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Ocean Thermal Energy Conversion

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Re: Ocean thermal energy conversion

Unread postby Graeme » Tue 09 Jul 2013, 16:07:45

Lockheed Martin's Search For Commercial Opportunities Leads It To The Sea

Consider an agreement it signed just last week in Beijing. It is teaming with a resort builder to construct the world’s biggest “ocean thermal energy conversion” plant off the southern coast of China. The plant would generate 10 megawatts of power by exploiting natural temperature variations in tropical seas, and unlike other renewable energy sources it would operate nonstop 24 hours per day, 365 days per year. Lockheed Martin executives want to scale the technology up to 100 megawatts in subsequent ventures, producing the same amount of electricity in a year that 1.3 million barrels of oil could while generating virtually no fuel costs or greenhouse gases.


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Re: Ocean thermal energy conversion

Unread postby Graeme » Thu 11 Jul 2013, 18:33:45

The Blue Revolution Is the Optimal Solution for Japan

During the past two months, I have spent some time in Japan and, no particular surprise, they are in deep trouble regarding energy supply. The great Tohoku earthquake, tsunami and nuclear disaster set them back to square 1945, and they will need to reinvent the country again. I have a sense they will ultimately recover, but only with the right decisions.


But I can offer a possible solution. The ocean is the only productive answer for Japan. They don't have much in terms of current, tidal and salinity gradient resources. Waves are possible, and this country has had several pioneering projects, with yet another one being planned. Certainly, continue this development, but I've long worried that this option will never become truly competitive, mostly because of the cost required to protect these devices from major storms.

Ocean thermal energy conversion (OTEC) remains as the best marine alternative. Japan's only successful experiment, led by Toshiba and Tokyo Electric Power Company, occurred 30 years ago on Nauru. Unfortunately, yet another natural disaster, a hurricane this time, wiped out the experiment. OTEC can be used to power a grazing plantship, where the economic opportunities would include: next generation fisheries, marine biomass plantations (from which methane and various biofuels can be produced at sea), electricity (plus hydrogen can be electrolyzed) and freshwater. Certainly, these platforms can be utilized to capture the the sun and winds, too. Of particular intrigue is the potential to prevent hurricanes and remediate global warming.


For the past two decades, I have provided at least a dozen lectures in Japan to spark interest in the ocean as the ideal venue for international cooperation, most recently to the Japan Marine Technology Society. The opportunity is now at hand for the country to take the leading role in partnering with the world to develop the Pacific International Ocean Station (PIOS), the proposed ocean version of the International Space Station (ISS).


The organizers of Blue Revolution Hawaii have already discussed Japanese participation in PIOS, for Shimizu's Green Float concept is very similar to our vision. Suddenly and dramatically, that 9.0 earthquake thrust the Blue Revolution into a commanding position as the optimal solution for Japan's future. At only one percent the cost of the ISS, PIOS can establish a marine pathway for economic progress, not only for Japan, but the rest of the world. Japan, if it chose to, can assume the leadership role for this magnificent global enterprise, and take that important step towards a progressive recovery.


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Re: Ocean thermal energy conversion

Unread postby Graeme » Sun 14 Jul 2013, 18:58:17

California, catch the next big energy wave

Less than a month later, Britain inaugurated an offshore wind farm capable of powering half a million homes. Additional "blue" energy sources, including wave- and tidal-power generators and "ocean thermal energy conversion," or OTEC, are being developed in Maine, Oregon, Scotland and China, but not in any significant way in California. Even Google, based in California, is making a major commitment to offshore wind powers but generated off the mid-Atlantic states, not here.

What's happening? California is the state most associated with alternative energy development, yet the state's greatest potential source of clean power (and its main geographic feature), the Pacific Ocean, is largely ignored.


California has access to innovators ready to take on ocean energy, both small companies such as Green Wave Energy of Newport Beach and larger corporations such as Science Applications International Corp. and Lockheed-Martin, which are eyeing ocean-energy projects applied to the West Coast. They say they need the state to provide some of the same financial, tax and regulatory support created by the Solar Initiative rebate program and Proposition 39, the sort of support Maine has given its offshore wind turbines. Lt. Gov. Gavin Newsom promised regulatory support at an Ocean Protection Council meeting two years ago, but words are not yet actions.


