Electric cars are considered the vehicles of the future, although they are not necessarily climate-friendly. Synthetic fuels, on the other hand, can be produced using renewable energies and, like petrol or diesel, can simply be filled up. The internal combustion engine could survive in this way.

The car of the future does not emit any CO2 and runs on electricity instead of petrol or diesel: electric cars are supposed to replace the combustion engine and protect the climate. As a rule, they are not (yet) really climate-friendly. Because the electricity used does not always come from renewable energies. In addition, the batteries used in production and disposal have so far been quite harmful to the climate.

Synthetic fuels, also known as PtX fuels or e-fuels, are ideally almost 100 percent climate-neutral and can be used in combustion engines like petrol or diesel. Are synthetic fuels a realistic alternative to electromobility?

Auto Experts Disagree About Efficiency Of Synthetic Fuels

“Without e-fuels, we will not be able to be climate-neutral by 2045 and we will not achieve the interim goals either,” says engine professor Stefan Pischinger from RWTH Aachen University to the “Redaktionsnetzwerk Deutschland (RND)”. The reason is therefore the enormous stock of combustion vehicles. The combustion engine still offers great development potential, especially in combination with e-fuels, and can thus make a major contribution to reducing CO₂ emissions, according to Pischinger.

The automotive economist and professor Ferdinand Dudenhöffer, however, has a completely different opinion. “E-fuels are a very expensive thing: unthinkable for cars, but in trucks there is a high probability that they will be replaced by fuel cells and battery-electric drives,” says the founder and director of the Center Automotive Research at the University of Duisburg-Essen to the RND. He already sees an opportunity for e-fuels – but in air or ship traffic. In the automotive industry, he considers fuel to be an evasive maneuver that mineral oil manufacturers, suppliers and vehicle manufacturers want to use to gain more time for conventional drives.

If diesel is produced from solar power via several energy-intensive transformations and this is then burned with an efficiency of 40 percent, the overall efficiency is 15 percent. “That means 85 percent of the energy is lost. It really doesn’t get any worse,” says Dudenhöffer. By way of comparison: in an electric car, 70 to 80 percent of the output energy arrives at the wheel. This means that a car powered by synthetic fuels needs about seven times the amount of energy as an electric car.

Andreas Radics from strategy consultant Berylls in Munich told the RND: “E-fuels could have been an answer to the question of how regions with an almost non-existent e-infrastructure will be served in the future when more and more manufacturers are moving away from classic combustion engine technology .” However, these technologies have found too little support in recent years and the die has long been cast, at least for cars. “Thus, although synthetic fuels have the potential to delay the shutdown of the internal combustion engine, they will not stop it,” says Radics.

Porsche builds first plant for e-fuels production

Synthetic fuels are still a long way from market launch, but research is ongoing. The head of development at Porsche, Michael Steiner, tells the RND: “If you want to operate the existing fleet sustainably in the future, then e-fuels are an elementary component.” Porsche, together with Siemens Energy, has started construction of what it says is the world’s first commercial pilot plant for the production of e-fuels in Chile, as the two companies announced in September. The factory is to produce almost CO2-neutral synthetic fuels. In 2022, around 130,000 liters are to be produced for the first time, which are to be used in the company’s own vehicles with combustion engines. The choice fell on the location in Chile because of the good wind conditions there.

Production of synthetic fuels very expensive

However, the production of synthetic fuels is very complex and expensive. Water is separated into hydrogen and oxygen using electricity. Subsequently, with the addition of CO2, synthesis gas is produced, which is processed into fuel using special processes. In order for the end product to be climate-neutral, the electricity must be green and no fossil fuels may be used. A lot of energy is required for the production and considerable capacities are needed to store electricity.

On the other hand, synthetic fuels can be produced with virtually no quantitative limits and burn quite cleanly compared to petrol or diesel. However, the complex manufacturing process affects the price. A liter of synthetic fuel would currently cost around 4.50 euros to produce. In fact, synthetic fuels make it possible to use excess energy from solar and wind power. It can be saved and used when there is no wind and the sun is not shining.

Use in plane and ship traffic is more likely. In addition to the possibility of absorbing CO2 from the environment and the climate-neutral production and use, there is another advantage in the storage of synthetic fuels: They could be sold through the existing network of filling stations and need no more space than kerosene or diesel. This means that the conventional tank can be used.

The weight of an electric vehicle increases with an increasing range, since the battery is correspondingly heavier. An electric motor in a ship or airplane, for example, has so far been unthinkable, since a huge battery would be needed to achieve a normal range. The weight of vehicles powered by synthetic fuels, on the other hand, does not increase significantly depending on the range. Synthetic fuels are therefore conceivable in ship and air traffic, which would hardly get by with an electric motor.

Sources: ADAC, RND, Zeit, Porsche press release, BDI,