Solar Updraft Towers, an alternate, alternative energy source

solar-towerA solar updraft tower collects warm air that forms near the ground, funneled by a canopy, and sends it up a chimney. Turbines in the airflow produce electricity.

I was first made aware of this device from the blog of Dr. Roy Spencer, Principal Research Scientist at the University of Alabama in Huntsville and former Senior Scientist for Climate Studies at NASA’s Marshall Space Flight Center.

Spencer says, “It’s a little like wind tower technology, but rather than just extracting energy from whatever horizontally-flowing wind happens to be passing by, the Solar Tower concentrates all of that warm air heated by the ground into the central tower, or chimney, where the air naturally rises. Even on a day with no wind, the solar tower will be generating electricity while conventional wind towers are sitting there motionless.” And it works at night.

“The total amount of energy that can be generated by a Solar Tower depends upon two main factors: (1) how much land area is covered by the clear canopy, and (2) the total height of the tower.” It also depends on the temperature difference between the power plant’s surroundings and the air underneath the canopy.

A prototype was built in Spain a few years ago.

See here for a You Tube demonstration of this project.

A private company, EnviroMission, is constructing a 200 Megawatt solar tower in the Australian outback.

This technology may be economically competitive with coal fired power plants, unlike current wind or solar generation schemes.

In the Spanish test, they expected that the ground under the canopy would be barren due to the very high temperatures. However, they found that the greenhouse effect (a physical barrier to cooling, unlike greenhouse gases) caused condensation at night and produced lush vegetation under the canopy. Perhaps special crops could be grown at these stations.

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15 comments

  1. I saw a show on this a few nights ago on the History Channel. It is very interesting technology and could prove to be very economic once the tower becomes operational. I’m a little leery of the Australian project, as I’m not sure the planned 2500 foot tall tower is going to be as sturdy as they think it is. It would be something to see, though!

  2. So kewl!  Thanks for sharing.  Nice how it has green-house like conditions underneath…maybe could have dual roles?  I wonder if plants underneath it would help produce more power since plants release heat too.

  3. If I understand the principle correctly, it would appear that the device could be particularly effective if built directly over Washington D.C.

  4. I wouldn’t start counting my solar-powered kilowatts just yet.  Tucson is home to two entities that could easily kill any major solar project.
    1) The Tucson shovelnose snake.  Currently this snake is under consideration for listing as an endangered species.  Once that happens, anything that threatens the preferred habitat of the snake is subject to close scrutiny, to say the least.  The “lush vegetation” that could grow underneath a Solar Tower’s ground canopy is NOT prime habitat for the shovelnose snake.  Expect any large Solar Tower project to quickly draw the attention of environmental activists, such as…
    2) The Center for Biological Diversity, one of the nation’s most effective environmental litigators.  According to Mark Kimble’s Tucson Citizen article of April 1st, they are headquartered here in Tucson.
    Does Tucson have the money to fund a protracted fight against the Center for Biological Diversity?  Do you want to risk it?

    Before you answer, you might want to ask the good citizens of Victorville, CA, what happened when they tried to build a solar power plant.

    Victorville is in the middle of the Mojave Desert.  Even better terrain than Tucson for a solar facility.

    However, Victorville is also the home of the Mojave ground squirrel.  Environmental activists have tied up the Victorville project for years, and the city could be out millions of dollars it put into the project.

    I am all for solar power.  I’d like to see Tucson become a Mecca for solar energy.

    Can we be sure that any major solar plant can actually be built, given today’s legal climate?  Do we have the money to pay the costs if we’re wrong?

  5. We’re not going to have another defaceing object to accompany those hideous wind farms are we? 
    The wind farm is inefficient, and are sometimes operated by electricity to con the public that the work when they don’t!

  6. Mr. Smith brings up a good point.  No matter what method of energy production is proposed, you can find an environmental group opposed to that method.

  7. Whatever happened to the conservation movement? With all this talk of changing to alternative energy sources, there is little to no discussion about ways to save energy. New, cleaner energy doesn’t by itself solve the problem. What we need is a broader discussion about our energy usage. If we don’t need as much, maybe we don’t need to produce as much.

  8. “Americans will always make the right choice, once there are no other alternatives”

    Winston Churchill

    1. Mornin’ Lefty! Quoting that bastion of socialism, Churchill? Maybe there is hope for you after all…PS-all forms of alternative energy should be examined, especially solar and geothermal. Gotta start somewhere!

  9. So, I went to this company’s website looking for things like efficiency and cost per kilowatt – and found nothing.  The YouTube piece did mention a million dollar cost for the tower for their 60 kW tower.  So then I looked up the average cost for an equivalent wind turbine, and got a cost of around 50 – 150K .  In reading your other blogs, I noticed that you rail against wind energy, but think this idea, which looks like it would cost 10 times as much, is a great idea.  Maybe you have other facts to share?

  10. We should concentrate more on Alternative Energy sources like hydrogen and solar because fossil fuels are already depleted and they are polluting the environment.

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