments and
permitting reviews. Action will be needed sooner, rather than later,
because this is essentially uncharted territory for environmental
protection boards and agencies. This suggests the need for aggressive
actions to develop new regulatory and policy guidelines.
Efforts are already underway to incentivize development and
integrate algae into the U.S. renewable fuels portfolio. For example,
the Energy Independence and Security Act of 2007 added algae to the
list of feedstocks qualifying as renewable biomass, which qualifies it
to help meet Federal Renewable Fuel Standards. In the near future,
standards organizations must begin developing certification and
qualification processes so end-users can justify switching to algae-
based fuels and co-products.
Downstream Challenges and R&D Needs
In addition to overcoming issues related to upstream and
cultivation subsystems, there are a number of engineering challenges
related to cost-effective downstream processing.
Harvesting/Drying
The isolation of algae from their culture medium is challenging for
two main reasons: (1) their small size (typically 3-20 microns); and
(2) the low concentrations in which they can be grown (typically less
than 2 g algae/L water). A compounding problem is the sensitivity of
the cell walls in many species to damage in high shear processes (e.g.,
centrifuging), which can result in leaching of the cell contents. To
date, three main methods have been developed for algal isolation:
filtration, centrifuging and flotation. Filtration is normally
performed using a cellulose membrane and a vacuum being applied in
order to draw the liquid through the filter.\44\ Although this method
is simple, the membrane tends to become clogged, rendering the process
extremely time consuming. Centrifuging, in a continuous or semi-
continuous process, appears to be more efficient in this regard;
however, it is extremely energy intensive and cannot readily be scaled
to very large applications. The third option, flotation, uses a bubble
column. Gas is bubbled through the algae suspension, creating a froth
of algae that can be skimmed off. Several variants of this process have
been published.\45\ \46\ \47\
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\44\ Clark WJ, Sigler WF. A method of concentrating phytoplankton
samples using membrane filters. Limnol. Oceanogr. 1963;8:127-129.
\45\ Guelcher SA, Kanel JS. U.S. Patent 5,776,349. 1998.
\46\ Guelcher SA, Kanel JS. U.S. Patent 5,910,254. 1999.
\47\ Borodyanski G, Konstantinov I. U.S. Patent 6,524,486. 2003.
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The extent to which the water content of the resulting algae paste
must be reduced depends largely on the method used for the subsequent
oil extraction step. Ideally, drying to ca. 50 percent water content is
required in order to produce a solid material that can be easily
handled. Given the fact that algae paste, as obtained by centrifuging
or filtering, typically consists of ca. 90 percent water, drying algae
is an energy intensive proposition. Consequently, solar drying is the
main approach that has been considered to date.\48\ Solar drying is
used commercially for drying grains and timber, and is inherently
inexpensive; however, drying large quantities of algae would
necessitate the use of a considerable areas of land.
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\50\ Kadam KL. Microalgae Production from Power Plant Flue Gas:
Environmental Implications on a Life Cycle Basis. Department of Energy,
National Renewable Energy Laboratory. NREL/TP-510-29417, 2001, Golden,
CO.
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Considering the methods available for algae harvesting, it is clear
that more research is needed in order to improve efficiency and to
reduce the required energy input. Flocculation appears to be a
promising alternative to the technologies described above, providing
that the necessary flocculants are either very inexpensive or can be
recycled. Rather than using solar energy for subsequent dewatering/
drying of the algae, a better approach might be to develop processes
that make use of low-grade waste heat from an existing CO2
source (e.g., power plant).
Oil Extraction and Product Generation
Oil extraction from algae is a highly debated topic: Several
methods exist and each has its advantages and drawbacks.\49\ The three
primary methods applied to date are (1) expeller/press, (2) solvent
extraction, and (3) supercritical fluid extraction. The expeller/press
method, while simple, requires dried algae and typically recovers ca.
70-75 percent of the oil. In contrast, solvent extraction is more
complex but is able to recover nearly all the oil (>95 percent). If wet
algae are used, then a water miscible co-solvent is necessary; this co-
solvent is usually required in order to lyse the cells (i.e., open the
cells to expose their contents), although other methods are available
to do this (e.g., sonication or acidification). Finally, supercritical
fluid extraction uses supercritical CO2 as the extraction
solvent. While this method is able to recover almost 100 percent of the
oil, it requires high-pressure equipment.
---------------------------------------------------------------------------
\49\ Oilgae Digest [Internet]. Copyright 2006 [cited April 2009].
Available from: http://www.oilgae.com/algae/oil/extract/extract.html.
---------------------------------------------------------------------------
Thus, the recovery of algae oil is an area where there is a
pressing need for research. Solvent extraction appears to be the
leading approach, given that it is suitable for use with wet algae.
However, several of the literature methods use complex solvent mixtures
and/or environmentally unfriendly chlorinated solvents, while overall
there is a relative paucity of published data.\50\ Complicating the
situation is the fact that optimization of the extraction process will
likely depend on a number of variables, such as the algal water
content, and the ease with which the cells can be lysed (which is a
function of the species of algae). The development of a generic set of
principles that can assist in this optimization process is a pressing
need.
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\50\ Guckert JB, Cooksey KE, Jackson LL. Lipid solvent Systems are
not equivalent for analysis of lipid classes in the microeukaryotic
green alga, Chlorella. J. of Microbiological Methods, 1989;8:139-149.
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As with vegetable oils and animal fats, options exist for the
production of biofuels from algae oil: (1) transesterification with
methanol to give to fatty acid methyl esters (biodiesel); and (2)
conversion to hydrocarbon fuels (e.g., jet fuel or diesel).
Transesterification is a well-established technology, while the
catalytic conversion of triglycerides to hydrocarbons via hydrotreating
has been recently commercialized.
In most scenarios, the solid recovered from the oil extraction
process (algae cake) will be used either as animal feed, as a feedstock
for fermentation to ethanol, or thermo-chemical conversion into other
fuels. The ability to use the cake as feed will depend on its
nutritional content and whether there is contamination by heavy metals
(e.g., Hg and As). Further, the oil extraction process can effect the
nutritional content: If the cells are lysed in the presence of water,
there is the risk that a significant fraction of the nutrients in the
cell will be leached into the aqueous waste phase and lost.
JP-8 military jet fuel (i.e., the military version of civilian-
grade Jet A-1 turbine-engine fuel) can be produced from the algae oil.
