Photovoltaics beat biofuels at converting sun's energy to miles driven

New study shows solar power is not only better in terms of energy efficiency, land use, and greenhouse gas emissions -- but cost competitive, too

In 2005, President George W. Bush and American corn farmers saw corn ethanol as a promising fossil fuel substitute that would reduce both American dependence on foreign oil and greenhouse gas emissions. Accordingly, the 2005 energy bill mandated that 4 billion gallons of renewable fuel be added to the gasoline supply in 2006. That rose to 4.7 billion gallons in 2007 and 7.5 billion in 2012.


Since then, life cycle assessments (LCAs) have shown that corn ethanol has modest if any effect on reducing CO2 emissions and may actually increase them, while posing a threat to natural habitats and food supplies, as food stocks are turned to fuel and marginal lands are put under the plough to keep up with demand. In 2010, fuel ethanol consumed 40 percent of U.S. corn production, and 2012 prices are at record highs. Since the U.S. also accounts for 40 percent of the world's corn, U.S. ethanol production has affected corn prices around the planet.