A Key to Decarbonizing Hard-to-Abate Sectors

eFuels are synthetic fuels produced by combining hydrogen (H₂) and carbon dioxide (CO₂). Their chemical structure closely resembles that of conventional fossil fuels, allowing them to be transported, stored, and used within existing infrastructure. This makes them a practical alternative in industries where battery-based electrification isn't feasible — such as global shipping and aviation, which require high energy density and long-range capability.

How are eFuels made?

eFuels are produced using Power-to-X (PtX) technologies, which convert renewable electricity into various energy carriers, fuels, and chemicals. While they can theoretically be made with fossil-based electricity and fossil CO₂, their sustainability depends on using renewable power and CO₂ captured from biogenic sources or through Direct Air Capture to maintain a closed carbon cycle.

Whether produced as gaseous fuels (using Power-to-Gas) or liquid fuels (using Power-to-Liquid), all eFuels follow a similar production process:

1. Renewable Energy: Green Hydrogen Production

Renewable electricity, sourced from wind, solar, or hydropower, is used to split water into green hydrogen (H₂) and oxygen (O₂) through electrolysis.

2. Carbon Capture: Sourcing CO₂

CO₂ is captured from the atmosphere, industrial emissions, or biogenic sources and purified for fuel synthesis. Biogenic CO₂ from biomass or biogas helps maintain a closed carbon loop, while Direct Air Capture (DAC) extracts CO₂ directly from the atmosphere, supporting carbon-neutral eFuel production.

3. Fuel Synthesis: Creating eFuels

The hydrogen and CO₂ are then combined in chemical reactions to form hydrocarbons, which can be processed into different fuels. This conversion can follow two main pathways:

Power-to-Gas (PtG): Produces gaseous fuels such as eMethane and eAmmonia, the latter requiring nitrogen to be separated from air.

Power-to-Liquid (PtL): Produces liquid fuels such as eMethanol, eDiesel, and eKerosene (eJet Fuel), which can be used as drop-in replacements for conventional fuels.

**Zoom in on eMethanol**
Explore the steps involved in the production process of eMethanol and discover its key sustainability benefits.

Click here

The Sustainability of eFuels

One of the key advantages of eFuels is their ability to reduce greenhouse gas emissions while integrating seamlessly into existing energy systems. Their sustainability is rooted in:

Carbon Neutrality

eFuels are produced using renewable electricity to power the electrolysis of water and generate hydrogen. This hydrogen is then combined with captured CO₂ to create synthetic fuels. When eFuels are burned, they release CO₂ - but it's the same carbon that was captured during production. This creates a closed carbon loop, meaning the emissions from fuel use are balanced by the carbon used in making the fuel, rather than adding new CO₂ to the atmosphere.

Use of Biogenic CO₂

Capturing CO₂ from biogenic sources such as biomass or biogas prevents additional carbon from entering the atmosphere and supports a circular carbon economy. Because the carbon originates from renewable biological materials, its reuse in fuel production helps ensure that emissions from fuel use are part of a balanced, short-term carbon cycle - contributing to global climate goals.

Powering Hard-to-Abate Sectors with Fossil-Free Fuel

Many industries face significant challenges in reducing their carbon footprint due to requirements for high energy density and infrastructure limitations. Unlike hydrogen in its pure form, eFuels can be transported, stored, and used with existing fuel infrastructure, making them a practical and scalable alternative to fossil fuels. They provide an immediate and scalable decarbonization pathway, particularly for the following industries:

Shipping

Shipping accounts for nearly 3% of global CO₂ emissions*, with heavy fuel oil (HFO) and marine diesel dominating the sector. With the International Maritime Organization's (IMO) target to reduce shipping emissions by at least 50% by 2050, transitioning away from fossil-based marine fuels is critical.

eMethanol offers a viable solution, as it can be used in both newly built and retrofitted ship engines with minimal modifications. It is compatible with existing bunkering infrastructure, allowing for a smooth transition to cleaner fuels. Additionally, eMethanol improves air quality by reducing sulfur oxides (SOx), particulates and nitrogen oxides (NOx) emissions, aligning with stricter maritime regulations.

