Question: how would hydrogen power cars?

Stuart Archer answered on 18 Jun 2013:

Hydrogen gives out a lot of energy when it burns, similar to a gas flame on a cooker, or a bunsen burner. Unlike natural gas however, the only waste product from burning it is water! There are two main ways we might use it to power:

1) Burn it in an engine similar to the ones we have in cars at the moment. The design would have to be modified quite a lot compared to current engines, but it’s possible to do it. This would probably be the easiest way to do it, however it’s not the most efficient way to use hydrogen, as in a car engine a lot of the energy that’s produced when you burn the fuel is wasted.

2) We could use it in a ‘fuel cell’. This is a device which uses the chemical reaction between hydrogen and oxygen together to generate electricity, which could then be used to power an electric motor in your car. Again, the only waste product from this is water. This is a much more efficient way to use hydrogen, as electric motors are much more efficient than petrol engines. The problem is that fuel cells are really expensive and difficult to make – we need a lot more scientists and engineers to work on them to make them cheaper!