April 29, 2014 – At a 242 hectare (600 acre) site near the city of San Luis in Arizona, a new solar technology is about to be installed. It is the product of Solar Wind Energy Tower, Inc., developers of a solar wind downdraft tower structures that generate electricity.
These towers are designed to capture the energy of downdrafts by exposing hot dry air to water within a tower structure. The air movement within the tower drives turbines connected to generators. Unlike existing solar and wind technologies that operate only when the Sun shines and the wind blows, these energy towers work continuously, day or night, in calm or windy weather.
Described as a hybrid energy system, each tower consists of a hollow cylinder featuring water injection near the top and wind tunnels with turbines at the bottom. The water is pumped to the top of the tower where it is sprayed into the air column as a fine mist. In the dry desert air heated by the Sun the moisture evaporates rapidly making the air cooler and more dense. It then begins to drop to the bottom of the tower generating speeds as high as 80 kilometers (50 miles) per hour. The air then passes through the wind tunnels containing turbines connected to generators. The bulk of the water gets recaptured and recirculated making the tower a very green power source with a zero carbon footprint. That footprint, although green, is very large. That’s why the land requirement is 242 hectares not including the vertical space requirements. To give you a sense of just how large, each tower is taller than the tallest nuclear power plant cooling tower in existence today. The one being built near San Luis will stand 686 meters (2,250 feet), more than three-quarters the height of the Burj Khalifa, the tallest building in the world. It will be the tallest building in North America.
These towers are highly suited to semi-desert and desert climates from mid-latitudes to the equator. And not all need to be as tall as the one in San Luis. To determine the size of a tower the company has proprietary software that can figure out the energy capacity of different global locations by looking at local weather, solar radiation and other data. It then can come up with an estimate on building parameters required to get optimal generating capacity.
In San Luis the new tower is rated to generate at peak 1,250 Megawatts per hour with an average computed at 435 Megawatts annually. That’s enough energy at peak to power close to a million homes based on average consumption of 10,000 Kilowatt hours for the average American household per year.
For the city of San Luis, population 26,000, it gains a lucrative contract selling water for tower operations in a 50-year contract. Project total cost is estimated at $1.5 billion U.S. with the Defense Department expressing interest in becoming a prime customer for the power it generates. The San Luis tower is expected to come online by 2018.
You can watch the video demonstration to get a better understanding of how these innovative solar towers work.