E-fuels vs. electric cars
Are synthetic fuels the better alternative to electromobility?
A bottle of synthetic fuel during an e-fuels test drive
© Tom Weller / DPA
Electric cars are seen as 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 gasoline or diesel, can simply be filled up. The internal combustion engine could survive this way.
The car of the future will not emit any CO2 and will use electricity instead of gasoline or diesel: electric cars should replace the internal 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 extremely harmful to the climate.
Synthetic fuels, also called PtX fuels or e-fuels, are ideally almost 100 percent climate-neutral and can be used in combustion engines like gasoline or diesel. Are synthetic fuels a realistic alternative to electromobility?
Auto experts at odds over synthetic fuel efficiency
“Without e-fuels, we will not be able to be climate-neutral by 2045 and we will not achieve the intermediate goals either,” says engine professor Stefan Pischinger from RWTH Aachen to the “Redaktionsnetzwerk Deutschland (RND)”. The reason is therefore the enormous number of combustion vehicles. Combustion engines, especially in combination with e-fuels, still offer great development potential 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: inconceivable for cars, in trucks they are likely to 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 with which mineral oil manufacturers, suppliers and vehicle manufacturers want to gain more time for conventional drives.
If diesel is produced from solar power through 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 doesn’t really get any worse,” says Dudenhöffer. For comparison: In an electric car, 70 to 80 percent of the output energy reaches the wheel. A car powered by synthetic fuels therefore needs about seven times the amount of energy as an electric car.
Andreas Radics from the strategy consultant Berylls in Munich told the RND: “E-fuels could have been an answer to the question of how regions with almost nonexistent e-infrastructure will be served in the future if more and more manufacturers are abandoning classic combustion technology . ” However, these technologies have found insufficient support in recent years and the die has long been cast, at least for cars. “Synthetic fuels therefore have the potential to delay the shutdown of the internal combustion engine, but they will not stop it,” says Radics.
Porsche builds first plant for e-fuels production
Synthetic fuels are still a long way from being launched, 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 long term, then e-fuels are an elementary component.” Together with Siemens Energy, Porsche has started construction of what it claims to be the world’s first commercial pilot plant for the production of e-fuels in Chile, as the two companies announced in September. The factory will produce synthetic fuels that are nearly CO2-neutral. 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 the wind conditions there are good.
Production of synthetic fuels is very complex
The production of synthetic fuels is, however, very complex and expensive. With the help of electricity, water is separated into hydrogen and oxygen. Then, with the addition of CO2, synthesis gas is produced, which is processed into fuel using a special process. 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 production and considerable capacities are required to store electricity.
However, synthetic fuels can be produced with virtually no quantitative limits and burn quite cleanly compared to gasoline or diesel. However, the complex manufacturing process has an impact on the price. A liter of synthetic fuel would currently cost around 4.50 euros to manufacture. In fact, synthetic fuels make it possible to use excess energy from solar and wind power. It can be saved and then used when there is no wind and the sun is not shining.
It is more likely that it will be used in aircraft and shipping. 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 via the existing filling station network and do not require more space than kerosene or diesel. This means that the conventional tank can be used.
The weight of an electric vehicle increases as the range increases, as the battery becomes correspondingly heavier. An electric motor, for example in a ship or airplane, has so far been unthinkable, as a huge battery would be required 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 shipping and air traffic, which would hardly get by with an electric motor.
Sources: ADAC, RND, time, Porsche press release, BDI,