Report Seminar 2

I

A

Seminar Report

On

OCEAN THERMAL ENERGY CONVERSION (OTEC)

Presented By

VIVEK DAYANAND PRASAD

Exam seat no. 120520902

T.E (MECHANICAL)

Guided By

Prof. P.V. Chopade

Mechanical Engineering Department

Indira College of Engineering & Management,

Pune – 410506

[2014-15]

II

Shree Chanakya Education Society’s

Indira College of Engineering &

Management, Pune.

C E R T I F I C A T E

This is to certify that Vivek Dayanand Prasad (T120520902) has successfully

completed the Seminar work entitled “Ocean Thermal Energy Conversion” in

the partial fulfillment of T.E. (Mechanical) for University of Pune.

Prof. P.V. Chopade Dr. Milind .K.Landge Prof. S. B.Ingole

Guide TE Coordinator HOD, Mechanical

External Examiner Date: Seal

Place:

III

ACKNOWLEDGEMENT

With immense pleasure, I am presenting this project report as a part of the curriculum

of T.E .(Mechanical). I wish to thank all the people who gave me endless support right from

the stage the idea was conceived.

I would like to thank Prof.Sunil Ingole (HOD, Mechanical Department), & Prof.

Milind Landage (TE Coordinator) for giving me opportunity to deliver a seminar on this

interesting topic.

I am heartily thankful to Prof. P.V. Chopade whose encouragement, guidance and

support from the initial to the final level enabled me to develop an understanding of the

subject. This seminar would not be possible without help of our internet department &

library department who helped me gathering the information from various sources.

Lastly, I offer my regards and blessings to all of those who supported me in any

respect during the completion of the project.

VIVEK D. PRASAD

T.E. (MECHANICAL)

Exam Seat no. T120520902

IV

ABSTRACT

Ocean Thermal Energy Conversion (OTEC) is an energy technology that converts solar

radiation to electric power. OTEC systems use the ocean's natural thermal gradient—the fact

that the ocean's layers of water have different temperatures to drive a power-producing cycle.

As long as the temperature between the warm surface water and the cold deep water differs

by about 20°C (36°F), an OTEC system can produce a significant amount of power, with

little impact on the surrounding environment.

The distinctive feature of OTEC energy systems is that the end products include not

only energy in the form of electricity, but several other synergistic products. The principle

design objective was to minimize plan cost by minimizing plant mass, and taking maximum

advantage of minimal warm and cold water flows. Power is converted to high voltage DC,

and is cabled to shore for conversion to AC and integration into the local power distribution

network.

OTEC utilizes the temperature difference that exists between deep and shallow waters —

within 20° of the equator in the tropics — to run a heat engine. Because the oceans are

continually heated by the sun and cover nearly 70% of the Earth's surface, this temperature

difference contains a vast amount of solar energy which could potentially be tapped for

human use. The oceans are thus a vast renewable energy resource, with the potential to help

us produce billions of watts of electric power.

V

TABLE OF CONTENT

1 INTRODUCTION.............................................................................................................................1

1.1 Basics:....................................................................................................................................1

1.1.1 Thermal Energy Conversion:..........................................................................................2

1.2 Background and History of OTEC Technology........................................................................3

2 TYPES OF ENERGY CONVERSION SYSTEM......................................................................................6

2.1 Closed-cycle...........................................................................................................................6

2.2 Open-cycle.............................................................................................................................7

2.3 Hybrid cycle...........................................................................................................................8

3 OTEC PLANT DESIGN AND LOCATION............................................................................................9

3.1 Land-Based and Near-Shore Facilities....................................................................................9

3.2 Shelf-Mounted Facilities......................................................................................................10

3.3 Floating Facilities.................................................................................................................11

4 COMPARITIVE ANALYSIS..............................................................................................................12

4.1 Advantages..........................................................................................................................12

4.2 Disadvantages......................................................................................................................13

5 OTHER APPLICATIONS..................................................................................................................14

