Forgot your password?
typodupeerror
Power China

World's Largest Ocean Thermal Power Plant Planned For China 112

Posted by Soulskill
from the harvesting-heat-waves dept.
cylonlover writes "Lockheed Martin has been getting its feet wet in the renewable energy game for some time. In the 1970s it helped build the world's first successful floating Ocean Thermal Energy Conversion (OTEC) system that generated net power, and in 2009 it was awarded a contract to develop an OTEC pilot plant in Hawaii. That project has apparently been canceled but the company has now shifted its OTEC sights westward by teaming up with Hong Kong-based Reignwood Group to co-develop a 10 MW pilot plant that will be built off the coast of southern China."
This discussion has been archived. No new comments can be posted.

World's Largest Ocean Thermal Power Plant Planned For China

Comments Filter:
  • by alen (225700) on Friday April 19, 2013 @02:51PM (#43496349)

    not like we can build this off the coast of Nantucket

    • by h4rr4r (612664) on Friday April 19, 2013 @02:56PM (#43496445)

      You realize the USA extends much further south than Nantucket, right?

      • Re: (Score:2, Troll)

        by ebno-10db (1459097)

        You realize the USA extends much further south than Nantucket, right?

        Yes, but no place much further south than Nantucket is worth going to.

        However, we might still be able to use some of that beach front real estate for OTEC. Or perhaps the poster is suggesting OTEC for Nantucket (or referring to the fact that Nantucket is a excellent place for offshore wind, blocked by various NIMBY's)

        • I got modded down for that? Note to self: some /. moderators are way too touchy, or think the results of the Civil War are still open to debate, or something. Sheesh.
      • by mackai (1849630)
        True on both. The idea has been around long enough to know the more obvious limitations. You need warm surface waters and access to deep cold water. Back in the 70's the only US sites viewed as suitable for land based OTEC was Hawaii and the territory of Puerto Rico. There were designs for grazing platforms that could float in tropical deep water but the problem was always how to get the energy from the platform to where it is needed. Biofouling is a tremendous problem as well. I think that it is a pretty s
    • by Anonymous Coward on Friday April 19, 2013 @03:08PM (#43496595)

      In Stockholm, Sweden we have since many years been running the worlds largest heat pump facility, 225 MW. http://sv.wikipedia.org/wiki/Hammarbyverket [wikipedia.org].
      It's using waste water from a nearby waste water treatment facility that serves a large fraction of the Stockholm metropolitan area of some 2M people.

      • In Stockholm, Sweden we have since many years been running the worlds largest heat pump facility, 225 MW.... It's using waste water from a nearby waste water treatment facility

        Now that's hot sh*t

        Sorry couldn't resist.

    • by Dabido (802599)

      Reminds me of an old poem.

      There was an OTEC from Nantucket ...

  • To the far east... kinda like making those three lefts...

  • Maybe I missed it but the picture gives me a vague impression that waves have something to do with it but I didn't see them mentioned? I suppose the water movement wouldn't be much use though.
    • by Baloroth (2370816) on Friday April 19, 2013 @03:14PM (#43496683)

      Maybe I missed it but the picture gives me a vague impression that waves have something to do with it but I didn't see them mentioned? I suppose the water movement wouldn't be much use though.

      No, it has nothing to do with waves. It uses the ocean's thermal gradient as a power source: because there is warm water on top, and cold on the bottom, we can use the difference to generate power (much like heat from a conventional power plant). Keep in mind it won't be very efficient, since the temperature difference is relatively low, but since you have quite a lot of seawater to utilize, efficiency isn't terribly important.

      • "The boundary between cold water and warm, the Thermocline, has been important to undersea warfare for hundreds of years of man's history. Now we have found away to harness that power for constructive purposes. Once what cloaked us can now feed us. Once what shielded us from death, now brings us life."

        Captain Ulrik Svensgaard, "The Ripple and the Wave"
    • by bobbied (2522392)

      Waves have nothing to do with this. Only the temperature difference between the surface water and deeper water. The higher the difference, the better which is why this works the best in tropical regions.

      They will "boil" the working fluid in heat exchangers near the surface, generate power with the vapor, then send the vapor down to deep cold water to get condensed. I suppose that they then pump the liquid back up to the surface to start over. Seems like it will work in theory, assuming the working flui

      • by dj245 (732906)

        Waves have nothing to do with this. Only the temperature difference between the surface water and deeper water. The higher the difference, the better which is why this works the best in tropical regions.

