Myths about eFuels

The chart from the German Aerospace Center (DLR) shows that there is no global shortage of renewable energy. Photovoltaics alone could meet the energy needs of the entire world using a very small area. This electricity from renewable sources then simply needs to be made transportable and storable. This is achieved by first converting electricity into hydrogen and then adding CO2 to produce an eFuel. This also explains the name of the synthetic fuel: electricity-based fuel. As hydrogen derivatives, eFuels are therefore essentially liquefied, and thus transportable, renewable electricity. Hydrogen itself could also be transported. However, this is very expensive, as hydrogen must be cooled substantially and kept under pressure. As the lightest element on Earth, hydrogen also diffuses quickly through transport pipes, creating another transport challenge.

Ultimately, the efficiency of eFuels production is therefore not that important. They simply need to be produced where renewable energy is not scarce. By comparison, producing eFuels using the conventional Fischer–Tropsch process in Germany would make about as much sense as an orange plantation in Germany. eFuels are produced in sunny and windy countries for the same reason.

The efficiency question can also be viewed from another angle: in terms of cost, time and resource efficiency, the most sensible approach is to reduce new CO2 emissions from existing vehicles and existing infrastructure. Unlike electric mobility, everything is already in place. More than 99 per cent of the approximately 1.4 billion cars worldwide have petrol or diesel engines. Reducing new CO2 emissions from the existing fleet therefore makes the greatest and fastest contribution to achieving global climate targets in the transport sector.

New CO₂ emissions and the greenhouse gas balance

Here, “new CO₂ emissions” means CO₂ emissions added to the atmosphere through the use of fossil fuels. Burning carbon-containing eFuels also releases CO₂. Any potential reduction must be assessed over the entire life cycle against a specifically identified fossil reference fuel. The electricity and CO₂ sources, production, transport and use are particularly important. A CO₂ cycle alone does not demonstrate climate neutrality.

By contrast, electric mobility requires entirely new infrastructure with high resource requirements and a correspondingly large CO2 footprint. Building very heavy electric cars also requires additional resources, further increasing their CO2 footprint (embedded CO2 emissions). Finally, Germany has a very high energy import requirement of 70 per cent, meaning that green molecules in the form of fuels have to be imported anyway. The liquid form is necessary because of its high energy density, which makes transport distance practically irrelevant (high transport efficiency). Once the liquefied electricity is in the country, it is more efficient to use it directly in systems independent of electricity, such as combustion engines and oil-fired heating, rather than first converting it back into electricity with losses and potentially storing it temporarily in batteries with further losses.