A fuel cell is a device that converts stored chemical energy into electrical energy. Hydrogen fuel cells utilize hydrogen gas and oxygen gas as fuel. The products of the reaction are water, electricity and heat. This is a stark contrast to internal combustion engines, coal fired power plants and nuclear power plants which all produce harmful products such as carbon dioxide and radioactive waste water which damage our environment. Oxygen is readily available in the atmosphere and so the cell will be supplied with hydrogen through an electrolytic process. Hydrogen can be separated from hydrocarbons by the application of heat in a process known as reforming. An electric current can also be used to separate water into its component elements of hydrogen and oxygen in a process known as electrolysis.
A hydrogen fuel cell combines hydrogen and oxygen to produce electricity, heat and water. The fuel cell continuously supplies electricity when there is uninterrupted supply of hydrogen to the cell. The cell consist of an anode, cathode and catalyst. Pressurized hydrogen enters the cell from the anode side. The gas is forced through the catalyst by the pressure. When the hydrogen molecules come in contact with the platinum in the catalyst, it splits into two hydrogen ions and two electrons. The electrons are connected through the anode where they make their way through an external circuit, doing useful work such as turning a motor before returning to the cathode side of the cell.
On the cathode side of the cell oxygen gas is being forced through the catalyst, where it forms two oxygen atoms. Each of these atoms have a strong negative charge, which attract the hydrogen ions through the membrane where they combine with the oxygen atom and two of the electrons from the external circuit to form water molecule. These reactions occur in a cell stack which is embedded in a module including fuel, water and air, coolant control hardware and software. This module can then be integrated into a complete system to be used in different applications.
Hydrogen fuel cells are known to be efficient( up to 55%) and are used on a wide variety of applications including cars, buses and as backup power on case of electricity failure. Recently boats are being constructed that are powered by hydrogen fuel cells. Heavy duty trucks are also being constructed and tested that will be capable of moving long distances while being fuelled by hydrogen. Proposals are also being considered to use hydrogen fuel cells on ships due to their high efficiency and the absence of moving parts, thus making maintenance of the ships less expensive.