Fuel cells offer the potential for clean, efficient energy fueled by one of the earth’s most common elements: hydrogen. Considerable research is underway to overcome the remaining obstacles to make this promise a reality. Fuel cells may someday be used on vehicles as an electrical power source and also to provide temporary or permanent site power.
A fuel cell is a battery that contains hydrogen and combines it with oxygen in the air to produce electricity. The byproduct of the chemical reaction is pure water.
The most common design for the fuel cell uses hydrogen gas that is separated from the air by a polymer membrane. A catalyst facilitates the combination of the hydrogen fuel with oxygen, and the membrane conducts away the electrical charge. The voltage produced in a single cell is 1.16 volts, so cells are combined into stacks to supply higher voltages.
Fuel cells can be used to produce power for an electric motor as well as directly producing electricity in place of a generator. In either case they facilitate the replacement of a gasoline or diesel engine.
The fuel cell produces no greenhouse gases or other air pollutants. The product of the chemical reaction is only water and a small amount of heat. The production of hydrogen may involve some pollutants, but these are far less than what is produced in combustion.
Because the fuel is a material that is readily available, it poses few issues of energy and national security, unlike the importation of petroleum.
The efficiency of energy from the fuel cell being converted to vehicle motion is as much as 60 pecent, compared to about 20 percent with gasoline engines. The fuel cell has the added advantage of being completely silent.
Other renewable energy sources have some of the advantages of the fuel cell, but most are not as flexible and portable. Even with recent advances, direct use of solar power is still inefficient when compared to fuel cells.
A major obstacle to widespread use of fuel cells is in the storage and distribution of the hydrogen fuel. Hydrogen gas is difficult to contain, and most methods add considerable weight to a vehicle. Transporting and dispensing the gas will also require new methods. Because of its volatility, the safety of hydrogen will always be a concern, and this may hinder public acceptance.
The operation of cells in very cold weather is a problem, since water is always present in and around the cell.
Presently the cost of fuel cells is not competitive.
