Hydrogen is touted as a clean future energy source: once our cars are powered by hydrogen, their only emissions will be water vapor.
In reality, there are two problems with the hydrogen economy.
First, hydrogen is not a source of energy, just a method of storing energy. To produce the hydrogen that powers the cars, you use electricity to convert water into free hydrogen and free oxygen. But if the electricity is generated using coal, then producing the hydrogen to fuel a car would create more carbon dioxide emissions than using gasoline to fuel that car.
Second, hydrogen itself can be polluting. A study done at the California Institute of Technology found that, if hydrogen replaced fossil fuels, 10 percent to 20 percent of the hydrogen would probably leak from pipelines, storage facilities, processing plants and fuel cells. Because it is so light, the leaked hydrogen would travel straight to the stratosphere, tripling the amount of hydrogen there. This hydrogen would oxidize, cooling the lower stratosphere and causing larger holes in the ozone layer, which has already been disturbed by pollutants such as CFCs.
This does not mean that we should avoid hydrogen entirely. It does mean that hydrogen is not the perfect technological fix that it is touted to be.
We need cleaner fuels. We also need to live more modestly and consume less fuel, if we do not want to disrupt the world's environment.For more information about the Cal Tech study, see