Hybrids (e.g. Toyota Prius) use the electric motors and battery as supplemental to the gasoline engine. That allows the car to capture energy when slowing down and shut off the gasoline engine when stopped. You do not need to plug them in. Indeed, except for plug-in hybrids (e.g. Toyota Prius Plug-in or Prime) that can go 10-50 miles on electric alone, they do not have any place to plug them in at all. Either type of hybrid can be driven on gasoline alone, although getting a plug-in hybrid may not make too much sense if you do not have a place to plug it into inexpensive electricity (the bigger batteries cost more and reduce cargo space).