Question: Don't you think that it would be better to run cars of waste fuels and things that we do not need, like waste products, instead of water which we need and fresh water is in short supply?

Jemma Rowlandson answered on 20 Jun 2014:

Hi!

That’s a really good question and it’s actually a really big part of science. There are a lot of people at the University of Bath who are looking at making biodiesel (which is diesel but made from anything that’s renewable) from waste coffee, or by growing algae (the green stuff you get on ponds) on waste. There’s even one group looking at producing electricity from toilet water!

Fuels from waste is a really good idea, but I do not think we will be able to produce enough fuel for everyone to use. I also know there is not enough water to power every single car in the world. In the future it’s unlikely there will be one thing for every single car, it will be a combination of everything.

So countries with access to lots of water can use it to make hydrogen to power hydrogen cars. Countries with lots of land will be able to grow extra crops to turn into biodiesel, and everyone will be able to use their waste to make some biodiesel as well. There will also be electric cars which are charged up hopefully from renewable energy, like wind or solar power.