Question: Hello :) Only 1 percent of the world's water is available to drink. So with the population of 7 billion, it seems impossible to cope with that much water. By using water in cars, we are using excess water, but are also helping the environment. Will the extra use of water be worth it, based on the reliability of this car that you are working on?

Jemma Rowlandson answered on 20 Jun 2014:

Hello!

You are absolutely right, in certain areas of the world there are already water shortages. This is likely to get worse in future as the population of the world keeps growing. It’s predicted to reach 10 billion by 2050!

In countries which have enough water yes, these cars will definitely be worth it. The great thing about hydrogen (which we get by splitting water) is that it is very high in energy and so you actually do not need that much of it to power your car. We will have to be careful though as even places like England have droughts in the summer months.

The big problem is that the materials we use to split water into hydrogen and oxygen are not very good yet. These need to get much better before we can start powering cars completely from water. At the moment we use fossil fuels to make the hydrogen, which is not very good for the environment.

In countries that do not have enough water then using cars that run on water is not a very good idea. It would only the make the situation much worse. Instead it would be better to use diesel made from plants or waste, called biodiesel.