Ocean thermal energy conversion Environmental Effects Assessment Program Plan, 1981-85

[From the U.S. Government Printing Office, www.gpo.gov]

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Ocean Thermal Energy Conversion
Environmental Effects Assessment Program Plan
TD 1981-85
195
.E4 U.S. DEPARTMENT OF COMMERCE
U55 1@ 0@, - nall Oceanic and Atmospheric Administration
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1982 ffi of Ocean Minerals and Energy
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K0. StiT OF CO Ocean Thermal Energy
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Conversion: Environmental
Effects Assessment Program Plan
1981w85

Prepared by:
Office of Ocean Minerals and Energy
2001 Wisconsin Avenue, N.W.
Washington, D.C. 20235

June 1982

I ZI"

U. S. DEPARTMENT OF COMMERCE
Malcolm Baldrige, Secretary
National Oceanic and Atmospheric Administration
John V. Byrne, Administrator
Office of Ocean Minerals and Energy
James P. Lawless, Acting Director

"'.T OF CO,
UNITED STATES DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
Washington. D.C. 20230

THE ADMiNISTRATOR

JUN 3 0 198Z

Honorable George H. Bush
President of the Senate
Washington, D.C. 20510

Dear Mr. President:

It is my honor to transmit the Ocean Thermal Energy Conversion
Environmental Effects Assessment Program Plan 1981-1985 of the
National Oceanic and Atmospheric Administration pursuant to
Section 107 of the Ocean Thermal Energy Conversion Act of 1980
(P. L. 96-320). This plan describes the program of research
for FY 1981-1985 that is necessary to begin to assess the effects
on the environment of ocean thermal energy conversion facilities
and plantships.

Sincerely yours,

John V. B

Enclosure

ATM
@John @V.B

E OF

,vv
UNITED STATES DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
Washington. D.C. 20230

THE ADMINISTRATOR

JUN 3 0 1982

Honorable Thomas P. O'Neill, Jr.
Speaker of the House of Representatives
Washington, D.C. 20515

Dear Mr. Speaker:

It is my honor to transmit the Ocean Thermal Energy Conversion
Environmental Effects Assessment Program Plan 1981-1985 of the
National Oceanic and Atmospheric Administration pursuant to
Section 107 of the Ocean Thermal Energy Conversion Act of 1980
(P. L. 96-320). This plan describes the program of research
for EY 1981-1985 that is necessary to begin to assess the effects
on the enviroment of ocean thermal energy conversion facilities
and plantships.

Sincerely yours,

John V. Byrn

Enclosure
@john @V.B

E Of

Ocean Thermal Energy Conversion Environmental Effects Assessnent Program Plan

TABLE OF CONTENTS

1. Background 1

1.1 Introduction 1

1.2 Ocean Thermal Energy Conversion Technology 2

1.2.1 Closed Cycle System 2
1.2.2 Open Cycle System 2
1.2.3 OTEC Applications 5
1.2.4 Thermal Resource Requirements 6

1.3 Development Schedule 6

1.4 Legal and Regulatory FraTewo-rk 9

2. Environmental Risk 11

2.1 The Potentially Affected Environment 11

2.1.1 The Atmosphere 11
2.1.1.1 Climate 11
2.1.1.2 Tropical Storms and Hurricanes 11
2.1.1.3 Carbon Dioxide 12
2.1.2 The Marine Environment 12
2.1.2.1 Nearshore Environment 13
2.1.2.2 Offshore Environment 16

2.2 Environmental Priorities 17

2.2.1 General Statutory Requirements 17
2.2.2 Enviromiental Effects of Individual
OTEC Plants 18
2.2.2.1 Water Mass Displacements 18
2.2.2.2 Inflow and Discharge of Water
and Contained Organism 23
2.2.2.3 Biota Attraction and Avoidance 26
2.2.2.4 Biocide Releases 27
2.2.2.5 Working Fluid Losses 28
2.2.2.6 Trace Releases of Toxic Constituents 29
2.2.2.7 Other Environmental Concerns 30
2.2.3 Cumulative Environmental Effects of
OTEC Plants 31
2.2.4 Direct Licensing Requirements 33

3. Environmental Research Plan 35

3.1 Strategy 35

3.2 Research Elements 35

3.2.1 Water Mass Displacements 35
3.2.1.1 Tomperature and Salinity Effects 35
3.2.1.2 Secondary Effects of Nutrient
Redistribution 36
3.2.1.3 Effects of the Redistribution of Other
Chemical Properties 36
3.2.2 Inflow and Discharge of Water
and Contained Organisms 36
3.2.2.1 Entrainment Effects 36
3.2.2.2 Impingement. Ef fects 36
3.2.3 Biota Attraction and Avoidance
Effects 37
3.2.4 Biocide Effects 37
3.2.5 Effects of Trace Releases of Toxic
Constituents 37
3.2.6 Cumulative Environmental Effects 37
3.2.7 Direct Licensing Requirements for
Environmental Information 38

3.3 NOAA Research Plan 38

3.4 Managemnt 41

3.4.1 Planning 41
3.4.2 Program Implementation 41
3.4.3 Review and Evaluation 41

4. References 43

5. Glossary 49

6. Abbreviations 54

ILLUSTRATIONS

Figure Page

1 Schematic Diagram of a Closed-Cycle Power System 3
2 Schematic Diagram of an Open-Cycle OTEC Power System 4
3 The OTEC Thermal Resource Area (Pacific) 7
4 The OTEC Thermal Resource Area (Atlantic) 8

TABLES

Table Page
1 Physical and Chemical Characteristics of OTEC Resource Areas 14
2 Characteristics of the Plankton in the OTEC Resource Area 15
3 Division of the Oceans into Provinces According to Their
Level of Primary Productivity 16
4 OTEC Environmental Research Budget: FY 81-83 40

OCEAN THERMAL ENERGY CONVERSION
ENVIRONMENTAL EFFECrS ASSESSMENT
PROGRAM PLAN

1. BACKGROUND

1 INTRODUCTION

Public Law 96-320, the Ocean Thermal Energy Conversion (OTEC) Act of 1980,
was enacted on August 3, 1980. The Act sets as its primary goal the establish-
nent of a legal regime which will permit and encourage the development of ocean
thermal energy conversion as a commercial energy technology. This goal is to
be achieved while providing for protection of the oceanic and coastal environments
where OTEC facilities are to be sited and while giving due consideration to
preventing or minimizing adverse impacts on other users of the ocean.

Among the provisions of this law is a requirement, in Section 107, that
the Administrator of NOAA, ". . . . initiate a program to assess the effects on
the environment of ocean thermal energy conversion facilities and plantships."
The law further requires (Sect. 107(c)) that The Administrator prepare a plan
to carry out this program.

The Administrator has delegated NOAA's responsibilities under P.L. 96-320
to the Office of Ocean Minerals and Energy which, among other activities, has
developed the plan, as presented in this document. It is a generic plan regarding
the environmental effects of OTEC development and thus extends beyond NOAA's
purview. The NOAA part of the plan is discussed in Chapter 3.

The Plan has the primary objective of obtaining the environmental
information and knowledge required to allow the ccnumrcial development of
OTEC to the maximum extent that is compatible with acceptable environmental
risk. Such development would provide a solar-based renewable energy source
that, in certain areas, can replace energy generated by burning imported and
other nonrenewable fossil fuels, such as oil and natural gas.

The development of OTEC will become viable earlier in U.S. tropical and
subtrcpical island ccmzunities than on the mainland because OTEC-produced
electricity will be cost competitive in those areas sooner. Electricity
costs range from two to eight times higher in island communities which are
almost totally dependent on imported oil. In addition, many island communi-
ties require fresh water, which is a direct beneficial byproduct of open
cycle OTEC plants and could be a product of a closed cycle plant if the power
was utilized for desalination. As OTEC designs are improved and conventional
power costs continue to increase, OTEC power is expected to becom cost
competitive in certain mainland areas also.

.The development of the Plan has had the great advantage of being able
to build on a substantial body of on-going and completed research directed
toward evaluating the potential envirorflTeantal effects of the development of
OTEC. We gratefully acknowledge the very great role the publications documenting

these studies have had in providing the scientific basis for development of
the Plan. We especially appreciate the expert advice and guidance that
certain Departmnt of Energy (DOE) personnel have provided.

The development of the Plan has also drawn upon the Final Environnental
Impact Statement for Commercial OTEC Licensing (NOAA, 1981a) by responding to
the research needs related to the potential environnental consequences. It is
also responsive to the final regulations for OTEC licensing (NOAA, 1981b)
that call for minimal regulation of OTEC activities. Under this regulatory
approach, case-by-case (e.g., site-specific) license terms and conditions
will be developed so as to allow for variabilities in both the OTEC resource
environments and the designs of OTEC plants.

1.2 OCEAN THERMAL ENEPGY COWERSION TECHNOLOGy

Ocean thermal energy conversion (OTEC) is a process for using solar energy
stored in the warm surface waters of the tropical and subtropical oceans to
perform useful work. This may be generating electricity for domestic and
industry consumption, or providing energy for industrial refining and manu-
facturing activities. Several different techniques have been considered as
the basis for OTEC power generation (NOAA, 1981a). These techniques utilize
either a closed cycle process or an cpen-cycle process, or a combination of
these basic processes (hybrid systems). The generating capacity of thdse
plants refers to the net power produced and accounts for inherent losses
related to plant operation.

1.2.1 Closed Cycle System

The closed cycle system (Figure 1) emplcys a working fluid (most likely
ammonia, although a number of candidates are being considered) enclosed in a
system of piping. This fluid is exposed across a heat exchanger surface to
oceanic surface waters that have been warmed by the sun. As the working fluid
warms, it vaporizes and this expanding vapor passes through and drives a gas
turbine, producing electricity. The electricity can be distributed to industrial
and residential users, or used directly on site to power energy-intensive
processing or manufacturing activities. After passing through the turbine,
the working fluid is returned to the liquid phase by exposure in a heat exchanger
to cold water drawn from the deep ocean. The working fluid is then revaporized
by being pumped back through the warm water heat exchanger, and the cycle is
repeated. This means of power generation does not use any fuel. It is based
on the cyclical vaporization and condensation of the working fluid that is made
possible by taking advantage of the temperature difference between the sun-heated
surface waters and the perpetually cold, deep waters of the tropical oceans.
Even the pumps used to draw in the warm and cold water do not need conventional
fuel as they are powered by a part of the energy produced by the process itself.

1.2.2 Open Cycle System

The open cycle system (Figure 2) is, in most ways, quite similar to the
closed cycle system. However, in the open system the seawater itself is the

Electric Power
Warm Output
Water
Intake

High Pressure Low Pressure
NH3 Vapor NH3 Vapor
25*C
o@'
Turbine
Generator

20*C 20*C 7*C

:X ol 11
X.

X
X:
U.) x:
Evaporator Condenser
X
X
X X, '..%I
x
X.

X:
U.

1 O*C 101C
Liquid
Pressurizer
SIC
23*C
High Pressure Low Pressure
NH3 Liquid NH3 Liquid

Warm Cold Cold
Water Water Water
Exhaust Intake Exhaust

Figure 1. Schemactic Diagram of a Closed-Cycle Power System
(Adapted from DOE, 1979a)

Vacuum
Pumps

Warm Loop Turbine/Generator Cold Loop

Evaporator Condenser
Demister

4- Degasifiers/Vacuum Pumps

Water Pumps/TurbinesjZ______

C>C

C>O %

%
Warm Inlet .0 %
Warm Outlet Cold Outlet

Control

Cold" Inlet

Figure 2. Schematic Diagram of an Open-Cycle OTEC Power System
(Adapted from Watt et al., 1977)

working fluid. Warm surface water is pumped into an evaporator in which the
pressure is reduced to the point where the seawater boils and about one-percent
evaporates. The resultant steam passes through and drives a steam turbine
resulting in electricity or other usable energy as in the closed system.
After leaving the turbine, the steam is cooled and condensed by exposure to
cold, deep water in a heat exchanger.

The cpen cycle technique has the advantage that the dissolved salts
do not accompany the surface water when it forms steam. Thus, a valuable
byproduct, fresh water, results when this steam condenses. To maintain the
efficiency of the open cycle technique, however, it is necessary to remove
non-condensable gases, such as oxygen and carbon dioxide, before the steam
passes through the turbine. These gases must be either discharged into the
at-nosphere or injected into the water being discharged from the plant.

The earliest commercial applications of the OTEC principle are expected
to use the closed cycle process. There is, however, considerable interest in
open cycle applications because of the additional benefit of fresh water production.

1.2.3 OTEC Applications

Generation of electricity is expected to provide the first ccnMrcial
application of the OTEC process. This will probably be from facilities which
are moored to or mounted directly on the ocean floor, or located partly on
land with their intake and discharge pipes extending out into the ocean. The
electricity frcm moored or bottom-mounted facilities will be brought to shore
by transmission cables. OTEC facilities located partly on land could be located
in areas where deep water is found very close to shore; such sites exist in
Hawaii, Guam, and other U.S. islands. OTEC facilities are expected to vary in
size from about 10 n*egawatts-electric (Me) (a size suitable for small islands)
to about 400 MWe (about half the size of a large nuclear power plant).

Another possibility for the implementation of the OTEC process is to use
the energy produced directly on the site. It could be used for production of
energy-intensive.products, such as hydrogen or ammonia, or for energy-intensive
processing activities, such as aluminum smelting.

Such onsite manufacturing or processing could take place on facilities
situated on, or close to, shore. For the offshore facilities, the product would
be moved ashore by a product pipeline or by vessels. However, the onsite
application of OTEC does not require a direct connection with land, as vessels
can transport the products to their destinations. Thus, self-contained Plantships
that would use OTEC techniques to obtain the energy needed to run onboard
manufacturing or processing activities could float unmoored or move slowly
under their own power as they sought out and followed optimum thermal gradient
conditions. Such plantships are expected to employ closed cycle systems.
Ammonia will probably be the first product produced on OTEC plantships. Within
this document, stationary facilities.and moving plantships.are collectively
referred to as plants.

1.2.4 Thermal Resource Bec
j@4irements

OTEC plants will depend on the temperature difference between warm water
withdrawn near the surface and cold water withdrawn 500-1500 meters below the
surface to drive a heat engine. A thermal difference of 18* to 201C is required
to make the operation of an OTEC facility cost-effective. The maximum difference
available in the tropical oceans of the earth is about 22 to 241C (Figure 3).
Around the shores of the United States, a somewhat lower value, approximately
22'C, is the maximum available. With a difference of 20*C, a 100 MWe plant
will require intake of surface water at a rate of 400-700 cubic meters per
second (Allender et al. 1978); larger flows will be required for lower temiperature
differences and, conversely, smaller flows will be required for larger temperature
differences. The Gulf of Mexico area on the mainland as well as tropical
islands such as Hawaii, Puerto Rico, and Guam are the locations where thermal
differences provide the most promising conditions for OTEC development (Figures
3 and 4).

1.3 DEVELOR4ENT SCHEDULE

The basic idea for OTEC development has been in existence for a number of
years. Several other nations have explored and are continuing to investigate
the possibilities for commercialization of OTEC technology. The French funded
but then.abandoned a large-scale OTEC development project in the 19301s.

