Hydrogen cars have been in the works since the late 1970s. There's a reason for that. Unlike fossil fuels, there is a never-ending supply of hydrogen and the only exhaust emission is environment-friendly water vapor.
While there were original concerns about nitrogen oxides being emitted, proper engine timing and optimized hydrogen concentrations were found to minimize or even eliminate the formation of nitrogen oxides, which cause acid rain and contribute to global warming, among other things.
Currently there are two approaches to hydrogen cars: using hydrogen with fuel cells or with a modified internal combustion engine.
Hydrogen cars that use both hydrogen and gasoline have two separate tanks that the driver can switch between easily. Nowadays having dual tanks, at least in the US, is a must as hydrogen refueling stops are still uncommon. Indeed, there are little more than 100 in the entire United States. This allows the car to run on regular fuel as needed. Not very “green", but practical.
Hydrogen cars using fuel cells get twice the range on the same amount of hydrogen. The hydrogen reacts with oxygen to produce water vapor exhaust and the electricity needed to power an electric motor.
One of the main problems of using hydrogen as a fuel is that it's not really a fuel by itself. It simply stores energy. The energy has to be extracted from the hydrogen in order to provide power, and the problem is to get that energy released without using fossil fuels.
Another major problem is storing it in the hydrogen car itself. To keep hydrogen liquid, it must be kept at -253 degrees Celsius (that's -455 degrees Fahrenheit!). Any warmer than that and it turns back into a gas. Current methods involve super-insulated tanks with elaborate venting systems to allow the warming gas to escape.
Whether or not hydrogen cars become commonplace depends on solving these problems, as well has having enough hydrogen fueling stations available. But, since hydrogen is unlimited, affordable hydrogen cars are certainly a possibility in the future.
Steve Longoria writes on the growing Alternative Fuel Vehicles market, encouraging people to adopt greener fuels and, ultimately, to help people save money. For more info on Fuel Cell Cars visit ezAlternativeFuelVehicles.com