Solar Towers Could Power the Future: Solar Updraft Power Plants
Posted by carrie_roll
Many of you have no doubt heard of solar updraft towers, but I had not until today.
Basically the idea is that a tower is constructed, and a large circle of the ground is covered with a material that sits 3-15 feet off the ground. Light can shine through the material, heating the air underneath the material and funneling it toward the only escape for the hot air, a tower at the center of the circle.
In the tower is a turbine. That turbine is turned by the heat rising upwards.
A successful research prototype operated in Spain in the 1980s, and many modelling studies have been published as to optimization, scale, and economic feasibility.
Here’s a video of the tower that was done in the 1980′s.
That video was taken before the tower collapsed in a storm in 1989.
The concept has come a long way since then. Although very little has been done to actually build towers in the world, but power companies are (slowly) beginning to look at this as a real possibility for meeting electricity needs in the short and long term.
The generating ability of a solar updraft power plant depends primarily on two factors: the size of the collector area and chimney height. With a larger collector area, a greater volume of air is warmed to flow up the chimney.
With a larger chimney height, the pressure difference increases the stack effect, ultimately producing a greater pull on the air flow and more electricity generated.
Heat can be stored inside the collector area greenhouse to be used to warm the air later on. Water, with its relatively high specific heat capacity, can be filled in tubes placed under the collector, increasing the energy storage as needed.
Turbines can be installed in a ring around the base of the tower, with a horizontal axis, as planned for the Australian project and seen in the diagram above; or–as in the prototype in Spain–a single vertical axis turbine can be installed inside the chimney.
Carbon dioxide is emitted only negligibly while operating, but is emitted more significantly during manufacture of its construction materials, particularly cement. Net energy payback is estimated to be 2-3 years.
A solar updraft tower power station would consume a significant area of land if it were designed to generate as much electricity as is produced by modern power stations using conventional technology. Construction would be most likely in hot areas with large amounts of very low-value land, such as deserts, or otherwise degraded land.
A small-scale solar updraft tower may be an attractive option for remote regions in developing countries. The relatively low-tech approach could allow local resources and labor to be used for its construction and maintenance.
Here’s Enviromission’s “sales video” for their huge tower project (expected to be completed in 2012) in Australia:
Apparently there’s some question as to whether Enviromission will be able to complete the project by 2012, but you can take a look at their web site to learn more.
Here’s the Wikipedia article on Solar Updraft Towers
http://en.wikipedia.org/wiki/Solar_updraft_tower
From: http://www.businessgreen.com/business-green/news/2243498/student-invents-solar-tower
Claus Volkening, 23, of the University of Portsmouth, has designed and laboratory-tested a solar updraft tower that uses water storage tanks to solve the problem of existing solar power plants which only generate electricity when the sun shines.
Existing solar updraft towers work by collecting heat energy from the sun and sending the warm air up through a tower which houses a turbine. Volkening’s model siphons off some of this energy and uses it to heat water – energy which is later released to keep the turbine turning at night.
“I wanted to find a way of generating solar power at night and found that by using water tanks to store the sun’s energy through the day, I could smooth out the energy available from a solar power plant,” said Volkening.
“Mine is the first working model that has proven this can be done – though more work needs to be done, including an investigation of other materials to be used as storage elements before it could be used as a blueprint for solar updraft tower plants around the world.”
The scale model is based on a 1km-high tower surrounded by glass or plastic above water tanks across a 16km square area to re-create a greenhouse effect.
Dr James Buick, who teaches Volkening at Portsmouth, said: “The technology behind solar updraft tower power plants is simple and they can be made from materials available anywhere in the world, which means, unlike other technologies, they are suitable for less-developed countries.”
Related article: http://www.livescience.com/technology/080702-pf-solar-tower.html
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What do you think Greenjoyment community? While the big companies are stalled working on this, let’s give this some thought.
We’re a bunch of DIY people around here. How could this concept be used to generate electricity in our own backyards?
Please post your thoughts using the comments below.
7 Responses to “Solar Towers Could Power the Future: Solar Updraft Power Plants”
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I don’t think that a solar updraft tower power station would consume a significant area is a problem if we want to use renewable energy.
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Ryan Fitzpatric says:
I cannot believe I had not heard of this concept before now. What an innovative use of convection physics!! Imagine if the collection material surrounding the stacks were completely solar pv panels, with agriculture growing in the greenhouse created.
again, great concept…it takes crazy ideas to come up with crazy solutions, innovation is the key, keep continuing to ask questions!!! -
Another thought, imagine the stack is like the trunk of a tree, only hollow…have artificial branches built on and give it an architectual look. maybe one day they’ll build a prototype that looks like an actual tree from far away…
or tell the utility companies to stop using their stacks for coal and convert their plants to solar towers!!! -
abc says:
I liked the introduction. It was simple and easy to understand here how solar updraft towers actually work.
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Can the space beneath the canopy be put to productive use? Farming? Solar panels?
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It sounds interesting. I’ve been trying to keep up with Solar but this is the first time I’ve heard of solar towers! I think I’ll be looking more into it after reading and watching these videos
This is thrilling. My first thought is I would need to have a very big back yard. It seems to me that one key factor is material under the canopy that would draw in and store a tremendous amount of heat, then a small unit may produce more electricity.