Two prominent competitors have emerged in the search for sustainable energy solutions: E-fuels (electric fuels or synthetic fuels) and batteries. Both technologies offer unique advantages and are shaping the energy landscape in different ways. For these reasons, the combination or coexistence of both technologies is important to achieve a more sustainable future.

Energy storage and portability

E-fuels: E-fuels are a versatile energy carrier that can be used to store energy in chemical form. This characteristic makes them suitable for sectors where portable energy is needed, such as aviation and long-distance transportation, where batteries face challenges due to their weight and limited energy density. In addition, e-fuels are ideal for storing large amounts of energy to compensate for seasonal fluctuations in the energy supply.

Batteries: Batteries are ideal for stationary applications and short-distance transportation. They store electricity and release it directly, which makes them attractive for urban mobility, energy storage in private households and the operation of portable devices. The conversion efficiency of electricity to electricity or to drive energy is very efficient, but the amount of energy that can be stored is limited.

Defossilization potential

E-fuels: E-fuels can be produced using renewable energy, which allows for carbon-neutral energy storage. The closed carbon cycle in their combustion, together with the possibility of replacing fossil fuels in hard-to-electrify sectors, contributes significantly to defossilization efforts.

Batteries: Batteries are inherently emission-free during operation. Their impact on the carbon cycle depends heavily on the power source used to charge them, in addition to the considerable amount of energy still required to manufacture them. In regions with a high proportion of renewable energy, batteries offer a good way to reduce carbon dioxide emissions.

Infrastructure expenses

E-fuels: The introduction of e-fuels hardly requires any adaptation of the existing fuel distribution networks, but does require adaptation of the existing distribution networks and billing systems. The capacity to produce e-fuels must also be created.

Batteries: The infrastructure for charging batteries ranges from charging at home to public stations and requires a massive expansion of the electricity distribution grid. This applies to both high-voltage grids and local low-voltage grids. The possible charging speeds are currently dependent on the expansion of high-voltage charging stations. If the proportion of charging processes increases due to an increase in users, the charging speed will depend heavily on the current availability of renewable electricity.
 

Energy density and range

E-fuels: E-fuels have a high energy density, which enables a long range without the weight restrictions of batteries. This property is particularly advantageous for sectors such as aviation, where long distances are covered.

Batteries: Although the energy density of batteries is constantly improving, it is still lower than that of liquid fuels. This has an impact on the range of electric vehicles and the feasibility of certain applications such as aviation.

Efficiency and losses

E-fuels: The production and utilization processes of e-fuels involve several efficiency losses. For example, electrolysis with an efficiency of 70% is an important efficiency loss during production. The efficiency of a combustion engine is typically only 40%. Many other factors along the entire life cycle of e-fuels influence the overall efficiency. 

Batteries: Batteries are very efficient at storing and converting energy. Energy expenditure for their production significantly reduces their overall efficiency.

Resources and raw materials

E-fuels: The production of e-fuels requires renewable carbon sources and renewable energy. Sourcing sustainable carbon sources and minimizing energy use are critical to the environmental footprint of e-fuels.

Batteries: Batteries rely on materials such as lithium, cobalt and nickel, leading to concerns about resource availability, mining methods and potential environmental impacts. Recycling and switching to more sustainable materials is an ongoing challenge.

Scale and acceptance

E-fuels: E-fuels require considerable investment in development and the expansion of production capacity. However, only minor adjustments are required in distribution and application. Most production processes for e-fuels are aimed at a drop-in quality that allows a 1.1 replacement of fossil fuels.

Batteries: Battery technology has advanced considerably and economies of scale are reducing costs. The introduction of electric vehicles and energy storage systems is accelerating and there are already established manufacturing processes. However, far-reaching conversion measures are still required in terms of infrastructure and the replacement of the vehicle fleet. 

E-fuels and batteries are two different but complementary paths to a sustainable energy future. E-fuels offer advantages in sectors that require high energy density and a long range, while batteries are beneficial in stationary applications and urban mobility. As both technologies complement each other, working together will bring us closer to realizing a comprehensive and sustainable energy transition.