 The Union of Concerned Scientists (UCS) published a study in 2012 that assessed average greenhouse gas emissions in the U.S. resulting from charging plug-in car batteries from the perspective of the full life-cycle (well-to-wheel analysis) and according to fuel and technology used to generate electric power by region.The study used the Nissan Leaf all-electric car to establish the analysis baseline, and electric-utility emissions are based on EPA's 2009 estimates.The UCS study expressed the results in terms of miles per gallon instead of the conventional unit of grams of greenhouse gases or carbon dioxide equivalent emissions per year in order to make the results more friendly for consumers.