EVs (electric vehicles) are powered solely by electricity and do not emit tailpipe emissions. Hybrids combine a gasoline engine with a battery and electric motor, but they cannot be plugged in—the battery is charged through regenerative braking and the engine itself. Plug-in hybrids (PHEVs) offer the flexibility to run on electric power for a certain range and switch to gasoline once the battery depletes. They can be charged using external power sources, making them a transition point between conventional and fully electric cars.