Algae can also be cultivated to serve many other commercial products
including: (1) Animal feed, (2) bioplastics, (3) paints, dyes and
colorants, (4) lubricants, (5) cosmetics, (6) neutraceuticals, and (7)
pharmaceuticals. Aside from co-products, algal carbon recycling
processes will likely find increased use in co-located pollution
control applications (e.g., fertilizer runoff reclamation and sewage
treatment).
Thus, in the area of algal oil processing to fuels, the main
research requirements concern the production of hydrocarbon fuels.
Research needs include the optimization of catalysts for hydrotreating
algal oil, and the development of processes that do not require
hydrogen (e.g., those based on cracking or hydrolysis to fatty acids
followed by decarboxylation). These latter processes have the advantage
of being amenable to on-site oil processing. Simultaneously, if the
algae cake is to be used as animal feed, research will be required in
order to ascertain the extent to which algal bio-accumulate heavy
metals present in flue gas (e.g., from coal-fired power plants) and, if
possible, identify species which show little or no tendency towards
bioaccumulation. There are also challenges and research needs related
to ensuring compatibility of resultant fuels with existing energy
distribution/storage infrastructures, engine systems, and extreme
operating environments.
Cross Cutting Technical Challenges & R&D Needs
Materials
As with any large-scale technological development effort, advanced
coatings and materials are needed to improve various component- and
process-level functions. In certain cultivation systems, new polymers
that enable the creation of super-hydrophobic coatings capable of
reducing hydrodynamic drag and cleaning requirements are needed, as are
low-cost, spectrally selective thin films used to reject infrared and
ultraviolet solar radiation. In some cultivating environments, new
optical components should be considered (e.g., planar waveguides) to
improve areal and volumetric yield through enhanced sunlight
distribution and utilization.
In downstream processing systems, new materials and coatings will
be necessary to address compatibility issues with energy distribution/
storage infrastructures, engine systems, and extreme operating
environments.
Process Control and Monitoring
There are a number of complex challenges related to process control
and monitoring of subsystems and at the interfaces between each
subsystem. Similar to other industries, this will require the
development optimization of a wide variety of pumps, mixing apparatus,
thermal management systems, new instrumentation, control systems, and
process algorithms.
Systems Engineering and Integration
There are two primary-systems integration issues related to algal
energy systems. The first is within the algal cultivation facility
itself where integration of such elements as sunlight transmission
systems, nutrient delivery systems, harvesting systems and pH
management systems is needed. This is complicated by higher-level
system integration issues (i.e., the cultivation system coupling with a
CO2 source and the integration of the microalgal growth
facility with downstream use/processing systems). For example, an
algal-based system could be used to recycle the CO2 emitted
from a coal-to-liquids plant that, in turn, uses the residue from the
algae as a gasification feedstock (with the coal) to produce liquid
transportation fuels. Another example would be to use algal energy
systems to recycle CO2 from bio-digesters, use nutrient-rich
digester sludge to fertilize algae, and use the waste matter, after
processing high-value products from the algae, as an input to the bio-
digester to make additional biogas. These examples point to integration
issues of significant scale.
Economic Challenges
Cost estimates for large-scale microalgae production and carbon
recycling has evolved considerably since the 1970s and 1980s. A
powerful conclusion from these early analyses was that there was little
prospect for any alternatives to the open pond designs, given the low
cost requirements associated with fuel production and limited knowledge
of externalities related to extensive water use and wildlife impacts.
At that time, the driving cost factors were considered to be
biological, and not engineering- or environmentally-related. The
analyses pointed to the need for highly productive organisms capable of
near-theoretical levels of conversion of sunlight to biomass. Even with
aggressive assumptions about biological productivity, the studies
reported that projected costs for biodiesel were much higher than
petroleum diesel fuel costs.
Today, the economics of algal energy systems is known to be more
complex and evolving rapidly. For example, new inputs to cost models
including carbon recycling and environmental reclamation opportunities
must be considered.
Regardless of technological and biological breakthroughs or carbon
mandates, the fact remains that the commercial marketplace will not
have an appetite for funding capital-intensive energy projects unless
the risk-return ratio is acceptable to debt and equity financiers. A
number of companies and government organizations have recently assessed
different input models and production designs and offered estimates of
costs for algal systems. The most popular of designs recently analyzed
include stand-alone open ponds, open raceways, and closed
photobioreactor cultivation systems.
Generally, these assessments have taken a first-order look at
capital and operations and maintenance (O&M) costs. The capital costs
are usually divided into costs associated with algal biomass growth,
harvesting, dewatering, and algal oil extraction systems. In addition,
there are more traditional project costs to include (e.g., engineering,
permitting, infrastructure preparation, balance of plant, installation
and integration, and contractor fees). O&M costs generally include
expenses for nutrients (generally N-P-K), CO2 distribution,
water replenishment, utilities, components replacement, and labor
costs. In addition to capital and O&M costs, the costs of the land
(owned or leased) must be considered.
Publicly released data reveal significant variations in capital and
O&M costs. Some entities have reported capital costs as low as $10k/
acre, while others have shown costs approaching $300k/acre. These wide
variations in costs are also seen in O&M projections. For example,
Sandia National Laboratories and National Renewable Energy Laboratory
recently conducted an assessment of previously reported, open
literature and concluded that average capital costs were roughly $57k/
acre (with a 1-sigma standard deviation of $72k/acre) of utilized
surface area and corresponding annual O&M costs were $27k/acre
(standard deviation of $25k/acre).\51\ This data represents over a
dozen different types of open and closed architectures. Some of the
data was older and does not reflect the results being achieved today.
It is challenging, therefore, to estimate the costs of such systems.
This uncertainty has been driven by three fundamental factors: (1)
There are no large-scale commercial algal biofuels production systems
with which to develop and substantiate the data; (2) the companies
developing new technologies and architectures are very protective of
their detailed financial data; and (3) because of the immaturity of the
market, there are many unknowns coupled with a number of companies
making aggressive claims.
---------------------------------------------------------------------------
\51\ Phillip T, Pienkos. Historical Overview of Algal Biofuel
Technoeconomic Analyses. National Algal Biofuels Technology Roadmap
Workshop, December 9-10, 2008.
---------------------------------------------------------------------------
Instead of forecasting the likely capital and O&M costs for a given
architecture and its reported yield, this report assesses what a
project would require in terms of cost to achieve commercial viability.
That is, using traditional discounted cash flow analyses, along with
justifiable assumptions on yields and revenues from algal biomass; what
would the capital and O&M costs need to be to satisfy the demands of
those financing an algae biofuels project?
