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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.
FP? Anyway, I've visited that type of plant (OTEC, Ocean Thermal Energy Conversion) already in Hawaii (near Kona), where there is one running since quite some years. One problem is that it only works for steep ocean wall drop offs, since otherwise the pipe is getting too long.
It uses about half of the created energy (through a normal Carnot cycle) for pumping (about 120kW). The other half is not quite competetive, but with the nutrient rich and cool water, fish farming and air conditioning can be done, heaving the whole investment to a black zero (or better).
I leave the exercise of finding the link to a Karma-hungry reader.
Hurricane Application Group, Dept of Meteorology Control, Ministry of Proactive Defense
Temperature difference in sea.
the temperature difference is enough to liquify certain gasses, and then expand it again.
Just like the refrigerating unit.
Not to mention the increase of pressure water gets deeper.
Having lived on a island in the south pacific for a year I learned how important fresh water is. The aircraft landing strip that we had acted as a big water collector - water would drain into pipes and then was cleaned by a chlorination process. The idea they propose is a good one and would work in many islands out there - where they desperately need easy access to electricity and fresh water.
I am sure more will be available about the subject at a later date but, here is what would be interesting to know:
+ How much power/water does one of these amonia powered drinking fountains produce?
+ Is it scalable, should I start writing my congress person to de-comission Califoria's oil powered plants?
same story here
Before adopting WHATWG, read the moonlight.NET EULA [http://www.microsoft.com/interop/msnovellcollab/moonlight.mspx]
I heard that in some arabian countries beer is less expensive than water.. In near future this could also allow folks down in US to get their industrial energy(Oil) from somewhere else than Irak? ;)
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.
The article wasn't clear whether the ammonia is re-absorbed or released into the atmosphere. I'm guessing it would have to be released, otherwise it'd be some kind of perpetual energy system. Assuming that's true - surely this system is just the same as burning fossil fuels? except it's releasing nitrogen based nasties instead of carbon based ones. Or am I misguided again?
Bringing cold water from the depths has an unmentioned potential side-effect. Will it be replaced by warmer water from elsewhere? Cold, deep waters often support amazingly rich ecosystems. Raising the temperature even a few degrees could easily destroy entrie habitats. Will these generators warm the depths, and what effect will that have on the deep ecosystems?
Fresh water and clean energy? Sounds awfully unamerican and likely to support terrorism.
This affects not only the athmosphere by releasing ammonia (which is only a minor problem), but also the temperature balance in the ocean. Things such as the major ocean currents are driven by differences in salinity and temperature of the water. The big currents control at least part of our climate - eg. if the Gulf Stream were to shut down (which some think it might all too easily do if the polar ice cap melts), we will probably have a new ice age
And before you start jeering and making stupid jokes about it, remember that only 30 years ago the idea that human pollution could affect our athmosphere and the seas, was regarded as utter nonsense and hysteria.
When I was about ten I read one of those cool-science-futures-for-kids magazines, which showed a floating OTEC with a vertical downpipe - that makes more sense, as it doesn't rely on rare coastal relief. I believe Bruce Sterling's novel Islands in the Net also had similar floating OTECs. Perhaps building such a device of the necessary scale (you have to pump a lot of water around, after all) just isn't economic?
Even if you do get mass OTEC production working, its quite debateable if it's really such a good idea. It's a lot of effort (money, materials, time) devoted to something that doesn't generate a terribly impressive amount of energy, and by its very nature it both warms the deep water and cools the surface water, which will have localised environmental consequences.
I despair that everyone is concentrating on renewable resources while so many people (particularly in hot western US states) live in essentially uninsulated houses with single glazed windows. Biomas, geothermal, wind, solar, and ocean generation are all expensive and uncertain - tripleglazed solarglass windows and super-thick wall insulation are available fairly cheaply right now, are guaranteed to pay for themselves way before a windmill, an OTEC, or even a biomass plant. Yet still we're paying to air condition the sky.
## W.Finlay McWalter ## http://www.mcwalter.org ##
The Moon's gravitational pull? The article isn't /.ed yet you know... ;-)
This system is driven by temperature differences, not tidal movements, meaning the ultimate power source is mostly the sun with some input from the earth's core. AFAIK we don't get much heat from the moon's gravity ... (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.)
In the long term, I hope fusion will be successful; so far, the biggest research reactors only just pass the break-even point (generating more power than they consume), but the difficult bits (getting a reaction going, then feeding fuel in and removing waste while the reaction continues) are just about solved well enough to build bigger reactors. In the short term: fission. Wind and solar still can't produce enough power; oil - well, we know where that gets us! Gas is OK (and at least the US has ample domestic sources of natural gas, so no need to pour cash into Arab states which hate us...) but still produces pollution. Coal is the worst of all: not only does it pollute on a scale normally only seen in nightmares, it even produces more radiation than fission! (All carbon is slightly radioactive, which is how carbon-dating works; when you burn coal by the truckload, all the little bits add up to more than the small amount of uranium used in fission plants.)
So: Kill fossil fuelled powerplants, build more fission, and keep researching fusion. "Renewables" are improving, but still can't do the job properly - apart from anything else, solar and wind power don't even work 24x7, and power storage is nowhere near advanced enough to compensate. So, those nice clean "renewable" plants still need a conventional power station as backup!
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.
Next to the sun and the wind, the Moon's gravitational pull on the earth is about the only other source of near infinite energy this planet has.
The Moon's gravitational pull on the earth is indeed a renewable energy source... but it's not a resource. A resource is something that is actually worth exploiting. Current experimental tidal power plants are extremely expensive, environmentally disastrous (they kill all the species that feed/lay eggs on the shoreline), and produce pathetically small amounts of energy. Google the Bay of Fundy experiment for more info.
Ocean thermal energy conversion isn't much better than tidal... too low-density and remote to ever be economical.
But you forgot the best renewable of all: GEOTHERMAL! It's good for at least a billion years and there's enough of it accessible within 3km of the earth's crust to power the whole world - ten thousand times over. We just have to wait until the technology catches up so that we can harness geothermal power effectively. When that happens, all this speculation of "wind" and "moon" energy will seem as silly and archaic as Wiccans exploring the healing powers of homeopathy.
Yes, but I think we all remember what happened last time the Japanes messed around with power plants. That's right: Godzilla. With Mothra defeated and major military forces otherwise occupied, the situation looks grim! Beware the denizens of the deep!
I think the DoE deep sixed research on this in the late 70's becasue these would have to be in international waters halfway around the world in order to be effieient.
-=fshalor