The developing domestic shortage of oil reserves and the resulting dependence
on foreign sources of supply and higher prices awakened U.S. interest in this
process in the early 19701s. Development of OTEC technology was especially
stimulated by the passage of the Solar Energy Research, Development, and Demon-
stration Act (P.L. 93-473) in 1974. Since that time the Department of Energy
and its predecessor organizations have been vigorously conducting a program to
develop and introduce economically competitive and environmentally acceptable
OTEC systems.
At present OTEC development has progressed to a point where ocean tests of
the system are feasible. A "proof of concept" demnstration using an experimental,
barge-mounted, closed cycle power system with cold water pipe (Mini-OTEC) was
successfully deployed in August, 1979 off Keahole Point, Hawaii, by a consortium
including several major corporations and the State of Hawaii. The 50-kilowatt
(kw) generators on this system ran two 20 horsepower seawater pumps and produced
slightly in excess of 10 kw of net electric power.

The Department of Energy also supported a larger scale at-sea test of
OTEC technology, using a former Navy Reserve Fleet tanker which was modified
to support closed cycle components, including heat exchangers, pumps, cold
water intake pipes, and working fluid systems. This system, the OTEC-1
Engineering Test Facility, served as an at-sea testing platform for heat
exchangers and biofouling control measures. OTEC-1 was deployed in late 1980
off Keahole Point, Hawaii, and tests were concluded in April, 1981. The results
of these tests are still being analyzed.

16*
is*
--17*
18'
19
..... 20

20*00'

2V 21*

22*

23*
EQ

22*

21
20*00'
20*
19*
:@--j 8
17'
16'
15*

% X..

40*00'S

120*00'E 140*00' 160*00' 180*00, 160*00' 140*00' 120*00' 100.00, 80*00'W

< 1000 m deep

*Contours indicate temperature differential M) between surface and 1000 m depth

Figure 3- The OTEC Thermal Resource Area (Pacific)

40*00'N

15*
7-- . . . . . . . . . .

16*

20*00'
-@2
20
22

'22*
21
EQ

19
20' 22*

21-

20* 19
17*
20*00'

1 6o

17*

5
j;o

40*00'S

100*00, W 80*00, 60*00' 40*00' 20*00' 0*00, 20*00'E

< 1000 m deep
*Contours indicate temperature differential (*C) between surface and 1000 m depth

Figure 4. The OTEC Thermal Resource Area (Atlantic)

If the economics are favorable, large OTEC plants may be producing
substantial amounts of baseload electricity for transmission to utility
grids by the 1990's. Smaller plants to serve U.S. tropical and subtropical
islands may be developed even faster than this, and several of these could
start operations in the present decade.

Electric generating plants will very likely be the first large-scale
ccmiTercial use of the OTEC concept. However, stationary OTEC platforms and
moving plantships with on-board energy-intensive manufacturing and processing
facilities also hold high prcmise. The first of these may well be built within
the next ten years and substantial development may have taken place by early
in the next century.

1. 4 LEGAL AND REGULATORY F?AMEWORK

The stated purposes of the Ocean Thermal Energy Conversion Act of 1980
(P.L. 96-320) are, "To regulate conme-rce, promote energy self-sufficiency,
and protect the environment, by establishing procedures for the location,
construction and operation of ocean thermal energy conversion facilities
and plantships to produce electricity and energy-intensive products off the
coasts of the United States; to amend the Merchant Marine Act, 1936, to
make available certain financial assistance for construction and operation
of such facilities and plantships; and for other purposes." The development
of OTEC technology is to be achieved with due regard for other uses of the
coastal seas and open oceans and for avoiding or minimizing envirorumntal
damage.

The Act directed the Administrator of the National Oceanic and Atmospheric
Administration (NOAA) to establish a licensing program governing the ownership,
location, construction, and operation of OTEC facilities and plantships other
than demonstration projects so designated by the Secretary of Energy. This
was accomplished in August, 1981 (NOAA, 1981b) and governs OTEC activities
conducted by United States citizens on the high seas and the ownership,
construction, and cperation of OTEC facilities and plantships documented under
United States law', located in the territorial seas of the United States, or
connected to the United States by pipeline or cable. The licensing program
ensures that OTEC facilities are constructed and operated with due regard for
national interest and security, the jurisdictions of other nations, environmental
protection, other uses of the oceans and coastal zone, other OTEC facilities,
and the avoidance of antitrust violations. The Administrator is empowered to
prescribe the conditions when issuing a license that he deems necessary to
protect these interests or that are required by any Federal department or
agency. The licensing regulations also provide for consultation and cooperation
with all other interested Federal agencies and departments, with potentially
affected coastal states, and with the views of interested members of the general
public.

The Act further directs NOAA to initiate a program to assess the environmental
effects of OTEC facilities and plantships. It specifies that this program must
address the short- and long-term effects of individual and multiple deployTrents

of OTEC facilities and plantships, as well as submarine electric transmission
cables and other associated equipmnt located in the water colLUM or on the
seabed. Specific areas which are to be considered include the nature and
magnitude of any oceanographic, atmospheric, weather, climatic, and biological
changes associated with OTEC development as a camme-rcial energy technology.
The research program is to be designed to provide the information necessary to
determine whether or not the potential cumulative environmental effects of
OTEC development require placing an upper limit on the number or total capacity
of the OTEC plants that receive licenses must also be addressed. This document
contains the initial plan for carrying out this enviromrental assessment.
The Secretary of the department in which the Coast Guard is operating is
required by the Act to establish by regulation and to enforce procedures with
respect to the equipment, training, and maintenance required for OTEC facilities
and plantships to promote safety of life and property at sea, prevent pollution
of the marine environment, clean up any pollutants which may be discharged fram,
OTEC facilities and plantships, and prevent or minimize any adverse impacts
from construction and operation of OTEC facilities and plantships. The Secretary
is further directed to promulgate (after consultation with NOAA) and enforce
regulations governing the movement and navigation of OTEC plantships to ensure
that their discharge plumes do not interfere with the operation of other OTEC
plantships or facilities, or adversely affect the territorial sea or area of
national resource jurisdiction of any nation.
The Administrator of NOAA and the Secretary of the Department in which the
Coast Guard is operating share responsibilities for enforcement of the Act and
regulations issLk--d under it. The Administrator is charged with establishing
compliance monitoring requirements on OTEC licensees. These requirements may
include placing Federal officers or employees aboard OTEC facilities and plant-
ships, as well as requiring monitoring of environmental effects of OTEC operations
conducted by licetisees.

2. ENVIRONMENTAL RISK

The net environmental impacts due to commercial OTEC development are
expected to be minimal ccopared to the impacts frcm fossil-fuel and nuclear
power production; however, there are uncertainties associated with the re-
distribution of large volumes of ocean water that must be more adequately
assessed (NOAA, 1981a). This chapter discusses the environment of the thermal
resource area, the environmental concerns, and the research needed to reduce or
mitigate these uncertainties to an acceptable level.

2.1 THE POTENTIAELY AFFECIED ENVIRONMENT

This section, condensed directly from the Final Environmental Impact
Statement (FEIS) for ccmirercial OTEC licensing (NOAA, 1981a) provides a generic
description of the oceanic, nearshore, and coastal environments within the
OTEC thermal resource area. As noted in Figure 3, the thermal resource area
includes the eastern Gulf of Mexico, several island communities (Hawaiian
Islands, Puerto Rico, U.S. Virgin Islands, Guam, and the Pacific Trust Territories),
and various plantship areas in the open ocean.

2.1.1 The Atmosphere

2.1.1.1 Climate - Climates within the OTEC resource area are influenced by
large-scale atmospheric patterns, the sea-surface temperature of surrounding
ocean waters, and proximity of landmasses. Two basic types of climates,
maritime and oceanic, occur within the OTEC resource area. Maritime climate
is strongly influenced by continental landrasses and is characaterized by
larger, more rapid temperature changes than the oceanic climate. The
oceanic climate is influenced to a greater degree by the ocean's sea-surface
temperature than the niLritiwe climate, and is therefore characterized by
smaller, more gradual temperature changes.

Local maritime climates within the OTEC resource area are often influenced
by an onshore-offshore wind cycle caused by differential heating of land-masses
and ocean waters. In areas with steep coastal mountain ranges, such as the
Hawaiian Islands, this wind cycle causes moisture-laden marine air to cool as
it rises against the coastal mountains, losing its moisture as precipitation.
Consequently, the windward sides of such islands typically experience heavier
rainfall than the leeward side (University of Hawaii, 1973). Strong upwelling
zones nearshore, although unlikely sites for OTEC development, can modify this
pattern. Surface layers of cold upwelled water can cause the moisture-laden
marine air to precipitate before reaching land. Such regions have heavy fogs
and arid desert-like coastlines.

2.1.1.2 Tropical Storms and Hurricanes - The OTEC thermal resource area is with-
in the tropical trade wind belt. Large-scale atmospheric disturbances in this
area are known as tropical cyclones and are classified according to windspeed:
tropical depressions are cyclones with maximum sustained windspeeds below 119
kilcffeters per hour; hurricanes are cyclones with windspeeds exceeding 119 kph.
Tropical cyclones commonly occur from May to November in the northern half of

the trade wind belt, and from December to June in the southern half (Crutcher
and Quayle, 1974). Tropical cyclones are most frequent in the eastern and
western North Pacific. In the western North Pacific and the North Atlantic,
cyclones reach hurricane intensity more often than in the eastern North Pacific.
Hurricanes are frequent occurrences in the Gulf of Mexico and Carribean Sea.
No hurricanes have been observed in the South Atlantic.

2.1.1.3 Carbon Dioxide - The atmosphere and the world oceans are the two
major reservoirs of carbon dioxide. The oceanic reservoir is estimated to
contain 3.5 x 1016 kilograms-of carbon dioxide in its various chemical forms,
whereas the atmosphere contains about 6.4 x 1014kg (Brewer, 1978); however,
the atmospheric carbon dioxide concentration is steadily increasing. Carbon
dioxide levels before the industrial revolution have been estimated at 270
to 290 parts per million (ppm) by volume; present-day levels are approximately
330 to 335 ppm (Keeling and Bacastow, 1977). The combustion of fossil fuels
is the major source of atmospheric carbon dioxide increases; additional sources
are cement production, which involves the removal of carbon dioxide from limestone,
and massive reductions in terrestrial biomass from the clearing of forests,
burning of firewood, and large-scale agricultural practices (Brewer, 1978).

The influence of vegetation on atmospheric carbon dioxide concentration is
evident in seasonal cycles of carbon dioxide concentrations. This annual
variation, averaging 6 to 7 ppm in the tropics, is attributed to the uptake
of carbon dioxide by green plants during summer growth periods and release
of carbon dioxide through decomposition and respiration during winter months
(Brewer, 1978). Large-scale destruction of forests in the tropical-subtropical
regions has released large amounts of carbon dioxide and significantly reduced
the land's capacity to absorb atmospheric carbon dioxide.

The deep ocean is a major sink for carbon dioxide. Since carbon dioxide
is less soluble in warm water than cold water, warm ocean waters contain less
carbon dioxide than colder ocean waters. In equatorial waters, carbon-dioxide-
rich water is sufficiently warmed to release carbon dioxide to the atmosphere.
This region is an area of carbon dioxide outgassing, whereas polar areas, where
cold bottom waters are formed, are sinks for atmospheric carbon dioxide.

Although the increase in atmospheric carbon dioxide can be readily
measured, the oceanic carbon dioxide increase is more difficult to detect.
Presently, the detection limit for carbon dioxide measurement in seawater
,is 50 parts per million, which approximates the total atmospheric increase
of carbon dioxide since the beginning of the industrial revolution. Consequently,
it is difficult to estimate the impact of industrial atmospheric increases in
carbon dioxide on oceanic carbon dioxide concentrations and to predict the
capacity of the oceans to assimilate further increases in atmospheric carbon
dioxide.

2.1.2 The Marine Environment

Physical, chemical, and biological properties in marine waters within
the OTEC resource area are not homogeneous but do exhibit some continuity
and uniformity, especially in terms of horizontal and vertical trends.

Circulation patterns within the OTEC resource area are important because
they affect thermal resource renewal and discharge plum dynamics. Circulation
patterns should both replenish the withdrawn water and disperse the discharged
water used by OTEC plants, thereby maintaining the thermal resource. Subsurface
currents and internal waves will apply stress to the cold-water pipe; winds,
waves, and tidal currents will apply forces that act on the platform.

Chemical characteristics relevant to OTEC environmental assessments include
nutrient and dissolved oxygen profiles from the surface to the intake, discharge,
and plume stablization depths. These values are necessary for assessing the
effect of water mass redistribution. Tables 1 and 2 summarize the available
physical and chemical data for several major regions of the OTEC resource area.

One of the most marked features of the marine environment is the transition
fram. nearshore to offshore marine environments. The nearshore environment is
the region extending seaward from the shore that is influenced by continental
conditions, such as terrestrial runoff, tidal mixing, and coastal upwelling.
The nearshore region is highly productive and the location of most of the
major world fisheries, thus its extent varies both geographically and
seasonally. The offshore environment is minimally influenced by continental
conditions.

2.1.2.1 Nearshore Environment - The nearshore marine environment can generally
be defined as the region between the shoreline and continental shelf break,
encompassing the intertidal, subtidal, inner-continental shelf, and outer-
continental shelf regions. Circulation patterns of nearshore areas are
variable, and are primarily driven by winds and tides, with some influence
from large-scale oceanic currents. Tidal currents frequently reach velocities
of 100 to 150 centimeters per second. Strong tidal currents, seasonably
variable winds, and irregularities in circulation patterns cause high mixing
of surface and bottom waters in nearshore areas.

Physical processes along the edge of continental margins cause upward
mixing of nutrient-rich deep waters, resulting in higher productivity at some
distance offshore of the continental shelf. Additionally, coastal upwelling
of nutrient-rich deep waters usually occurs in areas with narrow continental
shelves (e.g., west coast of North America, miost island systems), and is caused
by: (1) winds blowing parallel to shore, or (2) current divergences towards
the surface caused by continental features (e.g., escarpments, headlands,
submarine canyons). The upwelled nutrient-rich waters that result from mixing
over the continental shelf may be transported offshore by prevailing current
systems.