Figure 13 illustrates the results. The vertical axis represents the
total installed costs of a project including of the cost of the land,
capital equipment, installation, and other traditional project costs as
described earlier. The land accounted for here represents the utilized
surface footprint of algal biomass growth systems undergoing
photosynthesis, not the gross land area. This approach likely
underestimates the true land costs as there will be tracts of acreage
(sometimes as much as 2X) not directly contributing to photosynthesis,
but instead providing for access ways, harvesting, dewatering, oil
extraction, piping and plumbing, storage, laboratory space, and other
functions.\52\ The horizontal axis represents O&M costs as discussed
earlier.
---------------------------------------------------------------------------
\52\ Hassannia J. Diversified Energy Corporation.
SimgaeTM Algal Biomass Production System. [cited April
2009]. Available from: www.diversified-energy.com/simgae.
Figure 13.--Project Economic Analyses Used to Assess the Viability of
---------------------------------------------------------------------------
Commercial Algae Systems
The diagonal lines on the graph depict what are called zero net
present value (NPV) curves. These lines represent what a project would
need to achieve in total installed and O&M costs to be economically
viable from a commercial market perspective. Based on the economic
assumptions shown in the figure, projects that achieve costs on or
below these NPV lines will provide the required returns. If a project
falls on the line, it will return 30 percent (average) per annum to
equity providers and 12 percent (average) per annum to debt providers
over the 20-year project life. If a project is above the line, it will
fail to meet these required returns. If below the line, a project will
provide additional profit.
Note that the orange line represents a yield of 25 grams/m \2\ per
day and a sales price of $200 per dry ton of biomass produced. While
yield projections are a subject of major debate and speculation, this
productivity level represents what most experts would consider as a
reasonable and substantiated expectation using today's technology; one
that is plausible for future large-scale algal production systems with
sustained operations. Likewise, $200/ton is a metric often quoted and
likely represents the low-end of revenue potential by simply assuming
$0.10/lb, which can be considered the median for estimates of algal
biomass usage as a high antioxidant animal or fish feed (generally
quoted as somewhere in the range of $0.07-$0.13/lb).\53\
---------------------------------------------------------------------------
\53\ Gieskes TE. Organic Fuels Holdings, Inc., Integrated
Biorefineries [Internet]. March 2008 [cited April 2009]. Available
from: http://www.organicfuels.com/library/art/
Organic%20Fuels%20Presentation%20FO%20Lichts%202008%2004%2023.pdf.
---------------------------------------------------------------------------
Thus, the solid orange line illustrates the magnitude of the
challenge. Very few organizations have discussed total installed costs
of less than $40k/acre. For reference, the Sandia and NREL data point
is plotted on the figure as a red circle.
When O&M costs are factored into the analyses, a project must reach
the orange line, which lowers total installed cost hurdles. For
example, fertilizer such as N-P-K costs approximately $300-$400/ton. It
is reasonable to assume that an average algae strain will require 1 ton
of fertilizer for every 3 tons of dry algal biomass produced. At a
productivity of 25 grams/m \2\-day, annual fertilizer costs alone would
easily equate to over $4k/acre unless inexpensive nutrient-rich
wastewater were used. Very sizeable energy costs also need to be added
for pumping and flowing water, capturing and delivering CO2,
and harvesting the algae and extracting the oils. Finally, labor, water
composition, and hardware replacement costs need to be considered. It
is easy to see how O&M costs alone can derail a project's viability
regardless of how low (even to zero) total installed costs become, as
evidenced by the Sandia/NREL O&M average being off the graph's scale at
$27k/acre-year.
The solid green NPV line represents a more reasonable analysis for
algae biomass systems focused on biofuels production. In this case,
algae being grown contain 25 percent total lipid content, of which 80
percent is extractable and of the desired characteristics (i.e., non-
polar lipids) for biofuels production. Twenty-five percent of total
lipid content represents a reasonable and substantiated claim for an
alga strain that can be grown abundantly, at large scale, in outdoor
systems today. In this scenario, for every ton of algae produced, 400
pounds of oils for biofuels and 1,600 pounds of biomass for animal/fish
feed would then be available. Assuming $2/gallon for the oils sold, and
$0.10/lb for the remaining biomass, this equates to roughly $266/ton
for the algae produced. Based on the earlier discussion of O&M costs,
one can quickly see that even at $266/ton the economics appear very
challenging given the state of the industry today and for the near-term
future.
Also note that the NPV lines such as the solid blue or dashed green
line, begin to show an entirely different and much more plausible story
for the potential of algal biofuels. The blue line represents achieving
almost twice the dollar/ton sales price of algae biomass discussed
previously. How might this be possible? Using the same assumptions as
earlier, algal oil would have to be sold for prices in excess of $6/
gallon, which could be possible should corresponding petroleum prices
reach these levels. Alternatively, this could be achieved by focusing
on strains and production architectures that extract other, higher-
value components from the algae such as nutraceutical products. The
dashed green curve represents the same assumptions as the solid green
line, but in this case assumes achieving productivity numbers twice
that deemed reasonable today (i.e., 50 grams/m \2\-day).
The eventual answer will likely be a combination of greater
productivity coupled with a focus on co-generation of higher value
products from algae and carbon credits. In addition, emphasis needs to
be placed on reducing O&M costs across all elements of the algae
production value chain.
By assessing the viability of algae projects from a true market
perspective, it is apparent that total installed and O&M costs will be
a major hurdle to future commercialization. Technologies must be
developed to reduce costs and increase yields. This can be accomplished
only through a focused, comprehensive, and well-funded R&D program. In
parallel, the industry must consider business models that not only look
at the bioenergy potential of algae through the transportation fuels
market, but also consider carbon recycling, wastewater treatment, and
higher-value products in order to achieve economic viability. Finding
niche markets that take advantages of these opportunities will be
important in the early phases of this promising, yet challenging
industry.
Carbon Life-Cycle Assessment
It is critical for the development of algal production technologies
that accurate, industry-wide methodologies exist for estimating of
carbon lifecycle impacts. Because this industry is in its infancy,
these impacts are poorly understood and present significant hurdles for
various approaches to the bio-fixation of CO2 using algae.
Likewise, there remains a wide array of unanswered issues related to
large-scale algae production on human health, wildlife, and the
environment. If problems arise during the implementation stage of an
algae-based biofuel production process, they may be costly to correct
(if, indeed, a correction is even possible). Therefore, future LCA
activities should build upon the limited studies that currently
exist,\48\ \54\ \55\ but not be dependent on either the fundamental
datasets or results presented.
