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Environmental balance: studies with combustion cars pay off nicely


Are battery electric cars really better for the environment? Studies are now defending propulsion systems using hydrogen and synthetic fuels.

A report by Friedhelm Greis November 2, 2020, 2:28 p.m.

A power-to-liquid test facility at the Karlsruhe Institute of Technology (KIT) (Image: Patrick Langer / KIT)

In the debate about the future drive technology of cars, several studies advocate further use of combustion technology. "All vehicle concepts have the potential to make a significant contribution to reducing CO2 in mobility," said a study presented on Monday by the Association of German Engineers (VDI). In a further study (PDF), the Mineralölwirtschaftsverband is promoting the use of synthetic fuels. But the underlying assumptions are highly controversial.

Proponents and opponents of electric mobility have been arguing for years about how environmentally friendly electric cars actually are. The decisive question is how much carbon dioxide is actually generated in the production of the cars and the charging current. The actual consumption of the compared combustion vehicles is also important when considering.

Very high CO2 equivalents

What is striking about the VDI study, which was carried out by the Karlsruhe Institute of Technology (KIT): The study assumes a very high CO2 equivalent for battery production. Depending on the electricity mix, 185 kilograms of CO2 equivalent per kilowatt hour (China) or 124 kg CO2eq / kWh (Europe) are calculated.

According to a study by the University of Eindhoven, however, CO2 emissions of 75 kg CO2eq / kWh can be assumed for battery production. A Swedish meta-study now also assumes that there is an equivalent of 61 to 106 kg of carbon dioxide per kWh of battery capacity.

It is also noticeable that the VDI study calculates the fuel consumption of a combustion engine with 4.5 liters of diesel per 100 kilometers. Apart from the fact that the average consumption of diesel vehicles in Germany is around 7 liters, the study does not seem to take into account the so-called pre-emissions in fuel production.

According to the University of Eindhoven, the assumed CO2 emissions should be increased by 30 percent for combustion cars that run on gasoline. Cars that run on diesel should add 24 percent to their tailpipe emissions. However, the VDI study assumes an average electricity consumption for electric cars of 15.8 kWh per 100 km, which also seems too low.

Study promotes e-fuels

Based on these assumptions, the authors of the study come to the conclusion: "A complementary combination of technologies is the only chance (e.g. with a view to the existing fleet) to achieve the CO2 targets for 2030." One prerequisite for this, however, is: "To do this, all drives need both production with the lowest possible CO2 emissions and operation with a low-CO2 energy source."

So-called synthetic fuels (e-fuels) are said to be such a low-CO2 energy source. A study by the consulting firm Frontier Economics, which was commissioned by the Mineral Oil Industry Association and the Federal Association of Medium-Sized Mineral Oil Companies (Uniti), also argues for their use. In view of the client, the results of the study are not surprising.

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in a statement on the draft law is even calling for higher targets for hydrogen and synthetic fuels, Volkswagen believes the potential of these alternatives is overestimated.

Strong criticism of the studies

Felix Matthes from the Freiburg Eco-Institute expressed criticism of the studies. He described Frontier Economics' calculations in the Südwest-Presse as a "cheap trick" . The economic efficiency should not be composed of technical-physical and economic factors, this is "methodical voodoo" .

The debate about the alleged "miracle fuel" e-fuels is a "technology bet" and a "fatal sign" that combustion engines still have a future. So far, there is no pilot plant with a large output. Where the CO2 for the production of e-fuel should come from is also open. Taking it out of the air is difficult.

The Federal Association for E-Mobility (BEM) also criticized the studies. "The dispute can be better understood when you know that hydrogen and e-fuels have to be distributed to customers and that the mineral oil industry wants to use their existing lines a second time for this," said Markus Emmert from BEM.

In his opinion, however, it is too late for that. "Achieving the CO2 targets by 2030 in the mobility sector with e-fuels and hydrogen based on green energy is neither feasible, affordable, nor technologically resilient. The industrial associations' proposal only applies to maintaining old business models and existing infrastructures Facts bent, " said Emmert.

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Source: golem.de