Without a radically expanded and smarter electrical grid, wind and solar will remain niche power sources. To make use of clean energy, we'll need more transmission lines that can transport power from one region to another and connect energy-­hungry cities with the remote areas where much of our renewable power is likely to be generated. We'll also need far smarter controls throughout the distribution system--technologies that can store extra electricity from wind farms in the batteries of plug-in hybrid cars, for example, or remotely turn power-hungry appliances on and off as the energy supply rises and falls. Watch a demonstration of General Electric's software system for the grid or read more in the MIT Technology Review