Two types,of nearshore environments are present in the OTEC resource drea.
The Gulf of Mexico has a wide (hundreds of kilometers), shallow shelf strongly
influenced by coastal processes. Wind-induced turbulence, freshwater input,
tidal mixing, and partial isolation from the major ocean basins by the wide
continental shelf significantly affect the nearshore environment in the Gulf
of Mexico, causing high seasonal variability of physical, chemical, and biolog-
ical prcperties. Conversely, near-shore environments near islands are

Table 1. Physical and Chemical Characteristics of OTEC Resource Areas

ISLANDS OCEAN Gulf of
(Hawaii, Puerto Rico, Virgin Islands, (Atlantic and Pacific) Mexico
Parameter Pacific Trust Territories, Guam)
Mixed-Layer Depth (m) 40- 100 a.b,c 10-80 d,e 60-120 f
Photic-Zone Depth (m) 120-140 g,h 120-140 g,h 50-125 1
Nitrate 0-50 m 0.05-0.7 j.k,l 0.04-0.2 m,n 0.17-1.0 i'o
(mg-atom m- 3 ) 125 m 0.6-0.7 k,l 0.2-0.5 j'o 7 0
900 m 23-45 J,k,p 29-34 q 30 0
Phosphate 0-50 m 0.2-0.4 j,l*r 0.1-0.26 n,.q,,s 0.07-0.5 i't
-3 j,l,r q
(mg-atom m ) 125 m 0.2-0.5 0.3-0.6 0.5 t
900 m 2.0-3.0 j,r 1.4-2.0 rat q 1.9 t
Silicate 0.50 m 1.0-4.8 o'j 0,0-2.4 n,,q 0.5-4.4 i'o
(mg-atom m -3 ) 125 m 1.0-3.7 o'j 5*25 q 2 0
900 m 25-86 o'j 20-150 q 25 0
Dissolved 0-50 m 4.8-7.5 j,i,u 4.3-4.8 m,n,u 4.8 v
Oxygen 125 m 3.0-7.4 i'llu 3.0 n,u 3.6 0
W liter- 1 900 m 1.0-3.4 j'u*w 3.4 u 3.9 0

(a) ODSI, 1977a (i) EL-Sayed et al., 1972 (q) Sverdrup et al., 1942
(b) ODSI, 1977b (j) Lawrence Berkeley Laboratory, 1980 (r) Halminski, 1975
(c) ODSI, 1979a (k) Atwood et al., 1976 (s) Schulenberger, 1978
(d) ODSI, 1979b (1) Gunderson and Palmer, 1972 (t) Churgin and Halminski, 1974
(e) Molinari and Chew, 1979 W Arsen'ev et al., 1973 (u) Gross, 1977
(f ) ODSI, 1977c (n) Love, 1971 (v) Michel and Foyo, 1976
(g) Hargraves et al., 1970 (0) Cummings et al., 1979 (w) Gordon, 1970
(h) Gundersen et al., 1976 (p) Gundersen et al., 1972

Table 2. Characteristics of the Plankton in the OTEC Resource Area

ISLANDS OCEANIC Gulf of
(Hawaii, Puerto Rico, Atlantic and Pacific Mexico
Parameter Depth Virgin Islands) (Tropical)

Primary Productivity
mg C m-2 day 0-130 m 30-280 a,b 50-375 c,d,e 60-100 f

Chlorophyll-a 0-50 m 0.03-0.25 a,d,g,h,i 0.03-0.12 a,d,g,h,j,k.l,m 0.05-0.20 n
mg m 3 80-130 m 0.12-0.39 a,d,g,li,i 0.1-0.3 j,k,l,m 0.05-0.40 n

Microzooplankton 0-200 m 0.8 d 1.0 0 No Data
mg C M-3 200-350 m No Data 0.1 p No Data
350-1000 m No Data 0.01 q No Data

Macrozooplankton
Night/Day Biomass 0-150 m 1.25-1.65 c 1.1-1.8 o'-r's 2.3 t
Ratio

Macrozooplankton 0-150 m 0.5-0.8 utv,w,x 0.1-3.0 o,p,r,s 0.1-6.0 t*Y
Biomass mg C m-3 150-350 m 0.2 v 0.1-0.7 S,z No Data
350-1000 m No Data 0.4 0 0.25 v

(a) Gilmartin and Revelante, 1974 Q) Scripps Institute of Oceanography, 1969 (s) Youngbluth, 1975
(b) Beers et al., 1968 (k) Venrick et al., 1973 (t) Howey, 1976
(c) Koblentz-Mishke et al., 1970 (1) Eppley et al., 1973 (u) Nakamura, 1955
W Gunderson et al, 1976 (m) Schulenberger, 1978 (v) King and Hida, 1954
(e) Mahnken, 1969 (n) El-Sayed et al., 1972 (w) King and Hida, 1957
(f) Jones et al., 1973 (o) Hirota, 1977 00 Shomura and Nakamura, 1969
(g) Johnson and Horne, 1979 (p) Beers and Stewart, 1969 (y) Bogdanov et al., 1969
(h) Bathen, 1977 (q) Beers, 1978 W Vinogradov, 1961
W Hargraves et al., 1970 W Vinogradov and Rudyakov, 1973

characterized by a narrow continental shelf and thus are greatly influenced
offshore oceanic processes and experience less seasonal variation.

Differences in physical characateristics between island environments and
the Gulf of Mexico become evident when comparing the organisms comprising the
major fisheries in each region. Gulf of Mexico fisheries are primarily
benthic in nature (shrimp and demersal fishes), reflecting the enhanced benthic
productivity resulting fran mixing over the shallow continental shelf. Fisheries
around islands are mainly composed of offshore pelagic fish and small reef
fish, illustrating the influence of offshore and extreme nearshore processes
in these areas.

2.1.2.2 Offshore Environment - The offshore marine environment is generally
defined as the oceanic region seaward of the continental shelf break. Large-
scale oceanic currents prevail over most of this region and tidal and
continental influences are minimal. Vertical mixing occurs slowly, causing
offshore waters to became vertically stratified. Vertical stratification
hampers the recirculation of nutrients into the surface layer, resulting in
typically low productivity (Table 3). In areas such as the equatorial
Pacific and the North Atlantic, where conditions allow the transport of
nutrients to the surface layer, the open ocean is moderately productive.
Although the unit-area productivity in offshore surface waters is low, the
large area of the open ocean results in a major contribution to total world
productivity.

Table 3. Division of the Oceans into Provinces According to Their Level of
Primary Productivity (Ryther, 1969).

Mean Primary Total Primary Percentage Number of Ecologic Fish
Percentage Area Pr oductivity Productivity of Total Trophic Efficien:Y1 Production
Province 0 f ocean (k.2) (g dry weight (metric tons Productivity Levels (percent) (metric tons)
m-2 year -1) year -1)

Open Ocean 90.0 326 x 106 50 16.3 x 109 bl.5 5 10 1.6

Nearshore Zone* @.9 36 x 106 100 3.6 x 109 lb.0 3 15 120

Upwelling 0.1 3.6 x 106 300 0.1 X 109 0.5 1-1/2 20 120
Area

*Includes highly productive areas over the continental bhelf.

2.2 ENVIRONMENTAL PRIORITIES

The potentially significant enviromvental effects associated with commercial
OTEC developrwnt center on the marine environment because it is the source of
evaporator and condensing waters and the receiver of discharge waters used by
the plant. In the long term, there is also concern over potential climatic
effects if extensive development were to take place. As part of their research
and engineering studies directed toward development of OTEC technology, the
DOE and other organizations have devoted considerable attention to identifying
and studying potential environmental problems. Numerous reports describing
the results of these studies have appeared, and these have provided the primary
source material for preparing this section. Reports by the DOE (1979a and b)
have been especially useful in this regard.

2.2.1 General Statutory Requirements

Section 107 of the OTEC Act requires NOAA to initiate a program to assess
the effects on the environment of OTEC facilities and plantships. "The program
shall include baseline studies of locations where ocean thermal energy conversion
facilities or plantships are likely to be sited or operated; and research; and
monitoring of the effects of ocean thermal energy conversion facilities and
plantships in actual operation" (�107(a)). Among other things, the program
shall be designed to determine (�107(b)):

11(l) any short-term and long-term effects on the environment
which may occur as a result of the operation of ocean thermal
energy conversion facilities and plantships;

(2) the nature and magnitude of any oceanographic, atmos-
pheric, weather, climatic, or biological changes in the environ-
ment which m@y occur as a result of deployment and operation of
large numbers of ocean thermal energy conversion facilities and
plantships;

(3) the nature and magnitude of any oceanographic, biological
or other changes in the environment which may occur as a result
of the operation of electric transmission cables and equipment
located in the water column or on or in the seabed, including the
hazards of accidentally severed transmission cables; and

(4) whether the magnitude of one or more of the cumulative
envirom-ental effects of deployment and operation of large
numbers.of ocean thermal energy conversion facilities and plant-
ships requires that an upper limit be placed on the number or
.total capacity of such facilities or plantships to be licensed
under this Act for simultaneous operation, either overall or within
specific geographic areas."

In order to analyze the environmental concerns and trends, it is necessary
to have access to baseline information for those locations where ocean thermal

energy conversion facilities or plantships are likely to be sited or operated.
The Department of Energy has been conducting such baseline studies at a variety
of OTEC sites. This information, in addition to that developed by others, will
be used to discern the general level of environraental risk posed by OTEC
development. Because of the high costs of baseline studies, NOAA will rely
upon the existing baseline information, and new site-specific baseline infor-
mation supplied by applicants for a commrcial license, to neet the baseline
study requirements of the Act (�107(a)).
The potential effects of electric transmission cables will be site-specific
in nature and will also be addressed by an applicant for an OTEC license.
Probably the major potential effect here will be due to the placement of cables
in or on the seabed, where the effects will be very localized.

The more significant environmental concerns relating to the other statutory
requirements are discussed below, including for each concern, a discussion of
our present understanding and a summary of the research required to assess the
potential environmental effects. Each research need has been categorized as of
low, medium, or high priority, based on a judgment of the urgency of meting
the need. The basis of these judgments was provided by an evaluation of several
factors, including: (1) the likelihood that the potential detrimental effects
would really occur, (2) the severity of these effects if they did occur, and
(3) the potential that research in the area of concern has for aiding in prevention
or mitigation of these effects. The identified needs are those judged pertinent
to ccmmrcial OTEC development. NOAA would address some of these needs and
would rely upon certain States, industry, and universities to address others.

2.2.2 Environmental Effects of Individual OTEC Plants

Each separate OTEC facility or plantship, will have the potential for
causing envirom-Lental changes in its own irm-ediate zone of influence. This
subsection presents a discussion of the aspects of greatest concern regarding
the envirormental effects of individual plants.

2.2.2.1 Water Mass Displacements - OTEC plants will require the flow of very
large volumes of water. A closed cycle plant will need approximately 5 cubic
meters per second of both warm, surface water and cold, deep water for each
negawatt of net power generated, resulting in a total flow of 10 cubic weters
per second. The water taken in will, of course, also have to be returned to
the environment. The outflow may be through separate warm and cold water
discharges or as a mixed release. The discharges may also be at various depths
in the water column and may even vary as to whether they are above or below
the thermocline. Whatever the specific details, however, it is certain that
the intake and outflow of water associated with OTEC facilities of any appreciable
size will cause large-scale redistribution of ocean water and of its physical,
chemical, and biological properties.

2.2.2.1.1 Changes in Distribution of Temperature and Saliaity - The natural
thermal structure and salinity gradients near and downstream of OTEC plants
will be altered by large-scale releases of water. The inflows to these plants

may also disturb the distribution of these properties, although to
a lesser extent, as water near the intakes is pulled both vertically and hori-
zontally to meet the intake needs.
These alterations in the basic properties of the ocean have the potential
for causing environmental damage. Marine organisms are sensitive to the level
and degree of fluctuation in the teinperature and salinity of their environment.
Relatively large changes in these properties can directly kill the exposed
organisms. Smaller changes can have less obvious, but none the less highly
detrimental, impacts by affecting basic metabolic and other physiological
processes.

The potential for detrimental impacts exists for all the organism exposed
to OTEC-induced changes in distribution of temperature and salinity. However,
this potential is especially great for the cpen-ocean plankton. Because of
their requirement for deep, cold water, OTEC facilities will be sited in the
open ocean or in coastal areas where open ocean waters come close to shore.
Yet the open ocean organisms are well known to have very narrow tolerance
limits for changes in the properties of their environment. Thus, there is
concern that the OTEC facilities may cause large detrimental impacts on the
open-ocean planktonic community.

Status of Present Knowledge - In order to assess the biological effects of
OTEC-induced alterations in temperature and salinity, it is necessary to estimate
what changes will occur in the distribution of these properties. As the primary
effects are anticipated to be caused by the discharge plumes, it is especially
necessary to understand their behavior. In an attempt to do this, efforts have
been made to develop predictive mathematical models describing the behavior of
such plLmes.

These models have been of two primary t@(pes, near-field and far-field,
depending on the scale of water movement being investigated. Near-field models
are concerned with simulating plume behavior near the plant discharge in the
region where the geometry of this discharge, the initial density and momentum
of the outflow, and the density of the receiving water are the primary controlling
factors. This near-field zone is usually found to be limited to within about
1 kilometer of the point of discharge and is the region of rapid initial mixing.
Far-field models that predict plume movement and dispersion beyond the
near-field region have also been developed. In this region natural processes
such as the ocean currents, turbulence, and planetary rotation control plume
behavior. Dilution of the plum usually proceeds at a much slower rate in this
region than in the near-field.

The models presently available provide gross estimates of plum behavior
in the near- or far-field. Further development and refinement of such models
may be required. Such research will have to include the development of mathe-
matical formulations, as well as the collection and analysis of data which
describe the temperature and salinity distributions associated with OTEC
discharges. Such descriptive data will provide a basis for testing the
mathematical models and identifying their weaknesses so that they can be
improved.

In addition to the mathematical models, actual scaled-down physical models
of OTEC discharges have been used to aid in understanding plum behavior
(Allender et al., 1978). These are useful for studying near-field plume
behavior, but are much less practical for use in estimating plum characteristics
beyond the hnmediate vicinity of the discharge.
Predicting the OTEC-induced alterations in temperature and salinity
distributions is only the first part of assessing the environmental effects of
these discharges. It is also necessary to estimate what influence these altered
distributions will have on the exposed biota. In this area our knowledge is
especially weak, and this is particularly true with regard to the open-ocean
plankton of the tropical oceans. The great majority of the studies that have
dealt with open-ocean plankton have been carried out in temperate areas, relatively
close to the major scientific nations. There have been a number of expeditions
and other cruises that have collected tropical open-ocean plankton, so we have
a fairly adequate picture of the gross composition and relative abundance of
the form in this assemblage. However, little systematic physiological or
ecological work has been attempted with tropical plankton species, so we have
little basis on which to predict what effect a specific OTEC-induced alteration
in temperature or salinity would have on the organisms involved. Beyond the
effects on individual species, moreover, we have even less capability to predict
the consequences of an OTEC facility on the biological system in general.
The planktonic species are all members of the open-ocean planktonic ecosystem
and undoubtedly interrelate with each other in a complex network of ways, as
is generally true within ecosystems. However, we have practically no understanding
of the functional relations in the cpen-ocean tropical system, and so we can
not presently even attempt to predict the consequences to them of OTEC-induced
environmental alterations.
Summary of Research Needs: (1) Develop improved capabilities to predict
the water mass displacements and consequent alterations in distribution of
teRiperature and salinity caused by OTEC plants (High priority). (2) Determine
the tolerance of important individual member species of the tropical plankton,
especially open-ocean species, to temperature and salinity changes of the
magnitude likely to be caused by OTEC plants (High priority). (3) Determine
what effect temperature and salinity changes of this size are likely to have
on the functioning and ecological integrity of the open-ocean plankton ccmuunities
(High priority).
2.2.2.1.2 Nutrient Redistribution - Besides affecting the distribution of
temperature and salinity, water mass displacements caused by OTEC plants
will lead to a redistribution of many chemical properties. The most significant
redistributions will probably be those of the nutrients, especially nitrogen,
since it is often the limiting nutrient in ocean waters. The deep oceanic
waters are relatively enriched with regard to nutrients (Table 1) including
carbon dioxide (source of carbon), while in almost all tropical areas the
surface waters above the thermocline have much lower concentrations. Thus,
OTEC discharge plumes that stabilize above the thermocline way cause large-scale
nutrient enrichment of these impoverished near-surface waters. In almost all
cases phytoplarkton productivity in tropical surface waters is limited by the
availability of useable forms of nitrogen (i.e.,,primarily ammonium and nitrate
nitrogen). Consequently, adding nutrient-enriched water could result in large
increases in phytoplankton production and quite probably also in the types and

relative abundances of the forms that make up this assemblage. These changes
will, in turn, undoubtedly cause secondary effects on the herbivorous zooplarkters
that feed on the phytoplankton and so on up the trophic network of the ecosystems
involved.