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Re: Ocean thermal energy conversion

Unread postby Graeme » Tue 13 Aug 2013, 23:44:49

Atoll nations at cutting edge of climate and clean energy

A Pacific island nation that is at the centre of crucial climate change negotiations this year wants to build the world’s first commercial ocean thermal energy conversion (OTEC) project – a move that would allow it to look after its own energy needs and even export fuels for shipping and the like.

The Marshall Islands, a sprawling nation of 34 atolls and islands spread over some 2 million square kilometres in the western Pacific, has been battered in the past year by an unprecedented drought and rising seas that have flooded its airport and water catchment facilities.

Next month it plays host to the 44th South Pacific Forum, which this year will be focused on the real impacts of climate change. And it plans a few big announcements to try to encourage larger nations to lift their own ambition and actions

The first is a project that vice president Tony de Brum says has effectively “solarised” the nation. All of its 34 islands now have solar power for homes, schools and dispensaries – no mean feat given the spread and distance of the atolls. On its main islands, solar will account for 20 per cent of its electricity needs and has been installed at hospitals and colleges.

But de Brum has an even more ambitious plan. For much of the past decade he has been pursuing a dream to install the world’s first OTEC commercial plant, and he has been locked in negotiations with Japanese funders and technology developer Lockheed Martin.

In October, a $2.9 million location feasibility study funded by the World Bank will begin. De Brum believes a 20-30MW plant could be in operation before the end of the decade.

The Marshall Islands currently relies on hugely expensive diesel for its energy needs. It costs more than 60c/kWh, and government subsidies reduce the cost to consumers to around 42c/kWh.

But diesel sucks up 25 per cent of the nation’s GDP, and the high cost means that the few industries it has – such as the local fish processing plant that employs 800 people – cannot afford to expand.

De Brum believes that OTEC can deliver electricity at around 25c/kWh. He expects funding to come from international bodies, and be underpinned by a power purchase agreement from the US military, which has a large base on the islands and also depends on expensive diesel.

The plant is likely to be built at Kwajalein Atoll. de Brum says the warm waters of the Marshall Islands (see map, the Marshalls are in the heart of the best areas) means that an OTEC plant could be 30 per cent more efficient than a similar facility built in Hawaii, where a pilot project has been in operation.

That’s because the temperature difference is much larger in the Marshalls – up to 24C over 1,000 metres of depth. Every nation has cold water at 1,000m – but few have such warm water at the surface.

As Lockheed Martin explains, OTEC runs off the difference in ocean temperatures, which can be leveraged to produce power. Warm surface sea water passes through a heat exchanger, vaporizing a low boiling point working fluid to drive a turbine generator, producing electricity.


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Re: Ocean thermal energy conversion

Unread postby Graeme » Tue 03 Sep 2013, 20:13:49

OTEC Can Be a Big Global Climate Influence

Professor James Moum, physical oceanography, Oregon State University, commenting in LiveScience on the recently published study in the journal Nature Recent global-warming hiatus tied to equatorial Pacific surface cooling by Yu Kosaka & Shang-Ping Xie said, “Scientists have known that the eastern equatorial Pacific Ocean takes in a significant amount of heat from the atmosphere, but this new study suggests this small portion of the world's oceans could have a big influence on global climate.”


OTEC uses the temperature difference between cooler deep and warmer surface ocean waters to run a heat engine and produce useful work, usually in the form of electricity.

It too can have a big influence on global climate because it converts part of the accumulating ocean heat to work and about twenty times more heat is moved to the depths in a similar fashion to how Trenberth suggests the global-warming hiatus has come about.

The more energy produced by OTEC – done properly the potential is 30 terawatts - the more the entire ocean will be cooled and that heat converted to work will not return as will be the case when the oceans stop soaking up global-warming’s excess.

Kevin Trenberth estimates the oceans will eat global warming for the next 20 years.


