Plans to construct two enormous 3,000-feet tall towers in the desert as part of an innovative new wind power project took a step forward recently when initial zoning approval was granted. At nearly twice the height of the Empire State Building, the structures would tower over the surrounding countryside in southern Yuma County, Ariz.
Even so, the project has some major hurdles to overcome before getting under way. Not least of which is the cost of the towers—estimated at $5 billion—a figure which Clean Wind Energy Tower, the Maryland company behind the towers, could have a tough time meeting, especially if its recent financial struggles are anything to go by.
The “downdraft towers” are meant to convert wind into electricity and Clean Wind Energy Tower, claims they would generate enough electricity for 1.6 million homes.
The science behind the towers is quite ingenious. A fine mist of water droplets are sprayed at the top of the towers, which are are huge, hollow cylinders. In the desert heat, dry air absorbs the water. Now cooler and denser than the surrounding ambient air, the moisture-laden air picks up energy as it rushes down the cylinder’s interior at speeds of up to 50 mph. As it gains weight and sinks, this causes a downdraft. Turbines at the base of the tower take advantage of this downdraft within the hollow cylinder to power generators.
According to Clean Wind Energy Tower, the “downdraft tower” has vertical “wind vanes” the length of the structure that capture and channel wind through a separate system of tunnels to produce additional power.
The concept of the towers is very similar to the natural phenomenon of downbursts, powerful downdrafts usually associated with thunderstorms, which occur when heavy rains or hail meet with hot dry air. In nature, downbursts can be extremely dangerous, sometimes bringing down aircraft.
If it proves possible to harness this force, Clean Wind Energy Tower claims the energy produced would be significant: “up to 2,500 megawatts per hour,” which we assume means simply 2,500 megawatts. Of that, approximately one-third will be used to power its operations—which would include pumping water back up to the top of the tower, leaving up to 1,500 megawatts available for sale to the power grid. The company claims the capacity factor would be around 60 percent, which is around double that of a conventional onshore wind power plant.