With the ever-rising price of fossil fuels, it's no wonder alternative sources of transportation, such as the hydrogen powered car are getting new look. Cars that run off hydrogen, rather than gasoline, are cleaner for the environment, don't deplete a precious resource and they are not a far off invention.

The hydrogen car's potential implications for the environment, economy and even politics make it an interesting idea. These cars just might be the answer to getting around without wasting a precious, limited resource. And, they just might help stave off environmental issues as well. But, what are hydrogen cars and how do they work?

A hydrogen car is simply one that relies on hydrogen rather than gasoline for power. There are two basic types: combustion and fuel-cell conversion. Both are currently in existence, but neither have been moved into full-scale production for a number of reasons.

The combustion engine is similar to what is used in most automobiles now. It simply burns fuel to create power. Combustion engines already in existence can be modified for hydrogen burning.

Fuel-cell conversion, on the other hand, uses the hydrogen and turns it into electricity. This electricity provides the power for the engine's electric motor.

No matter the process, though, the byproduct of combustion or fuel-cell conversion is simply water. Rather than ozone depleting fuel, what's left behind is nothing more than good, old fashion H2O.

Adding to its environmental friendly stance, hydrogen is more or less a renewable source. It comes from the decomposition of methane or can be gleaned from water. Inasmuch, its only byproduct is water vapor. And, unlike fossil fuels it is fully renewable.

Despite its potential, hydrogen cars have not been moved into full-scale production for a number of reasons. The world's dependence on oil is a strong one and it will be hard to break. Entire economies depend on its production, processing and sale, so making the switch to hydrogen will be difficult at best.

In addition to a resistance from oil producers, auto manufacturers, too, must get on the bandwagon before this will become a reality. They are, however, beginning more and more to research and develop cars that run on hydrogen. The engines involved in modern cars can in fact be converted to burn hydrogen.

One of the biggest problems with switching to all hydrogen is a problem with storage. Car fuel tanks need to be better developed for this as would "hydrogen stations" where drivers can refuel. In addition, more study needs to be done to increase the miles per gallon hydrogen vehicles can muster.

Although much work still needs to be done to replace gasoline-based cars with hydrogen models, the idea is more than feasible. In fact, with gas prices soaring, it's looking more and more like a real possibility these cars will someday rule the roads. Already there are cars, buses, trucks and even rockets that use hydrogen for their power to some extent.