The exact effects of OTEC-induced nutrient redistributions will be very
dependent on the depth at which the discharge plums stabilize. Phytoplankton
production is only nutrient limited near the surface. Below a certain depth,
light becomes limiting. In oceanic waters this depth is often about the level
where light penetration falls to 10 percent of the surface value (MacIssac
and Dugdale, 1972). Thus, plumes that stabilize below this depth will have
much less effect on productivity and the ecosystem in general than those that
stabilize at a higher level.

Status of Present Knowledge - As was true regarding the effects of
alterations in temperature and salinity distributions discussed in the preceding
subsection, the first requirement for assessing the effects of OTEC-induced
nutrient redistributions is to determine how the distributions will be altered.
Beyond this need is a requirement to assess the biological consequences of
nutrient redistributions.

A first attempt at estimating the biological response to OTEC-related
nutrient alterations is reported by Sands (1980). Although these results can
only be taken as rough approximations, they indicate the possibility of large
increases of phytoplankton within discharge plumes. For a 40 MWO plant, the
estimates indicate as much as a 30-fold increase in phytoplankton biomass in
the plume 30 to 60 kilometers downstream of the discharge. Such large increases
would certainly have an appreciable effect on the entire biological community
involved. Thus, although no firm conclusions can be drawn from the limited
work conducted so far, the preliminary results show potential for substantial
impact and clearly indicate the need for further investigations.

Summary of Research Needs: (1) Develop improved capabilities to predict
the water mass displacements and consequent nutrient redistributions caused by
OTEC plants (High priority). (2) Determine the effects of these redistributions
on the productivity and other properties of the phytoplankton involved, with a
special focus on the relation between the depth and other characteristics of
the OTEC discharges and the resultant biological effects (High priority).
(3) Determine the secondary effects of nutrient redistribution on zocplankton,
fish, benthos, and other components of the ecosystem involved (High priority).

2.2.2.1.3 Redistribution of Other Chemical Properties - Although the
redistribution of nutrient concentrations is expected to be the most significant
chemical result of OTEC-induced water mass displacements, a number of other
properties vary in concentration between surface and deep water and so will
have their distributions altered by such displacements. Present estimates of
these alterations have not indicated any area of appreciable concern, although
the chemical changes caused by operating OTEC facilities should be monitored
when this is possible and the potential environmental effects reevaluated at
that time.

There is one further chemical redistribution that may be caused by OTEC
plants, but only by those utilizing the open cycle process. Non-condensable
gases (e.g., oxygen, nitrogen, carbon dioxide, etc.) can accumulate in open
cycle plants and cause adverse operating affects; thus will have to be removed.
This will mean that the water released fran these plants will be very low
in dissolved gases, particularly dissolved oxygen. As oceanic plankton
organisms require concentrations of this gas that are near the saturation
level for water, the releases of deoxgenated water from open cycle facilities
poses the potential for environmental degradation.

Status of Present Knowledge - Some very simple calculations are reported
by Sands (1980) concerning the potential of environmental harm from the lowered
oxygen concentrations in the plum from a 40 MWe open cycle OTEC plant. It is
estimated that rapid dilution of the plume with fully oxygenated ambient water
will result in oxygen concentrations in the centerline of the plum reaching
80 percent of ambient within 200 meters downstream of the discharge. Based
on this rapid replenishment of oxygen in the near-field, it is concluded that no
significant adverse effects should occur fram such discharges. Thus, although
these calculations are admittedly rough, there seems little basis for concern
regarding releases of deoxygenated water by open cycle plants.

Summary of Research Needs: (1) Develop improved capabilities to estimate
plum behavior for separate or mixed discharges of deoxygenated water from
open cycle OTEC plants (Low priority). (2) Determine the ecological and other
environmental effects of such discharges (Low priority).

2.2.2.1.4 Climatic Effects - Sea surface temperature is one of the controlling
factors for climate, as is obvious in many coastal areas. OTEC plants have
the potential for altering the climate in their vicinity since they operate on
the basis of extracting heat fram surface waters, and will be responsible for
redistributing waters that are pumped through or entrained by the discharge from
a plant. Since the cooling of surface waters would jeopardize the performance
of a plant, proper engineering and site selection should minimize any such
possible climate implications. However, theoretically there is an upper limit
to the number of plants that may be placed in certain regions without reducing
the surface temperature. Consideration must be given to this for extensive'
development scenarios.

OTEC operations also have another potential for causing climatic alterations.
This is related to the fact that the deep water discharged near the surface
will undoubtedly be supersaturated with regard to carbon dioxide (C02) at times
and may release quantities of this gas to the atmosphere. Changes in the
concentration of atmospheric C02 can have the potential for impacting global
or possibly regional temperatures.

Status of Present Knowledge - Bathen (1975), as reported in Sands (1980),
has used an advection model to investigate what effects the water discharged
fran OTEC plants moored off the big island of Hawaii would have on the temiperature
of the upper or mixed layers of the surrounding ocean. He estimates that the
presence of a 100-MWe plant would change the tezperature by 0.24 to 0.330C in
summer in an impacted area of 3.5 to 11 square kilometers (km2), depending
on current conditions. F)or a larger 240-.MWe plant the temperature change in

summer was estimated to be 0.54*C with an impacted area of 42 km2. These
estimated OTEC-induced temperature alterations are as large or somewhat larger
than the natural diurnal tenTperature fluctuations in the area, which are in
the range of 0.1 to 0.30C. However, they are still small and are predicted
to affect only a relatively limited area. Thus, there seems little basis for
concern that the plumes from any one OTEC plant, unless it is much larger
than any presently contemplated, will cause appreciable climatic effects.
With regard to C02 release, calculations of an upper bound (based on
the C02 in deeper waters in excess of that in surface waters) on the potential
release from a 400--MWe closed cycle plant indicate it to be only about one-fourth
of that given off by a typical coal-fired power plant of the same size (Sands,
1980). Thus, it is concluded that single plants are unlikely to have any
appreciable large-scale effects.
Summary of Research Needs - (1) Estimate the magnitude of the temperature
changes and C02 releases caused by the operation of typical OTEC plants
(Low priority). (2) Determine the climatic effects that result at likely
OTEC sites due to such temperature changes and 002 releases (Low priority).

2.2.2.2 Inflow and Discharqe of Water and Contained Organisms - OTEC plants
will take In -large quantities of water.. It is estimated that OTEC plants will
need approximately 100 times more water than nuclear plants with similar net
generating capacities. The pumping and movement of this water will transport
many of the ambient organisms through the plants, and these organisms will be
subject to the threat of serious damage in two ways. The smaller forms will
be carried along or entrained with the inflowing water and will be exposed to
a variety of hazards as the water passes through, and discharges from, the
plant. Some larger organisms will also be unable to resist the flow of the
intake water. However, these forms will be too large to pass through the
screens placed along the inflows to exclude large objects. Instead they will
be caught or impinged on the screens and probably killed.

2.2.2.2.1 Entrainment - The exact mesh size of the screens that will be
used in OTEC plants is not known and will undoubtedly vary to some extent
among facilities. However, it will probably be in the range from 0.95 to
1.3 centimeters (cm) (Sands, 1980). organisms larger than about three times
the mesh size usually impinge on intake screens. Smaller organisms pass through,
although if they are larger than the mesh size, they may impinge for a time
before they extrude through the mesh and are carried along in the inflow stream.
Thus, as a rough approximation, it can be assumed that organisms less than
about 3 to 4 cm in length will be entrained.
At this size, a variety of small forms, including the phytoplankton, most
of the members of the zooplankton and meroplankton, and many of the forms in
the ichthyoplankton, will be entrained with the water flowing through OTEC
plants. These organism will enter with both the warm and cold water inflows.
However, the numbers will undoubtedly be higher in the warm water flows because
near-surface concentrations of organisms are almost always higher than those
found deeper in the water column. This is especially true for the phytoplankton
forms which can only grow and reproduce in the upper lighted waters.

The organisms entrained with the cold water inflows will be placed under
extremely unfavorable conditions. They will be exposed to large temperature
and pressure changes as well as the physical abuse of passing through the
system and the chemical stress associated with the biocides used to reduce
biofouling of heat exchangers. It is anticipated that all or almost all of
these organisms will be killed.
The organisms entrained with the warm water inflows, at least those in
closed cycle plants, will be exposed to much smaller changes in temperature and
pressure, although they will experience the same physical abuse and biocide
stresses. It is possible that some substantial fraction of these organisms
will survive. This is not true for organisms entrained in the warm water
intakes for open cycle plants. These organisms will be exposed to rapid
decreases in pressure in the flash evaporator of such plants and will be left
behind in the residual water that results when steam is formed.

One of two strategies employed after the two intake water streams have
served their purpose: they may be discharged separately, or they may be
discharged as a mix (combined). Although the choice may depend upon site-
specific considerations, current thought leans toward the mixed discharge.
In either event, and despite what depth the discharge(s) is (are) made, the
effluents will initially seek an area somewhere near the bottom of the mixed
layer at the pycnocline or the seabed itself, whichever occurs first. The
dilution achieved at this point, defined as initial dilution, will be due
to entraim-Lbnt (defined as secondary entrainment) of surrounding ambient waters
along the effluent plum's trajectory. Initial dilution of about 10 to 1
is expected for an averaged size OTEC plant. Assuming that marine organisms
are concentrated and uniformly distributed within the mixed layer of the ocean,
an initial dilution of 10 to 1 mans that the total entrainment (e.g., that
due to the warm water intake and that due to secondary entrainment by a mixed
discharge) will be about 20-fold that pun-ped into the warm intake.
Status of Present Knowledge - Some first approximation calculations con-
cerning the amounts of biomass that will be entrained by OTEC power plants of
40 MWe and 400 MWe capacity are reported by Sands (1980). It is assumed
that only low amounts of phytoplankton and microzooplankton will be entrained
because the major concentrations of these forTm will lie deeper than the
warm water intakes of these plants. This assumption may not be entirely valid,
at least for certain plants. However, given this assumption, the calculations
suggest little likelihood of damage to the populations of these form because
relatively few of their members would be entrained. For the macrozooplankton,
on the other hand, the calculations suggest a much greater amount of biomass
will be entrained because many of these form undergo a diurnal vertical migration
that will cause them to be in the zone of inflow of near-surface intakes for
part of each day. Even for these forms, however, it is concluded that any
detrimental effects are likely to be quite localized.
Going beyond these generalized calculations, consideration is given
(Sands, 1980') to the special problems related to entraiment at OTEC plants
located on, or in close proximity to, shore. As many of the benthic invertebrates
and fishes that inhabit such coastal 'regions have larval and/or egg stages
that are part of theplankton, there is great potential for OTEC plants to
impact the populations of these forms. This problem could be especially acute

for certain larval forms as many'of these are attracted by structures in the
water or by lights. Using a set of simplifying assumptions, calculations are
made of what impact a 400--MWe plant would have if it drew in only coastal'
waters. The calculations indicate that such a plant would entrain each day
approximately 0. 05 percent of the total plankton in the coastal waters around
the Hawaiian Islands and 0.2 percent of that around Puerto Rico. obviously,
if a plant actually did this and destroyed the plankton contained in these
waters, it would almost assuredly have a very serious impact on the ecosystems
involved. This could have especially serious consequences, from an economic
standpoint, on certain commercial and sport fishery stocks.
Considerations of secondary entraim-ent significantly complicate the whole
entrainment issue. Although secondary entrainment does not involve transport
through a plant, it does involve the potential redistribution of a significant
number of organisms, as well as the exposure of these organisms to trace
constitutents and biocides. The effects of redistribution are not known but
have the potential for being significant. For sore situations, it may well be
that the discharge of OTEC waters should be through a discharge pipe that
extends to near the bottom of the mixed layer. This would result in minimal
initial dilution that would negate effects associated with secondary entrain-
ment of upper waters and the contained biota.

Summary of Research Needs: (1) Determine, for representative potential
OTEC sites and operating conditions, the composition and abundance of the
organisms likely to be entrained at the cold and warm water intakes
and by the discharge (High priority). (2) Estimate what fraction of these
are likely to suffer mortality or impainneent (High priority). (3) Estimate what
effect the estimated levels of mortality or impairment of these organisms
will have on their populations, and secondarily on the entire ecosystem (High
priority). Furthermore, this work should pay particular attention to the
effects on species that are commercially or recreationally important.
2.2.2.2.2 Impingement - Certain nektonic and large planktonic organisms
that have limited avoidance capabilities will be subject to impingement on the
intake screens of OTEC facilities. The organisms most likely to be affected
include small epipelagic and mesopelagic fish, small planktonic cephalopods,
macroplanktonic crustaceans, and large gelatinous zooplarkters, such as jellyfish
and comb jellies. Almost all impinged organisms will undoubtedly be destroyed
by the severe physical abuse involved. This may cause significant reductions
in the levels of the populations of the impinged forms which occur downstream
of OTEC plants and so may result in adverse impacts on the downstream ecosystems.
Status of Present Knowledge - Planktonic organisms have such weak pcwers
of locomotion that they tend to be carried along by water currents, although
some of them can nAgrate vertically and so alter the current regime to whiCh
they are subject. Thus, as a first approximation in calculating entraim-ent,
one can simply assume that the plankters present in a parcel of water will
accompany this water if it is drawn into an OTEC plant. This assumption is
not valid for the larger forms that are subject to impingement. Most of these
forms have quite strong powers of locomotion and so can take action to help
them avoid OTEC inflows. Thus, one must take not only the abundance, but also
the behavior, of these forms into account if the impacts of impingement are to
be evaluated.

Unfortunately, the abundance and behavior of the tropical planktonic and
nektonic forms likely to be impinged on OTEC intake screens are very poorly
understood. An attempt to evaluate the impingement problem for the nekton
concluded that the status of knowledge is so inadequate that it is not possible
to do this at present (Sands, 1980).

Operating experience with fossil fuel power plants has shown that impingement
of nekton can often be kept to a minimum by proper design and positioning of
intakes. This may well be possible with OTEC plants. However, the knowledge
concerning the forms that are likely to be impinged is presently so weak that
it is not possible to determine what effect design considerations will have.

