Unlimited Solar Energy from the Ocean?

probe

In the late 1800’s, the French physicist Jacques Arsene d’Arsonval proposed a method for generating electricity using the sea as a giant solar-energy collector. It is considered that the technology, termed “Ocean Thermal Energy Conversion” (OTEC), may enable the establishment of an efficient energy storage system across the world, supplying enough energy for our entire planet.

Jacques Arsene d’Arsonval
OTEC is based on the idea of exploiting the differences in temperature between deep waters and surface waters in order to generate electric power. Shallow ocean waters can heat up to a temperature of 29C in the tropics. Only one kilometer below these warm waters, temperatures are significantly lower, often falling below 5C. These extreme temperature differences are used to operate vapor turbines, which drive generators to produce electricity. Experts estimate that on an average day, 60 million square kilometers of tropical seas absorb an amount of solar radiation that is equal in heat content to about 250 billion barrels of oil. To get a better perspective on these numbers, this actually means that less than 0.001% of this energy converted into electric power would be sufficient to supply over 20 times the electricity consumed daily in the United States.

Throughout the years, a number of attempts were made to refine the technology and construct a practical prototype of an OTEC plant. D’Arsonval’s student, Georges Claude, was the first to succeed in building an OTEC plant in Cuba in 1930, which was capable of generating 22 kW of electricity using a low-pressure turbine. This experiment proved the viability of such a system or, in Claude’s words “Made my virulent opponents hold their tongues.” Five years later, Claude constructed another OTEC plant aboard a cargo vessel. Unfortunately, it was destroyed shortly after the vessel departed due to poor weather conditions. The appearance of large amounts of cheap oil in the mid-twentieth century eventually brought OTEC research to a halt.

A team of British architects, including Dominic Michaelis, Alex Michaelis, and Trevor Cooper-Chadwick, are currently working on a project they hope will bring the century-old idea back to life. They have proposed to construct a network of “floating platforms”, which in addition to being OTEC power generators, will be equipped with wind and wave turbines. In this way, the platforms will simultaneously exploit a number of natural energy sources to provide ‘around the clock’ electricity. The scientists say that a single “island” of this design will be able to produce around 250MW, while 50,000 of these "islands" will be able to meet the daily energy requirements of the entire world's population.

The architects say that an OTEC plant will not only be a supplier of green energy, but due to its unique conversion process, will also provide desalinated water as a byproduct. In addition to about 300,000 liters of fresh water each day, the OTEC plant may also be used to produce hydrogen fuel by using electrolysis. Alex Michaelis envisions the islands themselves as home to workers, who will operate and maintain the plants. Michaelis envisions the inhabitants will be able to grow seafood and vegetables, living and working in rotations on the islands.

Many critics have questioned the viability of the 50,000 artificial islands system, saying it is unlikely that the project can be implemented cost-efficiently. In response to this criticism, Michaelis says that "If we consider that we are at war to find a new form of clean energy, wartime effort in World War II produced vast numbers of planes, tanks, ships and other armaments on both warring sides. 20,300 Spitfires alone were built, making the construction of more than 50,000 of these plants seem a reasonable number."

TFOT previously covered a number of unique renewable energy technologies, including “EnviroMission’s” Solar Tower and JAXA’s project to build the world’s first space-based power generation system. You can also check out our article about “nano flakes” – a newly discovered material, capable of converting solar energy into electricity almost twice as efficiently as traditional solar cells.


http://www.seasolarpower.com/

http://www.tfot.info/news/1118/unlimited-solar-energy-from-the-ocean.html

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AlmightyCushion

Just wondering, how big would these islands actually be?

probe

AlmightyCushion wrote: »

Just wondering, how big would these islands actually be?

One's guess would be small oil platform size - but one suspects much lower cost given the fact that they aren't drilling for oil and speculating on its presence - not to mention all the costs of pumping, staffing and bringing oil ashore.

More like a "fat" buoy perhaps, (not to be confused with a fat boy who visits McDonalds three times a day to get supersized).

.probe

prospect

AlmightyCushion wrote: »

Just wondering, how big would these islands actually be?

