Manufactured fuels are seen by proponents as an opportunity for cars with internal combustion engines. What sounds good is, in detail, a question of weighing up.
The final EU decision on a blanket ban on new cars with internal combustion engines from 2035 has been delayed. According to Transport Minister Volker Wissing, Germany cannot agree at this point in time.
He is demanding a proposal from the EU Commission on how climate-neutral synthetic fuels can be used in combustion engines after 2035. These “e-fuels” could be a way to fuel internal combustion engines with clean energy. The question remains how useful that is.
What are e-fuels?
These are artificially produced fuels (Electrofuels). Technically, hydrogen is usually produced from water using electricity. Combined with carbon dioxide, the fuel – depending on the type of chemical compound – can have the properties of diesel, petrol or kerosene.
Are such synthetic fuels sustainable?
That depends on your base. The fuels are only considered to be climate-neutral in production if the electricity for them does not come from fossil sources but from renewable sources – for example from wind power, solar systems or hydroelectric power plants. Carbon dioxide can be extracted from the atmosphere for the production of e-fuels. But this separation also costs energy because the CO2 concentration in the air is very low. The combustion of e-fuels in engines produces just as many environmentally harmful exhaust gases as fuels from fossil sources. Only a lower release of soot is possible.
What is typical for the production?
So far there are pilot plants, the technology is in the development phase. The production is very energy-intensive. In any case, a lot of electricity is required. Engineers from the TU Bergakademie Freiberg calculate that with a consumption of 5 liters of e-fuel per 100 kilometers, around 50 kilowatt hours of electricity can be required to produce the fuel. According to electricity providers, this corresponds to half the monthly consumption of a German single household.
According to the ADAC, there are high efficiency losses in the production of e-fuels. In the end, only 10 to 15 percent of the energy used was left over in the entire chain. In an e-car, 70 to 80 percent of the output energy arrives at the wheel. E-fuels therefore consume at least five times as much energy as the e-cars available today.
Can e-fuels be produced in Germany?
According to the ADAC, the construction of a production plant costs not only technological know-how, but also a lot of time, space and an immense amount of money. The Bergakademie Freiberg operates a pilot plant. Their engineers do not assume that large-scale production would be possible in Germany. Because there is a lack of sufficient “green” electricity. However, e-fuels can be easily stored and transported, so that their place of manufacture is not decisive.
Does the technology work in practice?
ADAC tested e-fuels in summer 2022 in a used VW Golf VII 1.4 TSI. Over several thousand kilometers, there were no noticeable differences in technical properties, performance and driving behavior compared to fossil fuels. The existing filling station system is considered suitable for selling e-fuels – as an admixture or in pure form. In the foreseeable future, however, there will hardly be enough e-fuels to be able to drive the cars with combustion engines that are now registered.
What do proponents say?
According to the sports car manufacturer Porsche, which is investing in a large pilot plant in Chile, up to 90 percent of fossil CO2 emissions in combustion engines can be reduced with e-fuels in the future.
The medium-sized energy industry in Germany, as the voice of the mineral oil and energy industry, argues on the subject of efficiency that it should not only be considered how much energy the individual trip consumes. It’s about how much energy is needed and how much CO2 a vehicle causes from its production to the mileage to recycling. In this regard, e-fuels performed better than other technologies.
According to the Bergakademie Freiberg, there are currently around 1.4 billion vehicles with combustion engines worldwide. They could hardly all disappear in a short time without expending enormous amounts of energy on the production of alternative vehicles. Synthetic fuels could therefore be a solution for combustion engines. However, they do not make sense in cities, for example, because of the exhaust emissions. Car manufacturers such as Mercedes or VW assume that the electric car will prevail in the long term.
What do critics say?
For the Federation for the Environment and Nature Conservation, e-fuels are not an alternative for the traffic turnaround. Synthetic fuels should better only be used for unavoidable air and ship traffic. Greenpeace calls the e-fuel prospect a waste of clean energy that cannot be afforded. The Heinrich Böll Foundation argues that “green” hydrogen is a rare resource, a kind of champagne for the energy transition. It shouldn’t be used for cars, but for key industries.