Question: Do you think we will come up with an alternative to fossil fuels within the next 10 years or do you think much more work is needed?

Rhodri Jenkins answered on 19 Jun 2013:

We have a lot of alternative to fossil fuels … there’s just a few problems that mean we can’t really use them yet. The major reason is expense. To make something exactly like crude oil but is renewable we have the processes but it would cost at least 5 times the amount of oil currently to be economically viable.

Also, biofuels are good replacements, but not perfect because they don’t act in the same way as a lot of fuels. For example, ethanol has a lower energy density than gasoline, which just means you don’t get as much power from it and so you don’t get as many miles out of the engine. It’s also a bit corrosive and cars need to be modified to run on ethanol. Biodiesel is thicker than normal diesel, and this can lead to filter clogging and the engine not working as well, and sometimes stop working completely! So that’s not ideal.

On the larger scale of things, we’re always developing and using more renewable energy. We’re taking it up slower than we should be, but I reckon in 20 years time we’ll be getting our energy mostly from renewable resources. Some countries get a lot of electricity from renewables – Germany gets 20% where we get about 7%.