For all the attention paid to alternative fuels, there's only one that has made any real headway in the U.S.: ethanol. And now the evidence is piling up that biofuels may be even worse for the environment than the gasoline they're meant to replace. Corn ethanol is particularly inefficient — corn has comparatively less energy than gasoline or even sugar cane, and so a large amount of the crop needs to be distilled to make a gallon of ethanol. As ethanol scales up, more corn is used for fuel instead of food — causing food prices to rise. Worse, a study in October found a loophole in the Kyoto Protocol that allows unfettered biofuel pollution. Since biofuels are considered 100% carbon neutral under that pact — even though they clearly aren't — companies seeking to meet their carbon cap could invest in biofuels, which would clear more land, which would emit more carbon. There's still hope for second-generation biofuels like algae or cellulosic, but it's becoming clear that the greenest way to run our cars will come out of the electrical outlet.