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\54\ Aresta M, Dibenedetto A, Barberio G. Utilization of macro-
algae for enhanced CO2 fixation and biofuels production:
Development of a computing software for an LCA study. Fuel Processing
Technology. 2005;86:1679-1693.
\55\ Life Cycle Assessment: Principles and Practice. Available
from: U.S. Environmental Protection Agency, Office of Research and
Development, National Risk Management Laboratory. EPA/600/R-06/060,
2006, Cincinnati, OH.
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The earlier analyses all suffer from a few fundamental issues that
limit their usability for the present and future development of algae
based biofuel production. At a fundamental level, none of the available
LCAs direct their focus robustly at the production of algae in a manner
that would lead to sensible process development activities.
In order to achieve a more robust and useful assessment tool, a
base LCA should: (1) Define the metrics to be used for analysis of
future LCA activities in the base LCA to ensure an equivalent
comparisons; (2) not become fixated on a particular technology or
method of production to allow for flexibility as new technologies are
developed; and (3) work in tandem with an energy and economic study so
that environmental, energy, and economic costs can be directly
correlated. Recent energy and economic studies of note include those of
Benemann and Oswald \56\ and Campbell et al.\57\
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\56\ Benneman JR, Oswald WJ. Systems and economic analysis of
microalgae ponds for conversion of CO2 to biomass, US DOE
[Internet]. 2004 [cited April 2009]. Available from: USDoE.http://
govdocs.aquake.org/cgi/reprint/2004/915/91550050.pdf.
\57\ Campbell PK, Beer T, and Batten D. Greenhouse gas
sequestration by algae-energy and greenhouse gas life cycle studies,
CSIRO [Internet]. 2009 [cited April 2009]. Available from: http://
www.csiro.au/resources/Greenhouse-Sequestration-Algae.html.
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Algal Biomass Organization (ABO) Architecture for Green House Gas-
Life Cycle Assessment (GHG LCA) Computation.--During 2007-2008, an
international effort, primarily facilitated by U.S. industry and
academia, culminated in the formation of the non-profit Algae Biomass
Organization formed to ``promote the development of viable commercial
markets for renewable and sustainable commodities and specialty
products derived from algae.'' ABO has taken a leadership role in
facilitating public and private interactions, framing the major issues
and opportunities related to algae energy systems, educating policy
makers, media and others, and serving as an emerging national and
international trade association. The following summarizes ABO's
Technical Standards Committee work to determine algae's unique role in
energy security, climate, and sustainability with a specific focus on
GHG LCA computations.
The Committee first defined mechanisms where algal industry based
products reduce GHG emissions through three pathways:
--Substitution.--Algal fuels, feeds, and chemicals may be substituted
for conventional alternatives, with multiple routes to
emissions reductions, for example:
--Algal fuels may directly displace fossil alternatives.
--Algal fertilizers may reduce conventional, GHG-intensive
production.
--Algal animal feeds may reduce emissions via indirect land use
change.
--Novel algal products may enhance other mitigation strategies. For
example, building thermal efficiencies may be substantially
enhanced with algal-derived phase changing materials.
--Sequestration.--Long-lasting algal products (including plastics,
stabilized waxes, and humic acid) may sequester carbon away
from the atmosphere for extended periods.
--Photosynthetic uptake.--Algal soil amendments may enhance
CO2 uptake and storage by terrestrial plants (e.g.,
fertilizers, soil tackifier, and char additives).
Second, though greenhouse gas LCA protocols such as ISO 14040:2006
were previously developed (through ABO), the algal industry plans to
incorporate process elements that have not yet been fully defined or
analyzed. These unique elements generally fall within the industry
segments of cultivation, harvest and valorization shown in Figure 14
and highlighted with a red boundary. ABO is recommending development of
data and analyses methods for life-cycle analysis that focus on the
unique industry-specific details related to inputs, outputs and
processes within the denoted architecture boundary.
Figure 14.--Algae Biomass Industry--Segment and Products
Third, ABO is recommending that the parameters shown in Table 4 be
quantified to assess the overall GHG lifecycle impact of specific algae
cultivation, harvesting, and valorization processes. Different algal
process types, output product mixes, and methods of using input
resources can only be evaluated consistently and comparatively when the
LCA calculations are based on a common set of parameters. The
Committee's work continues, as it is assisting in the task of refining
the parameter descriptions and recommending appropriate computational
methodologies.
TABLE 4.--PARAMETERS TO BE QUANTIFIED
------------------------------------------------------------------------
------------------------------------------------------------------------
Algal Process CO2 Credit.................. CO2 feedstock flow into the
system.
Algal Process GHG Credit Debit....... Nitrous oxide & other GHG
emissions.
GHG impact of specific algal
products.
Indirect land use (iLUC)
effect.
Water vapor emissions GHG
effect.
Algal Process GHG Debits.................. Amortized construction
emissions.
Direct land use
displacement.
GHG footprint of all inputs.
CO2 leakage into atmosphere.
------------------------------------------------------------------------
RECOMMENDATIONS
Earlier sections of this report highlighted opportunities,
challenges, and research needs of algal energy systems from both the
biofuel production and carbon recycling perspectives. Below are
recommendations for a path forward, discussed in broad terms, in
anticipation of a national RD&D effort.
Program Goal
Integrated algae energy systems have the potential to offer an
effective low-risk alternative to first- and second-generation biofuels
and sequestration options that are currently under development. To
guide research through early stages of development, we recommend the
algae biofuel and carbon recycling community reach consensus on an
overarching technology goal drafted as follows:
To develop and deploy by 2020, integrated algal-biofuel and point-
source carbon recycling systems that offer 90 percent CO2
capture with 80 percent recycle at less than a 10 percent increase in
the cost of energy goods (fuel) and services (carbon abatement)
compared to today's best practices.
R&D Program Scope, Organization and Management
A geographically- and organizationally-diverse, well-managed and
results-oriented research, development, and demonstration (RD&D)
program built on private and public cooperation is critical to
fostering cooperation among carbon emitters and algae energy system
developers. Without such a program, the algae biofuels community will
struggle to integrate the numerous facets of algal production and
processing critical to making this area a successful economic
enterprise. Likewise, in the absence of value-added recycling options
and regulations limiting carbon emissions, utilities, small
CO2 emitters will have little motivation to consider carbon
reuse options. Thus, a robust RD&D program as drafted in Figure 15,
will only occur with government involvement both in sponsorship of
research and enactment of policy tools that incentivize and accelerate
commercial deployment. Specific recommendations include:
Congress and the administration should strengthen policies to
incentivize and accelerate commercial deployment of algal energy
systems through such vehicles as:
--Loan guarantees (EPA CT 2005--title 17).