        They will "boil" the working fluid in heat exchangers near the surface, generate power with the vapor, then send the vapor down to deep cold water to get condensed. I suppose that they then pump the liquid back up to the surface to start over. Seems like it will work in theory, assuming the working fluid has the proper boiling point and high enough latent heat of vaporization so enough heat can be moved. I'm worried that in order to get the proper temperatures for the phase changes is going to require working pressures that are going to be difficult to maintain or it will require large quantities of some nasty chemicals.

        It is more likely they will pump the seawater from the ocean to the plant, and have the working fluid remain on land. Whatever they use for the working fluid, it is almost certainly something that environmental groups will be upset about if it leaks into the ocean. This makes the system less efficient since pumping. The Navy has apparently determined twice [wikipedia.org] that such a system isn't viable. When I see any branch of the service shutting down a Lockheed project, that is a red flag that the technology isn't

        • by spitzak (4019)

          The article said the working fluid is ammonia.

          The heat exchangers are on the surface, not on land. The problem is that a pipe to land (rather than straight up to the surface) would be many times longer and would lose most of the temperature difference.

          • Ammonia isn't great to be around but as far as I know it's pretty harmless environmentally. Reactive enough that it'll be destroyed pretty quick if there's a release.

    • by Solandri (704621) on Friday April 19, 2013 @03:33PM (#43496907)
      Kinetic energy of water is 0.5*mv^2. For 1 ton of water moving 1 m/s, that's 500 joules per ton. If it's moving at 5 m/s (about the max you'll see in tidal areas), that's 12.5 kJ/ton.

      Water has a specific heat of 4.2 kJ/kg*C. If there's a 1 degree temperature differential, that's 4.2 MJ per ton. You have to go a bit deep to get to colder water, but by about 1km down it's around 4 C. So relative to tropical surface water, you're talking about a 25 degree difference, or an energy potential of 100 MJ per ton. Nearly 5 orders of magnitude more per ton than the kinetic energy in tidal currents.

      The catch being that it's much more difficult to extract power from temperature differentials than it is from kinetic energy. If it were easy, every car engine would have a stirling engine alongside it to extract energy from the waste heat. But stirling engines generate so little power per mass of the engine that it's more efficient just to forgo the additional weight and dump the waste heat via a radiator.
      • by MattskEE (925706) on Friday April 19, 2013 @09:46PM (#43500381)

        ...
          If there's a 1 degree temperature differential, that's 4.2 MJ per ton.
        ...

        The catch being that it's much more difficult to extract power from temperature differentials than it is from kinetic energy. If it were easy, every car engine would have a stirling engine alongside it to extract energy from the waste heat. But stirling engines generate so little power per mass of the engine that it's more efficient just to forgo the additional weight and dump the waste heat via a radiator.

        It's not just "more difficult", it's scientifically impossible to capture all of the power from temperature differentials. The maximum possible efficiency of such a heat engine is described by Carnot's Theorem [wikipedia.org] and is (1-Tc/Th) where Tc and Th are the absolute temperatures of the cold and hot reservoir. So if 100MJ of heat flows from a hot water reservoir into a cold water reservoir through a heat engine you can only capture a single digit percentage of that energy for the temperature differences under discussion

        So taking a 25 degree heat difference as 275K cold water and 300K hot water then the optimum efficiency of the heat enginer is only 8.3%, and the actual efficiency will of course be less.

        • by dbIII (701233)
          Yes, but the fuel cost for generating that temperature difference is free so it just comes down to capital costs and maintaince costs. Of course the capital cost is huge with a slow rate of return for investment (compared with housing bubbles or whatever) which is why a government is doing it.
      • by sincewhen (640526)

        Sorry to make a small correction to an informative post, but most of the waste heat from an ICE goes out the exhaust.

  • 10MW? (Score:1, Flamebait)

    by seven of five (578993)
    Why, that's almost enough to run the sign that says, "Powered by Green Energy!"
  • They'll find a way to make it out of lead or cadmium I'm sure.

  • by ebno-10db (1459097) on Friday April 19, 2013 @03:16PM (#43496701)

    Could OTEC help produce algae for biofuel?

    AFAIK nutrients are a serious constraint on the large scale use of algae for biofuel. For pilot plants you can always dump in fertilizer, but on a large scale it might be different, due to the energy required to make that fertilizer and the fact that there is a limited supply of phosphates [yale.edu]. Even sewage has its problems, as there is a limited supply (though some contribute much more than others) and it may be better used for agricultural fertilizer (humanure). However, deep ocean water often contains lots of nutrients because dead plankton tend to sink. That's why you get lots of phytoplankton (green water) in parts of the ocean where there are upwellings. Could the deep water that's brought to the surface for OTEC be used to fertilize algae grown for biofuel?

