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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
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?
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? ;)
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?
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!
It still is. As it turns out in reality, the 20th century was the one with the least chaotic "earth weather" and we now try to use _that_ as a baseline for "how it should be".
It won't work. The earth has a weathersystem totally independent of what us tiny humans do. Read up on the "small ice age" just a few hundred years ago, or where the "dark middle ages" got the nickname from.
"Global warming" is a myth. A popular one, but a myth nonetheless. "Global cooling" - which was popular a few centuries ago - is actually more likely to happen.
it's in my head
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.
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