--New regulatory and policy guidelines.
--New certification and qualification processes.
Figure 15.--Suggested Federal RD&D Program Organization and Structure
Congress should authorize and appropriate funds for a comprehensive
research, development, and demonstration program through the U.S.
Department of Energy focused on algae energy systems (including both
biofuel production and carbon recycling).
The RD&D program should include a balanced and distributed
portfolio of foundational, translational, and transformational
research, development, and scalable demonstrations executed by regional
consortia (Centers of Excellence) consisting of industry, academia, and
national laboratories.
Fundamental research should provide new knowledge discovery in
several areas such as elucidation of pathways for synthesis of lipids/
oils and other desirable products, determination of photosynthetic
carbon fluxes and partitioning into desirable products, exploration of
metabolic pathway engineering and synthetic biology, examination of
novel engineering processes leading to improved CO2 uptake
and areal/volumetric algae yields, and investigation into alternative
approaches to product synthesis.
Applied RD&D should involve laboratory and pilot-scale RD&D for all
three sub-systems (upstream, cultivation and downstream systems) and
the interdisciplinary activities that bridge between them. System
integration solutions, developed through public/private partnerships,
should lead to integrated demonstrations and deployments in the field.
Lessons learned from field tests should be reported to core RD&D
elements to guide future activities. A portion of the program should
also include research on disruptive technologies, targeting approaches
with a high degree of technical risk but also significant potential
return on investment.
Crosscutting RD&D should be included on topics such as advanced
materials, instrumentation and controls, systems engineering, and
economic modeling.
Demonstration and deployment elements of the program should be
designed to demonstrate the viability of algae energy system
technologies at a scale large enough to overcome real and perceived
infrastructure challenges. They should include systems-level
demonstrations that include carbon delivery and transport, heat and
water integration, and co-siting with wastewater or other nutrient-rich
waste streams. Technologies should be tested in the field to identify
and eliminate technical and economic barriers to commercialization.
The largest component of the demonstration and deployment program
should be regional partnerships similar to the Department's Fossil
Energy ongoing regional programs for geologic sequestration. As many as
seven regional partnerships should examine regional differences in land
and water use, cultivation techniques, ecosystem management practices,
and industrial activity that can effect the deployment of algae energy
systems. To begin the process, the Department's Fossil Energy Program
should build upon algal-related technology roadmapping activities
underway within EERE emphasizing and strengthening technology pathways
that entail carbon reuse from small point-source emitters (e.g.,
industrial boilers and ethanol plants). Their goal should be developing
pathways to deploy regional ``FutureGen'' (e.g., algae energy systems)
large-scale demonstration of multiple producing and processing
platforms with shared technology development.
The program should include initial supporting research on lifecycle
analyses of potential new algae energy system processes to identify
issues prior to their development. This should include a rigorous
upfront lifecycle analyses aimed at quantifying the energy, water, and
carbon balance of various technology pathways and system architectures
to ensure uniformity of data and overall viability prior to large-scale
demonstrations. The program should also participate in cross-cutting
studies to model future national energy and water use scenarios
incorporating algae energy systems.
The program should include an education component. Over the past
two decades applied microalgal research and biotechnology has not been
a significant element in educational or research programs. Few students
have graduated during this period with sufficient knowledge and
practical experience necessary to develop and sustain mass culture of
algae and carryout downstream processing of algal biomass. The decline
in the supply of scientists and engineers is severe enough to warrant
the establishment of an educational initiative toward producing a new
generation of scientists and engineers with the multidisciplinary
skills needed for emerging algal-based carbon recycling and biofuels
industries.
The program should leverage strengths from existing programs,
establish programmatic roles, and be coordinated from a Department-wide
perspective. Leveraged strengths include: Fossil Energy (upstream
systems, carbon capture and recycling); Office of Science (new
knowledge discovery & fundamental science); EERE Office of Biomass
Programs (cultivations systems); and EERE Industrial Technology
Programs (cross-cutting needs and downstream systems).
The Department should seek ways to streamline and strengthen
management of the program through use of administrative tools such as
experimental personnel authority and other updated contracting and
intellectual property management strategies.
Program Timeline
It is premature to assign an exact timeline and estimate of
resources required to achieve the program goal described; however, it
is reasonable to assume that cost-effective, broad-scale algae energy
system solutions will require at least a decade to complete (Figure 16)
and Federal investment similar in magnitude to other mainstream
sequestration and biofuel pathways.
Senator Bennett. Ms. Tatro, I think you hit on it exactly,
and words have meaning sometimes that seem innocuous enough.
But we have, as a government, as a people, we have come to
regard CO2 as a pollutant, and your testimony here
collectively says CO2 is a resource.
And if you simply make that semantic change in defining it,
the whole world changes, so I intend to start talking in those
terms. I gather you would be willing to start talking in those
terms. And that can be the shift in mindset that can get us in
the right direction.
Now, Mr. Klara, will DOE start thinking, okay, how do we
organize to take advantage of this resource to generate new
energy? Wouldn't that be a significant mind shift at DOE?
Mr. Klara. Oh, absolutely. But I am not sure that a mind
shift is quite needed. We have been investing around $35
million, for example, in fiscal year 2009 in reuse-related
concepts. As Senator Dorgan has stated, we are looking at a
very aggressive influx of funding, potentially out of the
stimulus funding, to this area as well.
I would also caution, also with the approach to having no
silver bullet to stabilizing emissions that, at the end of the
day, all the analyses continue to show that the emissions are
just so large that CCS will likely have to be the backstop.
Senator Bennett. I realize that, but I am encouraged by
what you have just said, the backstop.
Mr. Klara. Right.
Senator Bennett. If we think of it as a resource and how
can we use this resource? Oh, there is still some left over
that we have to deal with. All right, we will use sequestration
at the backend rather than the focus which is there now, which
is that everything--it is a pollutant. Everything we can do to
get rid of it is where we ought to be going. And the testimony
here is, no, it is a resource.
Now it may be a resource in overabundance so that that is
left over becomes a nuisance. But that significant mind shift I
think has to take place, and I realize in the stovepiping of
the way we organize our Government, you are focusing entirely
on energy. So you can't even talk to Dr. Constantz because he
is not producing energy. He is producing concrete.