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Re: Ocean thermal energy conversion

Unread postby Graeme » Thu 31 Oct 2013, 16:21:32

Lockheed Martin And Reignwood Group Sign Contract To Develop Ocean Thermal Energy Conversion Power Plant

Lockheed Martin LMT +0.56% and Reignwood Group have signed a contract to start design of a 10-megawatt Ocean Thermal Energy Conversion (OTEC) power plant, which, when complete, will be the largest OTEC project to date.

Lockheed Martin is the industry leader in the development of OTEC technology, holding 19 related patents. The Lockheed Martin-Reignwood 10-megawatt plant is considered to be a crucial step in the full commercialization of OTEC.

"The ocean holds enormous potential for terrawatts of clean, baseload energy," said Dan Heller, vice president of new ventures for Lockheed Martin Mission Systems and Training. "Capturing this energy through a system like OTEC means we have the opportunity to produce reliable and sustainable power, supporting global security, a strong economic future and climate protection for future generations."

Under this initial contract, Lockheed Martin will provide project management, design and systems engineering services.

"The signing of this contract reflects both companies' passion for green energy projects, and our willingness as a team to bring forth an exciting new renewable energy source that directly benefits people of all nations," said Shaohua Liu, senior vice president for Reignwood Group.


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Re: The Ocean Wave Energy Thread (merged)

Unread postby Graeme » Mon 03 Mar 2014, 17:16:01

20,000 megawatts under the sea: Oceanic steam engines

Claims for it have certainly been grandiose. In theory, ocean thermal energy conversion (OTEC) could provide 4000 times the world's energy needs in any given year, with neither pollution nor greenhouse gases to show for it. In the real world, however, it has long been written off as impractical.

This year, a surprising number of projects are getting under way around the world, helmed not by quixotic visionaries but by hard-nosed pragmatists such as those at aerospace giant Lockheed Martin. So what's changed?

It's possible that Verne dreamed up the idea for OTEC to help out Captain Nemo, the protagonist of Verne's deep-sea yarn who needed electricity to power his submarine, the Nautilus – it is the first written mention of the idea. "By establishing a circuit between two wires plunged to different depths, [it should be possible] to obtain electricity by the difference of temperature to which they would have been exposed," Nemo told his shipmate. Eleven years after the book was published, French physicist Jacques-Arsène d'Arsonval proposed the first practical design for a power plant that does exactly that. Instead of using wires, he used pipes to exploit the temperature difference between the cold deep ocean and the warm surface waters to generate steam energy.

The idea is brilliant. The ocean is a massive and constantly replenished storage medium for solar energy. Most of that heat is stored in the top 100 metres of the ocean, while the water 1000 metres below – fed by the polar regions – remains at a fairly constant 4 to 5 °C.

To make energy from that heat difference, modern-day systems pump warm surface water past pipes containing a liquid with a low boiling point, such as ammonia. The ammonia boils and the steam is used to power a turbine, generating electricity. Cold deep-ocean water is then piped through the steam, causing the ammonia to condense back into a liquid, ready to begin the cycle again (see diagram). Steam-powered turbines drive nearly every coal and nuclear power plant in the world, but their steam is produced by burning polluting coal or generating long-lived nuclear waste. OTEC, by contrast, provides steam in a clean and theoretically limitless way.


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Re: The Ocean Wave Energy Thread (merged)

Unread postby Graeme » Wed 26 Mar 2014, 16:20:29

Blue Is The New Green: How Oceans Could Power The Future

The antiquated Morro Bay plant is part of a pattern of seaside plants closing due to a combination of stricter environmental regulations coupled with California’s requirement that 33 percent of electricity in the state come from renewable sources by 2020. Two companies have filed preliminary permits with the Federal Energy Regulatory Commission (FERC) to test wave energy projects off the coast of Morro Bay, a town of about 10,000 people north of Los Angeles. Both projects would use the defunct plant as a much-needed transmission hub to push energy to the grid and from there to consumers throughout the region.
“If we aren’t able to use Morro Bay, there are other shore-based power plants shutting down along the coastline,” said Paul Grist, president and chairman of Archon Energy, one of the companies applying for a FERC permit. “They can’t meet the Renewable Portfolio Standard and they suck in and spew out millions of gallons of water.”

