As hard-to-abate sectors attempt to reduce CO2 emissions, the interest in efuels continues to rise. efuels, short for electrofuels, are a class of synthetically produced hydrocarbons which achieve lifecycle carbon savings compared to traditional reservoir-sourced hydrocarbon-based fuels. They approach carbon neutral following the consumption of CO2 in their production, which is then re-released into the atmosphere when combusted. Also known as power-to-liquid fuels, efuels have the same chemical structure as conventional fossil fuels so act as a drop-in replacement fuel, meaning they are interchangeable within current engines and fuel systems. The first Efuel World Summit took place in December 2022 and presented insights from across the value chain and political framework, which are both enabling and restricting the deployment of efuels.
Efuels are an energy carrier as they can store and transport energy from renewable sources, which addresses some challenges associated with intermittency and energy storage in renewable energy systems. Syngas is the essential building block of an efuel and can be formed from the reaction of green hydrogen and captured CO2 or gasification of waste products. Both processes, and the subsequent synthesising, require large quantities of energy, causing efuels to have had a slower uptake than electrification. This is changing as industry players are recognising the difficulty to decarbonise some sectors without them. A variety of industrial processes can be used to produce efuels, the most common is Fischer-Tropsch (FT) synthesis, as depicted in the schematic below.
why efuels?
Electrification of sectors such as heavy-duty transport, shipping and aviation is a challenge due to stringent energy density requirements as a result of space and weight restrictions. Efuels can provide the physical properties of traditional hydrocarbons without the emissions intensity, enabling low-carbon heavy-duty transportation.
The pre-existence of hydrocarbon infrastructure means that efuels can be directly and instantly integrated into the current fossil fuel supply chain and propulsion systems, allowing for a fast and simple transition solution. This provides an edge over the capital investment required to implement hydrogen, which cannot be used as a drop-in fuel, or renewables. Furthermore, utilising efuels in existing assets is a more environmentally sound solution than scrapping them. The trade-off between the energy consumption of efuel synthesis should be compared with the potential waste of hydrocarbon infrastructure and replacing fleets of vehicles.
building a business case for efuels
Developing a positive business case for the efuels market presents a key challenge due to large costs of production. The cost of carbon capture and hydrogen electrolysers is high, which makes it difficult for them to compete with cheaper, more established fuels. Government incentives, such as the $1.72/gal for sustainable aviation fuels (SAFs) introduced in the US, significantly improve their business case. Infinium efuels remarked that this was a key enabler for their business at the summit [1].
Aviation in particular is driving efuel development with examples including the Airbus partnership with the SAF+ Consortium in Canada, the HyshiFT Consortium in South Africa and the Liquid Wind consortium in Scandinavia [3]. A controversial source of efuel investment has been the luxury car brand, Porsche. Porsche funded HIF Global’s Haru Oni demo plant in Chile, which produces efuels consumed in Porsche’s Experience Centres. Funding is generally positive for market uptake, but in this case it could result from a reluctance to EV’s. Cars are easily electrifiable and don’t require efuels to decarbonise and the consumption of efuels in cars deprives them from hard-to-abate which need them to decarbonise. Efuels must be prioritised in these sectors for society to experience the most climate benefits, an opinion also voiced by some Members of European Parliament at the summit [1]. Nonetheless, this case is fairly unique and may not present as much of a threat if governments follow the European Parliament’s vote to ban the sale of petrol and diesel cars by 2035 [4].
image sourced from Infinium
further barriers to deployment
The source of CO2 can also present challenges. One pathway is through partnerships with industrial emitters to identify a high concentration CO2 stream to capture. Infinium’s partnership with ArcelorMittal to utilise captured CO2 from their steel plant in Dunkirk is a current example of this [1]. As sectors electrify, there may be fewer CO2 emission sources and efuel producers will have to implement technologies such as Direct Air Capture (DAC) and biomass which carry their own associated economic, operational and environmental challenges. DAC is an early-stage technology that requires scale-up, reduction of energy use, demonstrated industrial operation and cost reduction to commercialise. However, some advocate for DAC as key to an efuels ability to close the carbon cycle, whereas point-source CO2 capture will still contribute to atmospheric GHG accumulation [2].
There are also some uncertainties regarding the full extent of environmental benefits of efuels. In addition to the high energy consumption for the high temperature synthesis, producing green hydrogen is water intensive. This could present an obstacle to efuels being geographically independent in countries with scarce water. Furthermore, the combustion of efuels in internal combustion engines still produces NOx and particulates, leading to harmful effects on the environment and society. Efuels produced via FT lack aromatic molecules that prevent leaks in conventional aircraft fuel systems so need to be blended with kerosene for Sustainable Aviation Fuel (SAF) applications, further inhibiting its environmental credentials [2].
Concluding remarks
The feasibility, scalability and sustainability of efuels are still subjects of ongoing R&D, and their role in the energy transition depends on various factors, including cost-effectiveness and environmental impacts compared to alternatives. It’s a complex trade-off, but the ability of efuels to reduce GHG emissions in sectors where direct electrification is challenging, such as aviation and heavy transport, should not be ignored. Arcadia efuels is planning to start operation at the end of 2026 and has already agreed to supply SAF to Sunclass Airlines and Shell Aviation Denmark [1], providing evidence for the demand that supply needs to ramp up to satisfy.
Market expansion will involve scaling of hydrogen electrolysis and DAC capacity which can be achieved through industry collaborations across the supply chain. The efuel business case is also enabled by government incentives, which need to be amplified for the sector to attract investment. The role of efuels in the broader context of the transition to a cleaner and more sustainable energy system must be further evaluated to fully maximise their potential.
Presentations from the E-Fuel World Summit 2022 https://www.e-fuelworldsummit.com/
Low-carbon fuels for aviation, A Fantuzzi, P A Saenz Cavazos, N Moustafa et al., Briefing Paper No 9 March 2023, Institute for Molecular Science and Engineering, Imperial College London, doi.org/10.25561/101834
Sustainable Aviation Fuel – Ready for lift off? KPMG, Aviation 2030 https://assets.kpmg.com/content/dam/kpmg/uk/pdf/2022/11/sustainable-aviation-fuel.pdf