A fuel cell is an electrochemical device that produces electricity by separating the fuel (usually hydrogen gas) via a catalyst. The protons flow through a membrane and combine with oxygen to form water — again with the help of a catalyst. The electrons flow from the anode to the cathode through the load to create electrical current. As long as the reactants — pure hydrogen and oxygen — are supplied to the fuel cell, it will produce electrical energy.

A single fuel cell is basically a piece of plastic between a couple of pieces of carbon plates that are sandwiched between two end plates acting as electrodes. These plates have channels that distribute the fuel and oxygen.

A factor that draws interest to the fuel cell is that it can operate at efficiencies two to three times that of the internal combustion engine, and it requires no moving parts. Because it converts the fuel, hydrogen, and oxygen directly to electrical energy, the only byproducts are heat and water. Without combustion, fuel cells are virtually pollution-free.