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Harnessing Vertical Sea Temperature Gradient
Sterling D. Allan writes "Sea Solar Power Inc., run by three generations of James Hilbert Andersons, has developed a solar power technology that does not fluctuate with the weather, but is available constantly. Their solution is to harness the solar energy stored in the sea by tapping the thermal gradient that exists naturally between the surface and deep waters, using a reverse refrigeration cycle. The modeling and testing done by the Anderson family over three generations since 1962 predicts that the cost of energy generation through this method will be within a price range comparable to nuclear, coal, natural gas, and other contemporary grid power plants. Ocean Thermal Energy Conversion, or OTEC, was invented in 1881 by a French scientist, Jacques Arsene D'Arsonval. SSP should be ready to build their first full prototype 2-3 years from now."
Nuclear power doesn't derive its energy from the sun.
My blog
Just like hydro power, this one has the problem of disrupting the environment, albeit a very local environment. By moving water against the normal gradient, you will warm up water that's supposed to be cold, and cool off water that's supposed to be warm. I could imagine plankton blooms and oxygen depletion, among other side effects.
Passive solar collection (photovoltaic and otherwise) and wind power are really the only truly "green" power sources.
There exists no way of exchanging information without making judgments. --Bene Gesserit Axiom
Further, what of the potential for secondary effects? Climate changes brought about by changes in ocean current temperatures? Remember, el nino/la nina are caused by a change of only a few degrees. That's not unforseeable for a large-scale technology such as this.
Oh, and BTW - it makes a lot more sense to base this on something like an oil rig, rather than a ship. Just sayin', is all.
I knew I missed something...
Incidentally, does the thought of messing around with oceanic temperature gradients bother anyone slightly? It's probably not on a scale nearly wide enough to destabilise any currents, but it'd be good to have an oceanographer's opinion on this.
For the love of God, please learn to spell "ridiculous"!!!
"SSP should be ready to build their first full prototype 2-3 years from now.""
It will run Linux (everything else will by 2007-2008)
I did a report on OTEC when I was in junior high--18 years ago--based on an article in Scientific American. There are prototype facilities in a number of countries--I visited the facility in Hawaii five years ago, which was at least a decade old then.
It's an intriguing idea, but this smacks of somebody trying to get publicity to bring in venture capital or something of the sort.
Nucular. It's pronounced nucular. ;-)
It is pitch black. You are likely to be eaten by a grue.
why not just harness the wave energy?
The theory of relativity doesn't work right in Arkansas.
The article says that the current world consumption of energy is about 1/300th of the energy available from the oceans in this way. I'm not sure if that's a tiny fraction or not, actually. Local effects on the ecology could be significant for a large power generation facility.
But the article also says that they can produce fresh water as a by-product, and that the process works best in the tropics (i.e. the developing world), so this might have a chance, since it'd probably be better for the environment than more fossil fuel consumption.
Have you read my blog lately?
'Has developed'? How about 'is developing'?
I mean, in the last year, I've read about thermal stacks, hydrogen generation using thermal power, horizontally-oriented wind turbines, and probably some other alternative power methods. They're all great ideas, with great possibility, but the summary for every one reads like a sales pitch.
AC: Only on slashdot... could the sentence "My hovercraft is full of eels." be moderated "+4, Insightful
In fact I think there are three sources of energy on earth:
Solar
Nuclear
Stored friction (hot core)
everything is a stored form of something else, and the three above are a stored form of the big bang.
-nB
whois gawk date unzip strip find touch finger mount join nice man top fsck grep eject more yes exit umount sleep dump
No, but it does derive it's power from heavy elements that were created by the explosions of older stars.
"Prefiero morir de pie que vivir siempre arrodillado!"
The ocean is so grossly unimaginably big that we would need an absolutely huge operation to even cause a measurable effect. If you really tried to change the temperature by even a fraction of a degree using this method you would have to pump extremely large quantities of water---quantities so large that I don't think anyone would ever consider building something so massive.
People sometimes forget the scale of things. On a global scale, we are not even part of the equation.
