Synthetic fuels – also known as e-fuels – are beginning to make a play for attention in the decarbonisation of transport.

Although battery electric cars remain pivotal to the green agenda, e-fuels could help both heavy-duty vehicles and the existing parc of cars to meet climate change goals.

Last year, the European Council announced a proposal to phase out new combustion-engined vehicles by 2035, as part of its ‘Fit for 55’ plan (similar to the UK’s ban scheduled for 2030). However, the draft text also suggested vehicles running on CO2-neutral fuels could be sold after 2035. Now, a key EU vote may encourage the use of synthetic e-fuels for petrol and diesel engines.

Key markets including Germany and Italy are understood to believe the 2035 target should exempt carbon-neutral e-fuels. These are made using captured CO2 emissions that balance out the CO2 emitted when the fuel is burned. Some senior politicians have even threatened to block the vote unless vehicles running on synthetic fuels are permitted. It’s likely that some compromise will be found.

So what exactly is e-fuel technology?

Electrofuels, or e-fuels for short, are produced using renewable electricity. They are known as ‘drop-in’ fuels, and can replace regular petrol and diesel at filling stations.

Petrol and diesel are both made from crude oil. They are hydrocarbons, with a basic chemical structure that comprises hydrogen and carbon atoms. However, hydrocarbons can also be created synthetically, by using hydrogen from water and carbon from the air.

Through electrolysis, water is broken down into hydrogen and oxygen. The process requires a lot of energy – but this can be generated from renewable sources, taking carbon out of the atmosphere. This makes e-fuels fully climate-neutral.

The next step, and we hope you’re still following, is known as Fischer-Tropsch synthesis. Under high pressure, and with the aid of a catalyst, hydrogen is combined with CO2 extracted from the air and converted into liquid e-fuel.

Because electricity is used to produce e-fuels, it’s known as a power-to-liquid process. After further processing in refineries, e-fuel can become eGasoline or eDiesel: straight substitutes for conventional fuels. These can also be blended with regular fuels in any ratio – similar to using bioethanol to create the E10 and E5 petrol sold at pumps today.

The pros and cons of e-fuel

There are critics of e-fuels. Campaigners argue that cars powered by e-fuels still create tailpipe emissions. As the fuel itself is much purer, however, it is likely that pollutants will be significantly reduced – particularly when ultra-strict Euro 7 emissions rules come into force.

That’s certainly the view of Bosch senior vice president Martin Schultz who says the business is up for the challenge of developing and distributing CO2-neutral fuels.

His attitude reflects a growing industry impetus to make e-fuels work, not least from Germany and Italy – think Porsche and Ferrari.

Critics argue e-fuels also require a huge amount of power for production. Low carbon electricity is vital to make them truly sustainable. Yet proponents say that if production happens in areas where low carbon electricity is abundant, e-fuels can be just as green as EVs charged in areas where the electricity production is of a high-carbon intensity.

Porsche: an e-fuel pioneer

One notable ambassador for e-fuels is Porsche. The company’s R&D chief Michael Steiner sees an urgent solution is required for the operation of  existing fleets in a sustainable way.

“This goal can be achieved with green fuels, which are a sensible complement to electric vehicles,” he says.

Porsche doesn’t want to displace electric cars – it’s doing great business with the Taycan, already its second best-selling vehicle – but sees e-fuels as a complement to EVs.

Porsche recently opened a synthetic fuels plant in southern Chile. Said to be the world’s first large-scale commercial facility for carbon-neutral fuels, the plant already has its first customer: Porsche itself. Of the 130,000 litres it will produce every year, a large proportion will be used in Porsche’s motorsport activities.

The aim is ultimately for all new Porsches to use e-fuels as their ‘first fill’ off the production line.

Fleet Alliance and EV100

The global EV100 initiative, supported by the Fleet Alliance, aims to make electric transport the ‘new normal’ by 2030. A further EV100+ plan will help kickstart the transition to zero-emission medium- and heavy-duty vehicles (MDHVs). As a disproportionate source of greenhouse gas emissions, decarbonising MHDVs offers a huge opportunity to meet the objectives of the Paris Agreement – and e-fuels could play a pivotal role.

In the fight to decarbonise transport, e-fuels are set to move up the agenda. Watch this space.