    • I sure that once all the fish are gone, they can also use this to suck up remaining plankton and jellyfish and sell it as Li'l Lisa's patented animal slurry.
      • Do you have any reason to believe that what I asked about would necessarily be terribly destructive, or are you just one of those people reflexively, fanatically and thoughtlessly opposed to anything that's done by humans other than growing organic bean sprouts (hint: even organic farming is both highly "unnatural" and environmentally destructive). If you fall into that category, please join the Voluntary Human Extinction Movement [wikipedia.org]. It would benefit everyone.
  • by sonoronos (610381) on Friday April 19, 2013 @03:17PM (#43496719)
    OTEC isn't a serious contender for green energy. It sounds good because it seems to combine romantic elements of green energy: limitless sea water, temperature gradients with huge thermal sinking ability, minimal environmental impact, etc. The truth of the matter is that OTEC has serious fundamental limitations, the worst of which is the fact that economically viable energy output requires enormous amounts of water flow - beyond what is capable with modern technology. Pulling an ultra-high flow water column from deep enough in the ocean to create a good thermal differential from surface water requires enormous pipes, which current materials technology can't deliver - because the tensile strength of even the strongest materials would buckle under the weight of the pipes themselves. Heat exchanges have to be very efficient, and sea life/creatures easily clog up the internals of the heat exchangers, so conformal coatings have to be developed to allow good thermal transfer while preventing the accumulation of bio. Finally, it just can't compete with simple proven solutions like hydro-electric. Look at any company that bids on OTEC and you'll see that the real funding vessels are in conformal coatings, materials technology, and pump technology, among other things. I don't forsee anyone building a viable OTEC plant for the purpose of commercial energy production anytime soon.
    • by wisty (1335733)

      Well, it can't be any harder than building a working space elevator. At which point we can just beam solar power down. :/

    • by Firethorn (177587) on Friday April 19, 2013 @04:12PM (#43497623) Homepage Journal

      because the tensile strength of even the strongest materials would buckle under the weight of the pipes themselves.

      Couldn't this be handled by ballasting the pipes along their length to maintain neutral buoyancy?

      But yeah, there's lots and lots of problems to solve with this.

      I'm reminded of a show involving an aquatic zoo that mostly works off of piped in seawater - they have an enormous crew that's devoted to simply cleaning and maintaining the involved piping, because of the bio accumulation. One method they use is an iron 'pig' that they send through using high pressure to scrape off the collected masses inside the pipes. The forces involved are so much that the 'pigs' don't last long.

    • it just can't compete with simple proven solutions like hydro-electric

      Unfortunately we have a limited supply of that, and much of it is already tapped.

      I don't forsee anyone building a viable OTEC plant for the purpose of commercial energy production anytime soon.

      Maybe not, but the only way to really find out, or to seriously improve your component technologies, is to build pilot plants like this.

    • You're talking point seems to involve a closed system. The open system uses the warm surface water directly. No expensive pipes and there has been some limited successful electrical creation. I think the plant in the plant in Hawaii broke the Japanese record for net electrical generation.
    • by AmiMoJo (196126) *

      You think someone just pulled a nuclear 1000MW nuclear reactor out of his ass? These are tricky but my no means impossible problems to overcome.

    • by dbIII (701233)

      OTEC isn't a serious contender for green energy

      Nothing is really. Everything has consequences. We have to get away from this childish conception that some things don't (eg. the weirdness of calling nuclear "clean" despite the mining, enrichment and fuel rod manufacturing processess using some of the most toxic inorganic chemicals known).

      requires enormous pipes, which current materials technology can't deliver

      Where on earth did you get that rubbish from? It's not a space elevator, it's in water, and there

  • Damn China (Score:5, Insightful)

    by ebno-10db (1459097) on Friday April 19, 2013 @03:27PM (#43496817)
    Damn China. Who the hell do those people think they are? A forward project that is not absolutely guaranteed to return a profit, although it may be a key to future energy production. They'll probably blithely say that although this approach might not work, try a few of them and there's a good shot at finding at least one winner. And that winner could be worth a fortune and be essential to our future. Damn China, it acts like mid-20th century America. Any good libertarian or fiscal conservative can tell you how badly this country turned out after they wasted all that government money.
    • by khallow (566160)
      I wonder why people think that throwing money at buzzwords and fads of the day is useful. Research is just like any other investment. You have to know what you're doing and you have to make some sort of cost/benefit analysis just like anything else that you want to be useful. It doesn't have to be "absolutely guaranteed" to make a profit, but there should be a good possibility of getting a sufficiently positive return on investment in some sense.

      Damn China, it acts like mid-20th century America. Any good libertarian or fiscal conservative can tell you how badly this country turned out after they wasted all that government money.

