It's a dirty secret: the biggest renewable energy business in the U.S. isn't solar or wind or electric cars. It's plain old corn ethanol. Thanks largely to generous government subsidies, the U.S. produced 10.6 billion gallons of ethanol in 2009. That was enough to displace the need for 364 million barrels of oil, but study after study has shown that high levels of corn ethanol production simply aren't sustainable. Corn that could go to feed the world instead feeds our cars and not very efficiently. The growth of corn ethanol has more to do with political realities in the U.S. (think Iowa, home of both corn and the first Presidential caucus) than it does with environmental ones.
But that doesn't mean biofuels can't play a major role in a greener U.S. energy policy they just have to be the right kind. One of the best options on the horizon is biofuel made from algae, which counters a lot of the problems with corn ethanol. (The right strains of algae secrete oils that can be used to make fuel.) Algae do not need farmland to grow: tanks will do the job just fine anywhere there is spare land and a decent amount of sunshine. Algae also grow much faster than traditional crops, and the micro-organisms may be able to use to use wastewater or even saline water during their development, rather than fresh water. Startups like Sapphire Energy and Algenol in California and Florida are passing the pilot phase and nearing commercial development; they just need a little government help.