Sands (1980) also discusses an attempt to evaluate the magnitude of the
impingement problem for micronekton and gelatinous zooplarkton. This suggests
that the gelatinous plankters may experience the most serious consequences
because they have such limited powers of locomotion that they will be able to
do little to avoid the intake flows. For a typical 400-MWe plant, a daily
impingement of over 2000 kilograms (kg) of micronekton and 148 kg of gelatinous
forms is estimated. It is concluded that these rates may well cause a localized
depression in the abundance of these organisms immediately downstream fran
such a plant, but, because they reproduce quite rapidly, the ecological impacts
will probably be insignificant.

All of these estimates are very preliminary. Because biota avoidance
behavior, which is a very important determinant of amount of impingement, is
so poorly understood, it is not really possible to assess the significance of
the impingement problem. obtaining the information on the behavior of tropical
planktonic and nektonic species that is needed to make theoretical estimations
would be a very tine consuming and expensive proposition. Of necessity, assessing
the significance of the impingement problem will have to rely heavily on a
imre empirical approach based on actual operating experience with representative
OTEC facilities.

Summary of Research Needs: (1) Determine, for representative potential
OTEC sites and operating conditions, the composition and abundance of the forms
likely to be subject to impingement (High priority). (2) Estimate the impacts
that the estimated levels of impingement will have on downstream populations
and ecosystems (High priority). This work should also give special attention
to the effects on camriercially and recreationally important species and on
mitigating strategies.

2.2.2.3 Biota Attraction and Avoidance - Based on experience with offshore oil
platforms and other structures in the oceans, stationary at-sea OTEC facilities
will attract concentrations of organisms. The planktonic larval stages of
sessile forms, such as barnacles and mussels, will use the structures as a
base for settlement. Some motile forms will live on and among these sessile
organisms. All of this will increase the food supply for predaceous organisms
in the area. This, together with the protection offered by the structures and
the use of lights on the platforms at night, will attract such predators,
especially fish. Conversely, organisms sensitive to human activities and
presence may avoid OTEC areas as a result of construction activities, plant
operational support activities, and plant operation noise.

Status of Present Knowledge - The ecological significance of an OTEC
platform on biota attraction or avoidance is not clear at present. 'It is
possible that attracting fish to the vicinty of OTEC intakes will increase
the impacts on their populations. Studies at operating OTEC plants are needed
to assess such effects.

Summary of Research Needs: (1) Determine the kinds and amounts of organisms
attracted or repulsed by typical stationary at-sea OTEC facilities (Medium
priority). (2) Estimate the population and ecosystem impacts of the estimated
attraction or avoidance effects of such facilities (Medium priority). This work
should pay special attention to conmrcially and recreationally important species.

2.2.2.4 Biocide Releases - The biocides used to reduce biofouling in OTEC
plants will, by definition, be toxic to marine organisms. The presence of
these chemicals will contribute to the mortality of organism entrained with
the water passing through these plants. Also, if a biocide persists in a
plume after discharge, it may have detrimental effects on organism that migrate
into, or are entrained with, dilution water entering the plLune.
The magnitude of the detrimental effects will not depend solely on the
amount and type of biocide. Different species have quite different tolerances
to various biocides, and so the severity of problems involved with the use of a
biocide will vary depending on which organisms will be exposed. Also, seawater
contains a multitude of inorganic and organic chemicals. The biocide will
interact chemically, to a greater or less extent, with these substances forming
new compounds, some of which may be toxic thenselves. Thus, determining the
potential toxicity of biocides used in OTEC plants is a complex problem.
Unfortunately, there is even one further complication. With the large
surface areas of the heat exchangers used in closed cycle OTEC plants,
there is great potential for the working fluid to leak into the seawater flows.
As pointed out earlier, chlorine will probably be the biocide and ammonia the
working fluid in most closed cycle OTEC plants. When mixed, these two
substances interact and form products that may be more toxic than the chlorine
by itself.

Status of Present Knowledge - The toxicity of the biocides proposed for
use in OTEC plants will have to be determined. As chlorine will usually be
employed as the biocide, these determinations should focus on the effects of
this substance. Unfortunately, our present knowledge concerning the toxicity
of chlorine includes very little information on the tolerance limits for the
tropical/subtropical organisms that are the principal inhabitants of potential
OTEC sites. However, a review of the toxicity work that has been conducted
does reveal that phytoplankton tend to be the most sensitive organism and may
even be harmed at levels below the detection limit for chlorine of 0.1 milligrams
(mg) per liter (Department of Energy 1979c). As the photosynthesis carried
out by the phytoplarkton directly or indirectly provides the basis for all the
other living components of the ecoysytem, they will have to receive special
attention to assure that chlorine additions are kept within tolerable limits.
It will also be necessary to study the chemical reactions of chlorine in
seawater in order to estimate the major chemical products that will be formed

by chlorine additions. This subject is very poorly understood at present (e.g.,
Block et al., 1977). Beyond this the toxicity of the major products will need
to be determined, and potential effects of these substances estimated.

Some first order approximations of the chlorine concentrations that might
be expected downstream fran 40-MWe and 400-+Iwe OTEC plants are reported by
Sands (1980). It is estimated that the maximum concentration of chlorine in
the plum from a 40-MWe plant will be reduced to 0.01 mg per liter within
about 12 hours (5 km downstream) of discharge. However, the calculations show
that the plunre fram a 400-MWe plant will still have a maximum concentration
0.03 mg per liter after 10 days (100 km downstream). Thus, it is concluded
that 40-MWe plants will affect exposed organisms for less than a day and probably
have only localized inpacts. However, very large plants such as a 400-Mb one
may result in impacts that extend over rather large areas.
Summary of Research Needs: (1) Determine the toxicity of proposed OTEC
biocides (particularly chlorine) to representative species that are important
ecosystem compartments at potential OTEC sites (High priority). (2) Determine
the* chemistry of prcposed OTK biocides (particularly chlorine) in seawater
(both with and without working fluid leaks) and the toxicity of the major
campounds that are produced (High priority). (3) Estimate the type and amount
of environmental risk on downstream populations and ecosystems arising from
the estimated biocide toxic effects (High priority). This work should give
special, but not exclusive, attention to species of major commercial and
recreational importance.

2.2.-2.5 Working Fluid Losses - The working fluid used in a closed cycle OTEC
plant may leak into the environment. It is also possible that sone catastrophic
event, such as a major storm or a collision with a ship, could cause a large
volume spill. As all of the substances proposed as working fluids can, under
certain conditions, cause deleterious biological effects, the possibility of
such leaks and spills presents an environmental concern.
Status of Present Knowledge - A number of substances have been examined
as working fluid candidates for closed-cycle heat exchangers. These include
ccmiTon refrigerants (i.e. , the Freons") and other substances such as prcpane,
sulfur dioxide, and ammonia (Anderson, 1973).
A major consideration in choosing a working fluid is th6 amount of heat
exchanger surface area required per kilowatt of net power produced. Aamnia
has been found to be the most cost effective (Coffay and Horazak, 1980) and
require the least amount of heat exchanger surface area (Owens, 1978).
Estimated amounts of amronia working fluid range between 200 and 1000
cubic meters for a 40--MWe plant to 10,000 cubic meters for a 400-MWe plant.
As amronia may be the working fluid used in the initial development of OTEC
facilities, it is the only substance for which a serious attenpt at
evaluating enviromvental. impacts has been made.
Ammnia is soluble in seawater, with the un-ionized ammnia form being
equilibrium with ionized aumnium. hydroxide. In low concentrations ammnia
can act as a nitrogen source for phytoplankton and so serve as a stimulant to
biological production. However, at higher concentrations it beccmes toxic.

The toxic effect is increased at high pH levels because these favor the presence
of un-ionized ammonia which is the primary toxic form.

Most of the information available on ammonia toxicity toward aquatic
organisms relates to freshwater species. The limited studies that have been
conducted with marine organisms have almost always used temperate zone forms.
Thus, we have practically no ability to make detailed estimates of the impacts
that ammonia leaks would have on typical inhabitants of potential OTEC sites.
However, there is little doubt that large leaks or spills would cause toxic
effects on the environment.

Summary of Research Needs: (1) Determine the toxicity of proposed OTEC
working fluids (particularly ammonia) to representative species that are important
ecosystem carponents at potential OTEC sites (Medium priority). (2) Estimate
the type and amount of environmental risk to exposed downstream populations and
ecosystems arising from the estimated working fluid toxic effects (Medium priority).

2.2.2.6 Trace Releases of Tbxic Constituents - The release of trace amounts
of toxic constituents will arise from at least two aspects of OTEC facilities.
First of all the metallic structural elements will experience seawater corrosion
and erosion which will release metal ions. Secondly the hull will be covered
with a protective coating that will consist of a matrix containing a soluble
toxic compound. This coating will protect the hull surfaces and will also
retard biofouling, but will slowly release its toxic component to the environment.
Both of these types of releases give rise to environmental concerns.

A third possible source for release of trace amounts of toxic constituents
is the process wastewater generated from manufacturing or refining activities,
especially in plantships. Present plans for such activities involve primarily
production of ammonia,or refining of aluminum. Both of these would potentially
involve the release of toxic constituents in the waste water. However, there
is little information available at present on the types and amounts of such
discharges, and there seems no reason to believe that presently anticipated
developments will lead to appreciable environmental impacts. Consequently such
discharges will receive no further consideration here, although a research
program in this area may possibly need to be added in subsequent revision of
this OTEC environmental assessment plan.

2.2.2.6.1 Corrosion and Erosion of Metal Surfaces - OTEC structural con-ponents
will release trace metals as they are corroded and eroded by seawater.
Because of their very large surface areas, the heat exchangers will provide the
major sources of'these releases. However, the piping, pump impellers, and
other minor components will also have metal surfaces that will be exposed to
corrosion. Metal ions are toxic in high enough concentrations, although the
level where this starts to occur varies greatly among the various metals.
Thus, there is some potential for environmental impacts from the toxic effects
of these metal releases.

Status of Present Knowledge - The heat exchangers will probably be
constructed of aluminum, titanium, or stainless steel, although 90/10 copper

nickel alloy has also received consideration. Based on limited data, aluminum
and titanium have been found to be toxic only at relatively high concentrations
(Department of Energy 1979c). Stainless steel also seldom seems to cause
toxicity problems. Thus, there seems little reason for concern regarding the
release of these materials by corrosion or erosion of OTEC facilities. Copper,
on the other hand, is relatively toxic to aquatic life and might possibly cause
toxic effects if used, but this seems unlikely at present.

Summary of Research Needs: (1) Determine the toxicity of likely structural
component materials (particularly aluminum and titanium) to representative
important species from potential OTEC sites (Low priority). (2) Estimate the
type and amount of environmental risk to exposed downstream populations and
ecosystems from the estimated toxic effects of trace releases of structural
materials (Low priority).

2.2.2.6.2 Hull Coating Releases - The toxic compounds present in the hull
coatings of OTEC plants will either slowly diffuse into the water or will
be released gradually as the entire hull coating erodes.* In the past these
compounds have usually been salts of heavy metals (e.g., copper! mercuryl
zinc, and lead). However, more recently organometallic compounds, such as
organolead, organotin, organofluorides, and tributyl tin oxides, have received
more common use. All of these materials are, of course, quite toxic to marine
organism if they are present in any appreciable concentration.

Status of Present Knowledge - Little information exists on the tolerances
of the organism likely to inhabit OTEC sites to the toxic compounds in hull
coating mterials. However, for most of the more commonly used of these
substances, the EPA has established allowable limits that provide for protection.
of the environment when they are used as a hull coating. OTEC facilities
will have to conform to these limits. Based on this and the fact that it
is presently unclear exactly what types of hull coatings will be used, there
seems little reason to devote appreciable research efforts to this concern,
at least at present.

Summary of Research Needs: (1) Determine the toxicity of likely hull
coating materials to representative important species from potential OTEC
sites (Low priority). (2) Estimate the type and amount of environmental
risk to exposed downstream populations and ecoysystems from the estimated
toxic effects of release of these hull coating materials (Low priority).

2.2.2.7 Other Environmental Concerns - This section has attempted to consider
the major environmental concerns that have been identified related to individual
OTEC facilities. However, the list is not intended to be all-inclusive, and
other concerns have been identified such as release of sanitation wastes from
the crew operating OTEC facilities, disruptions of the benthic community from
implantation of OTEC mooring anchors and plant-to-shore transmission cables,
and interference with marine mammal communications due to OTEC generated
underwater noise. At present, the environmental threat appears to be minimal
for these potential problems; however, such problems may be judged at a later
date to pose a more significant danger. At present the plans for OTEC

plants are too vague to allow clear assessmient of all potential problems.
As planning progresses, it will be necessary to -reevaluate the situation. If
such evaluations reveal additional significant concerns or a need to cha ,nge
priorities, a change in emphasis will be required.

2.2.3 Cumulative Environmental Effects of OTEC Plants

The preceding section has discussed the major concerns related to the
environnental impacts of individual OTEC plants. These impacts, even where
possibly serious, will be limited to rather restricted areas. However, the
effects of siting multiple facilities may reinforce each other, causing impacts
over an entire region. On an even larger scale, the operation of a large
number of OTEC facilities throughout the world could affect the global oceans
and atmosphere with potentially serious large-scale consequences.
The OTEC Act of 1980 specifically expresses concern regarding such cumulative
environmental effects. It requires that determinations be made as to whether
limits are required in the numbers or capacities of OTEC facilities either
overall or in specific geographical regions.

Status of Present Knowledge - Man's past and present use of the oceans
does not include actual experience with anything which approaches the scale
of the operation of multiple, large OTEC plants. Thus, direct observations
pertaining to the effects of such operations are not available, and any attempt
to estimate them must be based on extrapolating fran the observed or estimated
impacts of much smaller scale activities, and from pertinent information on
the effects of natural upwelling in the oceans.

A first attempt at assessing the potential for serious environmental
impacts from the operation of multiple OTEC plants is discussed by sands (1980).
He presents simple calculations estimating some of the cumulative effects of
an OTEC "Park" in the eastern Gulf of Mexico containing 146 moored platforms
of 400-MWe capacity.

The calculations indicate that the water flow fran such a park would be
approximately 0.5-percent of the flow of the Gulf Stream. This might well
result in small-scale "OTEC water masses" being identifiable for long distances
downstream of such parks. As with the discharges from an individual facility,
these water masses will tend to exhibit higher nutrient values than would
occur naturally. These altered conditions will affect biological production
and quite probably result in substantial changes in ecosystem structure and
function over a large area downstream. In many ways these impacts. will probably
parallel the biological and chemical successional changes that occur naturally
downstream from areas of oceanic upwelling.

These water masses will, of course, also carry along any toxic substances
that they have acquired while passing through the OTEC park. If the OTEC
plants use chlorine as a biocide, residual concentrations of this substance
may be present appreciable distances downstream from the park. Sands does not
attempt to calculate the concentrations or biological effects of the residual
chlorine, but he does indicate that serious problems may occur.

