Wednesday, September 10, 2014

Solar power from space?

When I published Sustainable Energy - without the hot air, there were quite a few topics I could have included but didn't because they seemed a little too blue-sky. For example I have draft chapters on Osmotic Power and on Kite Power (and if I were to rewrite the book today I think that I would now include Kite Power after all). Another idea I dismissed at the time was "what if we put solar panels in space, in geo-synchronous orbit?" I dismissed that idea on the grounds that "the advantage of space over the deserts of Libya and Nevada as a location for solar panels is only roughly a factor of 4, and surely that's outweighed by the difficulty and cost of getting panels (and associated power-re-transmission systems) into space, compared with just plopping them on the ground in a desert?" However, Keith Henson has for some time been working out the details of a scheme that might prove me wrong.
It involves many clever ideas, and some ambitious ones - such as the idea of powering a Skylon freight-delivery space-craft by space lasers that are powered from the ground with GW-scale microwave transmitters! I encourage people who are interested to read Keith's 'dollar a gallon' post and his follow-up post.
Further reading: Solar energy in the context of energy use, energy transportation, and energy storage - a paper in which I provide data for the power per unit area of real solar farms, and discuss the need for significantly cheaper energy storage if ground-based solar power is ever to contribute a significant fraction of energy consumption.