The helicopter gives a sense of scale.

AngryHippie

Sounds promising, but will mostly affect the tropics, and even then only areas with deep water close by, the 1km depth necessary and 24 degree temperature differential will not be available everywhere, But 50,000 dotted around the globe sounds do-able. Even dodging tricky weather zones and bandit country would leave enough space.
It would probably work better as a part solution, in conjunction with whatever Wind, HE and Nuclear cesspits are already up and running or on the cards.

John_C

Would it be a good idea to build one and see if it works before planning for 50,000?

AngryHippie

John_C wrote: »

Would it be a good idea to build one and see if it works before planning for 50,000?

:rolleyes:
[COMIC STORE GUY] Worst Idea Ever [/COMIC STORE GUY]

probe

I wouldn't think that this is a high priority technology for the seas around Northern Europe - waves, ocean currents, and tidal offer a bigger bang for the buck.

It might be a runner in the Gulf of Mexico (especially when the oil rigs stop pumping - might even recycle them into ocean energy generating kit!).

If they got enough of this (like 50,000 units) going in the Caribbean and Gulf of Mex - they might even reduce the number of hurricanes by reducing the temperature of the sea (having extracted its energy to produce electricity)!

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Capt'n Midnight

wasn't there something about providing rain to Oz by having solar / wind / wave powered rigs spraying sea water so high that it would evaporate ?

TBH the low efficiency of OTEC would be a problem, almost all the energy recovered goes into pumping the water you only get a small fraction of the Carnot cycle energy. However, using them as cooling for Air Con would be worth it since you are saving all the overhead with refridgeration.

I liked the bit about using it at the poles, water is just above freezing, but the air could be -40 so you get the same thermal gradient without having to pump the water far. Would also provide a low grade heat source and passive solution might provide the rest.

probe

probe wrote: »

I wouldn't think that this is a high priority technology for the seas around Northern Europe - waves, ocean currents, and tidal offer a bigger bang for the buck.

.probe

Placing two (one north & one south) tidal barriers & generators across the Irish sea would produce a good amount of energy! (understatement)

probe

Capt'n Midnight wrote: »

wasn't there something about providing rain to Oz by having solar / wind / wave powered rigs spraying sea water so high that it would evaporate ?

TBH the low efficiency of OTEC would be a problem, almost all the energy recovered goes into pumping the water you only get a small fraction of the Carnot cycle energy. However, using them as cooling for Air Con would be worth it since you are saving all the overhead with refridgeration.

I liked the bit about using it at the poles, water is just above freezing, but the air could be -40 so you get the same thermal gradient without having to pump the water far. Would also provide a low grade heat source and passive solution might provide the rest.

In the ghetto where I live, the 3000 odd residents + businesses get their “air con” from the Mediterranean (at a certain depth, -100m from memory) the Med is 10C all year around. Meanwhile the outside air temperature might be 25C.

So they pump in the cold water at 10C, use the energy derived from thermally treating our trash to cool this water to 5C, and pump the 5C water to heat exchangers in each dwelling / office. As a result I can keep my apartment temperature at around 21C day and night, with the heat exchangers running 24h/24. Even in 2003, when 14,802 extra deaths occurred in France from the heatwave between the 1st and 20th of August*, the heat exchangers did the job. With an electricity bill of about €35 per month typically, and no nuclear energy in that – all hydro or incinerator output. (I’ve mentioned this before).

If I had conventional old fashioned air conditioning running instead, it would probably consume 15 kW of electricity per hour, make a huge amount of noise from compressors and fans running, making it difficult to sleep, (the heat exchangers are very silent), and it would cost me over €30 per day in electricity to keep the place cool day and night. Or around €54 per day, if I was on an ESB tariff!

The same heat exchangers heat the space in winter using hot water from the same infrastructure switched into winter mode.

Moving across the Atlantic, the US is a massive consumer of energy for air conditioning. And they really turn the thermostats soooo low over there. I’ve gone into shopping malls in Texas and Florida in the Summer, and while it was about 40C in the car park outside, it was about 18C inside the mall. At least in Europe, people are educated not to abuse air con from an energy waste point of view.