Sands does present estimates of the concentration of hull coating material
that would result in the eastern Gulf of Mexico from the siting of an OTEC
park in this area. The calculations show the release of amounts that are
equivalent to those needed to produce a concentration of 2.7 grams per cubic
meter (2.7 ppm) in a layer 60 meters deep over the entire area. He has no
information on the biological effects of maintaining such low, but still elevated,
concentrations of toxic materials over such a large area. However, he points
out that bioaccumulation of such substances might pose a hazard to sport and
ccmmercial fishes and to those who consume them.

Sands also presents calculations on the amounts of biomass that would be
entrained and impinged by an OTEC park. The rough calculations indicate that
such a park might impinge over 300,000 kg of micronekton each day. This is
equivalent to destroying about 1-percent of the entire daily potential nekton
production of the eastern Gulf of Mexico. Further, almost 130,000 kg of
macrozocplankton are estimated to be entrained each day. This is equivalent
to about 3-percent of the total macrozooplankton biomass in the upper 1,000
meters of the eastern Gulf of Mexico region. With our present state of knowledge,
it is not possible to assess the ecological consequences of environmental
disruptions of this magnitude. However, these preliminary calculations certainly
give rise to serious concern over large-scale OTEC development scenarios, and
indicate the need for research directed toward predicting the consequences.
Finally Sands reports the potential effects of an OTEC park on climate.
Interpolating fran calculations of Martin and Roberts (1977), estimates indicate
that a park with 146 large OTEC platforms in the Gulf of Mexico could cause a
decrease in.sea surface temperature of about 0.1 to 0.150C. Although the
resulting effects on the climate of a change of this magnitude cannot be made,
it is concluded large enough to indicate the necessity for further study.
A rough estimation of the amount of OC)2 that would be released from the
oceans due to the operation of an OTEC park is also made. Sands rep
,?rts that
the C02 efflux from such a park would be in the range from 2.18 x 10 kg
per day to 3.74 x 108 kg per day. As it is believed that such releases are
much less than would occur with coal-fired plants of the same capacity, it is
suggested that they do not present a great problem. However, it is concluded
that they might have an effect on the regional climate if all the plants of an
OTEC park were sited-in a relatively small area.
Summary of Research Needs: (1) Estimate the cumulative effects on oceanic
physical properties (especially water movements and temperature) of siting
multiple OTEC plants in specific regions and basins (High priority). (2) Estimate
the cumulative effects on oceanic chemical properties (especially concentrations
of nutrients and toxic substances) of siting multiple OTEC plants in specific
regions and basins-(High priority). (3) Estimate the cumulative effects on
biological properties (especially production and ecosystem integrity) of siting
multiple OTEC plants in specific regions and basins (High priority). (4) Estimate
the cumulative effects on the climate of specific regions of siting multiple
OTEC plants in those regions and on the global climate of siting many OTEC
facilities throughout the world (High priority).

2.2.4 Direct Licensing Requirements

The regulatory approach preferred by NGAA for licensing commercial OTEC
development is that of minimal regulation (NOAA, 1981a and b). Under the
minimal regulation alternative, NOAA will use minimal guidelines and performance
standards to conform to the goals and provisions of the OTEC Act of 1980.
These guidelines will be in conformance with NPDES regulations, Ocean Discharge
Criteria, and other applicable regulations as agreed upon by the Administrator
of NOAA, the Environmental Protection Agency, and other pertinent responsible
agencies. Simultaneously, NOAA is also required to ensure that OTEC plants do
not interfere with each other. This will require knowledge of the physical
and bio-chemical characteristics of the intake and discharge flows in the
vicinity of OTEC plants. Although the minimal regulation alternative results
in maximum flexibility for plant design and operation, it also is dependent
upon monitoring to ensure environmental compatibility. The monitoring of
environmental effects, which the licensee is required to perform by Section
110(3) of the OTEC Act, will alert NCAA to significant problem areas which
might need to become the subject of future license terms and conditions. Th
ensure the cost-effectiveness of such regulatory monitoring, careful thought
must be given to the design and implementation of monitoring programs. There
is need for research related monitoring of full-scale OTEC plants in order to
gain a better grasp of actual environmental effects. This research monitoring
could provide verification of theoretical and other assessment techniques
regarding OTEC environmental effects.

Status of Present knowledge - Under the minimum regulation approach, NOAA
will consider and respond to proposals made by license applicants, instead of
prescribing uniform standards for the applicant to follow, except where such
standards are mandated by regulation. The flexibility afforded the applicant
under this approach will allow the prospective OTEC plant owner to propose
what he considers to be the best environmental and engineering design for the
plant and to design a cost-effective means of mitigating or reducing adverse
environmental impacts resulting from plant operation. The flexibility would
allow incorporation of new technology into OTEC plant design.as the technology
is developed, and provide for site-specific license terms and conditions to
protect the environment.

One primary reason for adapting the minimal regulation approach is that
there is little experience with a full scale OTEC plant. Although physical
(hydraulic) and numerical models have been utilized to predict the intake and
discharge flow behavior near a plant (Ditmars, 1979), such predictions are
valuable but limited. While monitoring observations are being roade on the
operation of OTEC-1, these results are also limited since they reflect the
operation of a scaled down plant in the full-scale environment.
The discharge from one OTEC plant may reduce the thermal resource available
to other plants by either entering the warm water intake of a plant downstream
or by effectively "thinning" the mixed layer downstream and therefore increasing
the likelihood that cooler water near the bottom of the mixed layer will be
drawn up into the intake of neighboring plants (Ditmars and Paddock, 1979).
Jirka (1978), as noted by Ditmars, and Paddock (1979), has examined
the minimum plant spacing that would preclude the discharge from one plant

fram interfering with the effective thermal resources available to neighboring
plant. For a raw of plants oriented perpendicular to the dominant current
direction and an ambient mixed current depth of 70 meters, a minimum lateral
spacing of 480 meters is indicated for 100 MWe plants and 36,000 meters
for 400 Me plants. For the case of a rectangular grid of plants where the
mixed-layer depth is 70 meters, the ambient current 0.1 meters per second,
and five rows, a minimum spacing of 5,570 meters is estimated for 100 MWe
plants, and 160,000 meters for 400 MWe plants.

The above estimates only provide a perspective of OTEC plant spacing;
further work on plant spacing should address the problem of other environmental
impacts that may also bear on plant spacing limitations (Ditmars and Paddock,
1979). The predictions resulting from such studies could be verified through
monitoring ef forts.

SLzmary of Research Needs: (1) Develop a model that provides a conservative
estimate of the boundary surrounding a proposed OTEC plant, outside of which
another plant's efficiency would not be impacted (High priority). (2) Design
a monitoring program that will cost-effectively provide generic information on
the cperation and impacts of OTEC plants (High priority). (3) Implement research-
related monitoring programs for approved OTEC plants (High priority).

3. ENVIM4@=AL RESEARCH PLAN

3.1 STRATEGY

The preceding section has identified the major research categories
that require attention in order to reduce the uncertainties regarding the
relationship between environmental risk and commercial OTEC development.
Based on preliminary evaluation of the environmental concerns (NOAA, 1981a),
it is felt that the environmental risk associated with the development is
minimal; however, there are areas that require better definition to assure
this to be the case.

NCAA and DOE both have authority to address the environmental canpatibility
of OTEC technologies; however NOAA's responsibilities here focus on licensing
and facilitating cammercial develcpment of OTEC whereas DOE's responsibilities
have focused on the technology development.

It is apparent that, to avoid duplication, NOAA and DOE must coordinate
with each other in such a manner as to facilitate commercial application
of OTEC technology. Such has already been the case and, to this end, the
research plan is designed to build on the studies conducted by DOE. The DOE
studies primarily address relatively small scale (as ccrnpared to regional or
ecosystem level) single plant effects. The research program needs discussed
herein primarily focus on the large-scale and long-term ecosystem implications,
and on multiple facility impacts. Furthermore, the research elements that
NCAA will address are those judged to be critical to NOAA's regulatory
responsibilities.

3.2 RESEARCH ELEMENTS

The following research elements of the research plan are based on the
needs identified in Chapter 2 and on an assessment of studies completed by DOE
or now being ccmpleted in support of OTEC. They represent those topics that
should be addressed by NOAA, certain States, industry, and the academic sector
in order to provide more certainty about the environmental implications
of OTEC. Section 3.3 then discusses those elements that NOAA considers
essential to its responsibilities under the OTEC Act.

3.2.1 Water Mass Displacements

3.2.1.1 'Temperature and Salinity Effects - This research element responds to
the need to determine what effects temperature and salinity changes will have
on the ecological integrity of the cpen-ocean plankton cammunity. Using infor-
mation on discharge plume characteristics and species tolerance, a determination
will be made of effects on the mortality and distribution of the cpen-ocean
plankton ccmmunity for variable plume configurations (single and multiple
plants) and variable distances fran the near- to far-field. (High Priority)

3.2.1.2 Secondary Effects of Nutrient Redistribution - The most immediate
effect of nutrients in the open ocean is the assimilation by phytoplank6on
and conversion to biomass. The effects of this conversion on the rest of the
ecosystem are referred to as secondary effects and can be either beneficial
(e.g., increased fisheries) or detrimental (e.g., eutrophication with associated
problems).
This research element will focus on the secondary effects of nutrient re-
distribution on zopplankton, fish, benthos, and other involved components of the
ecosystem. The long-range implications to fisheries is of particular concern.
(High Priority)

3.2.1.3 Effects of the Redistribution of Other Chemical Properties
Chemical properties other than tenpera6u_resalinity, and nutrients will be
directly or indirectly affected by the water mass displacements resulting from
from OTEC operations. Such changes could relate to turbidity and dissolved
gases. For the latter category, the major concern relates to the discharge
of deoxygenated water from open-cycle OTEC plants. Such discharges could
impact.certain biota if sufficient dilutions are not achieved quickly.
This research element will determine the potential environmental effects
of the redistribution of other chemical properties, focusing primarily on
the potential problems of discharging deoxygenated water from open cycle
plants. Results of plume studies, combined with advective/diffusive
laws, will be used to determine the characteristics of the discharge plume
downstrean of a plant. This information will be coupled with knowledge of
species tolerances to assess the ecological inpacts. (Low Priority)

3.2.2 Inflow and Discharge of Water and Contained Organisms
3.2.2.1 Entrainment Effects - One of the major concerns of CITEC development
is the potential for adverse impacts on fisheries and other biota by primary
entrainment, due to the pumping of large volumes of water into and through an
OTEC plant. Secondary entrainment that results when the discharged waters
entrain surrounding ambient waters (process of initial dilution) will also be
addressed. This research element will consider the long term impact on
critical parts of the marine ecosystem, focusing on the effects to fisheries.
(High Priority)

3.2.2.2 Impingement Effects - Like entraiment, impingement of organisms on
OTEC intake screens is also a major concern associated with the puffping of
large volumes of ocean water. This research element will focus on the longer-
term effects of impingement to other critical parts of the marine ecosystem,
particularly fisheries. (High Priority)

3.2.3 Biota Attraction and Avoidance Effects
Biota may either be attracted to or repelled from CITEC structures, both

of which could have potential adverse effects. Based on observations near
OTEC-1 and other ocean platforms and structures, this effort will assess the
potential magnitude and ecosystem implications of such effects. (Medium Priority)

3.2.4 Biocide Effects

Dependent upon the biocide used to reduce the problem of biofouling in
OTEC heat exchangers, the release of biocides to the ocean poses concern from
the standpoint of both human and marine-ecosystem health. Information has
been developed on the sea water chemistry of chlorine (currently the preferred
biocide) and toxicity to certain biological species. Using such information,
and information on OTEC discharge plume characteristics, this research effort
will assess the primary and secondary effects on the marine ecosystem of the
use of potential biocides. (High Priority)

3.2.5 Effects of Trace Releases of Thxic Constituents

The release of trace constituents from OTEC plants could also pose
adverse implications for human and marine-ecosystem health. Some information
has already been developed on the release of trace constituents, (e.g.,
corrosion and leaching products). Such information should be assessed regarding
the potential for environmental risk. If significant risk is involved, this
research element will focus on the marine ecosystem, and possible public health,
implications. (Low Priority)

3.2.6. Cumulative Environmental Effects

Any enviromental concern over OTEC development is magnified when consid-
eration is given to multiple plants located within the same regional areas.
This relates to the cumulative and interactive effects that may develop if too
many facilities are placed within one geographic region. Research on such
effects will include (High Priority):

long-Range Biological Effects: OTEC involves the redistribution
,of large volumes of ocean waters of different chemistries, the use of
biocides in this water, and the entrainment and impingement of biota.
As a consequence, the potential exists for biological effects that may
be of a long-term nature, involving long"latencies and slow recovery.
Regional Heat Balance Alteration: OTEC relies upon extracting heat
frcm the surface waters of the ocean to generate electricity. This heat
represents the result of a number of processes including insolation,
evaporation, absorption, reflectance, advection, and convection. Like
any other renewable resource, this heat is renewable only at a certain rate.
Heat balance alterations, and thus seawater temperature changes, could
occur in certain regions if the rate at which heat is extracted exceeds
the capacity for renewal.

Climatic Perturbations: Since OTEC plants have the potential for

altering the heat content of ocean waters, and since they may involve
the release of carbon dioxide contained at greater concentrations in
deeper and colder ocean waters, there is also a potential for climatic
effects. Such effects are remote under early development scenarios;
however, this may not be the case for extensive development scenarios.
This research element will focus on these longer term and larger scale
problems. Site and regional specific environmental information will be
combined with operational and discharge characteristics of potential
OTEC plants located in certain regions to assess the long-term integrity
of the thermal and biological resources. The probability of climatic
impact due to present OTEC development scenarios is remote; thus, monitoring
of single plant effects on climate can be used as part of the analytical
procedure to assess the future probability of climatic perturbations.

3.2.7 Direct Licensing Requirements for Environmental Information

As discussed in Section 2.2.3, there are requirements for environmental
research that are directly linked to the licensing process. These relate to
developing a methodology for assessing the interference between multiple OTEC
plants, designing a monitoring program for operational OTEC plants, and imple-
menting monitoring programs. (High Priority)

Under the OTEC Act, NOAA must determine, within 21 days of receipt of an
OTEC license application, the extent of the area's within which operation of
the proposed OTEC plant might interfere with the operation of another OTEC
plant and within which the operation of another OTEC plant might interfere
with the operation of the proposed OTEC plant. This determination is a complex
one based on the design and operating characteristics of the proposed plant
and the physical oceanographic and meteorological characteristics of the
proposed site. Research on this topic will develop a methodology for defining
the areal extent of potential interference.

monitoring programs would serve two purposes: (1) satisfy licensing
requirements as called for under the NPDES permit system, and (2) provide
information needed to better assess the realm and degree of impact of this
new technology. Each licensee is required by law to perform monitoring in
accordance with an NPDES permit. NOAA plans to take advantage of this
opportunity by supporting some additional monitoring that would serve
research purposes.

