In the swarm of ideas for new energy technologies, one that sounds like science fiction is getting a more serious look from the U.S. Defense Department. Space solar power, or SSP, has been studied for over 40 years but has recently resurfaced in the climate change discussion, and was the subject of a 75-page study released by the Pentagon in October. The technology would generate electricity from solar panels attached to an orbiting satellite and convert it into microwaves for transmission to Earth, where it would then be transformed into direct-current electricity.
Artist's depiction of a solar satellite. Image by NASA
Space solar power is attractive because it creates no carbon emissions and relies on inexhaustible solar energy. However, like terrestrial solar power, the cost is high; the enormous cost of shuttle launch is one of the largest barriers to a space-based solar array. Through the last few decades, fossil fuels have been inexpensive enough that SSP was confined mostly to academic discussion. However, with oil prices rising--reaching $100 a barrel this week--and with accompanying concerns about energy security, the U.S. government is revisiting the topic, and Japan and Russia have been conducting ongoing research as well.
Removed from the filtering effect of Earth's atmosphere, space solar arrays receive eight times more energy than terrestrial solar panels. In addition, sunlight falls on them nearly constantly, as opposed to traditional solar panels which are subject to nighttime, weather-related, and seasonal decreases in output. The technology of the panels themselves is well-tested and already in use on satellites including the International Space Station. Though long-distance transmission of such powerful microwave beams poses significant technical and safety concerns, the U.S. Defense Department seems interested in further research, concluding its October report: "It is imperative that this work for 'drilling up' vs. drilling down for energy security begins immediately."
RELATED LINKS
U.S. Defense Department report: Space-Based Solar Power As an Opportunity for Strategic Security
Associated Press article: 'Drilling Up' Into Space for Energy
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