In a perfect world, all energy would come from electricity and hydrogen. Wind, solar, tidal, geothermal, and other renewable energy sources would provide enough electricity to power everything except air transportation. The “conventional” answer to transportation in the future was the hydrogen fuel cell. It doesn’t get any better than that. The fuel cell burns hydrogen and powers cars, trucks, and any other transportation vehicle. The hydrogen combines with oxygen to form water vapor. No other gases or pollutants are released.

The hydrogen fuel cell is an efficient generator of electricity, but it has one major problem: It needs hydrogen. So where does it get it? Therein lies the hydrogen myth. On Earth, there's no hydrogen to mine. You have to make it, and that requires wasting energy. You could conceivably mine hydrogen from the sun or Jupiter, but even Al Gore would probably agree that that would be tough to accomplish.

Last month, the Department of Energy (DOE) finally conceded that hydrogen won't be a part of the near-term solution to global warming, the peak oil crisis, or anything else you can think of. They're cutting back funding dramatically on hydrogen research. This is a triumph of physics over policy. In the long run, physics will always win, but we have way too many policy wonks in Washington without a clue about how the physical world works.

Even if hydrogen could be produced cheaply, it has another problem that makes it impractical as a fuel for transportation. Even when highly compressed, the energy density per liter or gallon is very low compared to gasoline or diesel fuel. Think about the size of the fuel tanks on the trucks that deliver gasoline to a station compared to the size of the tank on the truck. The ratio is about 90 to 1. That’s an efficient delivery system. If a hydrogen delivery truck had to burn hydrogen, the size of the fuel tank for the engine would be about one-quarter of the size of the delivery tank!