6 CASE STUDY: (INDIA)....................................................................................................................16

7 CONCLUSION...............................................................................................................................17

BIBLIOGRAPHY.....................................................................................................................................18

VI

LIST OF FIGURES

Figure 1-1 Seebeck Effect..........................................................................................................8

Figure 1-2 Peltier Effect.............................................................................................................8

Figure 1-3 Joulean Effect...........................................................................................................9

Figure 1-4 Thomson Effect........................................................................................................9

Figure 3-1 A Thermoelectric Refrigerator...............................................................................14

Figure 4-1 Schematic of Thermoelectric Cooler......................................................................16

Figure 4-2 The Combined TE-Direct Evaporative Air Cooler................................................17

Figure 4-3 Schematic of Thermoelectric Refrigerator.............................................................18

Figure 4-4 Schematic of Solar Cells driven Thermoelectric Refrigerator...............................19

Figure 4-5 Different location of TE generator in Refrigerator................................................20

Figure 4-6 TPM & TSF............................................................................................................21

LIST OF TABLES

(Eliminate this if there are no graphs)

LIST OF GRAPHS

(Eliminate this if there are no graphs)

Ocean Thermal Energy Conversion (OTEC)

1 INTRODUCTION

Oceans cover more than 70% of Earth's surface, making them the world's largest solar

collectors. The sun's heat warms the surface water a lot more than the deep ocean water, and

this temperature difference creates thermal energy. Just a small portion of the heat trapped in

the ocean could power the world.

1.1 Basics:

Most people have been witness to the awesome power of the world's oceans. For least

a thousand years, scientists and inventors have watched ocean waves explode against coastal

shores, felt the pull of ocean tides, and dreamed of harnessing these forces. But it's only been

in the last century that scientists and engineers have begun to look at capturing ocean energy

to make electricity.

Figure 1.1.1

The ocean can produce two types of energy: thermal energy from the sun's heat, and

mechanical energy from the tides and waves. Ocean thermal energy is used for many

applications, including electricity generation. Ocean mechanical energy is quite different

from ocean thermal energy. Even though the sun affects all ocean activity, tides are driven

primarily by the gravitational pull of the moon, and waves are driven primarily by the winds.

As a result, tides and waves are sporadic sources of energy, while ocean thermal energy is

fairly constant. Also, unlike thermal energy, the electricity conversion of both tidal and wave

energy usually involves mechanical devices.

“ICEM, TE Mechanical 2014-15” Page 1


1.1.1 Thermal Energy Conversion:

OTEC is a process which utilizes the heat energy stored in the tropical ocean. The

world's oceans serve as a huge collector of heat energy. OTEC plants utilize the difference in

temperature between warm surface sea water and cold deep sea water to produce electricity.

Intensive Energy

The energy associated with OTEC derives from the difference in temperature between two

thermal reservoirs. The top layer of the ocean is warmed by the sun to temperatures up to

20 K greater than the seawater near the bottom of the ocean. OTEC energy is different from

geothermal energy in that one cannot assume the cold reservoir is infinite. The physical

energy of two large reservoirs of fluid at different temperatures is

Equation 1.1

in J/kg where r is the mass of warm water divided by the mass of cold water entering the

plant(1). For optimal performance, r is approximately 0.5. It is assumed in this analysis that

the specific heat of the two fluid reservoirs is an average value over the often small

temperature difference, but varying with salinity in the case of seawater.

Thermal energy conversion is an energy technology that converts solar radiation to

electric power. OTEC systems use the ocean's natural thermal gradient—the fact that the

ocean's layers of water have different temperatures—to drive a power-producing cycle. As

long as the temperature between the warm surface water and the cold deep water differs by

about 20°C, an OTEC system can produce a significant amount of power. The oceans are

thus a vast renewable resource, with the potential to help us produce billions of watts of

electric power. This potential is estimated to be about 1013 watts of base load power

generation, according to some experts. The cold, deep seawater used in the OTEC process is


http://www.nrel.gov/otec/bibliography.html#overview


also rich in nutrients, and it can be used to culture both marine organisms and plant life near

the shore or on land. OTEC produce steady, base-load electricity, fresh water, and air-

conditioning options.

