It would be so wonderfully simple and convenient: simply replace the combustion engine with an electric motor and all emission problems would be solved. Then we could drive around as we please without a care in the world. This is the impression created in many places by the current debate on diesel driving bans, low emission zones and the mobility transition, as e-vehicles are subsidized with a purchase premium, exempt from vehicle tax and described as "emission-free".

In the face of the Bonn Climate Conference and the Jamaica coalition negotiations, this rosy view is now being shattered by a paper signed by 15 emeritus chairs of transportation at German-speaking technical universities and colleges. At their annual meeting in Fulda, they discussed the developments surrounding electrically powered road vehicles. The group sees electromobility as a long-term opportunity to improve climate and environmental protection, but calls for this to be placed in the overall context of transport and settlement policy - because changing the type of drive alone would not be enough. In particular, the professors point to unresolved issues and problems that have often been ignored.

No traffic is "emission-free"

They criticize shortcomings in the debate to date and "barely comprehensible discussions about exhaust emissions from diesel engines", which leads to a narrowing of the topic to drive technology. When electric vehicles are described as "emission-free" or "locally emission-free", one gets the impression that the laws of physics are being ignored. The fact is that the particularly dangerous emissions, particulate matter, are also produced locally by electric vehicles. 85 percent of PM10 particulate matter does not come from the engines, but from tire and brake abrasion, for example. It is also incomprehensible that e-cars are classified as CO2-free just because the electrical energy for the drive is produced elsewhere.

The current legislation, which obliges vehicle manufacturers to reduce fleet consumption, means that more large and heavy electric vehicles are coming onto the market because this is where the supposed savings are most profitable for manufacturers. However, the additional energy consumption caused by size and weight is not being addressed. The emissions from electric and hybrid drives are falsely calculated down to zero.

Any technical progress can trigger so-called "rebound effects". This means that the savings made by more efficient vehicle drives are at least partially offset by more intensive use and the purchase of larger and heavier vehicles. This effect has also meant that fuel consumption in conventional vehicles has barely decreased. Such a scenario has not yet been addressed for electric vehicles either. The emeritus professors call for the size and weight of vehicles to be taxed.

Doubtful driving pleasure

Anyone who has ever driven an electric vehicle will have noticed the tremendous acceleration power, which is due to the fact that electric motors with appropriate control can generate maximum torque over a wide speed range. The professors are skeptical about what is almost universally regarded as positive ("great driving fun"): high acceleration costs a lot of energy. Above all, however, it endangers pedestrians and cyclists, who do not have enough time to react as the quiet vehicles approach quickly. The only suitable measure here would be to limit the acceleration capacity without technical problems.

Where does the energy come from?

Another taboo subject is energy generation for electric vehicles. It is taken for granted that the electricity required must come from renewable sources - but is this realistic?

The position paper states that electric vehicles need to be charged at night in particular. Solar energy is not available during this time. So what happens on a windless winter night? Other, non-renewable energy sources such as gas and nuclear power have to step in. In addition, cars will compete with other consumers - namely when heating energy is also to be generated in a climate-neutral way and this is also generated electrically. Night-time electricity would then become even scarcer.

The scientists also contradict the myth that electric cars could be used to store energy in the grid: the time required for this would most likely not allow it. This is because the vehicles have to be charged overnight so that the full battery capacity is available in the morning. Otherwise, it may not be possible to carry out planned journeys.

Social consequences

The professors also point out that transport demand is characterized by high temporal and spatial peaks. Coping with demand at these times is already a major problem today. There are narrow limits to efforts to level out these peaks: Time- and location-based charges such as a city center toll mean that wealthy people can drive or charge whenever they want, while low-income households cannot. However, equal access to infrastructure is part of services of general interest and social participation. The researchers therefore believe that pricing measures are only justifiable if their social impact is taken into account and compensated for.

The alternative

The emeritus professors share the goal of converting motor vehicle traffic to drives without CO2 emissions. However, they insist that the discussion should not only be led by automotive engineers and business economists. Instead, traffic-reducing settlement and transport infrastructure planning should also be included, as otherwise all future automobile transportation will be associated with a globally unacceptable burden. Politicians are called upon to offer improved concepts for public and non-motorized transport and to improve cost transparency for transport users. However - as the authors realistically state - this is an unpopular topic and therefore taboo because it can only be achieved by changing behavior.