Let us kind of break down those sorts of stovepipes and
realize again this is a resource, and it is a resource that can
be used to turn into something very valuable.
Now, Dr. Constantz, how competitive are you with portland
cement? Without a Government subsidy, just doing what you are
doing, can you under price traditional portland cement in the
market today?
Dr. Constantz. Yes. Well, there are two components. There
is the cement and the aggregate, which is composed concrete.
Senator Bennett. Right.
Dr. Constantz. And both of them, in our case, half a ton of
the material sequesters half a ton of CO2 within it.
Our price to the gate is competitive with the price to the
gate of portland cement. It is much more competitive, though,
if you consider the future because, remember, the cement guys
are under the same constraints the power guys are under. So
they have to put emissions control in place, like in
California, we have AB 32. And that is going to drive their
cost to the gate up to about $90 a ton, and we will beat that
big time.
Senator Bennett. Sure. I understand that, and that is a
political decision rather than an economic decision. I am not
saying it is the wrong decision, but it is a political decision
to put that extra cost onto the traditional portland cement.
And the point I want to discover is even without that extra
cost on them, can you compete today?
Dr. Constantz. On the cement side, we can easily compete,
and it is very profitable. On the aggregate side, aggregate is
not a very high-value product. It sells for $10 to $20 a ton.
So there, by having a carbon credit or like in Australia we
have allocations that we get, that can be very profitable.
However, as I mentioned other specialty products like
lightweight aggregate sell for as much as $60, $70 a ton or the
angular aggregate for pervious concrete, which is used
everywhere today, or elongated. See, we can make them any shape
we want.
Senator Bennett. Sure.
Dr. Constantz. So there are a number of high-value
products. The aggregate is easier to get on the market. That is
tested with fewer tests than the cement, but we are in testing
for both of them. Our vice president of materials research is
the past president of the American Concrete Institute, and he
chairs the ACI 518 Committee that oversees all the other
testing committees. So we are very much in contact with that.
And the cement industry is really thrilled about this
because just by, for example, substituting the sand in their
mix design with our sand, they can bring a yard of concrete,
which is normally 500 pounds of CO2 net emitted,
down to carbon neutral. If they supplant both the sand and the
gravel in the concrete, plus only replace 20 percent of the
portland cement with our cement, they can bring it to a
negative 1,100 pounds per yard of sequestered CO2.
So we are negotiating with many, many powerplants, but we
are also negotiating with many, many cement plants. And at a
cement plant, an average cement plant produces a million tons
of cement a year. So that is 2 million tons of our product that
we can produce.
And because transportation is a large amount of the cost in
delivering concrete, which is the commercial product, by having
the aggregate produced locally right at the cement plant from
their emissions and being able to take that out along with
their cement to the ready-mixed plant is an incredible win for
everyone in the portland cement industry.
Senator Bennett. Okay. Will you furnish for the record some
national figures so that if everybody who is in the cement and
aggregate business shifted over, what the national amount of
sequestration would be?
Dr. Constantz. Sure. So, in the United States, we use about
124 million tons of portland cement a year, and that goes into
about roughly 600 million tons of concrete, okay? So from that
124 million tons of portland cement, we are producing 124
million tons of CO2.
The larger aspect of it is in the United States, we use 3
billion tons of aggregate a year. And approximately 500 million
of those tons go into concrete. The other 2.5 billion tons go
into asphalt and road base.
Senator Bennett. And all of that would include sequestered
CO2.
Dr. Constantz. All 300 million tons. And limestone is the
preferred aggregate because it is stable at high pH, and
concrete, as you know, has a pH of 14.
Senator Bennett. Okay. That is the kind of scale that I was
looking for.
Mr. Muhs, you have listened to Ms. Tatro. Can you two make
music together? Can you make fuel?
Mr. Muhs. Well, I think so. In both cases, we are using
solar energy, ultimately. And there are different uses for
solar. And biological systems obviously require sunlight.
One of the things that we have done at Utah State to try to
help the scalability of algae, for example, is improve the
volumetric growth of algae. That is how much algae you can grow
in a volume of aqueous or water solution. We are also looking
at using saline water from the Great Salt Lake, and we found
some strains of algae that have a lot of oil and grow very fast
there.
So I think, to follow on that question, yes, we can. And
one of the things that we are doing to try to embed better
solar energy use is look at ways to increase the amount of
sunlight we can get into these algae systems.
You have seen some of these vertical reactors and things of
that nature that Senator Dorgan had mentioned. By using
sunlight more constructively, we can reduce surface shading and
increase the volumetric growth by maybe a factor of 10. If we
do that, then we use 10 times less water. And in doing that, we
have a whole lot less energy moving energy around--or moving
water around, and it makes algae more scalable.
We think that--our industry colleagues who helped write our
report say 5 years, some of the academic folks say 10 years to
sort of commercial viability, economically. Maybe there
somewhere between those two points is where the real number
lies.
Senator Bennett. Well, Mr. Chairman, thank you for your
indulgence for this. I have been told, growing up there, that
the Great Salt Lake is only good for two things--salt and
sunsets.
And if, indeed, we can use the brackish water that is there
to create energy, that is enormous because one of the primary
challenges with respect to corn ethanol is the enormous amount
of water that it uses. And water is the new oil, looking ahead.
The water resources are going to be as scarce as the oil
resources around the world. And to be able to use this kind of
thing with brackish water, this is a very exciting prospect.
And I, again, thank you and congratulate you for convening the
hearing.
Senator Dorgan. Senator Bennett, thank you very much.
Senator Tester?
Senator Tester. Yes, thank you, Mr. Chairman.
I am going to stay with Dr. Constantz for a second. During
your answers with Senator Bennett, you had said that the price
without subsidies was competitive. And then I drifted for a
second, and then we were talking about not being competitive.
Is it competitive on the concrete and not competitive on the
aggregate? Is that what it was?
Dr. Constantz. Right. So concrete has both cement and
aggregate in it----
Senator Tester. Yes.
Dr. Constantz [continuing]. To make the concrete and the
price to the gate, the national average in the United States is
about $30. Most of the cost in a delivered yard of concrete,
though, isn't in that. It is in the transportation.
Senator Tester. Transportation.
Dr. Constantz. For aggregate, on a national average, it
would be sort of $10 to $20 a ton would be the retail price.
So, for cement, the average price varies around $100 to $110.
So the portland cement replacement component is extremely
profitable.
Now, in the aggregate, the specialty aggregates like the
lightweight aggregate can be $70 a ton.