Figure 1.1.2

OTEC requires a temperature difference of about 36 deg F (20 deg C). This

temperature difference exists between the surface and deep seawater year round throughout

the tropical regions of the world. To produce electricity, we either use a working fluid with a

low boiling point (e.g. ammonia) or warm surface sea water, or turn it to vapor by heating it

up with warm sea water (ammonia) or de-pressurizing warm seawater. The pressure of the

expanding vapor turns a turbine and produces electricity.

1.2 Background and History of OTEC Technology

In 1881, Jacques Arsene d'Arsonval, a French physicist, was the first to propose tapping the

thermal energy of the ocean. Georges Claude, a student of d'Arsonval's, built an experimental

open-cycle OTEC system at Matanzas Bay, Cuba, in 1930. The system produced 22 kilowatts

(kW) of electricity by using a low-pressure turbine. In 1935, Claude constructed another

open-cycle plant, this time aboard a 10,000-ton cargo vessel moored off the coast of Brazil.

But both plants were destroyed by weather and waves, and Claude never achieved his goal of

producing net power (the remainder after subtracting power needed to run the system) from

an open-cycle OTEC system.



Then in 1956, French researchers designed a 3-megawatt (electric) (MWe) open-cycle

plant for Abidjan on Africa's west coast. But the plant was never completed because of

competition with inexpensive hydroelectric power. In 1974 the Natural Energy Laboratory of

Hawaii (NELHA, formerly NELH), at Keahole Point on the Kona coast of the island of

Hawaii, was established. It has become the world's foremost laboratory and test facility for

OTEC technologies.

In 1979, the first 50-kilowatt (electric) (kWe) closed-cycle OTEC demonstration plant

went up at NELHA. Known as "Mini-OTEC," the plant was mounted on a converted U.S.

Navy barge moored approximately 2 kilometers off Keahole Point. The plant used a cold-

water pipe to produce 52 kWe of gross power and 15 kWe net power.

In 1980, the U.S. Department of Energy (DOE) built OTEC-1, a test site for closed-

cycle OTEC heat exchangers installed on board a converted U.S. Navy tanker. Test results

identified methods for designing commercial-scale heat exchangers and demonstrated that

OTEC systems can operate from slowly moving ships with little effect on the marine

environment. A new design for suspended cold-water pipes was validated at that test site.

Also in 1980, two laws were enacted to promote the commercial development of OTEC

technology: the Ocean Thermal Energy Conversion Act, Public Law (PL) 96-320, later

modified by PL 98-623, and the Ocean Thermal Energy Conversion Research, Development,

and Demonstration Act, PL 96-310.

At Hawaii's Seacoast Test Facility, which was established as a joint project of the

State of Hawaii and DOE, desalinated water was produced by using the open-cycle process.

And a 1-meter-diameter col seawater/0.7-meter-diameter warm-seawater supply system was

deployed at the Seacoast Test Facility to demonstrate how large polyethylene cold-water

pipes can be used in an OTEC system.

In 1981, Japan demonstrated a shore-based, 100-kWe closed-cycle plant in the

Republic of Nauru in the Pacific Ocean. This plant employed cold-water pipe laid on the sea

bed to a depth of 580 meters. Freon was the working fluid, and a titanium shell-and-tube heat

exchanger was used. The plant surpassed engineering expectations by producing 31.5 kWe of

net power during continuous operating tests.

Later, tests by the U.S. DOE determined that aluminum alloy can be used in place of

more expensive titanium to make large heat exchangers for OTEC systems. And at-sea tests

by DOE demonstrated that biofouling and corrosion of heat exchangers can be controlled.



Biofouling does not appear to be a problem in cold seawater systems. In warm seawater

systems, it can be controlled with a small amount of intermittent chlorination (70 parts per

billion per hour per day).

