What are the benefits of hydrogen-powered vehicles?

One of the most important benefits of a hydrogen economy is that fuel cells are nonpolluting. No carbon emissions are produced when electricity is generated in a fuel cell. A hydrogen fuel cell produces two byproducts -- heat and water. If every vehicle on the road were powered by a hydrogen fuel cell, the familiar clouds of smog that hang over many U.S. cities, most of which comes from vehicle exhaust, would largely disappear. According to the Environmental Protection Agency, half of all Americans live in areas where there's enough pollution to produce a negative effect on human health, so reducing smog would be a significant benefit.

Internal combustion engines, which burn fuels derived from the element carbon, produce several byproducts, primarily carbon dioxide, water, and the tiny particles of matter that we refer to as soot. The soot, when ejected into air breathed by humans, can cause asthma, lung cancer, and other diseases. In addition, most scientists believe that increased amounts of carbon dioxide in the atmosphere contribute to global warming, which could eventually cause damaging climatic changes over much of our planet.

Converting from­ internal combustion engines to nonpolluting fuel sources such as hydrogen will be important for reducing these problems in the 21^st century. But with more than 130 million gasoline-powered vehicles on the road today, it's unlikely that fuel cell cars will make enough of a difference in the near future to produce significant environmental improvements. It's estimated that early fuel cell cars will cost at least $100,000, which will put them out of the reach of the ordinary driver. Another point to make is that the infrastructure needed to make these cars practical, including hydrogen production plants and refueling stations, is not yet available. Some observers believe that, in the short term, environmental changes will come through the combined use of hydrogen cars and other types of vehicles, including battery-powered electric cars and cars that use other alternative forms of fuel.

Existing atmospheric pollution isn't going to go away soon. Soot settles out of the atmosphere in a matter of weeks or months, but carbon dioxide remains for a considerably longer time. Even if all sources of carbon emissions were eliminated today, it could still take decades for atmospheric carbon levels to return to normal. Furthermore, automobiles are only one source of carbon emissions. Others, such as coal-burning power plants, would also have to be greatly curtailed in order to prevent global warming.

More than half of the oil used in the United States is imported from other countries. This has a significant impact on the economy of the U.S. Two-thirds of this imported oil is used for transportation. Because so much oil comes from outside of the United States, changes in prices and supply are largely out of our control. Much of the oil comes from politically unstable regions in the Middle East. Attempts to free the U.S. from dependence on Middle Eastern oil date back to the 1970s; however, the amount of oil imported has actually increased since then. In addition, concern over U.S. oil dependency has grown even greater following the terrorist events of September 11, 2001.

Another problem with our dependency on oil is that rising oil prices have an effect on the entire U.S. economy, increasing the price of almost any product that uses oil in its manufacture or that requires oil to reach the marketplace. Oil prices have risen sharply in recent years, with the price of gasoline and diesel fuel hovering in the $4 to $5 per gallon range throughout 2008.

Will hydrogen be cheaper than gasoline? The U.S. Department of Energy estimates that current generation fuel cells produce electricity at a price of approximately $225 per kilowatt. Unfortunately, prices will need to drop to about $30 per kilowatt before hydrogen is competitive with gasoline as a fuel; however, the National Research Council predicts that the cost of the hydrogen itself, measured on a per mile basis, could soon be as much as 50 percent lower than the current cost of gasoline. Obviously, this advantage will continue to increase steadily as the price of gas goes up. The efficiency with which hydrogen is converted to electricity also gives it a substantial advantage.

Can hydrogen vehicles help break our oil addiction? Hydrogen vehicles will help reduce this dependence, but it will probably be decades before enough hydrogen vehicles are in everyday use to make a significant difference on oil imports. In the long run, however, the impact of hydrogen cars could be considerable.

Hydrogen cars aren't just the cars of the future -- several fuel cell vehicles (or FCVs) are on the road right now:

If the hydrogen economy is going to provide the United States with a future free of pollution and dependence on foreign oil, it must be sustainable. That is, it must be able to keep up with increased population growth, increased use of energy-hungry technology, changes in politics and changes in people's attitudes toward the environment and toward the welfare of future generations. It has been estimated that worldwide energy needs will double by the year 2050. It's unlikely that the rapidly diminishing supplies of fossil fuels could keep up with this demand, so new energy resources will be crucial.

One of the chief obstacles to a sustainable hydrogen economy is that the methods currently used to extract hydrogen from larger molecules rely on electricity -- and that electricity is generated largely by methods that create pollution. If hydrogen extraction is performed using electricity from a coal-driven power plant, it doesn't matter that the fuel cell doesn't pollute because the pollution occurred when the hydrogen was extracted. If hydrogen is to be a true nonpolluting power source, the electricity used to extract the hydrogen will need to be produced by a nonpolluting method such as solar power. At present this usually isn't the case, so a truly sustainable hydrogen economy will require substantial changes in power generation.

Storage is also a problem. Hydrogen fuel is stored in compressed liquid form and over time some of it escapes through evaporation. If a hydrogen car isn't driven on a regular basis, the evaporation losses will considerably increase the overall expense of the fuel. And compressing liquid hydrogen to a volume that can be carried in a car also requires a great deal of energy, and that energy may have been generated using methods that cause pollution.

Some experts believe that improvements in hydrogen production and storage will lead to a sustainable hydrogen economy in 15 to 30 years. However, the idea of a hydrogen economy has its opponents, many of whom believe that such an economy can never be sustainable and that our resources would be better used exploring other forms of power generation. It may be years before it becomes clear whether hydrogen is truly the fuel of the future.