Dynegy, the owner of the power plant, is the other company that applied for a FERC permit. A Houston-based utility company with around 13,000 megawatts (MW) of nationwide power generation capacity, their February 6 application with FERC came several months after Archon’s. If their project tests successfully and goes on to get the two dozen or so licenses and permits that would be needed, it would eventually generate 650 MW of power and cost more than $1 billion to build.

“Dynegy filed their permit many months after we did,” Grist said. “Our goal was to use that transmission corridor to the coast and Dynegy basically followed. Their application is further towards land than ours. I’ve talked with them and we’re going to try to work together and help each other out as much as we can.”

Archon Energy, co-founded by Grist in 1999 when he was 20 years old, is a small, independent power producer focusing on next generation technologies with minimal environmental impacts. In the fall of 2013, the company filed for a FERC permit to pursue testing on a one-by-fifteen mile site several miles offshore that would cost about $1 million. Grist said they are waiting for preliminary permits to start investing significant capital and holding consultations with stakeholders, including local community members and environmental groups. However, he’s had his eye on hydrokinetics — the production of energy from the flow of moving water — for a decade.

“There’s a lot of technology happening in wave energy conversion,” Grist said. “Wave energy will be coming of age in the immediate future.”


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Other Renewables Make Ocean Thermal Energy Plants Viable

While experiments with OTEC have persisted in fits and starts ever since the late 19th century, they have been continually hampered by a number of debilitating factors, including the difficulty of pumping huge amounts of cold water from the ocean’s depth and the fact that the process requires a temperature gap of at least 20 degrees Celsius to work, confining it to a thin belt of tropical and sub-tropical areas around the equator.

Recent scientific advances promise to overcome these hurdles however, and make OTEC a more economic and practical source of renewable energy.
Scientists are focusing in particular on combining OTEC with other forms of renewable energy, such as solar power or geo-thermal power, to enhance its potential and render it effective in a broader range of environmental conditions.
Paola Bombarda of the Polytechnic University of Milan has used computer models to prove that solar collectors have the potential to radically increase the power output of OTEC plants, by heating up warm ocean water to increase the temperature gap.

In a paper published by Bombarda in the Journal of Engineering for Gas Turbines and Power, she found that even cheap and rudimentary solar collectors, consisting of a mechanism as simple as lenses or tubes for trapping heat, are capable of tripling the daytime electricity output of OTEC plants.


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Re: The Ocean Wave Energy Thread (merged)

Unread postby sparky » Wed 26 Mar 2014, 19:54:40

.
A French guy build a functionning oceanic thermal plant in the Caribeans around 1930ies
in the book by Jules Verne "20000 leagues under the Sea " captain Nemo mention it as a possible source of thermal electricity
( he finaly used coal )
nothing came out of it , it work but it's too much trouble for to little return
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Re: The Ocean Wave Energy Thread (merged)

Unread postby Graeme » Thu 11 Sep 2014, 18:08:29

Ocean Thermal Gets a Second Chance

Prospects for generating electricity from the temperature difference in ocean water just got a boost with the installation of a 100 kilowatt turbine in Hawaii.

Makai Ocean Engineering put the turbine in place Tuesday at its Kailua-Kona facility, which will be the largest grid-connected facility to use ocean thermal conversion technology after piping and electrical connections are finished as planned by the end of the year. The system is designed to be a pilot project for developing larger plants, according to project manager Michael Eldred.

“It’s great technology for Hawaii,” Eldred said Wednesday. The islands get most of their electricity from burning petroleum, but OTEC is not yet cost effective.

“Our focus is to reduce the cost of the system,” he said.

OTEC technology works by using warm surface water to evaporate a working fluid such as ammonia to turn a turbine. Cold water from ocean depths is then used to condense the fluid.

A large 100 megawatt system would require 30-foot wide pipes to extend down from a platform thousands of feet to the cold deep water – an engineering feat that has yet to be accomplished. Such a system could cost $1.5 billion with existing technology, costs Eldred’s company is looking to shave by several $100 million, mainly by halving the costs of heat exchangers.

“We’re trying to make those smaller, more efficient,” he said. While he is cautious not to minimize the technological and economical hurdles that remain to be overcome, he is hopeful.


