BATTLE OF THE MX-5S IS FUEL FOR THOUGHT

SUSTAINABLE PIPS PETROL WITH A BETTER MPG RESULT

You might ask why there are two Mazda MX-5s roaring along in the picture above. Are we testing two cars? No, instead we're testing the fuel in their tanks. One MX-5's tank is full of regular pump petrol (E10 unleaded to EN228 95 RON specification) and the other car's is full of sustainable fuel.

The cars themselves have exactly the same engine and specification.

The fuel is called Sustain, and it's made by a company called Coryton.

But before we drive the cars a quick explanation of where sustainable fuel comes from and the processes used to make it.

The journey starts with ethanol produced from biomass such as agricultural waste. Like the husks from sugar beet for example, although you can make ethanol from any material that can be fermented.

The first step is to degas the ethanol which removes the oxygen and water leaving only hydrogen and carbon.

Next, these go through a series of catalysts which turns them into a hydrocarbon liquid.