Blog | Green hydrogen-based e-fuels | Hitachi Energy

As countries around the world accelerate their efforts to combat climate change, decarbonizing shipping and transport remains a key challenge. This is particularly the case for applications where large-scale electrification is not always technically or economically feasible, such as aviation, maritime shipping and long-haul trucking. Together, these sectors account for approximately 10% of global CO2 emissions₂ emissions.

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

In this article, we look at the potential of hydrogen-based e-fuels and discuss how Hitachi Energy is enabling large-scale green hydrogen production through an integrated Grid-to-Stack approach.

How are e-fuels produced?

e-fuels are synthesized mainly from CO₂ and green hydrogen produced by water electrolysis. WHAT₂ 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 exhaust gases as part of normal operation.

Like traditional fossil fuels, e-fuels are burned in engines, producing CO emissions₂ to the environment. However, because CO₂ was originally captured from the atmosphere, the net effect is carbon neutral. In other words, the amount of CO₂ emitted during combustion is compensated by the amount of CO₂ which was removed for eFuel production. This is in contrast to fossil fuels, whose carbon content is transferred from the ground to the atmosphere when burned.

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

• Fischer-Tropsch synthesis (FT) – FT synthesis is a well-known method for converting a mixture of carbon monoxide (CO) and hydrogen into liquid hydrocarbons. In the context of e-fuels, CO is usually produced from CO₂ through the reverse reaction of converting water into gas, using green hydrogen as a reducing agent. The FT process then catalyzes hydrogen and CO to create longer chain hydrocarbons that can be further refined into a variety of fuels including synthetic gasoline, diesel, jet fuel, etc.
• Production of synthetic methanol – 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 the water and impurities by distillation. The use of e-methanol is gaining popularity as a replacement for heavy fuel oil (HFO) in maritime transport. Dozens of methanol vessels are in operation around the world, with many more expected to be delivered by the end of the decade.
• Methanation via Sabatier reaction – Methanation involves the reaction of hydrogen with CO₂usually in the presence of a nickel-based catalyst to produce synthetic methane (i.e. e-NG).
• Production of synthetic ammonia – Synthetic ammonia is the only e-fuel that does not require CO₂. It is produced by chemically combining nitrogen (usually obtained from air separation) with green hydrogen. Like eMethanol, eAmmonia (i.e. green ammonia) is primarily being considered as a replacement for HFO in marine applications.

Key challenges

Despite the decarbonization potential of e-fuels, scaling production faces several challenges. In particular, the energy input required to produce e-fuels is much higher than that of fossil fuels. One solution to this problem is to use excess production from renewable sources.

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

Purchase of necessary quantities of cheap CO₂ producing e-fuels on a large scale is also a challenge. Many remote areas that are ideally suited to harnessing wind and solar resources to produce green hydrogen are not located near high-concentration industrial CO₂ sources or CO₂ pipelines. Although direct air capture is possible and can provide an unlimited source of CO₂ without geographic constraints, it can be difficult to justify the economics of such projects.

Electrical power solutions for eFuel power plants

As a global leader in sustainable energy technologies, Hitachi Energy enables large-scale eFuel projects through innovative electrification and energy-to-hydrogen solutions.

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

Based on early conceptual work and FEED research, we ensure that the entire plant power infrastructure is interoperable and optimized – from grid connection to electrolyzer stack terminals. This allows electrolyzers to operate safely and efficiently in all conditions while maintaining compliance with network regulations. We also support operations and maintenance with advanced digital solutions and long-term service contracts, enabling our customers to reduce their average costs of hydrogen production.

Last year, Arcadia eFuels selected Hitachi Energy to provide electrical power for the world’s first commercial eFuels plant for sustainable aviation fuels in Denmark.

The scope of work included detailed development of a solution that will optimize the connection and construction of the eFuel facility to the network. The contract awarded to Hitachi Energy also includes the option to deliver the electrical system upon completion of the FEED project, which reduces the overall project schedule by reducing long lead time items such as power transformers.

Once operational, the plant will consume 360 ​​MW of renewable electricity, water and CO2₂ to produce 100 million liters of e-fuels per year.

Looking to the future

Ecological hydrogen-based e-fuels are a viable path to the indirect electrification of some of the shipping and transport sectors. Although eFuel production costs are currently higher than traditional fossil fuels, increasing investment in renewable energy generation and electrolyzer capacity, along with continued advances in production technologies, will likely provide economies of scale and expand potential applications. The incentives provided by green regulations (i.e. IRA in the US, Fit for 55 and the REPowerEU Plan in the EU, etc.) combined with stricter emissions requirements for combustion engines will further accelerate their adoption.

Hitachi Energy is committed to supporting the eFuel industry and the green hydrogen economy with integrated solutions that enable plants to operate safely and efficiently. From early conceptual studies to ensure network compatibility through operations and maintenance, we can serve as your trusted technology partner throughout the entire project lifecycle.

More information about Hitachi Energy’s hydrogen solutions can be found here.