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Re: The Ocean Wave Energy Thread (merged)

Unread postby Graeme » Tue 14 Oct 2014, 17:04:58

Can OTEC solve our energy problems?

Short-Circuiting Sea Level Rise

Sea level rise can be short-circuited with energy systems that pay for themselves with the power they generate.

The heat of global warming is going principally into the oceans; mainly in the top, mixed, layer of the tropical seas.


Short-circuiting the movement of heat from the tropics to the poles by diverting it into the deep oceans reduces the long-term risk posed by icecap melting. It also reduces thermal expansion because the coefficient of expansion of sea water declines to a depth of 1000 meters.


One way to insure the surface continues to absorb heat is to move as much as possible of the accumulating excess into the deep oceans. A heat pipe can do this because it moves heat, rapidly, regardless of the pipes orientation with respect to gravity.

The existing difference in temperature between the ocean's surface and its depths offers the potential to replace all fossil fuels with as much as 25 terawatts of carbon free ocean energy.

The entities that can capitalize on this potential stand to profit handsomely even as they resolve the climate/energy problem.

The mass of the ocean below the thermocline insures a great deal of heat can be sequestered there absent any appreciable rise in temperature. To 2000 meters it only rose .09C from 1955 to 2010.


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Re: Ocean Thermal Energy Conversion

Unread postby Tanada » Wed 15 Oct 2014, 04:49:18

I reconstituted this thread from Archives and moved the posts that belong here from the Ocean Wave Energy thread. The two technologies are completely different so mushing them into one thread doesn't help anyone find them when searching.
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Re: Ocean Thermal Energy Conversion

Unread postby Graeme » Wed 15 Oct 2014, 17:00:03

T, At one stage there was a separate thread for this tech but somebody merged it. Now it's back to where it was. Thanks. I'd like to add the wiki page on OTEC.
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Re: Ocean Thermal Energy Conversion

Unread postby Graeme » Mon 03 Nov 2014, 20:20:06

Makai Ocean Engineering secures major pieces of equipment for OTEC plant

Makai Ocean Engineering has secured several major pieces of equipment for its ocean thermal energy conversion, or OTEC, demonstration plant, which aims to show the commercial viability of this key renewable energy resource that's a constant power source, the Hawaii-based company said.

OTEC produces electricity from the ocean using the temperature difference between deep, cold and warm water surface seawater.

Its plants pump large quantities of deep, cold seawater and surface seawater to run a power cycle and produce electricity.

Makai's Ocean Energy Research Center in Kona on the Big Island, the largest OTEC research facility in the world, has received two new heat exchangers and a 100-kilowatt ammonia turbine generator that are in various stages of installation and testing.

To date, the Waimanalo-based firm has tested four condensers and three evaporators at the facility, each made from either aluminum or titanium.

The facility has been designed to easily swap out OTEC heat exchangers and test as many as six simultaneously.

Heat exchangers will be the single-most expensive component in a commercial offshore OTEC plant and thus optimizing their lifetime, performance and cost are critical for OTEC's economic success, Makai said.


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Re: Ocean Thermal Energy Conversion

Unread postby Graeme » Fri 09 Jan 2015, 16:41:00

Ocean Thermal Energy Conversion can slow climate change.

Unlike many other renewable-energy resources that are variable, OTEC delivers electricity with or without desalinated water continuously all year round, using no fuel.

OTEC is now economically competitive in its closed-cycle mode with offshore wind farms costing on average $5600/kW (NREL), compared to $4000/kW for 100-MW OTEC plant (Dr Vega).

It is competitive with large desalination plants in its open-cycle mode.

A $1bn reverse-osmosis desalination plant expected to supply 120,000 m3/day in San Diego would be matched by a 51-MW OC-OTEC plant supplying the same and costing twice the cost of CC-OTEC at $8000/kW, a total of $408M, less than half the cost of the reverse-osmosis plant.

Dr Paul Curto, previously NASA chief technologist, wrote in OpEdNews on 12/15/2010:

"OTEC is a true triple threat against global warming. It is the only technology that acts to directly reduce the temperature of the ocean (it was estimated one degree Fahrenheit reduction every twenty years for 10,000 250 MWe plants in '77), eliminates carbon emissions, and increases carbon dioxide absorption (cooler water absorbs more CO2) at the same time. It generates fuel that is portable and efficient, electricity for coastal areas if it is moored, and possibly food from the nutrients brought up from the ocean floor. It creates jobs, perhaps millions of them, if it is the serious contender for the future multi-trillion-dollar energy economy."


