PRIMER: THE RISE OF E-FUELS

Synthetic fuels could make transport more sustainable.... but at a price

The likes of Porsche and Ferrari are banking on synthetic fuel to ensure their cars are exempt from the EU ban on the sale of new combustion engine vehicles by 2035. Synthetic fuel - or electrofuel (e-fuel) - is a form of petrol made using hydrogen from water and carbon from air. The problem is the electricity that's required to extract these elements. Nevertheless, companies are already producing e-fuel on a small scale, including some in the UK. So will we see e-fuel in petrol stations soon and can we, and the planet, afford to use it? We spoke to Prof Patricia Thornley, Director of the Energy and Bioproducts Research Institute (EBRI) at Aston University, to find out.

WHAT ARE E-FUELS?

E-fuels are synthetic fuels. We create them from the building blocks of carbon dioxide (CO₂) and hydrogen. You can use electrolysis to produce hydrogen and you can pull the CO₂ out of the atmosphere by direct air capture. Combining these produces a hydrocarbon fuel. If you get different mixes of these molecules, then that provides you with different fuels for different purposes: lighter molecules are suitable for, say, an aircraft's ignition fuel, while you'll need heavier molecules for car or marine engines.

HOW ARE THEY DIFFERENT FROM BIOFUEL?

With biofuels (for example, ethanol and biodiesel) you're growing material that contains carbon, hydrogen and oxygen, and trying to convert it into a liquid or gas that you can use. In many ways, that pathway is the same with e-fuels but it's different in that biofuel needs land. 

The main advantage of e-fuel is that you're not using plants but the disadvantage is that you're using more energy and this energy still has to come from somewhere.

HOW DOES E-FUEL HELP TO CUT DOWN CARBON EMISSIONS?