Every time you pump gasoline into your car, you're ever so slightly depleting the world's supply of fossil fuels. These fuels, which include petroleum and coal, are the condensed remains of living organisms from prehistoric times. The supply of these fuels is limited and will eventually run out. Worse, much of this supply of petroleum is controlled by a few nations blessed with an abundance of oil and these nations can dictate both the petroleum supply and its price. Furthermore, dependence on fossil fuels by a nation like the United States further complicates already complex matters of foreign relations and national security. Fossil fuels have met much of the world's energy needs for several centuries, but there is a limit to how long they can continue to do so in the future.
The universe we live in is made up of approximately 75 percent hydrogen, though there's surprisingly little pure hydrogen here on the surface of the Earth. Hydrogen gas generally exists as H2 molecules, in which two hydrogen atoms are bound together. Because H2 molecules are so light, uncontained hydrogen gas can easily float to the top of the Earth's atmosphere and can actually escape into space. Most of the hydrogen at ground level is bound up in molecular form with other elements -- in water, for instance, where hydrogen is combined with oxygen to form H2O molecules.
There are several methods that can be used to produce pure hydrogen from hydrogen-containing molecules. Hydrogen can be extracted from natural gas (by far the most common method), it can be removed from water through electrolysis or it can be produced biologically from algae or certain kinds of bacteria. Some of the more promising methods of hydrogen production are still being researched, while others, such as extraction from natural gas, are in common use.
In 1970 the chemist John Bockris coined the term hydrogen economy to refer to a future in which all vehicles would use hydrogen as a fuel. An important step in this direction has been the development of a device called a fuel cell, which generates electricity using hydrogen. Major car manufacturers have already produced concept cars powered by fuel cells, the Volkswagen Tiguan HyMotion and the Chevrolet Equinox Fuel Cell SUV are two examples, and at least one hydrogen fuel cell production model is already available in California, the Honda FCX Clarity.
Why the push for hydrogen technology? Is it really that much better than fossil fuel consumption? What about the hydrogen economy -- is it even possible? Take a deep breath and read the next page.
No more pollution?
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 21st 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.
No more foreign oil dependency?
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:
- The Honda FCX Clarity: This is the only fuel cell vehicle that can actually be leased by private individuals, but only in parts of California where hydrogen fueling stations are installed. Honda charges $600 per month for an FCX lease. The first FCX was delivered to a California family on July 25, 2008.
- Chevrolet Equinox Fuel Cell SUV: Fleets of fuel cell-powered Equinox SUVs have been touring California, New York and Washington, D.C., to demonstrate the technology. This vehicle is not currently available for lease or purchase.
- Volkswagen Tiguan HyMotion: Like Chevrolet, Volkswagen isn't ready to sell or lease this vehicle, but the HyMotion was part of a National Hydrogen Road Tour that ran from Portland, Maine, to Los Angeles, Calif.
- BMW Hydrogen 7: Although not yet available to the general public, BMW has been giving this vehicle to celebrities -- beginning with actor Will Ferrell -- for extended periods of use.
Is the hydrogen economy sustainable?
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.
For more information about hydrogen, fuel cells and other related topics, follow the links on the next page.
Related HowStuffWorks Articles
More Great Links
- Bossel, Ulf and Eliasson, Baldur. "Energy and the Hydrogen Economy." January 8, 2003. http://www.methanol.org/pdf/HydrogenEconomyReport2003.pdf
- Carseek. "Hydrogen Fuel Cell Car Technology." http://www.carseek.com/articles/hydrogen-fuel-cell-car.html
- Clayton, Mark. "Rising Call: Cut U.S. Oil Imports." The Christian Science Monitor. May 5, 2005. http://www.csmonitor.com/2005/0505/p01s04-usfp.html
- Friedemann, Alice. "The Hydrogen Economy - Energy and Economic Black Hole." Culture Change. Sept. 2004. (Aug. 22, 2008) http://www.culturechange.org/alt_energy.htm
- Gizmag. "Honda set to release hydrogen fuel cell car - and home fuelling station." (Aug. 22, 2008) http://www.gizmag.com/honda-fuel-cell-fcx/8394/
- Hall, Kevin G. "Oil independence is possible, but does U.S. really want it?" Milwaukee Journal Sentinel. March 4, 2006. http://www.jsonline.com/story/index.aspx?id=405957
- Huffman, Mark. "Hydrogen Fuel Cell Cars Bring Hope, If Not Relief." ConsumerAffairs. June 25, 2008. http://www.consumeraffairs.com/news04/2008/06/fuel_cell.html
- Llanos, Miguel. "Hydrogen cars ready to roll - for a price." MSNBC. June 23, 2004. http://www.msnbc.msn.com/id/4563676/
- Sinha, Vandana. "Volkswagen hits road with hydrogen fuel cell car." Washington Business Journal. August 11, 2008. http://www.bizjournals.com/washington/stories/2008/08/11/daily14.html? ana=from_rss
- Vergano, Dan. "So far, hydrogen-powered cars are fuel for future thoughts." USA TODAY. July 21, 2008. http://www.usatoday.com/tech/science/columnist/vergano/2008-07-20- hydrogen-cars_N.htm