A Maryland-based company wants to build two 2,250-foot-tall solar wind generating tunnels in the Arizona desert that would use downdrafts to provide a gigawatt of renewable energy to the grid. The towers, which would be the second-tallest structures in the world, would occupy public land just outside San Luis, AZ and use desalinated water from the Sea of Cortez to generate the downdrafts.
According to project proponents Solar Wind Energy, the towers -- which would strongly resemble nuclear power plant cooling towers, only on a much larger scale -- would harness downdrafts created by spraying water into the air at the towers' tops. The desert air would absorb the mist and become heavier and cooler, which would cause it to drop down into the tower.
Solar Wind Energy projects that the downdrafts thus created would reach speeds of 50 miles per hour. The wind would be channelled into turbine tunnels, where it would turn turbines.
This video from Solar Wind Energy may well help you visualize the process.
Each tower would have a maximum capacity of 1,250 megawatts, but the company expects that mean power production would run around 600 megawatts per tower, of which 100 megawatts would be required to pump the coolant water 2,250 feet into the air. Solar Wind Energy says it'll be able to reuse most of the cooling water.
The site outside San Luis that's being eyed for the towers is habitat for a number of endangered species, so approval isn't certain. San Luis' city government is enthusiastic about the idea, reports David Ferris at Forbes; unsurprising for a town in which one in four adults is unemployed.
If this sounds vaguely familiar, it's because a couple years ago the company EnviroMission suggested an even taller solar-wind tower in southern Arizona; that one would have been over 2,600 feet tall, generating 200 megawatts of power, and it came with a video that was far less informative but of much higher production value:
Where Solar Wind Energy's tower would have turned turbines by making cold air fall, EnviroMission's tower would have heated air in a huge ground-level greenhouse to drive turbines as it rose through the tower.
In 2011, EnviroMission's tower was supposed to come online in 2015. Solar Wind Energy's tower is planned to start generating power in 2018. According to our calculations, the next gigantic renewable energy skyscraper proposed for the Arizona desert will be announced in 2015, with a proposed startup date of 2021, and it will claim to generate power by blowing air sideways.