14 December 2020


Synthetic e-fuels are being developed that could bridge the gap between petrol and diesel and pure electric. How long until they are available for fleet use?

When it comes to alternative fuels for road vehicles, the majority of discussions centre around electricity and hydrogen. With the UK government announcing it was bringing forward the ban on petrol and diesel-powered cars and vans to 2030, it might seem that time is running out on the internal combustion engine. But there may be a solution that keeps these vehicles on the road for longer, and running in a more environmentally-friendly way too: e-fuels.

For fleets, e-fuels could mean a way to cover high mileages, without resorting to electric powertrains that may not be entirely suitable for the role, especially at the heavier, larger end of the road transport market.

E-fuels are sustainably-produced liquid fuels that, with minor alterations, can run in combustion engines. Cleaner than petrol and diesel, they may provide a useful alternative and allow businesses to keep vehicles on the road longer into the future, until new technologies are ready to take over.

Many major automotive and technology firms are looking into the viability of these synthetic fuels. Siemens and Bosch have both invested heavily in research, as well as pilot projects in Norway, while recently Porsche announced it has invested Euro20 million in a project in Chile with Siemens, with the aim of producing 55 million litres of e-fuels a year by 2024, and around 550 million litres by 2026, to power its sports cars. [1]

Porsche CEO Oliver Blume said: “Electromobility is a top priority at Porsche. E-fuels for cars are a worthwhile complement to that…They are an additional element on the road to decarbonisation. Their advantages lie in their ease of application: e-fuels can be used in combustion engines and plug-in hybrids, and can make use of the existing network of filling stations.”

There appears to be growing evidence that e-fuels have a role to play in reducing emissions: according to a study by Bosch [2], the use of e-fuels in Europe by 2050 as a supplement to electrification could save up to 2.8 gigatons of CO2: three times Germany’s carbon-dioxide emissions in 2016.

However, there are a number of issues that prevent them from becoming the ‘silver bullet’ that solves the transport emissions crisis. Principally, these are emissions, sustainability and cost.

What are e-fuels?

In order to understand how e-fuel could fit into the portfolio of fleet fuels, it is worth understanding how they are produced and the effects of this production.

There are various types of e-fuel in development, but the potentially most viable is a liquid fuel produced from hydrogen that can be adapted as an alternative to petrol or diesel.

Firstly, hydrogen needs to be produced from water by electrolysers using a sustainable electricity source such as wind or solar.

Then, using advanced carbon capture methods such as airborne capture, biomass or industrial exhaust capture, the carbon dioxide is combined with the hydrogen to make synthetic methanol, which can then be processed to become e-gasoline for use in combustion engines. The whole process is intended to be carbon neutral.

Because of its liquid nature, it can be delivered through existing infrastructures and filling stations with very little adaptation to equipment, and the volume and energy density of synthetic fuels are similar to existing petrol and diesel, so there is little drop off in performance and efficiency.

So why are we not prioritising production of e-fuel?

There are a number of issues as to why e-fuels are part of the solution, but not the only one.


The first is that although the production of e-fuels is carbon neutral, the burning of it in an engine still produces CO2. So the CO2 captured at the initial stage is released back into the atmosphere, meaning that in a world looking to cut emissions, it is at best levelling out, rather than reducing them.

E-fuels are still far better for the environment than traditional petrol or diesel in CO2 terms with emissions reduced by up to 80% [2]– and not least because other emissions such as NOx and particulates are able to be massively reduced too [3] – but it does not solve the underlying issue.


In order to produce synthetic fuel in a sustainable way, the hydrogen used for it needs to be split from water in an environmentally friendly manner too. And that means using solar and wind power – and extremely stable sources of solar and wind power, so that regularity of supply can be guaranteed.

Hence the reason that Porsche and Siemens project is taking place in Chile, with its excellent climatic conditions for wind and solar power, and the associated low cost of electricity. But producing vast quantities in this way to power the world’s vehicles requires an energy production infrastructure not yet in place.


The cost of e-fuels currently makes it prohibitive for widespread use, because the production process explained above is complex and multi-stage. According to a Royal Society report (see below), e-fuels cost around £4 per litre for a diesel equivalent version. However, as scale increases and production efficiency improves, those costs will reduce, although to what degree nobody really knows: estimates vary from £0.54p to £1.35 per litre by 2050, the Royal Society noted.

But the benefits are clear, if the cost can be reduced. During its research, Bosch has calculated that, over 100,000 miles, the cost of a hybrid running on e-fuel could be less than that of a long-range electric car, depending on the type of renewable energy used.


It seems that e-fuels have a place in the future make-up of powertrain technology, but they are unlikely to have a long-term future in new smaller vehicles such as cars and light vans where the direction of travel is very much heading towards ever cheaper, longer lasting batteries and even hydrogen.

In the medium term though, by the end of the decade it seems that e-fuels could be powering the last couple of generations of cars and vans with combustion engines.

But where they could make a difference is in heavier transport vehicles, where the number and size of batteries becomes prohibitive [4]. For a haulage fleet, or for plant machinery, e-fuels offer a sustainable alternative petrol and diesel, allowing them to travel long distance or work in extreme conditions using existing technology and operations without the need for radical change or experimentation with new powertrains.

It seems likely then, that in the next few years another fuel will be added to the fleet blend, and it will be a useful tool in the decarbonisation of transport, if not the overall solution.

Interested in e-fuels and how they might become a part of your future fleet mix? Here’s some further reading


[1] https://press.porsche.co.uk/prod/presse_pag/PressResources.nsf/Content?ReadForm&languageversionid=1161389&hl=unternehmen-presseinformation

[2] https://www.bosch-presse.de/pressportal/de/media/dam_images/pi9773/efuels_studie_bosch.pdf

[3] https://www.audi-mediacenter.com/en/press-releases/audi-advances-e-fuels-technology-new-e-benzin-fuel-being-tested-9912

[4] https://www.dena.de/fileadmin/dena/Dokumente/Pdf/9219_E-FUELS-STUDY_The_potential_of_electricity_based_fuels_for_low_emission_transport_in_the_EU.pdf

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