But you also have to consider the opportunity costs of doing this. If we would raise the global atmospheric temperature 1/10 of a degree with all the carbon we were burning, what will the net effect be if we can convert a significant portion of our energy sources from burning carbon to mixing a small amount of cold and warm water?
The radical sect of Islam would either see you dead or "reverted" to Islam.
Don't worry. Global warming will make it all balance out.
"Prefiero morir de pie que vivir siempre arrodillado!"
Deja vu!?!
There is a global circulation system called thermohaline. Basically in three relative small areas of the oceans the water sinks until the bottom, and then spread around the world. This water slowly go up again and the system is closed with surface warmer waters flowing in direction of the areas of generation.
I'm not even considering the energetic balance of the proposed structure, but if it works it might reduce the vertical thermal gradient and make the thermohaline circulation weaker. Maybe stop it. The movie "The Day After Tomorrow" is a fantasy about it, but be sure at least that the surface temperature on the North Atlantic would reduce since is one of those areas of generation of deep waters. You can imagine how would be the winter on Europe and North America? Would need a lot of energy to keep people warm there!
There are a few prototypes. Search for OTEC on google. The problem is, there isn't enough of a temperature difference to efficiently extract any useful energy. You basically have to pump HUGE quantities of water (like a 10m diameter pipe) to the surface and have enormous heat exchangers and stuff that extract the energy. You use a lot of energy to pump the water and it requires enormous capital investment for very small amounts of energy.
Wikipedia entry on the subject of Ocean thermal energy conversion: http://en.wikipedia.org/wiki/OTEC
I'd hardly call this "debunking". I happen to know David Battisti, and I think he's a good and credible atmospheric circulation researcher. On the other hand, plenty of other good and credible oceanographic circulation researchers I know would refute this, and have done extensive work on the amount of heat transported by the Gulf Stream, and its role in sustaining thermohaline circulation and associated climate effects. A press release about paper maketh noth scientific truth.
Not only that, but even if the Gulf Stream is not the primary deliverer of heat to northern Europe, the 20-line press release you cited does not claim that Europe's climate will not be affected by a change in thermohaline circulation.
So if you're searching for a thin vine to cling to the increasingly untenable view that carbon-loading of the atmosphere is not a major problem, better not grab too hard on this one.
I guess I am being punished by my mechanical engineering background.
It is possible that there is some good information on this site (somewhere), but quite frankly I do not know what you would want to waste time separating the real information from the quackery.
----- There are two kinds of people in this world, my friend; those with loaded guns, and those who dig.
Fission reactors, our only current form of nuclear power, split uranium nuclei into smaller fragments and thereby release energy. However, to form the uranium atom in the first place from smaller constituents therefore required energy. This energy is thought to have come from a supernova ~6 billion years ago, predating the formation of the solar system. Thus current reactors are, by some (possibly warped!) definition, still using fossilized "solar" power. The same can also be said of geothermal which relies mainly on natural decay of nuclei formed by the same supernova.
Only if we ever get fusion reactors working then we really say that we are no longer reliant on solar based power...and that's because we will have made our own mini-sun.
pebble bed reactors don't go china syndrome. environmentalists attitudes about nuclear is based on decades-old technology and watching too much "silkwood"
thermocline, solar, biodiesel, wind, tidal turbine, wave generated, etc.: these are all very cute boutique energy sources. but when all put together and maxed out in terms of realization of potential they won't dent 5% of our energy needs
oil and gas and coal are incredibly dirty and even geopolitically dangerous and increasingly expensive
put it all together and pebble bed reactors are an environmentalist's and energy policy maker's best friend
now we just need the lowest common denominator of uneducated environmentalist's opinions to catch up with reality
ps: YOU CAN'T MAKE BOMBS OUT OF IT
educate yourself, don't let your uneducated fears dictate your opinion
as time goes by, nuclear is only going to look more and more attractive to this world, once everyone gets a real education of the positves and negatives of nuclear compared to everything else
because the biggest thing going against nuclear really is only inertia and ignorance
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Tidal energy is based on the motion of the moon, not the sun or its rays.
global warmng isn't really an issue. Truth be told we don't know what the hell is happening to the enviorment.
