Fuel cells convert natural gas directly into electrical energy. They are many times more efficient than are combustion engines, such as the car engine. These require an intermediate step. First, they convert chemical energy into thermal energy (heat) and mechanical energy (force). With this force, they drive a generator, which only then generates the electric power. In the process, a large portion of the originally available energy is lost.
via Renewable Energy News – RenewableEnergyWorld.com http://ift.tt/SFLflS