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."

Comments

Unfortunately, it's not a passive energy source

[csoto]

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.

Re:Unfortunately, it's not a passive energy source

[paco3791]

The problem with any power generation scheme is that there are always side effects, you just have to pick your poison.

With photovoltaic systems you have the nasty chemicals currently associated with manufacture, with wind power you have what some people consider noise and landscape pollution, along with bird strike problems, although this problem is probably over hyped with newer windmill designs.

There is, as they say, no free lunch.

Re:Unfortunately, it's not a passive energy source

[Chandon Seldon]

Absolutely any technique to generate power will have environmental consequences. Wind power takes wind energy out of the atmosphere, which could cause climate change if used on a large scale. This proposal is about the same.

A very important point to remember is that we will use an increasing amount of energy for the forseable future and that energy will be generated somehow. Coal is the default power technology. Every time a wind / nuclear / tidal / etc power plant doesn't get built another coal plant is built instead. So the question isn't "Is there an environmental impact from this power source?" - we know that answer, there always is - the question is "Is this better than coal?".

Re:Unfortunately, it's not a passive energy source

[caseih]

No, even photovoltaic solar panels aren't passive. They prevent energy that would reaching the ground from doing so, altering the energy balance there. In short there is no form of energy that we can extract from nature that doesn't alter in some way (large or small) the natural energy flows and balance in nature.

Re:Unfortunately, it's not a passive energy source

[winkydink]

Passive solar collection (photovoltaic and otherwise) and wind power are really the only truly "green" power sources.

The processes to manufacture these are also green? Ever seen a semiconductor fab? Clean? Yes. Green? I dunno, what color is arsine gas? If you smell garlic, it ain't the pizza joint next door.

Re:Unfortunately, it's not a passive energy source

[forand]

The sun doesn't raise the average temperature systematically, otherwise we would all be dead. The ammount of energy that the Earth gets from the Sun is, over time, exactly the same as it puts out. This fluctuates with the ammount of green house gasses in the atmosphere, but in general the Earth re-radiates the energy it gets from the Sun.

That said if we convert the energy into electricity then use it to power our lights and stuff it will get back into the atmosphere and get radiated away. So the energy is there for the taking.

Re:Solar????

[Lifewish]

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.

Re:IANAO

[14erCleaner]

If the energy they're taking is but a tiny, tiny fraction of the thermal energy availible in the ocean (which i think is most likely the case) then it won't be an issue.

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.

Choice of phrase

[jtorkbob]

'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.

Re:Solar????

[networkBoy]

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

Re:waves?

[lilmouse]

Waves depend on things like wind and tides to work. Winds change with the weather, and tides change all the time (at least tides are regular). Whereas it's *always* possible to get a 20degree heat gradient.

Besides, if you put your heatsinks below the surface of the water, you don't have to worry so much about storms and such.

--LWM

Re:Sound too good to be true? Perhaps it is...

[electroniceric]

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.

Re:IANAO

[rocket jockey]

global warmng isn't really an issue. Truth be told we don't know what the hell is happening to the enviorment.

Sounds like a hoax

[Yartrebo]

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.

Evolution in action

[Macka]

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.