Decarbonizing the transport sector is a key challenge in the fight against climate change. The focus here is on various technologies, in particular electromobility and eFuels (synthetic fuels). It is often argued that eFuels are inefficient and therefore not a viable alternative. But how justified is this argument really?
What does efficiency mean in the context of eFuels and electromobility?
The term efficiency is often used to emphasize the advantages of electric vehicles. However, many efficiency considerations only refer to the electric motor and ignore the upstream energy system. However, a fair comparison must consider the entire system, including energy generation, conversion, storage and use. System efficiency (well-to-wheel) refers to the overall efficiency from the origin of the energy (e.g. sunbeam, gust of wind) to the movement of the vehicle. This is crucial in order to evaluate and meaningfully compare the actual sustainability and efficiency of different technologies.
Overall view of the energy efficiency of eFuels and electromobility
eFuels are produced from renewable energies, water and COâ‚‚. The process includes: | Electric vehicles use electricity, ideally from renewable sources. The process includes: |
---|---|
|
|
From this, an overall efficiency for eFuels in the wtw approach of 14.1% can be calculated. |
This results in an overall efficiency of electric mobility of 13.4% in the wtw approach |
Importance of the production site for renewable energies
The efficiency of energy generation depends heavily on the location:
- Photovoltaics: In Germany, the utilization efficiency is around 10.5 %, while it is twice as high in sunny countries such as Morocco or Algeria.
- Wind power: German wind turbines achieve an average efficiency of around 22 %, while wind turbines in Patagonia achieve up to 75 %.
Conclusion: The production of eFuels in regions with high utilization efficiency of renewable energies can increase overall energy efficiency.
Availability of renewable energies
Effizienzrelevanz:
-
- In Germany: Limited space and lower utilization efficiency make renewable energy a scarce resource.
- From a global perspective: Renewable energy is available in abundance in many regions.
Transportation and storage:
-
- eFuels: Conversion of surplus green electricity into transportable and storable liquid fuels.
- Hydrogen: Direct transportation is difficult and expensive due to storage and transportation challenges.
Use of existing infrastructure and existing vehicles
The vast majority of the global vehicle fleet is equipped with petrol or diesel engines. Converting this existing fleet to climate-neutral eFuels can be done quickly and efficiently:
- Cost and resource efficiency: No need to build new vehicles or infrastructure.
- Rapid COâ‚‚ reduction: Immediate reduction in new COâ‚‚ emissions through the use of climate-neutral fuels.
In contrast, electromobility requires:
- New infrastructure: Establishment of a nationwide charging network with high resource requirements.
- Raw material-intensive production: Production of batteries with high environmental impact and additional COâ‚‚ footprint.
Energy import and transport efficiency
Germany imports around 70% of its energy requirements. Imported green molecules in the form of eFuels offer several advantages:
- High energy density: Liquid fuels enable efficient transportation over long distances.
- Use in existing systems: Direct use in combustion engines and heating systems without additional conversion losses.
Overall assessment of efficiency
System efficiency should always consider the entire energy system – from the source of the energy to its use in the vehicle. This holistic view shows that eFuels and electromobility are comparable in terms of overall efficiency.why efficiency is not everything:
- Availability of renewable energies: In many regions, there is no shortage of renewable energy, so efficiency losses are less significant.
- Use of resources: The use of existing vehicles and infrastructure saves resources and reduces the ecological footprint.
- Flexibility: eFuels can store and transport surplus renewable energy, which contributes to the stability of the energy system.
Conclusion: Efficiency is an important criterion, but not the sole measure for evaluating energy sources.
Electromobility has a higher overall efficiency, but eFuels offer advantages in terms of flexibility, storability and the use of existing infrastructure. A holistic view, which includes ecological, economic and social aspects, shows that both technologies have their justification and that the combination of electromobility and eFuels can help to make the decarbonization of the transport sector efficient and socially acceptable. An open-technology approach makes it possible to utilize the strengths of both options and effectively tackle the challenges of the energy transition. for more information, see Energy efficiency of eFuels in context.