E-fuels are a petrol and diesel alternative. They are seen as a potential way to keep combustion engine cars on the road for longer amid plans to end the sale of such vehicles over the coming decade or so.
But are e-fuels practical and actually a suitable fit for a net-zero future? Porsche thinks so. It opened a fuel refinery in Chile in late 2022, and has successfully petitioned the European Commission to exempt cars using this fuel from the EU’s 2035 ban on petrol cars. The UK government has not made any such exemption.
Porsche plans to race 30 Porshe 911 cars this September as part of the Goodwood Revival event. And these aren’t new cars made from the ground up to work with e-fuels. They are pre-1966 models, according to Car Magazine. Could e-fuels completely derail attempts to phase out the internal combustion engine?
What are e-fuels?
Normal petrol is refined from crude oil. Plant and animal life millions of years old is turned into this crude oil through an extended process of applied pressure and heat.
Our reliance on fossil fuels is a bit like living in a house whose cupboards are stuffed with cash, assuming that’s how the economy works.
E-fuels are not made using refined crude oil. Water is split into hydrogen and oxygen. That hydrogen is combined with carbon dioxide to produce hydrocarbons, the principal constituent of petrol.
These chemical reactions are fuelled by electricity. And as this energy can be harnessed from renewable sources such as solar and wind, it can be argued e-fuels are a relatively environmentally friendly way to fuel a vehicle.
The problem with e-fuels
Cost and efficiency are the major arguments against e-fuels. Electric cars are described as between 70-90% energy efficient depending on whose stats you read. Octopus EV says 77%. Renault claims its EV engines are 90% energy efficient.
The combustion engine maxes out at about 40% efficiency according to Nissan, after decades of improvements. When using e-fuels you have to deal with this energy loss, compounded by the energy costs involved in the creation of the fuel itself.
This makes e-fuels extremely expensive. A 2017 study part funded by the European Climate Foundation suggested subsidies of at least 1-1.50 Euro per litre would be required to make production of the fuel at “significant volumes” remotely viable.
Even then, there’s no suggestion e-fuels are a credible like-for-like replacement for today’s petrol use.
Who are e-fuels for?
The major backers for e-fuel tell you a lot about their intended audience. Ferrari and Porsche are the most vocal proponents of the technology. These two companies’ images are wound up in the gears of a combustion engine, even if Ferrari has stated its intention to make 80% of its line-up EV or hybrid by the end of the decade, according to InsideEV.
Some people just can’t give up a roaring engine in favour of an EV playing “roaring_engine.mp3” through a speaker when the pedal is depressed.
This is not just a vanity technology, though. There are suggestions e-fuel should be used to reduce the emissions of airplanes.
However, even here we’re talking about blending a small amount of e-fuel with conventional fossil fuel-derived stuff. It is again due to the difficulty of producing e-fuels at scale, as P2X Europe co-CEO Christoph Weber explained in an interview with Siemens Energy.
”Global aviation consumes 1 million barrels of kerosene per day, accounting for about 6 percent of total petroleum consumption. So if we’re producing 20,000 tons, you might think that’s just a drop in the ocean,” says Weber. “But bear in mind that e-Kerosene is blended. If we are looking at a blend ratio of 1 to 3 percent, for example, this immediately puts things into perspective.”
E-fuels may be able to make a positive impact in aviation, but at the time electrical vehicle battery energy density is still so far off that of traditional airplane fuels. In April CATL announced an electric plane battery with a density of 500Wh/kg, while typical jet fuel has a density of 12,000W/kg.
