Solar Concept I Had Not Seen Before

Uses huge greenhouses combined with a very tall column to generate convection currents that drive turbines.    Apparently can still generate power at night taking advantage of the difference between soil and ambient air temperatures.  I have no idea if this makes a lick of sense financially (without subsidies).

  • Arthur Felter

    Since we see pictures depicting plumes of "pollution" coming out of cooling towers from nuclear reactors, this is only fair. (Pardon my bad photoshop job)

  • randian

    Even if it works, seems a little too Rube Goldbergish to be financially viable.

  • John O.

    One existed in Southern Spain in the 1980s as a prototype, it since has collapsed and was demolished. Another was built in China in 2010. Its a very practical system from a design standpoint but implementing it means using a large surface area and the tower needs to be sufficiently tall enough as its actual efficiency is not all that great. However, it can be built for cheap with a variety of materials.

  • aczarnowski

    Huh? What's simpler that this?

    Damming rivers? No. Nuclear? Haha. Digging coal out of the ground and putting it on trains? Natural gas pipelines? Solar panel manufacturing and setup? Super heated reflector towers running liquid salts to make steam to drive turbines? Wind turbine manufacturing and construction of wind farms?

    The number of moving here parts is miniscule and the biggest one is air. Turbines are the primary complex component and they're a known quantity in an easily serviceable location instead of 200' up a pole or at the bottom of a water shaft. Unlike water or nuclear coolants, air won't break down the structure. And I'm guessing no new material tech, chemistry, or toxic manufacturing wastes are required (like solar panels) in the construction.

    Devil in the details and all that, but seems pretty slick to me.

    The econ will still be interesting. Land costs, permits for new systems, infrastructure to the site, NIMBY, convincing everybody that it won't spontaneously start tornadoes, blah, blah, blah, will all add up.

  • rdk

    At least 10 years ago one of these was proposed for Mildura in Victoria, but needless to say was never built. Given the government subsidies in Australia for useless projects it must have been an extraordinarily expensive proposal to end up going nowhere.

  • MingoV

    Sending heat up a stack obviously means less heat for the plants. Since most greenhouses exist in cooler regions, it makes little sense to remove much of the heat.

    Soil and ambient air temperature differences depend on many factors. If it is cloudy at night, then the air doesn't cool much and the gradient is small. If the surrounding surface is a light color (such as snow), then it will reflect solar energy during the day which will reduce the temperature gradient at night. Even under ideal conditions, the convection current system described will generate small amounts of energy.

    It is doubtful that such a system will provide cost-competitive energy.

  • Eric Hammer

    That's a huge amount of land covered under a roof. The land might be cheap, but how much does the glass/plastic to cover it cost? That might be a deal breaker right there.

  • LarryGross

    1. – this is exactly why the gov does “pilots”. some fail. some succeed.

    2. – in terms of structure – have folks seen the cooling towers for Nukes?

    3. – in terms of weather changes. Have folks seen the smokestacks from coal or cooling towers for Nukes?

    4. – in terms of Nukes – what would be interesting – given the economics of Nukes – would be to compare them to wind and solar – rather than coal-burning generation.

  • William Newman

    Rube-Goldberg-ish-ness can be managed with enough engineering determination --- see internal combustion engine, practicality of --- but thermodynamic limits are hard to overcome. I do not like the way that this approach takes hot energy (visible and near-infrared photons, roughly the temperature of the surface of the sun) and degrades the energy to lukewarm (warm air) before feeding it to a heat engine. Thermodynamics guarantees that after that degradation, almost all of the energy will leave as waste heat. (All their power output comes from feeding a heat engine with a small fractional difference in absolute temperature.) There's a reason well-developed heat engine technologies go to a lot of trouble to operate at high temperatures (and to vent their heat into low-temperature sinks, for that matter). Thus e.g. exotic alloys in gas turbine blades, compressed water in steam power systems, and other technologies you might have wondered about: now you know a big part of the reason. A system like this will naturally have to cover a rather bigger area than e.g. a park of solar panels in order to produce the same amount of usable energy. This system does have advantages for naturally incorporating short-term energy storage, which a big expensive problem for solar today. But I think having to cover several times as much land as solar cells (ideal efficiency bounded above by about 5%, probably: I'm guessing roughly 15 degree Celsius heat difference between engine input and engine output, and roughly 300 Kelvin temperature at output) is a disadvantage so large that it will prevent wide application of this approach in anything like a rational economic system.

  • marque2

    I read about this first 15 years ago. So far I am guessing fail fail fail, because I haven't seen any serious effort to put up a real farm.

    I have also seen proposals of this type in reverse. Pipe water up the side of the tower and spray mist down the center. This would cause a downward flowing convection. Also not built.

    Government pilots are completely unnecessary, and in many cases where they seem to be "needed" isbecause the government has screwed up an industry somehow, through price controls, wacky tort laws, or taxes, etc.

  • LarryGross

    well the "king" of Rube Goldberg has to be NUKES! No other technology possesses the potential to kill thousands in a failure mode and yet we agree to subsidize it!

    comparing Nukes - dollar for dollar to solar/wind is an interesting comparison when you include the subsidies for insurance.

  • KevinM

    Did something like this 20+ years ago.

    Henderson, Tx. Power plant burned Lignite, and the residue was used to make gypsum for sheetrock.

    They used the setup for the drying shed. Huge "metal" building clad in fiberglass skylight R panels instead of metal. The tower provided convection to pull in dry air and move it over the gypsum.

  • Don

    If I recall correctly, about 10 years ago some folks suggested something similar (but reversed) along the CA coast, specifically LA. The were going to take desalinated sea water and spring into the top of a tower, where it would cool the air and make it drop. Their idea was to use to remove the polution from the air with the moisture, and the down-draft would be used to generate enough electricity to make the system power-neutral or even possibly a power gain.

    Of course, light rail is supposed to be financially sound, and ethanol is supposed to be good for the environment, so take it for what it's worth (which, of course, is very damned little).

  • Philip Ngai

    I haven't seen any estimates of what the temperature inside the greenhouse would be but expect it to be high enough to kill all plant and animal life inside, not to mention blocking all rainfall and killing the plants that way too.

    The Ivanpah solar power facility suffered a great deal of expense and trouble to minimize the impact on the desert turtles that either lived there or migrated through there.

    Any birds that accidentally flew into these greenhouses would most likely die too.

  • markm

    I'd concentrate more on the cost of building the second-highest tower in the world...

  • Walter Guyll

    Check out Walt and Leigh Richmond's 1964 story Shortstack, with an interesting variation:

    http://www.technovelgy.com/ct/content.asp?Bnum=2235