A schematic demonstration of the Solar Wind Downdraft Tower, which uses both solar and wind energy to generate clean electricity. Video and feature image credit: CleanWindEnergy; YouTube
As Jessica has reported, U.S. renewable energy use is increasing. Despite a perhaps troubling rise in overall energy use, the rise in renewables is promising and is continually helped by innovations that make renewables cheaper, easier, and more competitive with fossil fuels.
There may soon be a new clean energy technology in town, at least in one Arizona town. The Solar Wind Downdraft Tower, the first hybrid solar-wind energy technology, recently secured its first installation location in San Luis, Arizona. At an estimated project cost of $1.5 billion, the initial tower is slated for operation as early as 2018.
Although it may be mistaken for a nuclear power plant, the to-be-tower will generate über-clean electricity simply by moving air (so far, only predictions and models have been performed). “Solar Wind Energy’s Tower is unique in that it does not have any operational limitations in terms of time,” states the website. “It’s capable of operating around the clock, 24 hours per day, and seven days per week. …It also has the ability to be operated with virtually no carbon footprint, fuel consumption, or waste production. It generates clean, cost effective, and efficient electrical power without damaging effects.”
Just how will it achieve this seemingly incredible feat, based on Solar Wind Energy Tower, Inc.’s predictions?
A water injection system at the top of the tower mists the air, which is warmed by the sun’s rays hitting the sides of the tower. The heat evaporates water droplets into the hot dry air, cooling air in the process. This cooler, denser air falls down into the tower, accumulating speeds in excess of 50 mph along the way. Wind tunnels equipped with giant turbines at the bottom of the tower create an escape route for the fast-moving air, turning the turbines and feeding generators, which feed nearby houses with electricity. Watch the video above to see it all (or at least a schematic of it all) in action.
According to reports, the tower is set to stand a massive 2,250 feet tall. In a phone call, Solar Wind Energy Tower, Inc. secretary and chief marketing officer Robert Crabb says that the tower will be constructed of steel-reinforced concrete. According to him, the project is only coming to fruition now because advances in building materials have finally made such a large concrete structure possible. We know from Jessica’s previous reporting that even now, there are problems (precisely 99) with pushing concrete to towering heights.
Using a proprietary software program, the company can calculate energy generation capabilities of a tower based upon a specific geographic location. With these calculations, it predicts the new San Luis factory will be able to generate up to 1,250 megawatt hours (mWh) per hour that the factory is running, with an average yearly generation (factoring for decreased output during the winter) of 435 mWh per hour.
According to estimates from the U.S. Energy Information Administration, the average American household uses about 30 kWh per day. That seems fairly accurate, as a check of my own electric bill (I live in an ~2,500-square foot 1905-built house in Columbus, Ohio) shows that my average daily use is about 38 kWh. Considering 24-hour operation, the San Luis Wind Tower will be able to power enough electricity on average to feed almost 350,000 houses daily.
As part of the new Arizona deal, the city of San Luis will supply water for operation of the tower. Crabb failed to specify just how much water that will be, which to me suggests it’s not an insignificant amount (which could be a problem amid concerns about water scarcity). The tower is currently limited to hot climates for optimal operation, although its real estate may unfortunately soon widen.
Researchers at MIT are also creatively trying to harness the wind’s power with a different technology that captures high winds floating 1,000 feet in the air. The Buoyant Air Turbine (below) is a helium-filled flying turbine that is designed to capture the stronger and more consistent winds that prevail at higher altitudes than on the ground. Head over to the MIT press release to read more.
Where do you think wind will stand in the future of renewable energy?