A large proportion of the US population lives around the coast or close to the Great Lakes, and no doubt they have similar low temperatures in their surrounding waters at -100m depths. The energy and CO2 savings would be globally material if they adopted this heat exchanger technology, taking advantage of low ocean/lake water temperatures at a given depth.

One has to ask oneself why the political process in English speaking countries is so poor at getting the people responsible for planning to think creatively and make maximum use of God given resources to meet the energy needs of their communities? Forcing developers in turn to deliver.

.probe

*http://fr.wikipedia.org/wiki/Canicule_europ%C3%A9enne_de_2003

Capt'n Midnight

something like 8% of elctricity in US is on air con
or was it 8% of all energy use ?

probe

Capt'n Midnight wrote: »

something like 8% of elctricity in US is on air con
or was it 8% of all energy use ?

You can double that :-) - AirCon consumes 16% of electricity according to the US DoE. And that number dates back to 2001, when "global warming" was only starting to appear on the big picture radar...

http://www.eia.doe.gov/emeu/recs/recs2001/enduse2001/enduse2001.html

.probe

probe

Deleted User wrote: »

Placing two (one north & one south) tidal barriers & generators across the Irish sea would produce a good amount of energy! (understatement)

Aside from the bill for concrete and stones, and all the rest of the hardware, you would have to make provision for shipping. In my boat, I don't want to have to deviate my course by say 50 km east or west of the optimal heading to go through one of your "canal locks".

Perhaps marine turbines might achieve the desired objective?

Something along the lines of : http://www.marineturbines.com/technical.htm

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Capt'n Midnight

This is a little closer to home.
http://www.4ni.co.uk/northern_ireland_news.asp?id=71434

Strangford Lough, which has one of the fastest tidal flows in the world, is to be home for the SeaGen marine turbine, will produce energy for 1,000 homes when it becomes operational.
...
However, it will now be deployed by a crane barge at the end of March, makers Marine Current Turbines said.

The turbine has the capacity to generate 1.2mw of electricity, four times more than any other tidal turbine. It will operate in Strangford Lough for up to five years and will be installed by the crane barge Rambiz, in an operation which will take up to 14 days.

The turbine will first be picked up from Harland and Wolff in Belfast after final assembly.

Concerns remain over the environment, however, though the makers say that a team of environmental scientists will be in the lough to monitor the turbine's operation and effect on marine life.

Strangford is a breeding ground for common seals, but the company says that the speed of the rotors is so low - no more than 10 to 15 revolutions per minute it is said - that they are unlikely to pose a threat to marine wildlife.
...
MCT intends to manufacture and deploy a series of SeaGen devices in projects off Anglesey and on the Canadian seaboard within the next two to four years.

Should be doable else where
Lough Foyle, and Carlingford Lough
Shannon Estury

BRIAN1956

probe wrote: »

I don't want to have to deviate my course by say 50 km east or west of the optimal heading to go through one of your "canal locks".

Especially as the government:rolleyes: would put a Toll charge on everyone using the said "canal locks"

probe

BRIAN1956 wrote: »

Especially as the government:rolleyes: would put a Toll charge on everyone using the said "canal locks"

The concession for which would probably be sold off to a CRH type subsidiary/associate/related company for 50 years.

No Visa/MasterCard/Europay accepted (like 99% of Irish motorway tolls, pig inefficient, and unlike any other canal lock or autoroute toll in Europe).

A two hour queue at peak times for boats travelling up and down the Irish Sea while people fiddle with cash, wait for barriers to open, and wait for people to come off coffee breaks and open up a lane. No thanks.

.probe

Capt'n Midnight

But there would be two new roads on the dams

the short one would be giants causeway to mull of kintyre
larn to stranrare is longer ,deeper and there are a lot of uxb's on the sea bed

the long one to wales, and the tolling system would probably cost more than the bridge if the M50 is anything to go by

Húrin

50,000 of them? I don't see why people always have the urge to put all their eggs in one basket when it comes to renewable energy.

I expect that putting huge numbers of these things all over the seas would result in great damage too. Those heat currents exist for a function, you know.