A second generation Solar Power Satellite is nearing completion in earth orbit. Only the big transmitter array was launched from Earth. The main truss segments and photovoltaic panels were manufactured in orbit, using asteroid mining materials. Technological developments and decreasing launch costs have revigorated research into this method of energy production. Organisations such as JAXA (Japan) and EADS Astrium (Europe) are currently considering 'proof of concept missions'. I would love to see this tech developed!
Sketchup 3D / Photoshop - 2013
This, along with Nuclear Fusion could be the major provider to man's energy requirements for the future. Of course, I'm sure the fossil fuel companies don't even want to see such devices ever launched, at least not while they have coal and oil to exploit.