A fuel cell (FC) powerplant is an electrochemical engine that converts fuel and an oxidant electrochemically into electric energy, water and other chemical byproducts. When hydrogen is used as the fuel, the only products of the electrochemical reactions are water and electric power. Other conventional and advanced powerplants for transportation, such as the internal combustion (IC) engine, the Diesel engine and others, are thermal combustion engines. The theoretical or thermodynamic efficiency of a fuel cell or electrochemical engine is much higher than the thermodynamic efficiency of a heat engine. The practical efficiency of a fuel cell is highest at partial load, whereas the practical efficiency of a heat engine is highest at maximum power.
A survey is presented of the different fuel cell types and their characteristics. The proton-exchange-membrane (PEM) fuel cell is shown to be the best available fuel cell for transportation applications. Using hydrogen for its fuel, the PEM fuel cell powerplant is a true zero emission vehicle (ZEV) engine.
Onboard compressed hydrogen storage will be discussed and other options of hydrogen generation are considered and analyzed. The results of design packaging studies for the fuel cell power system and the associated fuel storage and supply in a small vehicle, a mid-size vehicle and in a van will be presented.