Thomas Edison would think this technology slick. Solar aficionados would probably brand it cool; and engineers would think it elegant and sophisticated. They would all be right, and also impressed by the size of the application.

Time for a mental picture…ready? Think of a several square mile in size circular greenhouse array where hot desert air enters the edge of the greenhouse. Rising from the center of the circular greenhouse is a chimney-like structure, perhaps twice the size of the Empire State building. Hot air rises, and in this design, quite rapidly – fast enough to spin electricity generating turbines at the base of the chimney, probably enough to generate 100-200 MW of power, enough for maybe 100,000 to 200,000 homes.

If you have ever felt a rush of air up a fireplace chimney, or exited an elevator in a tall office building and experienced a rush of air around the elevator chase, then you know what I am talking about here. Solar chimneys [often referred to as solar towers, or solar updraft towers] take this effect to much greater levels.

Check out this video:

This technology is not new, dating back to the turn of the last century, with several early designs built and tested in the 1930s. All that circular space at the bottom of the chimney can be used to grow crops and maybe ornamental plants. Locating these systems in arid or desert areas would be ideal; and might be a very useful power generation option for sun-soaked, resource poor developing countries.

Solar Chimneys - Channeling Thomas Edison

How It Works

Design Concept

Greenhouse with Plants

The incorporation of solar absorbing materials inside the vast greenhouse area, something as simple as black containers holding water, stone or cement floors, could extend the daily hours of operation past when the sun sets-a kind of thermal flywheel.

In the next several years, sites in Arizona and West Texas could host demonstrations of this technology.

Editors Deep Dive