A fuel cell is an electrochemical energy conversion device, similar to a battery in that it provides continuous DC power, which converts the chemical energy from a fuel directly into electricity and heat. When operated directly on hydrogen, the fuel cell produces this energy with clean water as the only by-product. Unlike a battery, which is limited to the stored energy within, a fuel cell is capable of generating power as long as fuel is supplied.As such, the fuel cell system also has similarities to an internal combustion engine, except that it operates very efficiently at low temperatures and with minimal moving parts.
Although hydrogen is the primary fuel source for fuel cells, the process of fuel reforming allows for the extraction of hydrogen from more widely available fuels such as natural gas and propane or any other hydrogen containing fuel.