The all-new 2013 Ford Fusion Energi plug-in hybrid has been rated by the U.S. Environmental Protection Agency to deliver up to an estimated 108 MPGe city, 92 MPGe highway and 100 MPGe combined. Not only is Fusion Energi one of five electrified vehicles offered by Ford, but one of the most technologically-advanced offerings ever delivered by the automaker. It began with a simple cardboard box.