Sometimes you have to think big. That’s certainly what Dr. Phillip Carlson would say. He’s the guy that invented the “energy skyscraper” back in the '70s. It was a colossal tower that would reach up into the sky to create what you might call artificial weather, which would deliver consistent 50 miles-per-hour winds to the base where an array of wind turbines would convert that wind into electricity.
The principle is basically the same as the chimney effect in which hot air rises and cool air descends. In order for the effect be sufficient to produce significant amount of power, you need a very tall chimney. Spraying water enhances the effect, especially if the air coming up is hot and dry.
Carlson was clearly ahead of his time. After the Arab oil embargo of 1973 came and went, interest in energy went back to sleep as oil had become abundant once again. But the idea was picked up by Technion, the Israel Institute of Technology. They proposed construction of a full scale version in the Southern Arava Desert that would be close to 4,000 feet tall and 2,000 feet in diameter. It’s worth noting that the tallest building in the world today, the Burj Khalifa, in Dubai, is 2,700 feet tall. Needless, to say, the cost of constructing such an engineering marvel would be prohibitive, which is why the Technion project did not proceed.
But now, an American company called, Solar Wind Energy Tower (SWET) is moving forward with plans to build one of these in Southwest Arizona, outside the town of San Luis, Arizona, and another one across the border in San Luis Rio Colorado, Mexico. Their design is only 2,250 feet tall, practically a miniature version of the original. The company has purchased land and received approval from the city council for the Arizona project. The town has also agreed to provide the water necessary to run the tower for 50 years.
The SWET tower, as designed, is expected to produce some 4 million MW-hours per year; that’s more than the Hoover Dam. If this seems unbelievable, it’s not. The underlying science is sound. That doesn’t mean there won’t be unanticipated problems with these if they ever get built. (See Video below.)
In the meantime, there are some significant hurdles to be overcome to get to that point. First, there is the cost. One tower is estimated to cost $1.5 billion. While the company has signed an agreement for preliminary financing, they have yet to write any Power Purchase Agreements (PPA) which is how the tower will eventually pay for itself.
Another big problem is water. Even though much of the water will be recirculated, some 8,000 acre-feet will be lost to evaporation each year. That’s enough to irrigate a 1,000 acre farm. That’s an inherent conundrum with this technology. It depends on using water in places where it is very dry. If there were a source of sea water nearby, the project could be self-sufficient, using excess power to pump and desalinate water. Failing that, the operators would be looking for some other way to trade electricity for water, I’m not aware of one other than pumping it from the nearest source.
A third problem is access. This tower will provide huge amounts of power in the middle of nowhere, which is probably the only place you could built a 2,000 foot tall tower. That means long distance power lines, running at very high voltage to minimize the inevitable losses.
None of these problems are insurmountable, and, in fact, the company plans to begin construction by 2018. On their side are lower costs than other large scale solar and wind projects, and a considerably smaller land footprint. Another plus-- unlike other wind farms, this provides consistent, steady wind.
It remains to be seen, whether this will be happen. The road to a renewable future will have a number of twists and turns in it, as well as numerous forks. One of those forks is between centralized utility scale projects, versus small decentralized rooftop systems. There will be room for both, but the current trend seems to favor the smaller systems for any number of reasons including resiliency, storage requirements, and transmission losses. But that also represents a departure from today’s utility business model, which won’t go away without a fight. The exceptionally low oil prices are also not helping.
As for those, even though lots of people are rushing out to buy monster SUVs, I don’t expect these low prices to be around for long.
Image courtesy of Solar Wind Energy Tower, Inc.
RP Siegel, PE, is an author, inventor and consultant. He has written for numerous publications ranging from Huffington Post to Mechanical Engineering. He and Roger Saillant co-wrote the successful eco-thriller Vapor Trails. RP, who is a regular contributor to Triple Pundit and Justmeans, sees it as his mission to help articulate and clarify the problems and challenges confronting our planet at this time, as well as the steadily emerging list of proposed solutions. His uniquely combined engineering and humanities background help to bring both global perspective and analytical detail to bear on the questions at hand.
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RP Siegel, author and inventor, shines a powerful light on numerous environmental and technological topics. His work has appeared in Triple Pundit, GreenBiz, Justmeans, CSRWire, Sustainable Brands, Grist, Strategy+Business, Mechanical Engineering, Design News, PolicyInnovations, Social Earth, Environmental Science, 3BL Media, ThomasNet, Huffington Post, Eniday, and engineering.com among others . He is the co-author, with Roger Saillant, of Vapor Trails, an adventure novel that shows climate change from a human perspective. RP is a professional engineer - a prolific inventor with 53 patents and President of Rain Mountain LLC a an independent product development group. RP was the winner of the 2015 Abu Dhabi Sustainability Week blogging competition. Contact: firstname.lastname@example.org