The controversial rise of e-fuels

While industries worldwide have pledged to become climate-neutral by 2050, one sector where significant change is afoot is mechanised transport, which accounts for 16 per cent of global greenhouse gas (GhG) emissions.¹

Here, electric vehicles (EV) are familiar avenues for change. According to the consultancy EY, EV sales doubled in 2021 and jumped 55 per cent in 2022, accounting for 13 per cent of all vehicle sales.² This trend is set to accelerate, with ambitious national targets being published by governments. The US, for example, plans to reach an EV proportion of two-third of new cars in less than a decade.

But in recent months, governments, regulators and auto makers – particularly in Europe – have also been giving serious thought to alternatives to the electrification of road vehicles.

Synthetic fuels, or e-fuels, have emerged as a potential complement to the EV, with both Germany and Italy calling on the European Commission to integrate them into its green transport agenda. However, opinions differ over whether such fuels are genuine alternatives to battery power.

How are e-fuels produced?

E-fuels are created by combining CO2 captured from the atmosphere with hydrogen obtained from water through electrolysis. As long as this process is powered by energy from renewable sources, it is considered carbon neutral – any carbon released by burning this fuel has just been recycled from carbon that was already in the atmosphere.

The obvious advantage of e-fuels is that they can be used in any conventional combustion engine. There is no need to replace the car park, to build alternative fuelling facilities or create new power storage technologies. In other words, the entire transport sector doesn’t need to be revamped.

So why haven’t e-fuels entirely replaced oil? Inefficiency, for one thing. A 2019 study³ highlighted all the stages during which energy is lost in creating e-fuels, which range from carbon capture to hydrogen generation to chemical synthesis of the fuels.

Then there’s the inefficiency of internal combustion engines.

The International Council on Clean Transportation (ICCT), an independent research organisation, estimated e-fuel efficiency at converting total energy inputs into motion at only 16 per cent, compared to 72 per cent for electric vehicles. E-fuels biggest problem is that cars running on them still cause air pollution, a health hazard that scientists are only just beginning to understand. 

A supplement for battery power

But it’s not all bad news. E-fuels might not be the best solution for passenger vehicles, but they could come into their own in supplementing batteries, which are comparatively heavy and bulky. That’s because e-fuels have an energy density comparable to diesel, gasoline or kerosene, which means they can provide a large amount of energy using relatively small volumes. That makes them a useful alternative for the decarbonising ships and planes, both of which need to cover long distances.

E-fuels might not be the perfect solution, but they represent an alternative avenue worth exploring.