In 1984, scientists at a DOE national laboratory, the Solar Energy Research Institute

(SERI, now the National Renewable Energy Laboratory), developed a vertical-spout

evaporator to convert warm seawater into low-pressure steam for open-cycle plants. Energy

conversion efficiencies as high as 97% were achieved. Direct-contact condensers using

advanced packings were also shown to be an efficient way to dispose of steam. Using

freshwater, SERI staff developed and tested direct-contact condensers for open-cycle OTEC

plants.

British researchers, meanwhile, have designed and tested aluminum heat exchangers

that could reduce heat exchanger costs to $1500 per installed kilowatt capacity. And the

concept for a low-cost soft seawater pipe was developed and patented. Such a pipe could

make size limitations unnecessary, as well as improve the economics of OTEC systems.

In May 1993, an open-cycle OTEC plant at Keahole Point, Hawaii, produced 50,000

watts of electricity during a net power-producing experiment. This broke the record of

40,000 watts set by a Japanese system in 1982. Today, scientists are developing new, cost-

effective, state-of-the-art turbines for open-cycle OTEC systems.



2 TYPES OF ENERGY CONVERSION SYSTEM

2.1 Closed-cycle

Closed-cycle systems use fluid with a low boiling point, such as ammonia, to rotate a

turbine to generate electricity. Warm surface seawater is pumped through a heat exchanger

where the low-boiling-point fluid is vaporized. The expanding vapor turns the turbo-

generator. Then, cold, deep seawater—pumped through a second heat exchanger—condenses

the vapor back into a liquid, which is then recycled through the system.

In 1979, the Natural Energy Laboratory and several private-sector partners developed

the mini OTEC experiment, which achieved the first successful at-sea production net

electrical power from closed-cycle OTEC. The mini OTEC vessel was moored 1.5 miles (2.4

km) off the Hawaiian coast and produced enough net electricity to illuminate the ship's light

bulbs, and run its computers and televisions.

Then, the Natural Energy Laboratory in 1999 tested a 250 kW pilot OTEC closed-

cycle plant, the largest such plant ever put into operation. Since then, there have been no tests

of OTEC technology in the United States, largely because the economics of energy

production today have delayed the financing of a permanent, continuously operating plant.

Outside the United States, the government of India has taken an active interest in OTEC

technology. India has built and plans to test a 1 MW closed-cycle, floating OTEC plant.

Figure 2.1.3



2.2 Open-cycle

Open-cycle OTEC uses the tropical oceans' warm surface water to make electricity.

When warm seawater is placed in a low-pressure container, it boils. The expanding steam

drives a low-pressure turbine attached to an electrical generator. The steam, which has left its

salt behind in the low-pressure container, is almost pure fresh water.

2.2.4



Figure 2.2.5

It is condensed back into a liquid by exposure to cold temperatures from deep-ocean

water.

In 1984, the Solar Energy Research Institute (now the National Renewable Energy

Laboratory) developed a vertical-spout evaporator to convert warm seawater into low-

pressure steam for open-cycle plants. Energy conversion efficiencies as high as 97% were

achieved for the seawater to steam conversion process (note: the overall efficiency of an

OTEC system using a vertical-spout evaporator would still only be a few per cent). In May

1993, an open-cycle OTEC plant at Keahole Point, Hawaii, produced 50,000 watts of

electricity during a net power-producing experiment. This broke the record of 40,000 watts

set by a Japanese system in 1982.



2.3 Hybrid cycle

Hybrid systems combine the features of both the closed-cycle and open-cycle

systems. In a hybrid system, warm seawater enters a vacuum chamber where it is flash-

evaporated into steam, similar to the open-cycle evaporation process. The steam vaporizes a

low-boiling-point fluid (in a closed-cycle loop) that drives a turbine to produce electricity.

