5 Facts About Hydrogen Cars

1. Two Basic Types of Hydrogen Vehicles
Today, most hydrogen transportation research and development is focused on hydrogen fuel cell vehicles. Here, hydrogen and oxygen - actually air - react in the fuel cell to produce water, heat and the electricity that's supplied to one or more electric motors to drive the vehicle. Another way to use this fuel is in a hydrogen internal combustion engine, or H2ICE, vehicle where hydrogen is combusted in a modified gasoline or diesel engine.

2. Hydrogen is Not a Fuel
Hydrogen in itself not fuel, but rather an energy carrier. Thus, energy must be expended to produce hydrogen. Hydrogen can be made using non-renewable or renewable energy sources. Today, hydrogen is produced mainly using natural gas or by coal gasification. Hydrogen can also be produced from water (H20) by electrolysis, which separates the hydrogen from the oxygen. If the electricity for electrolysis is produced by renewable resources - solar, wind, geothermal, or hydroelectric energy - there can be zero emissions including no carbon dioxide. Nuclear powerplants could also produce hydrogen and electricity. Plus, it's possible to produce hydrogen directly from sunlight and water using a metallic catalyst. It is argued that even if the electricity for electrolysis is produced at a fossil fuel powerplant, vehicles running on electrolyzed hydrogen are more efficient and less polluting than their counterparts operating on individual gasoline or diesel engines. That's because centralized powerplants can produce power more efficiently and their emissions can be easier to control.

3. Tanking Up with Hydrogen
Storing hydrogen on board a vehicle is challenging because hydrogen has very low density. Today, it is stored as a highly compressed gas or as a liquid at very low cryogenic temperatures. These storage containers can take up a considerable amount of space, especially if providing reasonable driving range is an important goal and storing greater amounts of fuel on board is needed. Also, considerable energy must be expended to compress or liquefy hydrogen gas. This adds significantly to the cost, consumption of fossil fuels, and possibly pollution and greenhouse gases if not done using clean, renewable resources. Research currently being done for storing hydrogen in metal hydride materials could result in at least a partial solution.

4. Hurdles to Overcome
Perhaps the greatest impediment to hydrogen vehicles is the lack of a hydrogen refueling infrastructure. Before hydrogen fueled vehicles can reach widespread use, hydrogen will have to be as readily available as gasoline, or at least as available as diesel fuel. Hydrogen stations are being built in various places around the world but they are still extremely limited in scope. Private and state initiatives like California's 'California Hydrogen Highway' are also funding or in other ways encouraging the building of a hydrogen fueling infrastructure in anticipation of the mass production of hydrogen vehicles. The actual timeline for this commercialization of hydrogen vehicles in unsure because hydrogen fuel cells are costly to produce, they're still made in very small quantities, and they require costly precious metal catalysts such as platinum.

5. Is a Hydrogen Vehicle in Your Future?
Some hydrogen fuel cell and H2ICE vehicles are already on the road. For example, General Motors is placing over 100 Equinox fuel cell vehicles on American highways as part of its Project Driveway demonstration program. A small number of motorists in California are now driving Honda FCX Clarity hydrogen fuel cell sedans in a program that is expected to grow to several hundred cars. BMW has fielded more than 100 Hydrogen 7 sedans in public demonstrations with its hydrogen internal combustion engines. Ford has delivered H2ICE E-350 shuttle buses to numerous customers. Many other automakers have developed and fielded concept fuel cell vehicles, and this process will continue in ways that pave the way for production models in the future