Capturing the Potential of Green Hydrogen-based eFuels

As countries around the world accelerate efforts to combat climate change, decarbonizing shipping and transport remains a key challenge. This is particularly the case for applications where electrification at scale is not always technically or economically feasible, such as aviation, marine shipping, and long-distance heavy-haul trucking. These sectors combined represent approximately 10% of global CO₂ emissions.

Carbon-neutral eFuels derived from green hydrogen will play an important role in decarbonizing the shipping and transport sectors by reducing their reliance on traditional fossil fuels.

In this article, we look at the potential of hydrogen-based eFuels and discuss how Hitachi Energy is supporting large-scale green hydrogen production with its integrated Grid-to-Stack approach.

How are eFuels produced?

eFuels are primarily synthesized with CO₂ and green hydrogen produced via water electrolysis. The CO₂ can be captured from the atmosphere (i.e., direct air capture) or from a high-concentration industrial source, such as a power plant, that would otherwise release flue gas as a normal part of operation.

Like traditional fossil fuels, eFuels are combusted in engines, which results in the release of CO₂ into the environment. However, because the CO₂ was originally captured from the atmosphere, the net effect is carbon neutral. In other words, the amount of CO₂ emitted during combustion is offset by the amount of CO₂ that was removed for production of the eFuel. This contrasts with fossil fuels, whose carbon content is transferred from the ground to the atmosphere when burned.

Today, there are several proven technologies and processes for producing hydrogen-based eFuels. Some examples include (but are not limited to):

• Fischer-Tropsch (FT) synthesis – FT synthesis is a well-established method for converting a mixture of carbon monoxide (CO) and hydrogen into liquid hydrocarbons. In the context of eFuels, the CO is typically generated from CO₂ via the reverse water-gas shift reaction, using green hydrogen as a reductant. The FT process then catalyzes the hydrogen and CO to form longer-chain hydrocarbons that can be further refined into various types of fuels, including synthetic gasoline, diesel, jet fuel, etc.
• Synthetic methanol production - The production of synthetic methanol (or eMethanol) involves combining hydrogen and CO₂ under pressure at elevated temperatures in the presence of a metal catalyst. The methanol is then separated from water and impurities via distillation. The use of e-methanol is gaining significant traction as a replacement for heavy fuel oil (HFO) in shipping applications. Dozens of methanol ships are in operation globally, with many more under contract to be delivered through the end of the decade.
• Methanation via the Sabatier Reaction – Methanation involves reacting hydrogen with CO₂, typically in the presence of a nickel-based catalyst, to produce synthetic methane (i.e., e-NG).
• Synthetic ammonia production – Synthetic ammonia is the only eFuel that does not require CO₂. It is produced by chemically combining nitrogen (typically derived from air separation) with green hydrogen. Like eMethanol, eAmmonia (i.e., green ammonia) is being considered primarily as a replacement for HFO in marine applications.

Key challenges

Despite the decarbonization potential of eFuels, scaling production faces several challenges. In particular, the energy input required to produce eFuels is much higher than that of fossil fuels. One solution to address this is to make use of renewable overproduction.

According to the International Energy Agency (IEA), achieving a 10% share of eFuels in aviation and shipping could increase renewable electricity demand by roughly 2,000 TWh/yr by 2030. It will require over 400 GW of green hydrogen production capacity, which is significantly higher than the projected output of the entire global electrolyzer project pipeline through the end of the decade¹.

Procuring necessary volumes of low-cost CO₂ for eFuel production at scale is also a challenge. Many remote areas that are ideal for the deployment of wind and solar resources to produce green hydrogen are not co-located with high-concentration industrial CO₂ sources or CO₂ pipelines. While direct air capture is possible and can provide an unlimited source of CO₂ without geographic constraints, the economics of such projects can be difficult to justify.

Electrical power supply solutions for eFuel plants

As a global technology leader, Hitachi Energy is supporting large-scale eFuel projects with electrification and power-to-hydrogen solutions.

One example is our Grid-to-Stack approach, which is a holistic lifecycle solution for connecting green hydrogen plants to the high-voltage grid. Grid-to-Stack covers the complete power supply package of the plant and addresses key challenges that operators face, such as power conversion, reactive power compensation, harmonic filtering, and safety.

Relying on early-stage conceptual and FEED studies, we ensure that the plant’s entire power supply infrastructure is interoperable and optimized -- from the grid connection down to the electrolyzer stack terminals. This allows electrolyzers to operate safely and efficiently under all conditions, while complying with grid code. We also support operations and maintenance with advanced digital solutions and long-term service agreements, enabling our customers to reduce their levelized cost of hydrogen production.

Last year, Hitachi Energy was selected by Arcadia eFuels to carry out an electrical FEED for the world’s first commercial eFuels production facility for sustainable aviation fuels in Denmark.

The scope of work included a detailed study for a solution that will optimize the eFuel facility’s grid connection and design. The contract awarded to Hitachi Energy also includes an option to deliver the electrical system when the FEED is completed, which supports reducing the project’s overall timeline by mitigating long-lead items such as power transformers.

When operational, the plant will use 360 MW of renewable electricity, water, and CO₂ to produce 100 million liters of eFuels per year.

Looking Ahead

Green hydrogen-based eFuels is one of the pathways to indirectly electrify parts of the shipping and transport sectors. While eFuel production costs today are higher than that of traditional fossil fuels, increasing investments in renewable generating and electrolyzer capacity, along with ongoing advancements in production technologies will likely drive economies of scale and expand potential use cases.

Hitachi Energy is supporting the industry with electrification solutions, from early-stage conceptual studies to ensure grid compliance, through to operations and maintenance across the entire project lifecycle.

More information on Hitachi Energy’s hydrogen solutions here.