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New Power Plant Produces Both Energy & Fresh Water
joshmccormack writes "An article in Sunday's New York Times (Free Reg, mah peeps) tells of how Japanese scientists have found a way to make fresh water and energy from temperature differences in ocean water. This may change the rules of what land is considered habitable, and the value of energy." Fascinating stuff, next step is rumored to be beer and power.
same story here
Before adopting WHATWG, read the moonlight.NET EULA [http://www.microsoft.com/interop/msnovellcollab/moonlight.mspx]
Japanese Technology May Help Islands Reap Pacific's Waters
By AGENCE FRANCE-PRESSE
KYOTO, Japan, March 22 -- A number of Pacific island nations are discussing using new Japanese technology that can both desalinate seawater for drinking and produce electricity by exploiting the difference in temperatures between the surface of the sea and the depths of the ocean.
The Republic of Palau in the western Pacific is working with Saga University in southern Japan to build a system that can produce enough drinking water to meet the needs of its 20,000 residents, while producing electricity, said the country's president, Tommy Remengesau Jr.
The concept was highlighted this week at one of the 350 sessions at the Third World Water Forum, which is under way here. It has attracted 10,000 participants from around the world, along with ministers and some heads of state from more than 150 countries.
The university is preparing to build an experimental power plant off the coast of Palau that brings up cold seawater from the depths of the sea to an evaporator chamber near the ocean surface.
As the water is heated by the surrounding warm surface water, it releases ammonia gas, which then drives the system's power generator, said Yasuyuki Ikegami, deputy director of the Institute of Ocean Energy at Saga University.
Meanwhile, the heated water would be transferred to a separate low-pressure chamber where it boils at a lower temperature, producing steam, which would be condensed and collected as fresh water for human consumption, leaving salt crystals behind.
One experimental system, which produces power but no usable water, is scheduled to be put into use off the coast of India this month, Mr. Ikegami added.
"It works well especially in the western Pacific, where the temperature difference between the ocean's surface and deep seawater is" as much as 43 degrees Fahrenheit, he said. "It is environmentally sound."
With some financial assistance from the Japanese government, the university was hoping to build the experimental plant in Palau for $7.5 million, said Haruo Uehara, president of Saga University, although he declined to disclose details of the financing because it was still being negotiated.
Palau was hoping the plant could be built next year, Mr. Remengesau said.
"It is a big help for us," he said. "When there is rain, we have no problem. But we are hit by the drying effects of El Niño. When there is no rain, where can we get drinking water?"
The fresh water produced by the system will cost less than $1 for more than 250 gallons, Mr. Uehara said. "It is no more costly than regular tap water in other countries, including Japan," he said.
The system, while more expensive than ordinary generators, has raised hopes among leaders of other Pacific islands, which are too small to build many dams to catch water and are trying to cut back on their consumption of oil to run power generators.
Allan Marat, deputy prime minister of Papua New Guinea, said Pacific island nations had fallen victim to global warming, adding that he too was interested in the university's system.
"We are in the middle of the largest body of water" on earth, said Robert Woonton, prime minister of the Cook Islands. "Yet, we are faced with lack of safe potable water." He said he wanted to consider setting up Saga University's system in his country.
Other countries in arid zones have also shown interest, including Saudi Arabia, which was sending a delegation to the university, Mr. Uehara said.
I leave the exercise of finding the link to a Karma-hungry reader.
Just eaten, sorry
- Ugly but Informative
- Great Description page
- a Vendor who sells OTEC and other enegry harvesting alternatives. Has some nice diagrams.
- Pedestrian newspaper article.
</karmawhore>--I hate big sigs.
I've seen a few posts here speculating that if ocean thermal energy conversion is scalable, we potentially have a miraculous supply of renewable energy. Sorry to pop bubbles, but OTEC is way too inefficient, expensive, and low-density to work on a larger scale. It's only viable for remote islands that need fresh water, in very warm areas, with a seawater temperature gradient of at least 20 degrees celsius. Otherwise, it's too expensive and inefficient to bother.
A theoretical 100MW plant (Current experimental sizes are lower than 1 MW) would require a hugely expensive floating platform, connected to the mainland by a hugely expensive submarine electric cable.
Because OTEC is a very low-density resource, a 100 MW plant would have to be massive... pumping, processing and discharging a volume of water equal to the flow of the Colorado River into the Pacific Ocean. On top of the massive construction costs, electricity generated would cost about $0.22/kW (as opposed to wholesale price of $0.02-$0.03.kW in the US). If just 1% of world energy consumption (60,000 MW) was met by OTEC, the cost of building the infrastructure would be $1,000,000,000,000 (one trillion dollars) and the discharge from the plants would exceed the combined discharge of every river one the planet into the oceans. Scalable? Maybe not.
