The most commonly researched and most developed application of using hydrogen as a fuel source is in conjunction with a hydrogen fuel cell. Fuel cells operate by mixing hydrogen and oxygen to produce water and electricity. The electricity can then be used to provide power to homes, schools, and even businesses or to power cars and other vehicles. Some experts believe that internal combustion engines (ICEs) that are fueled by hydrogen are just as important. Hydrogen could be used as fuel for transportation by creating internal combustion engines for vehicles that run on hydrogen or hydrogen fuel mixtures.
A fuel cell works sort of like a battery. In hydrogen fuel cells, the hydrogen is converted to electricity through an electrochemical reaction. A fuel cell does not run out of power as long as its fuel, hydrogen, is present. There are several types of fuel cells. Some use phosphoric acid as an electrolyte (a substance that conducts electricity). Others use molten carbonate as electrolytes.
The most common type of hydrogen fuel cell in use is the proton exchange membrane (PEM) fuel cell. General Electric first invented this fuel cell in the 1960s as a source of electrical power for the Gemini spacecraft. Though they were expensive, these fuel cells were efficient producers of energy.
PEM fuel cells are usually stacked when they are used in vehicles. That means a number of identical fuel cells are put together to provide a significant amount of energy. The more fuel cells that are put together, the more voltage created. The number of fuel cells stacked in each vehicle varies by the amount of power needed.
Hydrogen fuel cell vehicles
While fuel cells were used early in the United States space program, most discussion of hydrogen fuel cells has focused on vehicles such as cars, buses, and vans. Most major car companies around the world are working on fuel cell technology in some form. Each company has produced its own concept cars and is working toward solving the problems related to building such cars on a mass scale. Even a high-end, limited production company like Rolls Royce has researched hydrogen fuel cells for cars. This company is hoping to have a fuel cell–powered hydrogen prototype completed by 2008. Rolls Royce has been working on hydrogen fuel cell research since 1992.
Daimler Chrysler began research on fuel cells in the 1990s. The company’s first fuel cell car was introduced in 1994 and called NECAR 1. Many different versions followed, some of which were tested on the road. In 1997 the car company also introduced a fuel cell bus called the NEBUS. This was followed later with the Mercedes-Benz Citaro bus. About thirty of these buses were used on a test basis in cities throughout Europe between 2003 and 2006.
General Motors (GM) has been working on hydrogen fuel cell technology for many years. The company produced its first fuel cell–powered car in 1966. Though this research area was dropped soon after, GM resumed its work on hydrogen fuel cells in the early 1980s. By the early 2000s GM had about six hundred employees researching fuel cells. The company formed a partnership with Toyota in 1999 to share hydrogen fuel cell research.
Some of GM’s experimental vehicles have been used on a limited basis. In 2003 Federal Express agreed to use one of GM’s fuel cell vehicles for one year on normal routes to see how it would work. GM has also conducted test runs of one of its hydrogen fuel cell cars, the HydroGen 3. This vehicle contains 200 hydrogen fuel cells and costs about $1 million to build. HydroGen 3s are being used by the federal government in Washington, D.C., on an experimental basis.
Toyota and Honda also have invested in hydrogen fuel cell technologies. Beginning in 1992 Toyota started working on fuel cell hybrid vehicles, coming up with four prototypes. Road testing of one of the company’s fuel cell–powered cars began in 2002. These cars were used at the University of California, Irvine, and University of California, Davis.
Honda began its research into this technology in 1989. Its fuel cell vehicles have been tested on roads in the United States since about 1999. One concept car, the Honda FCX, was tested by the city of Los Angeles in 2002. In 2003 this vehicle was certified for commercial use by the Environmental Protection Agency and the California Air Resources Board.
A number of countries are using hydrogen fuel cell–powered buses on an experimental basis. From 1998 to 2000 several hydrogen-powered buses were used in Chicago and in Vancouver, British Columbia, Canada. British Columbia later bought three other buses to use experimentally in the early 2000s. Vancouver had more buses delivered in 2005 for a further three-year experimental run. In London, England, three of these buses began running in 2003.
