What are e-fuels?

E-fuels, also known as electrofuels and Power-to-X fuels, are fuels made using renewable or decarbonized electricity. Green hydrogen is the corner stone of all types of e-fuels. Green hydrogen is obtained through the process of electrolysis, which uses renewably generated electricity or decarbonized electricity to split water molecules into hydrogen and oxygen. Electrolysis may be performed using three types of technology: alkaline electrolyzer cells (AEC), proton-exchanged membranes (PEM) and solid oxide electrolyzer cells (SOEC).

BV_E-fuel production routes

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What are the different types of e-fuel?

Many kinds of marine e-fuels exist, including gases like e-hydrogen, e-methane and e-ammonia or liquids like e-methanol or e-diesel. Gases can be liquefied at cryogenic temperature to form liquid hydrogen, liquid ammonia or e-LNG (liquefied e-methane). Some are considered low-carbon fuels, such as e-methane, e-methanol and e-diesel, which are produced using green hydrogen and CO2. Their sustainability profile can be further improved if the carbon used is taken from biogenic sources.

Other e-fuels provide a zero-carbon fuel option for ships, such as e-ammonia and e-hydrogen. E-ammonia combines green hydrogen and nitrogen via the Haber-Bosch process, and e-hydrogen is made via electrolysis. These carbon-free fuels, once produced at scale, could enable ship owners and operators rapidly reduce their fleets’ environmental footprint.

    Julien Boulland Global Market Leader, Sustainable Shipping Bureau Veritas M&O

    Sustainable Shipping expert

    Bureau Veritas M&O

    The major advantage and disadvantage of e-fuels is the same: their green hydrogen base. Today, green hydrogen presents significant challenges in terms of cost, scalability and global availability. But once the shipping and chemical industries can make green hydrogen abundant, e-fuels could leap to the forefront of marine decarbonization solutions.

    What are the advantages of marine e-fuels?

    E-fuels offer key sustainability advantages compared to other fuels:

    • They enable ships to significantly lower their emissions on a well-to-wake basis  
    • In their liquid and gaseous forms, e-fuels are easier to store and transport than electricity, and many e-fuels are compatible with existing fossil fuel infrastructure.
    • Finally, the wide selection of e-fuels makes them a potential solution for multiple vessel and engine types. Shipowners would be able to choose the e-fuel best suited to their ships’ needs, equipment, and cargo carrying capacity.



    What are the challenges of marine e-fuels?

    Reaching the required scale of production for e-fuels, however, will take time:

    • E-fuel production Current production processes are at relatively low capacity, due to a lack of renewable electricity generation plants dedicated to producing e-fuels. To build a sufficient number of plants quickly and at a feasible cost, industries will require incentives.
    • E-fuel competition Once e-fuels are scaled up, competition among sectors may keep costs high for some time.

    In this way, e-fuels mimic many of the advantages and challenges of their fossil fuel-based counterparts, including questions of cost, bunkering and infrastructure.

    Bureau Veritas’ services for e-fuels

    Our e-fuel Classification Rules

    Our experts have developed Rules for methanol- and ethanol-fueled ships (NR 670) and tentative Rules for ammonia as fuel (NR 671). The notations METHANOLFUEL-PREPARED and AMMONIAFUEL-PREPARED have been developed to anticipate the further conversion of new ships.

    Supporting e-fuel pioneers

    Bureau Veritas further offers a comprehensive view of the energy production chain for traditional and renewable energies, enabling our experts to assess e-fuel sustainability. We work closely with the oil and gas, chemical, and renewable energy sectors every day, ensuring the quality and origins of all types of e-fuels. An extensive network of laboratories supports our VeriFuel offer, enabling shipowners to evaluate the quality of their marine e-fuels at any time.

    E-fuels FAQs

    • Are e-fuels available now for shipping?

      E-fuels are currently scarce and costly, due to a lack of green hydrogen production facilities and distribution infrastructure. A significant scale-up of green hydrogen would be required to drive down e-fuel costs and increase availability. However, e-fuels like e-methane or e-methanol will be easy for ships to adopt once they become widely available since they are compatible with engines powered by fossil-fuel.

    • E-fuels vs. biofuels; which is better?

      Under ideal conditions, zero-carbon e-fuels would have a sustainability advantage over biofuels, which are carbon-neutral. In the short-term, e-fuels and biofuels both benefit from the ability to use the same infrastructure as their fossil fuel equivalents. In the long-term, however, considerations of safety, storage, availability and price will determine which fuel is most advantageous for different shipowners.

    • Are e-fuels safer than fossil fuels?

      E-fuels require the same safety precautions as their fossil fuel-based counterparts. For example, ammonia and e-ammonia are the same molecule and are both corrosive and toxic at low concentrations. This is the same for hydrogen and e-hydrogen, and both are explosive and flammable. Shipowners using e-fuels will therefore need to comply with the same onboard safety regulations for equipment and crew members.

    • Are e-fuels liquid or gas?

      E-fuels can be produced as either liquid or gas. E-methanol, e-ammonia, and e-LNG are most likely to be transported by ships in liquid form. E-hydrogen and e-methane are typically produced as a gas, but both can be liquefied for marine transportation.