2.3.6



3 OTEC PLANT DESIGN AND LOCATION

Commercial ocean thermal energy conversion (OTEC) plants must be located in an

environment that is stable enough for efficient system operation. The temperature of the

warm surface seawater must differ about 20°C (36°F) from that of the cold deep water that is

no more than about 1000 meters (3280 feet) below the surface. The natural ocean thermal

gradient necessary for OTEC operation is generally found between latitudes 20 deg N and 20

deg S. Within this tropical zone are portions of two industrial nations—the United States and

Australia—as well as 29 territories and 66

developing nations. Of all these possible sites, tropical islands with growing power

requirements and a dependence on expensive imported oil are the most likely areas for OTEC

development.

Commercial OTEC facilities can be built on

* Land or near the shore

* Platforms attached to the shelf

* Moorings or free-floating facilities in deep ocean water.

3.1 Land-Based and Near-Shore Facilities

Land-based and near-shore facilities offer three main advantages over those located in

deep water. Plants constructed on or near land do not require sophisticated mooring, lengthy

power cables, or the more extensive maintenance associated with open-ocean environments.

They can be installed in sheltered areas so that they are relatively safe from storms and heavy

seas. Electricity, desalinated water, and cold, nutrient-rich seawater could be transmitted from

near-shore facilities via trestle bridges or causeways. In addition, land-based or near-shore

sites allow OTEC plants to operate with related industries such as mariculture or those that

require desalinated water.

Favored locations include those with narrow shelves (volcanic islands), steep (15-20

deg) offshore slopes, and relatively smooth sea floors. These sites minimize the length of the

cold-water intake pipe. A land-based plant could be built well inland from the shore, offering

more protection from storms, or on the beach, where the pipes would be shorter. In either



case, easy access for construction and operation helps lower the cost of OTEC-generated

electricity.

Land-based or near-shore sites can also support mariculture. Mariculture tanks or

lagoons built on shore allow workers to monitor and control miniature marine environments.

Mariculture products can be delivered to market with relative ease via railroads or highways.

One disadvantage of land-based facilities arises from the turbulent wave action in the

surf zone. Unless the OTEC plant's water supply and discharge pipes are buried in protective

trenches, they will be subject to extreme stress during storms and prolonged periods of heavy

seas. Also, the mixed discharge of cold and warm seawater may need to be carried several

hundred meters offshore to reach the proper depth before it is released. This arrangement

requires additional expense in construction and maintenance.

OTEC systems can avoid some of the problems and expenses of operating in a surf

zone if they are built just offshore in waters ranging from 10 to 30 meters deep (Ocean

Thermal Corporation 1984). This type of plant would use shorter (and therefore less costly)

intake and discharge pipes, which would avoid the dangers of turbulent surf. The plant itself,

however, would require protection from the marine environment, such as breakwaters and

erosion-resistant foundations, and the plant output would need to be transmitted to shore.

3.2 Shelf-Mounted Facilities

OTEC plants can be mounted to the continental shelf at depths up to 100 meters.

A shelf-mounted plant could be built in a shipyard, towed to the site, and fixed to the sea

bottom. This type of construction is already used for offshore oil rigs. The additional

problems of operating an OTEC plant in deeper water, however, may make shelf-mounted

facilities less desirable and more expensive than their land-based counterparts. Problems with

shelf-mounted plants include the stress of open-ocean conditions and more difficult product

delivery. Having to consider strong ocean currents and large waves necessitates additional

engineering and construction expense.



Platforms require extensive pilings to maintain a stable base for OTEC operation.

Power delivery could also become costly because of the long underwater cables required to

reach land. For these reasons, shelf-mounted plants are less attractive for near-term OTEC

development.

3.3 Floating Facilities

Floating OTEC facilities could be designed to operate off-shore. Although

potentially preferred for systems with a large power capacity, floating facilities present

several difficulties. This type of plant is more difficult to stabilize, and the difficulty of

mooring it in very deep water may create problems with power delivery. Cables attached to

floating platforms are more susceptible to damage, especially during storms. Cables at depths

greater than 1000 meters are difficult to maintain and repair.

