Solar Chimney for California?
One of the Alternative Energy Blog's most popular posts was on a proposed solar chimney in Australia (also known as a Solar Tower). It works using the solar chimney to cover a large greenhouse which covers several square miles. As the hot air rises, it would escape up a 990m tower in the centre of the structure. Wind turbo-generators mounted in the chimney would convert this 50km-an-hour rush of hot air into electricity.
Two things I particularly like about the concept are that, firstly it can run almost continuously not just when the sun is out, and secondly it produces a significant (100MW+) amount of electricity. Also as Liam commented "it's the coolest looking power plant I've ever seen" (see the post on the proposed solar tower in Australia for a much bigger and cooler picture). And as Doc Savage says in the next comment it could be a great opportunity for Southern California.
Well now that might just be happening. In an intriguing one line press release Californian company SolarMission has agreed to "build, own, maintain, and operate 2,600 megawatts of solar towers. "
Where and when these towers are going to be built is not specified.
I look forward to more details.
Industrial Info.com press release
posted by James at 1:35 am
10 Comments:
It looks like a wonderful plan.
Check out this idea for improving its efficiency.
http://www.globalwarmingsolutions.co.uk/the_solar_chimney.htm
Perhaps a living machine could be incorporated into the greenhouse so that in addition to producing food the facilities could treat wastewater.
My rough calculations show you'd need 9,545 kg of plastic tarp to make a tube 990 meters high. Then if you put a gigantic hot air balloon at the top (120,000 cubic meters, or a sphere 60 meters across) to capture the upward rushing hot air, you wouldn't need a fixed concrete tower. How much cheaper would this be, I wonder, when balanced with the risk of the plastic tube and balloon crashing down on the greenhouse below?
This tube and baloon... how would you stabalize it? cables? they have weight and you'd need a larger baloon. Also, how long would it take for the baloon to leak and the plastic to degrade by the intense solar radiation at the candidate solar tower locations?
points to contend with for your alternative
Very interesting project. Do you have fresh news about it?
It would seem to me that building a concrete (or block) structure up the side of a mountain might be cheaper and safer than a stand-alone tower. I see no need for a round "greenhouse," maybe a pie-slice shaped one would work as well. And, you might be able to recover some of the energy above the point of discharge.
Has anyone considered the affect of introducing pre-heated air at that level of the atmosphere? I really like the idea but tornados and other bad weather come from really warm air being introduced into the atmosphere in isolated areas.
No matter how we produce power for our toys we will someday have to pay the price, there is no such thing as environmentally safe or free power.
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Do your part to save our world and quit breathing already...
Has anyone considered the conservation of angular momentum? Air from a large region, with initial rotation matching that of the Earth, should, by the time it converges at the tower, be spinning like a tornado. The turbine design should not neglect this.
With an efficiency of something like 2-3%, I fail to see how the solar wind tower concept can be competitive with the more conventional and current photovoltaic cell technology, which is reaching conversion efficiencies of some 25%. Both are land intensive, but PV power does not require mile high towers, just conventional generators to convert dc to ac.
DC power can be used to produce hydrogen directly via the standard electrolysis process, which requires DC currents.
As a matter of fact, sharing the same land area underneath the solar collector, PV panels could function almost as efficiently under the glass as with direct illumination. And virtually all of the thermal losses in the PV panels would be trapped and contribute to warming of the air and not wasted as when they are used conventionally.
The PV panels could even be mounted in conventional arrays, and motor driven to maintain perpendicularity to incident light, for maximum collection efficiency, as the sun arcs across the sky.
Greater savings might even be achieved at somwhat lower cost if, instead of glass, the solar wind tower collector was made with partially light transmitting PV glass panels, coated with a non-reflective front surface, and IR reflecting rear surface, eliminating the need for a separate glass roof.
Significant light and heat would be left over to drive the wind power component.
Since a good part of the cost of PV energy conversion is the cost of the land, used in conjunction with the solar wind tower generator, no additional land would be required.
If it works, I'm sure we'll see our beautiful desert landscapes blighted with these gadgets in due time, to service our insatiable demand for even more electricity.
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