In my last blog entry I began to discuss the benefits of using hydrogen as a virtually pollution-free fuel source. In effort to capitalize on the potential of hydrogen, fuel cells would have to replace internal combustion engines. So exactly how does a fuel cell work? At its core the fuel cell uses electricity to power motors located on or near the wheels themselves.
Without over complicating the explanation, the concept for the most common fuel cell designs works like this: An electrolyte membrane is sandwiched between a positive electrode and a negative electrode. Hydrogen is introduced to the negative side while oxygen to the positive. The hydrogen molecules travel through the membrane but become stripped of their electrons in the process.
These now free electrons are forced to travel through an external circuit where they recombine with the hydrogen ions on the positive side, where, when combined with the hydrogen ions and oxygen molecules form water. It is this flow of electrons through the external circuit that produces the electrical current needed to power the wheel motors. It’s really that simple.
The bottom line is that fuel cell vehicles could use pure hydrogen gas stored directly on the vehicle or extracted from a secondary fuel (methanol, ethanol, or natural gas). Of course secondary fuels would have to be first be converted into hydrogen gas by an on board reformer. Fuel cell vehicles fueled with pure hydrogen would emit no pollutants, only water! Reformer-equipped models would, however, produce small amounts of air pollutants albeit a mere fraction of that which is currently produced by the internal combustion process.