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Re: Ocean Thermal Energy Conversion

Unread postby Graeme » Sat 17 Jan 2015, 14:24:16

Prescribing a Cure for the Health of Both the Planet and its Inhabitants

Climate change is the greatest malady facing mankind because although not everyone is in imminent peril, none of us will go unscathed. No other disorder threatens trillions of dollars worth of infrastructure and climate is the threat most likely to metastasize into an existential problem if the worsening condition goes unaddressed.

The market for a cure is therefore immense as is the potential for profit and unfortunately also larceny.

A cure is the end of a medical condition and in the case of climate change that will not be brought about by a cessation of fossil fuel burning alone. Carbon is forever a 2008 Nature article points out, because CO2 emissions and their associated warming linger for millennia.

My colleague, Dominic Michaelis, published an article this week claiming Ocean Thermal Energy Conversion can slow climate change. He bases that slowing on the production of 5 terawatts of OTEC power but since the ocean's potential output is three times that great; the process comes as close to a climate “cure” as there is, particularly in terms of a source of energy.

As he points out OTEC reduces the temperature of the oceans, eliminates carbon emissions, and increases carbon dioxide absorption, generates fuel that is portable and efficient, food and desalinated water, creates jobs and reduces sea level rise and cyclonic action.


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Re: Ocean Thermal Energy Conversion

Unread postby Keith_McClary » Thu 19 Mar 2015, 15:07:15

Ocean pipes 'not cool,' would end up warming climate
One proposed strategy—called Ocean Thermal Energy Conversion, or OTEC—involves using the temperature difference between deeper and shallower water to power a heat engine and produce clean electricity. A second proposal is to move carbon from the upper ocean down into the deep, where it wouldn't interact with the atmosphere. Another idea, and the focus of this particular study, proposes that ocean pipes could facilitate direct physical cooling of the surface ocean by replacing warm surface ocean waters with colder, deeper waters.
"Our prediction going into the study was that vertical ocean pipes would effectively cool the Earth and remain effective for many centuries,"
...
what they found surprised them.
...
Their simulations showed that while global temperatures could be cooled by ocean pipe systems in the short term, warming would actually start to increase just 50 years after the pipes go into use. Their model showed that vertical movement of ocean water resulted in a decrease of clouds over the ocean and a loss of sea-ice.
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Re: Ocean Thermal Energy Conversion

Unread postby hvacman » Thu 19 Mar 2015, 16:31:24

OTEC has several fundamental technical/environmental/economic problems that will probably always keep it as a novelty item, "in the 'some day in the future" category.

1. Hostile environment - it's putting complex moving machinery out in the deep ocean, for crying out loud!
2. Distance from the utility grid. Power that will make a difference has to be transmitted from generator to the main grid. Undersea high voltage/high amperage conductors are $$$$$. Also a big factor with off shore wind.
3. Very low thermal efficiency - Thermal efficiency is proportional to the difference in the ABSOLUTE temperatures of the cold sink and hot sink. Assume the cold ocean bottom is 10 deg. C (283 deg. K) and the top is 25 deg. C (302 deg. K). Ideal thermal efficiency would be 15/283, or 5%. Figure losing 30% of that due to various process inefficiencies. One has to move a HUGE amount of water, with HUGE heat exchangers, to generate a LITTLE power.
4. Potential for environmental impacts large. Think about it. OTEC works by de-stratifying the ocean. All the ocean's life has evolved to live in various thermal layers within the ocean. If OTEC were to be placed in megawatt or gigawatt capacities, you're really going to turn a good chunk of the ocean upside down.

All off-shore energy-production systems, be they wind, wave, OTEC, have may of the same technical challenges as off-shore drilling, with a couple of orders of magnitude less potential extractable energy. Why bother? It is so much more simple/cost effective to use PV, close-shore or on-shore wind, combined with aggressive electric energy efficiency measures.
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