3.3 NOAA RESEARCH PLAN

NOAA has-carefully assessed the relative roles of the various research
elements listed above in terms of NOAA's responsibilities, timeliness, and
cost-effectiveness. It has decided that there are two general areas of
research that are critical to its responsibilities in the early commercial
stages of OTEC, and which will be addressed with the available funding:

(1) Effects to fisheries

(2) Direct licensing requirements

In the next few years, NOAA will focus on developing methodologies to determine
the flow and circulation that will be induced by an OTEC operation, the resulting
redistribution of physical-chemical properties, and the potential effects to
fisheries. Studies to be initiated during EY 81-83, and the projected budgets,
are noted in Table 4.

As a start, $60K was directed in FY 81 towards a study on initial screening
procedures for discerning the general interaction of an OTEC plant with the
marine environment. The strategy for this consists of three steps: character-
ization of the plant and site, characterization of the seawater intake and dis-
charge flow fields, and consideration of the major marine environmental issues
associated with OTEC operations. The final report, to be completed in FY 82,
will aid NCAA in responding to early.applications for a commercial OTEC license.

During FY 82-83 ($125K in EY 82, $150K in EY 83), a study of the flow and
circulation induced by an OTEC plant will couple what has been learned through
past research efforts on the vertical redistribution of water column properties
to a larger scale model, or models, that will account for regional circulation.
The intent will be to provide an estimate of the regional influence of an OTEC
plant. This study will address NOAA's responsibilities for determining the area
of influence of OTEC operations, and therefore the interference between multiple
OTEC plants. It will also provide a means for assessing the redistribution of
physical, chemical, and biological properties. Definition of the redistribution
of properties will, in turn, provide NOAA with the means for assessing biological
and other effects. The intent of this study will be to provide a conservative
methodology, so as to identify plausible worst case possibilities.

NOAA believes that the "Achilles heel", if any, to OTEC siting and operation
could be the effect to fisheries or other biologically important resources such
as corals. Thus, the second emphasis of the NOAA research effort in FY 82-83
will be the potential effects to such resources. The key concerns here will be
entrainment and impingement; however, consideration will also be given to the
effects of nutrient and seawater redistribution, and biocide usage. NOAA further
believes that there is much information that has been gained in this regard from
the operations of nuclear and fossil-fueled power plants. Thus, as a first
step, NOAA will conduct a review of what has been learned from such operations
within the context of an OTEC operation ($125K in FY 82). The product will
include an assessment of risk to fisheries by an OTEC operation, and the identi-
fication of potential mitigation strategies. It will also outline the details
of research efforts on fishery effects that would reflect an up-to-date appraisal
of needs that are consistent with OTEC development scenarios at the end of FY
82. Based on the results of this synthesis, $200K will be directed in FY 83
towards additional research on fishery effects.

The other research elements listed in Section 3.2 will be addressed by
.the staff in the NOAA Office of Ocean Minerals and Energy, working with available
and developing knowledge including the oceanographic and other site-specific
information that will be submitted to NOAA by applicants for c<xm-ercial OTEC
licenses. NOAA will also be exploring cost-sharing arrangements with certain
States, and the private and academic sectors, to seek further support for research
-needed beyond FY 83.

Table 4. NQAA CTEC ENVIRONMENTAL RESEARCH BUDGET: FY 81-83

BUDGET
PRCUECTIONS a
FY RESEARCH ACTIVITY $K

1981 1. OTEC License Screening Procedures 60
Totals $60K

1982 1. Direct Licensing Requirements 125

2. Fishery Effects 125
Thtals $250k

1983 1. Direct Licensing Requirements 150

2. Fishery Effects 200
Totals $350K

Notes:

a) Budget figures include estimated management costs.

3.4 MANAGEMENT

3.4.1 Planning

This document presents NOAA's initial development of an overall plan
for conducting a program to assure the environmental compatibility of OTEC
cperations. This planning activity will obviously need to be a continuing
process. As results are obtained, new concerns will be identified and old
ones found to be of greater or lesser significance than previously believed.
Shifts in the direction in which OTEC development is proceeding may require
changes in emphasis in the assessment program. Thus, the plan for environmental
assessment will need to be updated and revised. This will be carried out on a
regular basis, and a revised version of the plan will be issued every two years.
The information and opinions on which each revision will be based will be
drawn fram as wide a range of sources as possible, including public interest
groups and industry.

3.4.2 Program Implementation

The OTEC enviromental assessment program will be accomplished using a
variety of mans to carry out the required research. A certain amount of
analysis and synthesis, especially regarding overall impacts, will be conducted
by staff within the NOAA Office of ocean minerals and Energy. Additional
support will be sought from other organizational elements of NOAA and, in
some cases, other organizations. The latter will include certain States,
the private sector, and universities.

The personnel responsible for directing the OTEC environmental assessment
will be part of the grot4p in the Office of Marine Minerals and Energy that
is responsible for NCRA's involvement in OTEC development. In addition to
directing the environmental assessment program, this group will be responsible
for writing all required environmental impact statements and establishing
the environmental terms and conditions of an OTEC license. The assignment of
the management of all of NOAA's activities regarding OTEC to one group is
intended to ensure that the program is well-coordinated and that there is
continuity and consistency in the policies adapted.
Investigators that are funded by the program will be periodically
required to submit written reports on the technical progress of their projects
and to participate in review and evaluation meetings. They will be strongly
enccuraged to publish the results of their work in the cpen scientific literature
in order to obtain.peer review and better dissemination of their results to the
scientific camnunity.

3.4.3 Review and Evaluation

A working group made up of individuals involved in the issues associated
with OTEC development will be established to provide advice and recommendations
on the relevance and timeliness of the program in terms of: (1) legal and

regulatory requirenents, and (2) scientific and engineering validity. This
group will actively assist in the planning and evaluation of the program and
in determining whether it is using the resources available in the most efficient
and effective way to met the stated goals.

4. REFERENCES

Allender, J. H., J. D. Ditmars, R. A. Paddock, and K. D. Saunders. 1978. (YrEc
physical and climatic impacts: An overview of modeling efforts and needs.
Preprint from Fifth Ocean Thermal Energy Conversion Conference. February
20-22, 1978. Miami Beach, Fla.

Arsen'ev, V.S., L.I. Galerkin, E.A. Plakhin, and V.V. Saponzhirkov. 1971.
Major hydrological and hydrochemical features of the region investigated
during the 44th cruise of the VITAZ. In: Life Activity of Pelagic
Communities in the Ocean Tropics. Vinogradov, M.E., ed. Israel Program
For Scientific Translation Jerusalem. 298 pp.

Atwood, D.K., P. Duncan, M.C. Stalcup, and M.I. Barcelona. 1976. Ocean ther-
mal energy conversion: resource assessment and envirormental impact for
proposed Puerto Rico site. Final report NSF Grant AER 75-00145.
NOWACML. Miami, FL. 104 pp.

Bathen, K.H. 1977. An evaluation of oceanographic and socioeconanic aspects
of a nearshore ocean thermal energy conversion pilot plant in subtrcpical
Hawaiian waters. National Science Foundation, Energy Research and
Development Administration.

Bathen, K. H. 1975. A further evaluation of oceanographic conditions found
off Keahole Point, Hawaii, and the environmental impact of nearshore ocean
thermal energy conversion plants on subtrcpical Hawaiian waters.
Dept. Planning Economics, Univ. Hawaii. 77 pp.

Beers, J.R., D.M. Steven, and J.B. Lewis, 1968. Primary productivity in the
Caribbean Sea off Jamaica and the tropical north Atlantic off Barbados.
Bull. Mar. Sci. 18:86-104.

Beers, J.R. 1978. Personal ocmmunication to Interstate Electronics Corporation
Anaheim, CA. Institute of Marine Resources University of California,
San Diego, CA.

Beers, J.R. and G.I. Stewart. 1969. Micro-zooplankton and its abundance
relative to the larger zoonplankton and other seston components. Marine
Biology 4:182-189.

Block, R. M. , G. R. Helz, and W. P. Davis. 1977. Fate and, effects of chlorine
in marine waters. Chesap. Sci. 18:92-101.

Bogdanov, D.V., V.A. Sokolov, and N.S. Khromov. 1969. Regions of high bio-
logical and cam-nercial productivity in the Gulf of Mexico and Caribbean
Sea. All Union Scientific Research Institute of Marine Fisheries and
Oceanography. pp 371-380.

Brewer, P.G. 1978. Carbon dioxide and climate. Oceanus 21(4):13-17.

Churgin, J., and S. Halminski. 1974. Temperature, salinity, oxygen and
phosphate in waters off United States. Volume II. Gulf of Mexico.

National Oceanographic Data Center. Washington, D.C. 117 pp.

Crutcher, H.L. and R.G. Quayle. 1974. Mariners worldwide climatic guide
to tropical storms at sea, NAVAIR 50-lC-61. Naval Weather Service
Command. Washington, D.C.

Cummings, S.R., Jr., D.K. Atwood, and J.M. Parker. 1979. Inorganic nutrients
and dissolved oxygen variation determined from historical data at three
proposed ocean thermal energy conversion (OTEC) sites: Puerto Rico,
St. Croix, and Northern Gulf of Mexico.

Department of Energy. 1978. Large scale distribution of OTEC thermal resources.
Delta.T('C) between surface and 1,000 m depth. ODSI. Contract No.
EIT-78-C-01-2898.

Department of Energy. 1979a. Environrmntal development plan for ocean thermal
energy conversion. U.S. Dept. Energy, Asst. Sec. Energy Tech., Asst. Sec.
Env., 48 pp.

Department of Energy. 1979b. Environmental readiness doomient-ocean thermal
energy conversion. U.S. Dept. Energy, Asst. Sec. Env., 26 pp.

Department of Energy. 1979c. Environmental assessment-ocean thermal energy
conversion (OTEC) program. Preoperational ocean test platform. U.S. Dept.
Energy, Asst. Sec. Energy Tech., Vol. 1.

Department of Energy. 1980. Draft Report - The potential environmental
consequences of ocean thermal energy conversion (OTEC) plants. A
workshop held at Brookhaven National Laboratory. Upton, New York.
January 22-24, 1980. 106 pp.

Department of Labor. 1972. Occupational safety and health standards,
air contaminants. Occupational Safety and Health Administration.
37 Federal Register 22139-22144, Oct. 18, 1972.

Ditmars, John D. and R.A. Paddock. 1979. OTEC physical and climatic
environmental impacts. Proceedings of the 6th OTEC Conference.
June 19-22, 1979. Washington, D.C. 13.11-1 to 13.11-8

El-Sayed, S. Z., W.M. Sackett, L.M. Jeffrey, A.D. Fredericks, R.P. Saunders,
P.S. Conger, G.A. Fryxell, K.A. Steidinger, and S.A. Earle. 1972.
Serial atlas of the marine environment, folio 22, chemistry, primary
productivity-, and benthic algae of the Gulf of Mexico. American
Geographical Society. New York, New York.

Eppley, R.W., E.H. Renger, E.L. Venrick, and M.M. Mullin, 1973. A study of
plankton dynamics and nutrient cycling in the central gyre of the north
Pacific Ocean. Limnology and Oceanography 18(4):534-551.

Gilmartin, M. and N. Revelante. 1974. The "island mass" effects on the
phytoplankton and primary production of the Hawaiian Islands. J. Exp.
mar. Biol. Ecol. 16:181-204.

Gordon, D.C., Jr. 1970. Chemical and biological observations at station
Gollum, an oceanic station near Hawaii, January 1969 to June 1970.
Hawaii Institute of Geophysics. Report No. 70-22. University of
Hawaii, 50 pp.

Gross, M.G. (1972). Oceanography: A view of the earth. Prentice-Hall Inc,
Englewood CLiffs, NJ. 580 pp.
Gundersen, K.R., J.S. Corbin, C.L. Hanson, M.L. Hanson, R.B. Hanson,
D.J. Russell, A. Stoller, and 0. Yamada. 1976. Structure and biolo-
gical dynamics of the oligotropic ocean photic zone off the Hawaiian
Islands. Pacific Science 30:45-68.

Gundersen, K.R., C.W. Mountain, D. Taylor, R. Ohye, and J. Shen. 1972. Some
chemical and microbiological observations in the Pacific Ocean off the
Hawaiian Islands. Limnology & Oceanography 17(4):524-531.
Gundersen, K.R. and R.Q. Palmeri. 1972. Report on aquaculture and ocean energy
systems for the county of Hawaii. Center for Engineering Research,
University of Hawaii. Honolulu, Hawaii.
Halminski, S.J. 1975. Temperature, salinity, oxygen, and phosphate in waters
off eastern Central America and northern South America. National
Oceanographic Data Center. Washington, D.C. 189pp.
Hargraves, P.E., R.W. Brody, and P.R. Burkholder. 1970. A study of phyto-
plankton in the Lesser Antilles region. Bull. Mar. Sci. 20(2):331-349.
Hirota, Jed. 1977. DOMES zooplankton. Part 1 - Data report. Deep Ocean
Mining Environmental Study (DCMES). Unpublished manuscript No. 5, NOAA/
Environmental Research Labs. 713 pp.
Hodgman, C.D., ed. 1959. Handbook of chemistry and physics, 40th ed.
Chemical Rubber Publishing Co., Cleveland, CH.
Holtzclaw, P. 1981. 'Personal Ccmmunication to Interstate Electronics
Corporation, Anaheim, CA. Environmental Protection Agency,
Washington, D.C.

Howey, T.W. 1976. Zooplankton in the Gulf of Mexico: distribution of dis-
placement volume, occurrence of systematic groups, abundance and diver-
sity amount ccpepods. Ph.D. Thesis, Louisiana State University. 99 pp.
Jirka, G.H. 1978. Preliminary guideline for the siting of multiple ocean
thermal energy conversion (OTEC) plants (Draft). Dept. Envir. Engr.,
Cornell Univ., Ithaca, N.Y.

Johnson, P.W. and A.J. Horne. 1979. Phytoplankton and biomass distribution
at potential OTEC sites. In: Preprints of the Sixth OTEC Conference.
U.S. Department of Energy, Washington, D.C.
Jones, J.I., R.E. Ring, M.D. Rinkel, and R.E. Smith, eds. 1973. A summary of

knowledge of the eastern Gulf of Mexico. State University System of
Florida. 615 pp.

Keeling, C.D. and R.B. Bacastow. 1977. Impact of industrial gases on climate.
In: National Research Councel. Studies in Geophysics: Energy and
Climate. National Academy of Sciences, Washington, D.C.

King, J.E. and T.S. Hida. 1954. Variations in zooplankton abundance in
Hawaiian waters, 1950-1952. United States Department of Interior
(USDOI), Fish & Wildlife Service. Special Scientific Report: Fisheries
No. 118. 65 pp.
King, J.E. and T.S. Hida. 1957. Zooplankton abundance in the central Pacific,
Part II. Fish. Bull. 57:365-395.

