In an effort to help drivers use different fuel sources, the US Energy Department has released an iPhone app that can point drivers in the direction of alternative fueling stations. The locations include electric charging stations, and others that offer biodiesel, natural gas, ethanol, hydrogen, and propane options. The app — which is even clad in iOS 7's simple style — allows users to search through over 15,000 stations for ones that are nearby them on a map. It's part of an ongoing effort by the Department of Energy, through its Office of Energy Efficiency and Renewable Energy, to promote alternative fuels as a way to produce fewer greenhouse gases. A similar tool is already available on the department's website, but the mobile app could be a big help for drivers of electric cars, as in many areas charging stations are still few and far between.