Gosh, I am disappointed in the quality of nerds these days. Ever heard of the back of an envelope? For god's sake, units of energy are defined by how much they heat water, so it's not hard to figure this one out.
Projection from http://www.eia.doe.gov/oiaf/ieo/world.html is that the world will use 645 quadrillion BTUs of energy per year in 2025. If we assume this all comes from the ocean at 100% efficiency, this would be enough to raise a patch of water, 100m deep by 1024km on a side, by 1 degree C. Insignificant next to the whole ocean? sure. But certainly significant compared to local or even regional climate variation! (not that hydrocarbons aren't worse, or that this can't be spread out but hey, now all the slashdot blather can be vaguely informed. sheesh).
I really, really doubt that this thing is practical. Organic Rankine Cycle Turbines (which are proposed) are very expensive to operate on dry land, as has been shown by research into solar thermal power in California. At least in those cases the efficiency was around 20%. The best they can hope for with OTEC is about 1.5% efficiency. Theoretically they could get 3.25% (Carnot efficiency), but experience with Organic Rankine Cycle Turbines has shown that 300C solar plants (Carnot Efficiency ~50%) only get around 20%, so one could expect to get about 1.25% efficiency out of their OTEC setup.
On top of this, all the equipment must be marine grade (ie., pricey). Power must be transferred to shore. It also must be a functioning ship with all the expense associated with that.
But what makes me most suspect is the claim of making fresh water. Ordinary Rankine Cycle Turbines do produce fresh water via distillation, but the Organic Rankine Cycle is a closed cycle and no fresh water is produced. The only condensation you'll get are hydrocarbons, which are recycled to create more vapour.
Also, the tidal force actually also gives energy to the moon, so its orbit is slowly getting bigger. Only a few cm per year, but there it is.
Correct me if I've got my wires crossed, but I thought the sea temperature was about a constant 4 degrees all the way down, once you get below a certain distance of the surface. The reason being, that water colder than 4 degrees has lower density, therefore always floats upwards. That's why the ocean isn't frozen at great depths. It doesn't mean you couldn't tap that gradient anyway, but the depth required presumably wouldn't be all that much as long as you'd got at least as far as the 4 degree level.
In this case its survival of the smartest. Maybe the birds around the Altimont Pass are particularly stupid and are doing the rest a favour by removing themselves from the gene pool. If I look at my front window, a quarter mile away is one of the biggest wind turbines I've ever seen. Can't say I've spotted a single bird carcass lying on the ground underneath it.
Personally I don't believe wind turbines kill birds. I call bullshit. The blades just don't turn fast enough. And anyway, birds very quickly get out of the way of fast moving objects. When was the last time you ran over a bird in the road with your car? Drive at 'em as fast as you like. They see you coming and by the time you get there, they've moved.
"Research by raptor experts for the California Energy Commission (CEC) indicates that each year, Altamont Pass wind turbines kill an estimated 881 to 1,300 birds of prey"
/ bdes/altamont/altamont.html
That is not a large number at all, cars, buildings, pets, power lines, etc, etc kill WAY more than that. And the altamont pass is the single worst wind farm in north america for bird of prey deaths, because they were stupid and built it not only in the middle of a migratory path, but in the middle of the highest concentration of breeding golden eagles anywhere in the world, and with the blades positioned right at the typical altitude of those birds flight paths. This is exactly what caused the myth; old, improperly planned wind farms that haven't been fixed. Learn to find facts instead of just repeating nonsense you heard from whackjobs.
The fact that you think the tiny number of bird deaths produced by the worst wind farm on the continent is "substantial numbers" is just silly. And the fact that you pretend its indicative of modern, properly planned and constructed wind farms is just plain stupid. You can't say wind farms in general kill substantial numbers of birds just because a couple of bad wind farms were built.
The quote is from this page, there's more info there about what can be done to improve altamont specifically:
http://www.biologicaldiversity.org/swcbd/programs