Riser cables, which span the distance between the sea bed and the plant, need to be

constructed to resist entanglement. As with shelf-mounted plants, floating plants need a stable

base for continuous OTEC operation. Major storms and heavy seas can break the vertically

suspended cold-water pipe and interrupt the intake of warm water as well. To help prevent

these problems, pipes can be made of relatively flexible polyethylene attached to the bottom

of the platform and gimballed with joints or collars. Pipes may need to be uncoupled from the

plant to prevent damage during storms. As an alternative to having a warm-water pipe,

surface water can be drawn directly into the platform; however, it is necessary to locate the

intake carefully to prevent the intake flow from being interrupted during heavy seas when the

platform would heave up and down violently.

If a floating plant is to be connected to power delivery cables, it needs to remain

relatively stationary. Mooring is an acceptable method, but current mooring technology is

limited to depths of about 2000 meters (6560 feet). Even at shallower depths, the cost of

mooring may prohibit commercial OTEC ventures. An alternative to deep-water OTEC may

be drifting or self-propelled plantships. These ships use their net power on board to

manufacture energy-intensive products such as hydrogen, methanol, or ammonia (Francis,

Avery, and Dugger 1980).Electricity generated by plants fixed in one place can be delivered

directly to a utility grid. A submersed cable would be required to transmit electricity from an

anchored floating platform to land.



4 COMPARITIVE ANALYSIS

The world population is 6.1 billion in 2000, and it is still growing explosively. At the same

time, energy consumed by human is also increasing explosively, as shown . By considering

future economic growth and environmental problems it is obvious that in the 21st century we

cannot rely on the current mainstream resources, i.e. oil, coal, and uranium for the world

energy supply. Thus, we must face the urgent and important problem of developing an

alternative energy source to fossil and nuclear fuel. For the alternative energy sources we can

easily consider, for example, such as wind, solar and geothermal power. However, ocean

energy should become also an important potential energy source which must be obtained.

4.1 Advantages

1. OTEC uses clean, renewable, natural resources. Warm surface seawater and

cold water from the ocean depths replace fossil fuels to produce electricity.

2. Suitably designed OTEC plants will produce little or no carbon dioxide or other

polluting chemicals.

3. OTEC systems can produce fresh water as well as electricity. This is a

significant advantage in island areas where fresh water is limited.

4. There is enough solar energy received and stored in the warm tropical ocean

surface layer to provide most, if not all, of present human energy needs.



5. The use of OTEC as a source of electricity will help reduce the state's almost

complete dependence on imported fossil fuels.

4.2 Disadvantages

1.OTEC-produced electricity at present would cost more than electricity generated from

fossil fuels at their current costs. The electricity cost could be reduced significantly if the

plant operated without major overhaul for 30 years or more, but data on possible plant life

cycles is unavailable.

2. OTEC plants must be located where a difference of about 40° Fahrenheit (F) occurs year

round. Ocean depths must be available fairly close to shore-based facilities for economic

operation. Floating plant ships could provide more flexibility.

3. High capital cost and an overall lack of familiarity and research with OTEC technology.



5 OTHER APPLICATIONS

OTEC systems are not just limited to just producing electricity and because of the unique

design of these power stations are potentially available to tackle other ventures in

combination with electricity to offset some of the expenses associates with OTEC.

A. Fresh water production

Desalination is just one of the effective potential products that could be produced via OTEC

technology. Fresh water can be produced in open-cycle OTEC plants when the warm water is

vaporized to turn the low pressure turbine. Once the electricity is produced the water vapor is

condensed to make fresh water (Takahashi and Trenka, 1996). This water has been found to

be purer then water offered by most communities as well it is estimated that 1 MW plant

could produce 55 kg of water per second. This rate of fresh water could supply a small

coastal community with approximately 4000 m3/day of fresh water (Takahashi and Trenka,

1996). This water can also be used for irrigation to improve the quality and quantity of food

on coastal regions especially where access to fresh water is scarce.

