Thursday, October 16, 2008

Could Solar Power Satellites Beam Down Gigawatts of Energy?

by Jeremy Elton Jacquot, Los Angeles

solar power satellite image

Image from NASA

How pie-in-the-sky is Ben Bova's space satellite scheme? Mr. Bova, the president emeritus of the National Space Society and a prolific science fiction author, penned a column in last Sunday's Washington Post calling on the next president to build an armada of solar power satellites (SPS) -- basically large accumulations of solar cells -- to help meet a substantial chunk of our energy needs. The idea of building orbiting solar systems in space is nothing new (see my posts about Japan's Space Solar Power Systems and India's space plans); the concept, as described by its creator, aerospace engineer Peter Glaser, would be a satellite in high orbit (where sunshine is always present) that would use microwave transmission to beam solar power to receiving stations on Earth.

The obvious benefit: a continuous 24-hour, 365-day supply of solar energy. Powered by solar energy itself, a single SPS could generate up to 10 gigawatts of power continually, according to Bova. If that's even remotely true, just imagine how much continuous power a group of these SPSs could provide.

The solar power satellite: a costly proposition
Things get a bit trickier when Bova delves into some of the cost issues. For instance, he says that an SPS could deliver electricity at a cost of only about 8 - 10 cents per kilowatt hour, which would make it very competitive with conventional power sources. He does recognize that the upfront costs -- both to build the satellite ($1 billion apiece) and to launch it (see: SpaceX launches) -- would be fairly substantial; launching it into space successfully would be a whole other story.

Over time, as economies of scale take hold and component prices drop, the scheme would begin to look much more appealing. How long that will take, though, is anybody's guess. We have the technologies in place -- solar, satellite and microwave -- but putting everything together (and making sure it all works) will be a tremendous challenge.

Assessing the potential spillover benefits
Such a large-scale project would definitely provide a boost to our ailing economy, creating both many new jobs and contracts for a variety of companies, and it would give NASA a worthy new pursuit. Bova suggests making NASA's primary goal the construction of a demonstration model SPS able to deliver 10 to 100 megawatts of power by the end of the president's second term. It's hard to imagine either a President Obama or President McCain having the stomach to fund such a project if it doesn't start making measurable progress sooner -- 8 years is a long time to wait for a technology that may not even work in practice.

Still, this project may also help spur interest in other space-related technologies and developments and could, in later years, create an entire new industry around space launchers. If you're interested in reading more about the history of the SPS, its technology and functional aspects, I recommend you read Wikipedia's (surprisingly) informative page on the topic. Or, better yet, get your hands on a copy of Ben Bova's "Powersat," a novel all about building the first SPS.

Original here

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