| Photovoltaics beat biofuels at converting sun's energy to miles driven Jan 17th 2013, 15:59 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. Now a new study shows solar power is not only better in terms of energy efficiency, land use, and greenhouse gas emissions -- but it is cost competitive, too. | |