Synthetic fuels: how useful are e-fuels?

After the vote on the end of combustion engines from 2035 was postponed, the debate on exceptions for synthetic fuels continues. Where are the opportunities and where are the disadvantages of e-fuels?

Actually, the EU countries should have decided at the beginning of March on the ban on new cars with combustion engines from 2035 – but nothing came of it: Germany, among others, threatened to veto it. Because Federal Transport Minister Volker Wissing, FDP, is dissatisfied with the proposal from Brussels: In his opinion, it is not open enough to technology. Synthetic fuels, so-called e-fuels, are not sufficiently taken into account. Countries like Italy, Poland and Bulgaria also do not want to agree to the plans.

In October, the EU Parliament and the member states agreed in principle that from 2035 only vehicles that no longer emit CO2 should be newly registered. At Germany’s insistence, the EU should now examine whether and how synthetic fuels can also be used in the future. But how sensible is the use of e-fuels anyway?

What are e-fuels?

E-fuels, short for the English word electrofuels, are synthetic fuels with which internal combustion engines can run. They are made from water and CO2 using electricity. This process is called “Power-to-X” – electricity can be used to produce either e-gasoline, e-diesel or e-kerosene. If green electricity is used and the required CO2 is extracted from the atmosphere, e-fuels can theoretically be used in a climate-neutral manner.

Who is already using e-fuels?

So far there have been smaller pilot plants for the research and development of e-fuels. The TU Bergakademie Freiberg in Saxony is leading the way. In the Emsland town of Werlte in Lower Saxony, for example, work is being done on CO2-neutral kerosene.

Of the German car manufacturers, Porsche in particular relies on e-fuels. Together with Siemens, the Stuttgart-based carmaker has taken a stake in a factory for the production of e-fuels in Chile. The location is well suited for production, because the south of the country is considered to be windy. According to the sports car manufacturer, up to 90 percent of fossil CO2 emissions in combustion engines can be reduced with e-fuels in the future. Formula 1 also relies on this fuel, from 2026 only e-fuels may be used.

How expensive are e-fuels?

At the moment, the production of synthetic fuels is still complex and expensive. For the ADAC, a price of less than two euros per liter seems feasible. On the one hand, this is supported by the fact that the production costs for renewable electricity are falling, and on the other hand, increasing mass production is making e-fuels cheaper.

The interest group “eFuel-Alliance” predicts that the production costs will be less than one euro in 2050 – provided that the synthetic fuels are manufactured in large-scale industrial production.

What are the critics saying?

The use of e-fuels is energy-intensive. They need about five to six times as much electricity as a battery-electric vehicle for the same mileage, writes Falko Ueckerdt from the Potsdam Institute for Climate Impact Research when asked tagesschau.de. E-fuels have the advantage that they can be produced worldwide at locations with high renewable potential and then shipped. But Ueckerdt finds: “But that cannot offset the efficiency disadvantage.”

The ADAC also speaks of high losses in effectiveness. According to the Verkehrsclub, only 10 to 15 percent of the energy used in the process was left over in the “well-to-wheel” analysis. For comparison, 70 to 80 percent of the output energy of an electric car would reach the wheel.

Ulf Neuling, project manager for fuels at the Agora Verkehrswende think tank, sees the future of e-fuels not only in maritime shipping but above all in e-kerosene for air transport, because there no alternative is foreseeable, especially on long-haul routes. “Instead of pushing e-fuels into other markets where superior emission-free alternatives are already available, business and politics should focus their ambitions primarily on aviation,” demands Neuling.

What do e-fuel advocates say?

The “eFuel Alliance” initiative shows that e-fuels can be mixed with conventional motor fuels and could replace them completely. The initiative also states that the aircraft, ships and more than 1.3 billion vehicles that are available today could continue to be used in the future – without conversion and in a climate-neutral manner.

In addition, the existing gas station network could theoretically be used for refueling. This could be a relief if the expansion of the charging infrastructure does not progress quickly enough.

The Mittelständische Energiewirtschaft Deutschland (MEW) is also one of the supporters: it is the voice of the mineral oil and energy industry. When it comes to efficiency, the advocacy group argues that it is not enough just to look at how much energy the individual journey consumes. It is also about “how much energy (not just electricity, but all forms of energy) is required and how much CO2 a vehicle causes from its production to the mileage to recycling.” Taking that into account, e-fuels performed similarly well or even better than other technologies.

The MEW refers to a study by the consulting firm Frontier Economics from 2020. In the study commissioned by the mineral oil industry association and the federal association of medium-sized mineral oil companies, the focus was on the overall economic energy efficiency of the various drives.

The authors of the study argue that the efficiency of the use of green electricity reported in “previous conventional analyses” is actually much lower in battery-powered vehicles. Sticking point: The study takes into account the differences between wind and solar systems, for example, depending on their location. For example, battery-electric vehicles are largely dependent on the less efficient domestic electricity generation, while e-fuels can be produced with imported hydrogen that has been produced abroad with higher electricity yields.

If you take this factor into account, the efficiency advantage of the battery-electric drive melts away: While previous analyzes assumed 70 percent energy efficiency, the overall analysis of the study put it at only 13 to 16 percent.