With 220 million cars across American roads and development in China, India and across Eastern Europe, worldwide demand for oil is exploding, along with the price of gasoline.

"We have a window of maybe two years before there is a major oil supply disruption," said Milton Copulos of the National Defense Council Foundation.

In response to these concerns, the Department of Energy (search ) is working with automakers on a massive shift to get gasoline out of U.S. cars. Hydrogen, they say, is the energy source of the future.

Some hydrogen-powered cars (search) are already in production but it could be many years before they are ready for the market. In the meantime, electric hybrids (search) such as Toyota's Prius are gaining ground.

Hybrid vehicles are only a stopgap technology, but one that could ultimately lead to a safer, more stable future.

Click on the video box at the top of this story to see a report by FOX News' Erik Liljegren.