      So can oh, "good liberals" and a lot of other people. They hav

  • by GodfatherofSoul (174979) on Friday April 19, 2013 @03:44PM (#43497129)

    Back before we became a bunch of short-sighted corporatists who laugh at anything that doesn't turn a profit in one quarter.

    • by ebno-10db (1459097) on Friday April 19, 2013 @04:20PM (#43497709)
      Don't be ridiculous. A good fiscally conservative country like the US would never do anything risky or pointless like building a railroad across a continent, or a canal between oceans, sending people to the moon or trying to develop new energy sources. Our wise statesmen realize that the proper approach is to let foolish countries like China play with this stuff while we sit back and collect the eventual profits (preferably carried on the backs of unicorns).
  • by Ugmo (36922) on Friday April 19, 2013 @03:57PM (#43497355)

    If it works China will use the partnership to steal any useful technology, produce it themselves and out compete Lockheed. See partnerships with high speed train manufacturers and solar cell production.

    • We'd do that if we could in the US. There are just a few small unfortunate details that keep us from competing solely on cost, such as minimum wages, child labor laws, reasonable workplace safety laws, and relatively little currency manipulation. Work out those bugs and you can stop the Chinese copycats dead in their tracks.

      There may be some good news in this particular case. For instance, we should be happy that a domestic company is involved at all in this. And OTEC, as it stands now, may only be a tran
  • by Anonymous Coward
    That means that they are turning over all of the technology to China. Way to go L-Mart. Not a brain inside of that company.
  • A byproduct of the process (that at present technology levels produces very little net electricity) is fresh water. If Mr. AC Clarke is correct, look for these to become much more cost efficient in the not too near future.
    • by spitzak (4019)

      You must be thinking of something else. According to the article the plant produces cold water but it is still seawater. (I believe they mean that it pumps cold water up from the bottom and it is still colder than the surrounding water even after the heat exchanger).

      • Wiki the Ocean Thermal Energy Conversion article.
        • by spitzak (4019)

          Interesting, did not know about the low-pressure boiling method. However the article pretty clearly describes the closed loop method which does not boil the water.

          • Right, you are. The technology is still in it's infancy even though it's been studied for over a hundred years, leaving room for development in closed, open, and hybrid systems. According to the Wiki article, vast amounts of cheap petroleum stunted the growth of research into it. (Like many renewable energy sources) I merely suggest that if petroleum and fresh water simultaneously become scarcer, this is, at the very least, offtoperesting.
  • So if we extract the energy from the ocean, we would be cooling the ocean.
  • I wonder if plants couldn't be completely submerged to avoid bad weather.

  • I recall reading a great article about a test site where the cold water was circulated through pipes that cooled soil& irrigated plants via condensation from ambient moisture, making hot volcanic soils viable for many crops that would otherwise be unable to grow. Chilled soil agriculture [wikipedia.org] Fresh water was also produced by air condensers. This tech is not all about electricity, it can directly and indirectly produce other outputs.
  • by godel_56 (1287256) on Friday April 19, 2013 @07:15PM (#43499387)

    I've been wondering for a few years, if OTEC were implemented on a large scale (multiple GW), could this cause localized weather effects?

    You'd probably need to implement large scale OTEC in some kind of gulf stream, so that the newly cooled surface water would be carried away and replaced by new warm water. So you'd have a surface plume of colder water maybe tens of km long and wide situated in the center of a large area of warmer water. Could this act as a seed for some kind of major weather event, such as hurricanes, cyclones etc?

    • by dbIII (701233)
      Take a look at rivers distant from the equator for some idea although at a much larger scale than one of these facilities is likely to ever be.
      In other words, try again, and try thinking instead of parroting something this time. Funny thing is the luddite playbook is written by people that don't know a lot of the world around them and you can do better than whatever party line you are following by just opening your eyes and paying attention.
  • I know it needs a much greater difference between "hot" and "cold" ends to generate electricity .. but it's VASTLY simpler (e.g., no moving parts at all)!

    I remember (vaguely) reading about this, a prototype plant down on one of Cuba's coasts, built in the 30's (?) by an American professor. It was basically a bunch of scrap iron (old hot water radiators?), cold end hanging down in a nearby handy ocean trench, hot end in some pools of water bulldozed out on the coastline, was just a test but generated 10KW .

  • Hawaii (and to a similar extent Puerto Rica, also considered as a pilot plant site) has some pretty steep submarine gradients - up to a couple of degrees (note), making deep cool water relatively easily available relatively close inshore - under a megametre.

    But, where are they going to find such a gradient off the Chinese coast? Without getting into a territorial fight with Indonesia, the Philippines, or Taiwan? (The Gulf of Bohai is far too shallow to consider.)

    .
    (note) Yes, this should be of concern to

The person who's taking you to lunch has no intention of paying.

Working...