The idea of orbiting solar arrays beaming power to Earth has been around since 1968. In 1971, Peter Glaser patented a microwave-based power transmission technology. Since then, most of the research has centered around that same problem of wireless transmission. Initial costs associated with launching solar arrays into orbit have also been problematic, to say the least.
Now, in early 2010, the European space company Astrium is looking for a partner to get a demonstration project off the ground.
The advantages of space-based solar over terrestrial solar are numerous and large. Earth based solar power is subject to dust gathering on the arrays, cloudy weather, shorter and longer days of the year and power loss through the atmosphere. These things combined mean that solar facilities currently produce just 20-40 percent of what the hardware is capable of.
Space-based solar, on the other hand, isn’t subject to dust. In orbit, there are no cloudy days. Sun exposure, which peaks at just under 15 hours on June 21 (in the San Francisco area) is 24 hours a day in space. Dust isn’t an issue and neither is atmospheric power loss. On Earth, sunlight provides about 950 watts per square meter of exposure. In space, the figure is around 1360 watts per square meter. Not only would space based solar be available around the clock and in cloudy weather, substantial advantages already, but there would be about 44 percent more of it in the first place.
Astrium has been testing power transmission through infrared lasers with the University of Surrey in the United Kingdom. IR lasers are safer to use than microwave power transmission. Those who have burnt popcorn in their house already understand the associated risk with microwave transmission. In short, misdirected microwaves could “cook” anything in their path. Astrium’s chief technology officer Robert Laine says that laser-to-electricity conversion has been progressing rapidly. When his team reaches 80 percent efficiency, he says, space-based solar becomes a winner.
In the mean time, Astrium is looking for partners to launch a 10-20 kW demonstration project. The company is considering governments, utilities, space agencies — anyone with an interest in sci-fi and (probably) large sums of money to invest. Of course, this could be the project that makes truly clean power (finally) viable on a large scale. Of course, it will have to beat Solaren and PG&E into space if it wants to be “first”.