Is indirect electrification more efficient than an electric car?

A recent study points to the underestimated potential of e-fuels. Renewable energy could be used to extract synthetic fuels. Does this make the overall balance even better than with purely electric vehicles?

Synthetic fuels are illustrated by a car fueled by a green charging station on which Green Energy stands


The electrification of the drive is already in full swing, so you can hear it again and again. But has the development taken the right path? “Generally speaking, this is very much discussed in terms of engineering – and the question of the future of our mobility has long since become a social debate. When asked about the drive of the future, a holistic view and assessment is necessary, which includes, among other things, acceptance issues, “emphasizes David Bothe of Frontier Economics Limited. Together with the Institut der deutschen Wirtschaft (IW), Frontier has recently produced a study that deals with the underestimated potential of e-fuels. E-fuels are understood to mean synthetic fuels produced by (renewable) energy from water and carbon dioxide. Findings from the study will also be presented by Bothe at the International Motor Congress in Baden-Baden.

Taking a holistic view of the system costs of mobility

In order to realize the climate protection targets that are being pursued, Germany will in the long run also have to complete the transport sector almost completely switch to renewable energy. After all, of the 2,472 terawatt hours (TWh) of total final energy used in Germany every year (as of 2015), around 30% are used in the transport sector. “Public discussion usually focuses on the direct electrification of vehicles. Our energy-economic considerations show that chemical energy sources derived from renewable electricity as e-fuels certainly have a better economic efficiency, “says Bothe. Various technologies are currently being researched or tested. The various approaches to synthetic fuels are summed up under the generic term “Power-to-X”.

What is “Power-to-X”?

Power-to-X refers to various technologies Storage or otherwise use of mostly renewable electricity – synthetic fuels (“power-to-liquids” and “power-to-gas”) are therefore part of PtX. Worldwide demand for PtX could easily reach 20,000 TWh by 2050, according to a Frontier study – half of the current global crude oil market. The study by Frontier and IW states literally: “The worldwide demand for electrolysers and other conversion capacities (methanation plants and plants for the production of synthetic liquid fuels) would then be in the region of 8,000 gigawatts. This would trigger investments of an estimated average of € 215 billion a year in PtX plants (electrolysers, other conversion plants, CO2 capture plants from the air). By comparison, global investment in the oil and gas sector currently amounts to about 746 billion euros per year. “

Since renewable energies are basically inexhaustible, it is not primarily the efficiency that is crucial, but which energy use path has the lowest system costs – and technically and socially. “From a systemic point of view, it can be seen that the conversion losses of e-fuels are more than compensated for by the advantages offered by chemical energy sources for energy supply,” emphasizes Bothe.

E-fuels a number of advantages

In a recent study, the consulting firm Frontier Economics shows that a self-sufficient energy supply in Germany by the year 2050 can save 250 billion euros through the use of gaseous and liquid e-fuels – compared to one far-reaching electrification of vehicles. The central cost advantages of e-fuels are the high energy density and the associated ease of storage and the ability to continue to use the existing infrastructure and familiar end applications for liquid and gaseous energy sources – from the classic internal combustion engine to the already existing, nationwide service station network. The end user would not even have to change over during the refueling process. The challenges with switching to electric cars are quite different: here as well there is a lack of infrastructure as on comprehensive solutions for rapid charging of vehicle batteries. All this could lead to a greater social acceptance of indirect electrification compared to the electrification of the vehicle drive.

Provide acceptance for automotive change

In addition to the economic and technical aspects, it is often overlooked that the energy transition can only succeed if there is broad social support for this project, says Bothe. “The benefits of e-fuels more than outweigh potential disadvantages. Even with a long-term shift of the transport sector to almost 100% renewable energies, a mix of electricity and electric fuel is the most economical solution for the energy supply. “This offers prospects for the internal combustion engine, but also for alternative applications based on fuels such as hybrid systems and fuels Fuel cells.

The study results for e-fuels will be presented by David Bothe at the International Motor Congress, which took place from 26.-27. March 2019 in Baden-Baden.