When you think of wind power, you may think of wind turbines, which harness fast-moving air. But this wind tower generates its own wind and then harnesses it. Creating wind eliminates the sporadic and unreliable nature of this renewable energy. Two structures, designed by Clean Wind Energy Tower, Inc., have gotten zoning approval for development in Arizona.
The Downdraft Towers are each 2,000-foot tall hollow cylinders covered with vanes. Inside the cylinder, water is pumped to the top and sprayed into a mist. That cools the air, which then sinks rapidly to the bottom at speeds of 50 miles per hour. At the same time, the vanes on the outside pull in additional (presumably intermittent) wind. The downward rushing wind exits at the bottom, passing through turbines that produce electricity.
Ron Pickett, CEO, told Discovery News that the tower will be designed for a peak output of 1,100 megawatt-hours and will average about 675 MWh, about 535 of which will be sold to the grid and the rest of which will power the pumps and internal systems. It should be enough, Pickett said, for about 800,000 homes.
It will be located near the town of San Luis, which is near the border of California and Mexico in the southwestern corner of the state. The water will come from the Sea of Cortez and be desalinated before use to reduce corrosion. Pickett said about 90 percent of the water used can be recovered and the cost of the desalinization and piping is part of the estimated $2 billion price tag for the project.
There are still hurdles. Earlier this year the Greater Yuma Economic Development Corporation and Marine Corps Naval Station in Yuma both expressed concerns about the impacts. The first group asked about the water use, and the latter about power lines near an active airstrip. But neither was strongly opposed to the project.
Pickett said he is confident that the company can raise the necessary funds to build the towers. International Energy Agency reports estimate a coal plant costs some $1 million to $1.5 million per megawatt-hour, which would put the cost of an equivalent plant at $1.5 billion. A nuclear power station would be much more, so the costs aren't wildly different from other power generation technologies.
All that said, if the building goes forward, it could make the conventional wind turbine tower a thing of the past.