Aviation

Aviation is responsible for 2.5% of global energy-related CO₂ emissions** and remains one of the most challenging sectors to decarbonize. It requires high-density fuels that can power long-haul flights while meeting stringent safety and performance standards. The International Air Transport Association (IATA) aims for 65% of emission reductions to come from SAFs by 2050***, highlighting the critical role of eFuels in achieving net-zero aviation.

eKerosene (eJet Fuel) serves as a sustainable drop-in replacement for conventional jet fuel, reducing lifecycle emissions without requiring modifications to existing aircraft or fueling infrastructure. It can be produced using Fischer-Tropsch synthesis or through Methanol-to-Jet (MTJ) conversion, offering multiple renewable pathways for sustainable aviation fuel (SAF).

Chemical Industry

The chemical industry is one of the largest consumers of fossil carbon, responsible for about 5% of global CO₂ emissions****. Many essential chemicals, such as methanol, ammonia, and hydrocarbons, are traditionally derived from fossil resources.

eMethanol, eAmmonia and synthetic hydrocarbons offer a renewable alternative, reducing carbon emissions while maintaining chemical performance. These eFuels can serve as a feedstock for a wide range of products, including plastics, synthetic fibres, and other petrochemical products, replacing fossil-based inputs.

What fuel options are there for the shipping industry in the pursuit of carbon reduction? Claes Fredriksson, CEO and Founder of Liquid Wind, shares his insights in an exclusive interview with Topsoe.

See video

Energy Storage and Transport

One of the critical challenges of renewable energy is variability in supply. eFuels address this challenge by storing excess renewable electricity in a stable, transportable form, making them a key enabler of energy system flexibility.

Storage: Liquid eFuels can be stored long-term and, with a higher energy density by volume compared to batteries, they can store more energy in a smaller space. For eMethane, it can be liquefied to become LBG (liquefied biogas), similar to fossil LNG (liquefied natural gas), enabling efficient storage and transportation. Additionally, eMethane can be converted into DME (dimethyl ether), a versatile fuel that can be used in diesel engines or as a replacement for LPG (liquefied petroleum gas), broadening its potential applications.

Transport: Liquid eFuels (e.g., eMethanol, eDiesel) can be transported using existing fuel distribution networks, while gaseous eFuels (e.g., eMethane, eAmmonia) can be injected into gas grids or transported in pressurized tanks.

Global Reach: By leveraging existing infrastructure, eFuels ensure that renewable energy can be efficiently distributed across industries and regions.

Local eFuel Production: A Path to Energy Independence

Producing eFuels locally using regionally available renewable electricity and biogenic CO₂ enhances energy security while reducing dependence on imported fossil fuels. This approach offers several key benefits:

Energy Independence: Countries and regions can diversify their energy supply and reduce reliance on external fuel sources.

Efficient Use of Renewables: Local production maximizes the use of wind, solar, and hydropower resources, optimizing regional energy potential.

Reduced Transport Emissions: By producing fuels closer to where they are consumed, emissions associated with long-distance fuel transportation are minimized.

Summary

eFuels provide a sustainable, scalable alternative to fossil fuels. Made by combining renewable hydrogen and captured CO₂, these fuels offer a solution for decarbonizing hard-to-abate sectors such as shipping, aviation and chemicals, while integrating seamlessly into existing infrastructure. Their ability to support energy storage, transportation, and local production also contributes to greater energy independence. With continued advancements, eFuels have the potential to play a vital role in the global transition to a low-carbon economy.

*https://theicct.org/sector/maritime-shipping/

**https://www.iea.org/energy-system/transport/aviation

***https://www.iata.org/en/programs/sustainability/sustainable-aviation-fuels/

****https://www.sciencedirect.com/science/article/pii/S2590332223002075

Content contributor

Thomas Stenhede, Senior Technical Adviser, Liquid Wind