Scientists are planning to build a massive type of new power generator in south-western Arizona, which relies on evaporative cooling to create wind. It should deliver enough energy to power a medium to large city with no negative environmental impact.

The downdraft energy tower relies on the principle that cool air will sink while hot air rises. At the top of the tower, mist will be sprayed so that passing air is cooled, causing it to sink rapidly. The air then escapes at the bottom of the tower by passing through hundreds of wind turbines, generating power.

The overall efficiency of this process is around 45%, and these losses result from the need to pump cooling water to the top of the tower as well as other thermal losses. The cost of energy production will be lower than other power sources, and the tower will be able to provide enough electricity for a city of one million people.

The tower would stand about 3,000 feet tall and there would be several design issues to overcome before being able to build a structure taller than the Earth’s highest building, the Burj Khalifa. The company behind the project, Clean Wind Energy, has already leased the land necessary to build the tower.

The concept of the downdraft energy tower was first patented in 1975 by Philip Carson, and currently Israeli scientists at the Technion Israel Institute of Technology are working to fine-tune the tower at the projected scale.

[via Treehugger]