It is scaleable - provided you have the right sort of coast, with very deep war relatively close to the shore. It will therefore be very suitable for most Pacific islands, many of which are the tops of seamounts. I don't think the coast of Calif is quite so precipitous - and the power consumption per mule of coast is probably thousands of times that of (low population, low power consumptoion, lots of beach) Pacific islands. So don't get too excited.
Consciousness is an illusion caused by an excess of self consciousness.
Not like a fusion plant, that has all those problems radioactive waste is generating. (And the waste from fusion plants is not even useable for building ammunition like the uran is)
You are mistaking fusion with fission. Nuclear fission (breaking apart) is what we use now in the power plants. Nuclear fusion (coming together) is what we are experimenting with and are just getting to work for very short times in experiential reactors. Fusion takes 2 small atoms like H and He and forces them together. It does not use highly radioactive fuel (U-23x), nor does it produce waste with a 10,000 year half life.
Also, weapons can be made from the depleted U from fission plants. They put it in the tip of tank shells because we can't make it fly any faster so we make it heaver. (U is around 10% heaver than Pb). It will not work for a nuclear weapon, but it can be refined and converted into stuff the that can make one.
Go to the link -- it's good.
Yeah, it's big in Iceland and New Zealand, and 10% of California, but it still acounts for a lot less than 1% electricity production worldwide. I think someday it will account for 90%... the rest being hydro and solar.
Or is this how all OTEC plants work??
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
However, on reflection, it seems much more likely that the reporter simply misunderstood something and that the "ammonia gas" is just the liquid used inside a traditional heat pump.
Except, Deep ocean water comes from a high pressure, and it has a significantly higher nitrogen content than the surface water. Algae blooms will be common near the outlets because of this, and plankton feeds on algae. these plants will be like deep water upwellings that occur due to geography in places around the world, like antarctica. In places where there is a deep water upwelling life is extremely abundant. This is why the effluent could be used for aquaculture as mentioned in another post.
"Renewables" are improving, but still can't do the job properly
Not so, according to a USDA study, ethonol yields a 34% energy gain ( USDA REPORT FINDS ETHANOL IS ENERGY EFFICIENT)and that is including growing and harvesting. Wonder what the efficiency of oil is when you figure in transport from who knows where and add the cost of defending it?
I think there are better sources of energy that are just on the horizon but I think ethonol is a good temporary solution. It has enviornmental benifits and I think its better than subsidies for farmers (and taxpayers).
Why have 1 person driving a backhoe when you could employ 20 with shovels?
You don't know much about science at all. Do you really think it's appropriate for you to be spouting out pet environmental theories given your stupendous lack of knowledge of basic mechanisms of energy transfer?
Did you bother to read the article to see how this works? No.
But that sure didn't stop you from rushing out and writing a post about the potential environmental horrors of the release of ammonia gas.
Conservatives and big oil don't have to destroy the environmental movement...their own stupidity is quite sufficient for the task.
(Just as well, really: any energy we extracted from it would be orbital kinetic energy. Draining that is bad, since it would cause the orbit to decay and squish people.)
Not quite, the energy is from the relative angular speed of earth's rotation and of the moon's orbit around earth. The angular momentum of the orbiting moon is a good bit larger than that of the spinning earth, so in the end we'd slow down earth's rotation and speed up the moon in it's orbit a bit until eventually the angular velocity is the same, i.e. day and month are identical.
However the power density to be got from the tidal wave is not high enough to be extracted efficiently. There is a nice comparison of alternateive energy sources in "Gerthsen Physik", the conclusion is that only solar power, nuclear fission and nuclear fusion have enough fuel available and offer high enough power density to support man's growing energy demands.
Alternative sources like wind energy are great for local supply, especially in remote areas, but don't scale up enough to suport everyone.
Alex
Heisenberg may have been here
My father actually designed a good portion of the pipes &tc. for a similar project in Hawaii (probably not be the Kona project mentioned, he was working on this recently). It was intended to provide power to a very rural section of the islands, as well as supporting an aquacultural project in the same area. The cold ocean water was drawn up from the depths through a VERY long pipe, then fed through the aquacultural facility. Deep, cold ocean currents carry a great deal of nutrients and is relatively rich in dissolved oxygen as compared to the surface water, and the fish they're raising just go gangbusters with it. The major problem they ran into was designing an exclusion system to keep local fish from being sucked into the uptake. They used a cone-shaped netting system in the end, as I recall. My father is the head designer at Ershigs, Inc.'s Bellingham, WA location.