Space solar power satellite have been proposed for a long time, but obstacles ranging from cost to solar panel technology and transmission efficiency have kept it from becoming a contributor to Earth's energy needs. At last, however, projects in Japan (using microwave beaming of the energy) and Europe's EADS Astrim (using an infrared laser) are on the way toward becoming space test systems by 2015.
COMMENT: I don't know how well this will work out. The environmental impact statements alone will be huge projects. But it's worth testing, and it can only be tested thoroughly by putting a satellite in orbit and trying it. Ummm...by the way, NASA, where's the American demonstration satellite? We should be among the explorers of this potentially important technology, and we have done design studies and computer sims and so on, but we should either create a demonstration satellite or coordinate with Japan and/or EADS in a joint project.