It is the next step for biofuels: genetically engineered plant life that produces hydrocarbons as a by-product of its normal metabolism. The result will be fuel—common gasoline, even frut—using nothing but sunlight and CO2. In July, Exxon Mobil announced plans to spend more than $600 million in pursuit of algae that can accomplish the task. Joule Biotechnologies claims to have already succeeded, although the company has yet to reveal any details of its proprietary system.


Uranium and plutonium are not the only fuels that can power a nuclear reactor. With an initial kick from more traditional fissile materials, thorium can set up a self-sustaining “breeder” reaction that produces uranium 233, which is well suited to nuclear power generation. The process has the added benefit of being resistant to nuclear proliferation, because its end products emit enough gamma rays to make the fuel dangerous to handle and easy to track.


Studies show that simply making customers aware of their energy use lowers it by 5 to 15 percent. Smart meters allow customers to track their energy consumption minute by minute and appliance by appliance. Countless start-ups are offering the devices, and Google and Microsoft are independently partnering with local utilities to allow individuals to monitor their power usage over the Web.


According to a Stanford University study released in July, the high-altitude winds that constantly blow tens of thousands of feet above the earth hold enough energy to supply all of human civilization 100 times over. California’s Sky WindPower has proposed harvesting this energy by building fleets of giant, airborne, ground-tethered windmills (below), while Italy’s Kite Gen proposes to accomplish the same feat using kites.