Koblentz-Mishke, O.J., V.V. Volkovinsky, and J.G. Kabanova. 1970. Plankton
primary production of the world ocean. In: Scientific Exploration of
the South Pacific. W.S. Wooster, ed. National Academy of Science,
Washington, D.C.
Lawrence Berkeley Laboratory, Marine Science Group. 1979. Cruise data from
candidate OTEC sites. Lawrence Berkeley Laboratory. Unpublished
reports and date sheets. University of California, Berkeley, CA.
Love, C.M., ed., 1971. EASTROPAC Atlasses, 1967-68. NMFS Circ. 300. 11
Volume.
MacIssac, J.J. and R.C. Dugdale. 1972. Interactions of light and inorganic
nitrogen in controlling nitrogen uptake in the sea. Deep-Sea Res. 19:
209-232.
Mahrken, C.V.W. 1969. Primary organic production and standing stock of zoo-
plankton in the tropical Atlantic ocean - Equalant I and II. Bull.
Mar. Sci. '19:550-567.

Martin, P.J. and G.O. Roberts. 1977. An estimate of the impact of OTEC
operation on the vertical distribution of heat in the Gulf of Mexico,
p.IV-26 to IV-34. In Ocean Thermal Energy Conversion Conference.
March 22-24, 1977. New Orleans, La.
Michel, H.B. and M. Foyo. 1976. Caribbean zooplankton. Part I. Siphonophora,
Heteropoda, copepods, Euphausiacea, Chaetognatha, and Salpidae. office
of Naval Research, Dept. of the Navy. Washington, D.C. 549 pp.
Molinari, R.L. and F. Chew. 1979. ocean thermal and current structures in
the tropical South Atlantic relative to the placement of a grazing OTEC
plant. U.S. Dept. of CormTerce. NOAA TL-chnical memorandum ERL AOML-35.
57 pp.
Nakamura, E.L. 1955. Abundance and distribution of zooplarkton in Hawaiian
waters, 1955-56. U.S. Dept. of the Interior, Fish '& Wildlife Service,
Special Scientific Report, Fisheries No. 544. 20 PP.

National Oceanic and Atmospheric Administration. 1981a. Final environmental
inpact statement for campercial ocean thermal energy conversion
(OTEC) licensing. Office of Ocean Minerals and Energy, Washington, D.C.

National Oceanic and Atmospheric Administration. 1981b. Notice of final
rulemaking for the licensing of ocean thermal energy conversion faci-
lities and plantships. 15 CFR, Part 981.

Ocean Data System, Inc. 1979a. OTEC thermal resource report for Guam.
Prepared for U.S. Departzent of Energy, Washington, D.C. Contract No.
ET-78-C-01-2898. l5pp.

1979b. OTEC thermal resource report for Pacific plant-ship. 5-10ON
90-950W. Prepared for U.S. Departzent of Energy, Washington, D.C.
Contract No. ET-78-C-012898. 20 pp.

1977a. OTEC thermal resource report for Puerto Rico. Prepared for
Energy Research and Developmnt Administration, Division of Solar
Energy, Washington, D.C. Contract No. EC-77-01-4028. 60 pp.

1977b. OTEC thermal resource report for Hawaii. Ocean Data Systems,
Inc. Prepared for Energy Research and Development Administration,
Division of Solar Energy, Washington, D.C. Contract No. EC-77-01-4028
16 pp.

1977c. OTEC thermal resource report for Central Gulf of Mexico.
Prepared for Energy Research and Developiment Administration,
Division of Solar Energy, Washington, D.C. Contract No. EC-77-C-01-
4028. 103'pp.

Richards, W. E. and J. R. Vadus. 1980. Alternative energy sources session--
ocean thermal energy conversion: technology development. U. S. Dept.
Canurerce, Nat. Oceanic Atm. Admin. , 'Itch. Rept. OOE9. 24pp.

1@?@ther, J.H. 1969. Photosynthesis and fish production in the sea. Science
16:72-76.

Sands, M. D. 1980. Ocean thermal energy conversion (OTEC)--draft programmatic
envirormental assessnent. Prepared for U. S. Dept. Energy. Contract No.
W-7405-ENG-48. Interstate Electronics Corp., Anaheim, Calif. 2 volumes.

Sax, N.I. 1979. Dangerous properties of industrial materials, 5th ed.
Van Nostrand Reinhold Co., New York, N.Y. 1018 p.

Shomura, R.S. and E.L. Nakanura. 1969. Variations in marine zooplankton from
a single locality in Hawaiian waters. Fish. Bull. 68 (1):87-99.

Schulenberger, E. 1978. Vertical distributions, diurnal migrations and
sampling problems of hyperiid anphipods in the North Pacific Gyre.
Deep-Sea Research 25(7):605-623.

Scripps Institute of oceanography. 1969. Physical, chemical and biological
data report, CLIMAX II Expedition. 27 August-13 October, 1969. SIO
Reference 75-6. University of California, San Diego, California.
Sverdrup, H.U., M.W. Johnson, and R.H. Fleming. 1942. The oceans: their
physics, chemistry, and general biology. Prentis-Hall, Englewood
Cliffs, NJ. 1087 pp.
Venrick, E. L. J.A. McGowan, and A.W. Mantyla. 1973. Deep maxima of photo-
. synthetic chlorophyll in the Pacific ocean. Fish. Bull. 71 (1):41-52.
Vinogradov, M.E. 1961. Quantitative distribution of deep sea plankton in
the Western Pacific and its relation to deep-water circulation. Deep
Sea Research 8:251-258.
Vinogradov, M.E. and Y.A. Rudyakov. 1971. Diurnal variations in the
vertical distribution of the plankton biomass in the equatorial west
Pacific. In: Life Activity of Pelagic Ccomanities in the Ocean
Tropics. Vinogradov, N.E., ed. Transl. from Russian. Akad. Nank
USSR. Israel Prog. Scientific Translation, Jerusalem. 298 p.
Watt, A.D., R.S. Matthews, and R. E. Hathaway. 1977. Open cycle ocean
themal energy conversion. A preliminary engineering evaluation.
Final report. U.S. Department of Energy, Washington, D.C. ALO/3723-
73/3.
Youngbluth, M.J. 1975. Zooplarkton studies 1973 and 1974. In E.O. Wood
et al., Cabo Mala Pascua Environmental Studies. Repr. from: Techn.
Rpt. No. 188, Puerto Rico Nuclear Center.

5. GLOSSARY

ADVECTION The process of transport of water or of an aqueous
property solely by the mass motion of the oceans,
most typically via horizontal currents.

AMBIENT Pertaining to the existing conditions of the
surrounding environment.

ASSEMBLAGE A group of organisms having a common habitat.

BATHYPELAGIC ZONE The biogeographic realm of the ocean lying between
depths of 1,000 and 4,000 meters.

BENTHOS All marine organisms living on or in the bottom of the
sea.

BENTHIC CORMUNITY A community of organisms living on or in the bottom
of the sea.

BIOACCUMULATION The uptake and assimilation of substances, such as
heavy metals, leading to a concentration of these
substances within organism tissues.

BIOCIDE A substance capable of destroying living organisms.

BIOFOULING The adhesion of various marine organisms to underwater
structures.

BIOMASS The mass of living matter, including stored food,
present in a population, expressed in terms of a given
area or volume of water or habitat.

CHLOROPHYLL A group of green plant pigments that function as
photoreceptors of light energy for photosynthesis.

CHLOROPHYLL a A pigment used in photsynthesis that serves as a
convenient measure of phytoplankton biomass.

CONTINENTALMARGIN The zone separating the emergent continents from the
deep sea floor; generally consists of the Continental
Shelf, Continental Slope, and Continental Rise.

CONTINENTAL SHELF That part of the Continental Margin adjacent to a
continent extending from the low water line to a
depth, generally 200 m, where the Continental Shelf
and the Continental Slope join.

CONTINENTAL SLOPE That part of the Continental Margin consisting of the
declivity from the edge of the Continental Shelf down
to the Continental Rise.

CONTINENTAL RISE A gentle slope with a generally smooth surface between

the Continental Slope and the deep ocean floor.

CRJSTACEANS Animals with jointed appendages and a segmented
external skeleton composed of a hard shell. The group
includes barnacles, crabs, shrimps, and lobsters.

DIATCMS Microscopic phytoplarkton characterized by a cell wall
of overlapping ailica plates. Sediment and water
column populations vary widely in response to changes
in environmental conditions.

DILUTION A reduction in concentration through the addition of
ambient waters. Expressed as the ratio of the sum of
the volumes of ambient water plus plum water to the
volume of plume water. A dilution of 5 connotes

4 parts (by volume) ambient water + 1 part (by volume ) plume water
1 part (by volume) plume water

DINOFLAGELLLATES A large diverse group of phytoplarkton with whip-like
appendages and with or without a rigid outer shell,
some of which feed on particulate matter. Some
members of this group are responsible for toxic
red-tides.

DISCHAX4GE PLUME The fluid volume, derived fram, the discharge pipe,
which is distinguishable froTn the surrounding water.

DISSOLVED CKYGEN(DO) The quantity of oxygen (expressed in mg/liter,
ml/liter or parts per million) dissolved in a unit
volume of water. Dissolved oxygen (DO) is a key
parameter in the assessment of water quality.

ECOSYSTEM An ecological community with its physical environment,
considered as a unit, each influencing the properties
of the other, and each necessary to the maintenance
of life.

EPIPELAGIC of, or pertaining to that portion of the oceanic zone
into which enough light penerates to allow photo-
synthesis; generally extends fran thesurface to
about 200 m.

FAR FIELD The region where natural ocean processes beccme the
dominant factors in the mixing of discharge waters.

GELATINOUS ORC7ANISMS Generally, the large organisms ccimposed of a jellylike
substance, including the cnidarians, salps, and
ctencphores.

GRADIENT The change in value of a quantity with change in a
given variable, such as distance (e.g. change in
temperature with depth).

HEAT EXCHANGER A material (usually metal) with a high coefficient of
thermal conductance which is used to exchange heat
between the working fluid and the heat source or
sink.

ICHTHYOPLANKTON Fish eggs and weakly motile fish larvae.

IMPINGEMENT A situation in which an organism is forced against a
barrier, such as an intake screen, as a result of the
intake of water into a facility such as powerplant.

INDIGENO(JS Having orginated in and being produced, growing or
living naturally in a particular region or environment.

IN SITU In the natural or original position; pertaining to
samples taken directly from the environment in which
they occur.

INVERTEBRATES Animals without backbones

ION An electricially charged group of atcms, either
negative or positive.
KIDCWATT ELECTRIC One thousand (103) watts of electric power
(kWe)

KILCKATr HOUR A unit of energy used in electrical measurement equal
(kWh) to energy converted or consumed at a rate of 1,000
watts during a 1-hour period.

MACROZOOPLANKTON Zooplanktonic organisms with lengths between 200 and
2,000 microns, ccmposed mainly of copepods,
chaetognaths, and larvae.

MACROPHYTOPEANKTON Phytoplanktonic organisms with lengths.between 200
2,000 microns.

MACROFOULING Sessile organisms, visible to the naked eye, which
ORGANISMS affix themselves to structures exposed to seawater
(e.g., barnacles, mussels, and sea anemones).
MEGAWATT ELECTRIC One million (106) watts of electric power.
(MWe)

MEGAZOOPLANKTON Zooplarktonic organisms with lengths greater than
2,000 microns, includes euphausiids, and large
copepods and chaetognaths.

MERCIPLANKTON Organisms that spend only a portion of their life
cycle as plankton; usually ccn-posed of floating

developmental stages (i.e., eggs and larvae) of
benthic and nektonic organisms. Also know as
temporary plankton.

MESOPELAGIC Relating to the oceanic depths between 200 m and
1,000 M.

MICRONEKTON Small weak-swimming nekton such as nesopelagic f ish,
small squid, gelatinous organisms, and fish larvae.

MICROZOOPLANKTON Planktonic animals with lengths between 20 and 200
microns, composed mainly of protozoans and juvenile
copepods.

MIXED LAYER The upper level of the ocean that is well mixed by
wind and wave activity. Within this layer, tempera-
ture, salinity, and nutrient concentration values
are essentially homogeneous with depth.

NANNOPLANKTON Minute planktonic plants and animals that are 50
microns or less in size and include algae, bacteria,
and protozoans. Individuals of this size will pass
through most nets and are usually collected in
centrif Liges.

NEAR FIELD The region in which the plume momentum is the dominant
factor controlling entrairurent and mixing of the plume
with the ambient receiving waters.

NEARSHORE ZONE The zone extending seaward from the shore to a
distance where the water column is under minimal
influence from continental conditions.

NEKTON Free-swimming aquatic animals, essentially moving
independent of water movements.

NERITIC Pertaining to the region of shallow water adjoining
the seacoast and extending from the low@tide mark
to a depth of about 200 m. -
NUTRIENT Any substance that promotes growth or provides energy
for biological processes.

OCEANIC The portion of the pelagic zone seaward from the
approximate edge of the continental shelf.
OFFSHORE ZONE A region in which physical properties are influenced
only-slightly by continental conditions.
OPEN-CYCLE SYSTEM A powerplant system in which the coolant and/or
working fluid passes through the plant only once and
is then discharged.
PELAGIC Pertaining to the open sea or organisms not associated

with the bottom.

PHOTIC ZONE The layer of the ocean from the surface to the depth
where light has been attenuated to 1% of the surface
value. The zone in which primary production shows
a net increase.

PH010SYNTHESIS Synthesis of chemical compounds in light, especially
the manufacture of organic componds from carbon
dioxide and a hydrogen source, with simultaneous
liberation of oxygen by chlorophyll-containing plant
cells.

PHYTOPLANKTON Mostly microscopic passively floating plant life of
a body of water; the base of the food chain in the
sea.

PLANKTON Organisms whose movements are determined by the
currents and not by their own locomotive abilities.

PLUME See DISCHARGE PLUME.

PRIMARY PRODUCTION The amount of organic matter synthesized by organisms
from inorganic substances per unit time and unit
volume of water, or in a column of water of unit areas
extending from the surface to the bottom.

r
IHER114OCLINE The region of the water column where temperature
changes most rapidly with depth.

UPWELLING The rising of water toward the surface from subsur-
face layers of a body of water. Upwelling is most
prominent where persistent winds blow parallel to
a coastline so that the resultant water current sets
away from the coast. The upwelled water, besides
being cooler, is rich in nutrients, so that regions
of upwelling generally have rich fisheries.
WATT A unit of power equal to the rate of work represented
by one ampere under a pressure of one volt; taken as
the standard in the U.S.

WOWING FLUID The medium in an OTEC plant that is vaporized by
warm. ocean water, passed over a turbine to generate
electricity, and finally condensed by cool ocean water.
ZOOPLANKTON The passively floating or weakly swimming animals of
an aquatic ecosystem.

6. ABBREVIATIONS

C carbon

C02 carbon dioxide

cm centimeter(s)

C degrees Celsius or centigrade

DOC United States Department of Commerce

DOE United States Department of Energy

GWe gigawatt electric

kg kilogram(s)

kg C kilogram(s) carbon

km kilometer(s)

KWe kilowatt electric

m meter(s)

mg milligram

MWe megawatt electric

ppm parts per million

ppt parts per thousand

Additional notation

X-1, X-2 etc. means per x, per x squared, etc.
(i.e. m-2 means per square meter, m-3 means per cubic meter, etc.)

668 091159
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NOAA--S/T 82-188
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