In his State of the Union address, President Obama challenged Congress and the American people to consider a greener economic future through the pursuit of a number of efforts, including cleaner vehicles and energy sources. While a full realization of a cleaner fleet of vehicles is underway, the systems to support them are not as far along. A recent MIT Energy Initiative report reveals that plug-in hybrids have the potential to perform as low-carbon contributors, but only if the power sources that serve them are in place.