A recent Wired article talks about getting solar power from space. I wrote a report on this back in high school over ten years ago. Back then the major concerns were the initial cost and the safety of delivering the electricity via concentrated microwave beam. I wonder how much the technology has changed in that time. From what the article says it still isn't good enough, but it seems that the largest barrier is the political one: "Neville Marzwell, advanced concepts innovation technology manager at NASA, spent five years researching methods of improving a satellite's ability to collect solar energy before his program was cut. Marzwell claims that politics played a part in the decision to kill the space solar power program. The United States 'doesn't have the political will to fund the research' because of pressure from fossil-fuel lobbyists, Marzwell said. 'We could have become the Saudi Arabia of the world electricity market,' Marzwell said. But because the coal and oil industries don't want threats to their profits, they applied political pressure, causing the program to be scrapped, according to Marzwell."