|"The purpose of a fuel cell is to produce an electrical current that can be directed outside the cell to do work, such as powering an electric motor or illuminating a light bulb or a city. Because of the way electricity behaves, this current returns to the fuel cell, completing an electrical circuit. " ~Americanhistory.si.edu.|
There are five basic types of fuel cells: alkali, molten carbonate, phosphoric acid, proton exchange membrane and solid oxide. Lots of research, promotion, venture capital investments in this technology that has applications is so many areas: automobile/motor, marine, residential and commercial building, etc.