Senator Tester. It can work. Okay.
And did you say in your testimony that you did not have to
separate the CO2 flow?
Dr. Constantz. Yes. I think that is the principal
distinction. If you have a coal plant and you want to get into
chilled ammonia or MEA, you also have to scrub all your
SO2. And even if you are currently compliant with
SO2, it is not to the level you would need it to be
to then put an MEA unit on the end.
So if you own a coal plant and you want to do MEA or
chilled ammonia, you have to upgrade your sulfur control and
take more parasitic load and then put on the other. We take raw
flue gas, and we have greater than 70 percent absorption.
Senator Tester. Okay. You have 70 percent absorption from
the CO2, and the NOX and the
SOX are not an issue because they are automatically
absorbed, too?
Dr. Constantz. Right now, we know we are taking all the
SO2. And we are investigating the NO conversion to
NO2 and the mercury, arsenic, lead, selenium as
well.
Senator Tester. Okay. So the jury is still out on those,
but you are----
Dr. Constantz. For sure, the SO2, yes.
Senator Tester. Okay, all right.
Dr. Constantz. As well as the CO2. My VP of
emission control has 15 patents going on already. It is
something we are pretty knowledgeable about.
Senator Tester. You said you are making 5 tons of cement a
day?
Dr. Constantz. In a batch process.
Senator Tester. In a batch process.
Dr. Constantz. But we have a continuous pilot plant up and
running now, which is running 24-7, just putting out a ton a
day. And that plant is allowing us to look at the key process
indicators, which are needed to define a plant of any scale
according to the EPC contractors.
Senator Tester. So what is the inhibitor of Colstrip,
Montana, with their four coal-fired generators, starting up a
cement plant in Colstrip, Montana? What is stopping that?
Dr. Constantz. Actually, we have been having a lot of
support. We put a grant together for a coal plant, and we went
out to the local ready-mixed suppliers, and they all wrote very
laudatory letters of support saying if you make it, we will
sell it.
Senator Tester. Oh, for sure.
Dr. Constantz. And so, just you have to have a local cement
market. But even if you don't have a local cement market, they
are putting in asphalt roads. You need the road base. There are
plenty of uses almost anywhere.
And the fact is the electrical powerplants and the cement
plants are always in the same place because they are where the
people are. And they are both things that are hard to
transport.
Senator Tester. Yes. So what is stopping it?
Dr. Constantz. Well, we are going as fast as we can.
Senator Tester. Is it because there is not a price on
CO2 that is stopping it, or what is stopping it?
Because if you can make money making cement out of
CO2, eliminate and not have to separate all the
CO2 by scrubbing and all that stuff, and if you use
your flue gas, what is inhibiting this from happening?
Because it looks to me like if I was on a board of
directors, I would say, ``Do this. Do it tomorrow.'' And we
just eliminated one big old headache.
Dr. Constantz. Well, that is what my board is telling me.
Senator Tester. So there is nothing inhibiting it other
than a lack of knowledge?
Dr. Constantz. We are moving as fast as we can. I am giving
one of the addresses at the National Coal Council next Friday.
Senator Tester. Very good.
Dr. Constantz. And I will have a much more extensive
discussion of what----
Senator Dorgan. Can I just----
Senator Tester. Yes, go head.
Senator Dorgan. If I might just interrupt? My staff has
indicated there still is remaining lifecycle testing for
CO2 lifecycle balance in this process, is that
correct?
Dr. Constantz. Actually, one of my specialties is isotope
geochemistry, and we have a whole team. We have 18 Ph.D.s in
the company. One of them is just using Carbon-13 analyses. So
this will be the most--these are the most sophisticated
lifecycle analyses ever done on any carbon technology.
And we are following--we can tell an atom of carbon from
coal versus water versus the atmosphere and where it goes in
these analyses.
Senator Dorgan. And then the technical testing to meet the
industry standards? Are you there?
Dr. Constantz. Well, that is what we presented back in
February at the World of Concrete, the ASTM testing.
Senator Dorgan. And have they been accepted?
Dr. Constantz. The way it works is every State has their
own department of transportation. So, in California, we have
Caltrans. Caltrans has a lab in Sacramento. You send them your
product. They do their own testing. Every State is different.
And that takes them about 18 months to do that testing on
concrete.
Senator Tester. Okay. Thank you.
And I want to move on. And by the way, I think that how we
deal with our carbon is just how we deal with our energy
policy. It has to be multifaceted, very diverse. And so, I
think there is room for everybody in this equation.
But it does intrigue me that you are this far along with
this technology, and I have heard of it, but I certainly didn't
think it was this far along, which is good news.
I want to talk a little bit about algae for a second. Has
all your work been enclosed, Mr. Muhs? All your work--or Mr.
Klara, all the work been done in enclosed systems, or is there
some work that is being done out in the open?
Mr. Muhs. A lot of work being done in open systems. They
are easier to build. They are easier to operate.
Senator Tester. Are they limited to the southern part of
the United States, or can they be done all over?
Mr. Muhs. They are not limited to the southern part of the
United States. Matter of fact, the issue of water supply is
such that it may be just as viable up north in some--one
limiting factor may be temperature in northern regions.
Senator Tester. And in the end, have you done any analysis
on once it gets right down to it, of making diesel fuel out of
the algae, and how many gallons of water it takes to make a
gallon of diesel fuel? This is a big discussion about coal to
liquids.
Mr. Muhs. In the enclosed systems, it is very minimal
because you are essentially recycling most all the water.
Senator Tester. Okay.
Mr. Muhs. In the open systems, it is much higher. And I
looked at an analysis yesterday from Sandia and Los Alamos on
water use and algae, and I still don't have a number from them
yet in terms of actual in open systems.
Senator Tester. We would love to get that, although I would
imagine a lot of it depends upon sunshine.
Mr. Muhs. Exactly. Where you are at, for example, arid
climates are going to have a whole lot more evaporative losses
than up north.
Senator Tester. Exactly. I am just going to make the
assumption that when you use wastewater, it improves the
quality of the wastewater?
Mr. Muhs. That is correct.
Senator Tester. Because it removes the nutrient load?
Mr. Muhs. It removes the nutrients. For example, in Logan,
Utah, we have a huge wastewater facility, and we are already
working towards that.
Senator Tester. Is lack of nutrient load an issue when you
are not using wastewater?
Mr. Muhs. It can be. It can be because, obviously, you need
the same nutrients that regular farm crops need, and so issues
in algae, one of the main ones is proximity to nutrients as
well as proximity to CO2, enhanced CO2.