B. Air conditioning and Refrigeration

Once cold water pipes are installed for an OTEC power plant the cold water being pumped to

the surface can be used for other projects other then to provide the working fluid for the

condenser. One of these uses is air conditioning and refrigeration. Cold water can be used to

circulate through space heat exchangers or can be used to cool the working fluid within heat

exchangers (Takahashi and Trenka, 1996). This technology can be applied for hotel and

home air conditioning as well as for refrigeration schemes.

C. Aquaculture and Mariculture

Another possibility for taking advantage of OTEC plants is the use of the water pipes to

harvest marine plants and animals for the purpose of food. This proposition is still under

investigation however it is proposed that seawater life including salmon, abalone, American

lobster, flat fish, sea urchin and edible seaweeds could be harvested for ingestion using the



cold water pipes that would be readily available from the OTEC power plants (Takahashi and

Trenka, 1996).

Mariculture is another possibility that is currently being researched that would take advantage

of the cold deep ocean water being transferred to the oceans surface. This water contains

phytoplankton and other biological nutrients that serve as a catalyst for fish and other aquatic

populations (Takahashi and Trenka,1996). This water could serve to increase native fish

populations through the recycling of trace nutrients

that would not be otherwise available.

D. Coldwater Agriculture

Because the coastal areas suitable for OTEC are in tropic regions there is a potential to

increase the overall food diversity within an area using the cold water originating from the

deep ocean. It has been proposed that burying a network of coldwater pipes underground the

temperature of the ground would be ideal for spring type crops like strawberries and other

plants restricted to cooler climates (Takahashi and Trenka, 1996). This would not only supply

the costal populations with an increased variety of food but reduce the cost of transport of

cooler climate foods that would otherwise have to be shipped.

Figure 4.2.7



6 CASE STUDY: (INDIA)

Conceptual studies on OTEC plants for Kavaratti (Lakshadweep islands), in the

Andaman-Nicobar Islands and off the Tamil Nadu coast at Kulasekharapatnam were initiated

in 1980. In 1984 a preliminary design for a 1 MW (gross) closed Rankine Cycle floating

plant was prepared by the Indian Institute of Technology in Madras at the request of the

Ministry of Non-Conventional Energy Resources. The National Institute of Ocean

Technology (NIOT) was formed by the governmental Department of Ocean Development in

1993 and in 1997 the Government proposed the establishment of the 1 MW plant of earlier

studies. NIOT signed a memorandum of understanding with Saga University in Japan for the

joint development of the plant near the port of Tuticorin (Tamil Nadu).

It has been reported that following detailed specifications, global tenders were placed

at end-1998 for the design, manufacture, supply and commissioning of various sub-systems.

The objective is to demonstrate the OTEC plant for one year, after which it could be moved

to the Andaman & Nicobar Islands for power generation. NIOT’s plan is to build 10-25 MW

shore-mounted power plants in due course by scaling-up the 1 MW test plant, and possibly a

100 MW range of commercial plants thereafter.



7 CONCLUSION

OTEC has tremendous potential to supply the world’s energy. It is estimated that, in

an annual basis, the amount solar energy absorbed by the oceans is equivalent to at least 4000

times the amount presently consumed by humans. For an OTEC efficiency of 3 percent, in

converting ocean thermal energy to electricity, we would need less than 1 percent of this

renewable energy to satisfy all of our desires for energy.

OTEC offers one of the most compassionate power production technologies, since the

handling of hazardous substances is limited to the working fluid (e.g., ammonia), and no

noxious by-products are generated. Through adequate planning and coordination with the

local community, recreational assets near an OTEC site may be enhanced. OTEC is capital-

intensive, and the very first plants will most probably be small requiring a substantial capital

investment. Given the relatively low cost of crude oil and of fossil fuels in general, the

development of OTEC technologies is likely to be promoted by government

agencies. Conventional power plants pollute the environment more than an OTEC plant

would and, as long as the sun heats the oceans, the fuel for OTEC is unlimited and free



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x


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