Narrator: Hydrogen plus oxygen equals a non-polluting car. This is Science Today. Jim Heffel, an engineer at the University of California, Riverside, led a team that created a prototype fuel-cell vehicle. A fuel cell is incredibly simple.

Heffel: You add hydrogen and oxygen -- or air -- and it converts it to electricity and water.

Narrator: In other words, an electric car. But instead of spending hours charging it up, all you have to do is put hydrogen back into the tanks. As a fuel, hydrogen itself is non-polluting and renewable -- all you need is water.

Heffel: And the other advantage with the electric vehicle is you're also going to use regenerative braking.

Narrator: That's a system where the braking energy is converted back to electricity.

Heffel: So every time you step on the brakes, you can get some of that energy back.

Narrator: One of the main obstacles to making fuel cell cars practical is the current low price of gasoline. But as Heffel points out, gas will start running out eventually and as it does, renewable resources are going to start looking awfully good. For Science Today, I'm Steve Tokar.