Senator Tester. Has anybody done any analysis about the
amount of wastewater? If we were to maximize this to all its
ability, do we have plenty of wastewater to fill the need in
the country?
Mr. Muhs. That is a good question. I don't have an answer
to that. My estimate would be that we do have an excess supply
of wastewater right now, and it would take quite a long time
for us to get through that before we need it.
Senator Tester. All right. Yes, I would tend to agree with
that.
Ms. Tatro, you talked about disincentives in policies that
we may put forward or potentially appropriations. Could you
give me any examples of that that exist now that is a
disincentive to any one of these industries or potential
industries that we have done?
Ms. Tatro. I myself and my organization are not policy
experts, so let me just caveat this response.
Senator Tester. No problem. Neither am I.
Ms. Tatro. I can't cite a particular policy that has
disincentivized recycling, and I don't know what all the
conversations are in Washington about various ways to either
put a price on carbon or to limit the cap and trade. All of
those policies have implications for recycling, and I don't
know. I just think that needs to be part of the conversation in
the formulation.
Senator Tester. I agree. I just need to make sure that we
don't have unintended disincentives in some policy we make. So
if you see that coming down the pipe, I would love to hear
about it. Because, truthfully, I think that it needs to be a
multifaceted arrangement that we deal with CO2, and
I don't want to disincentive anybody if they have got a good
idea.
Which brings me to my next question, you had talked about
the fact that we haven't really called for these new ideas. Is
that the same case since Dr. Chu is in the DOE, or are there
things we can do that really could help excite people to step
up to the plate?
Ms. Tatro. Absolutely. I am really excited by Dr. Chu's
direction and the support I think he also has from Congress in
creating these collaborative energy grant challenge centers
that may be focused on some of these problems. That is a
fabulous way to get cross-organizational teams working on some
of these problems.
I am very excited. I think he sees the benefit of getting
coordinated teams across different parts of the Department of
Energy and with different Federal agencies to motivate people
to work on these problems. I am very excited by what I see. I
think it will help tremendously, and I know we appreciate the
support from Congress that he is receiving for that.
Senator Tester. Okay. Just a couple more, and then I am
done.
Mr. Muhs, you talked about one-tenth the area of a State
like Utah or North Dakota could be used to fill all our diesel
needs. Is that in a closed loop, open loop, or does it matter?
Mr. Muhs. That was based on something in between,
essentially in terms of----
Senator Tester. A little bit of each?
Mr. Muhs. Yes. Essentially took values for production that
were lower than enclosed but higher than open systems to make
that calculation.
Senator Tester. All right. The other thing, Ms. Tatro, you
talked about a heat engine that could make methane out of
CO2 and water and sunlight and heat. I will ask you
the same question I asked Mr. Muhs. What is the water use in
making the methane? Is it 1-to-1 or less than that or more than
that?
Ms. Tatro. The product that is produced is methanol, which
is a liquid material.
Senator Tester. Yes, methanol. I am sorry.
Ms. Tatro. That is all right. But then the question is
still valid, and I don't know the number off the top of my
head. The amount of water that is used compared to the amount
of CO2 to produce a gallon of fuel?
Senator Tester. Yes.
Ms. Tatro. Let me get back with you on that number. I don't
know it off the top of my head.
Senator Tester. That would be great. I would just love to
know it.
And that is probably about it. I want to thank you all for
your testimony. I think that you have all thought outside the
box.
Mr. Constantz, do you see CO2 as an asset at
this point in time? You can make money off CO2?
Dr. Constantz. Yes, in many ways. From aggregate, from
cement, from fresh water, and if there is further carbon
monetization from the CO2 emitter, we believe it
could be a very profitable and job-creating enterprise.
Senator Tester. Mr. Klara, my apologies. I didn't ask you
any questions, next time.
Mr. Klara. No problem, sir.
Senator Tester. Thank you. Thank you very much.
Senator Dorgan. I think my colleague, Senator Tester, just
talked about thinking outside the box, and Senator Bennett
talked about stovepipes. In many ways, it is kind of the same
discussion.
We do in our Government, I think, push a lot of money
toward research and so on, but a lot of it is done in a
stovepipe. And I think when we try to address this larger issue
of climate change and carbon capture and so on we really do
need to think outside the box.
I was just thinking, as Senator Tester was asking
questions, about Dr. Venter, Dr. Craig Venter, who came to see
me a while back. This is probably such a simpleton, layman's
description. But he has got scientists, I think a couple
hundred scientists working on the prospect of perhaps of
creating synthetic microbes that would consume coal and in that
consumption produce methane.
And so, that is thinking outside the box, right, perhaps
doing it in situ. I have no idea about the carbon issue there,
but I am assuming consuming coal underground with synthetic
microbes and turning coal into methane probably also is an
outside-the-box approach to deal with the carbon issue.
But the reason that I wanted to have this hearing is that I
want us to begin thinking differently about this issue and this
challenge. We do have issues in front of us that the Congress
is going to be required to address. And the question is not
``whether,'' it is ``how'' do we address it?
And I appreciate very much your willingness to come. Some
of you have traveled a long distance to just share with us some
thoughts about what you are working on and what we might
consider in a different way when we consider the word
``carbon'' and ``CO2'' and what we might do with it.
I, too, think that if we are smart and we go about this the
right way, we might well find that you can create an asset in
terms of trying to deal with what we consider a liability. If
that is the case, we ought to run in that direction and say to
those that are looking at sequestration, good for you. Keep up
your work as well because we need to do a lot of everything to
find out what works really well.
And the other piece I would say, finally, is this. It is
one thing to do something in a laboratory. It is quite another
thing to scale it up and demonstrate it at commercial scale.
And even as we encourage the development in laboratories, we
need to encourage the scaling up at commercial scale of those
opportunities so that we know what we have here. Does this
work?
Then I think the private sector will beat a path to the
door of that person who has demonstrated an idea that will
provide the ability to make some money and sequester carbon at
the same time.
CONCLUSION OF HEARING
Senator Bennett and I have a 10 o'clock markup at the
Energy Committee that we have to attend, and let me thank all
of the witnesses for coming this morning. Your entire
statements will be part of the record, and you may feel free to
submit any additional material you wish for 2 weeks from the
date of this hearing.
This hearing is recessed.
[Whereupon, at 10:10 a.m., Wednesday, May 6, the hearing
was concluded, and the subcommittee was recessed, to reconvene
subject to the call of the Chair.]
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