e-methanol

The main feedstocks for producing e-methanol are low-emissions electricity, water, and renewably sourced CO₂, i.e. biogenic CO₂ or CO₂ removal solutions such as direct air capture (DAC) or direct ocean capture (DOC). Renewably sourced CO₂ is combined with hydrogen (separated from water using electrolysis powered by low-emissions electricity) to produce e-methanol.

Mature low-emissions electricity generation technologies like solar, wind, and hydro are commercially available, but large-scale build-out is needed to support e-methanol production. The potential use of nuclear power for e-methanol production remains uncertain and an area for further exploration. Scaling up low-emissions electricity generation is one of the main feedstock challenges for e-methanol production.

While water is globally plentiful, accessible fresh water makes up just under 1% of the planet’s water. Of the remaining water, almost 99% is seawater, which is accessible and can be purified by desalination – but the briny discharge requires sustainable disposal.

Renewable CO₂ can be waste CO₂ released by combustion or decomposition of biomass and its derivatives. Point sources of renewable CO₂ are too limited to provide for full maritime decarbonization, but global volumes should be sufficient in the near term to supply e-fuels for a small fraction of the world fleet. However, access to this CO₂ is challenged by competition from other uses, such as permanent sequestration. Carbon removal solutions such as DAC and DOC are very costly due to low efficiencies of selecting ppm-level concentrations of CO₂ in air and dilute concentrations in the ocean, respectively.

The key challenges in the production of e-methanol therefore remain the availability of renewably sourced CO₂ and the build-out of low-emissions electricity generation at scale.

E-methanol is produced by combining renewably sourced CO₂ with hydrogen that has been separated from water using electrolysis powered by low-emissions electricity. The production of methanol through low-emissions electricity for hydrogen synthesis is relatively new, largely due to the recent adoption of electrolysis.

The electrolyzer stack is the core technology needed to split water into oxygen and hydrogen. Global electrolyzer production today is challenged by a scarcity of raw materials, the low stack manufacturing technology maturity and capacity, and the need to produce replacement stacks (current stacks have an average lifespan of 3-12 years).

Additionally, substantial infrastructure for dedicated low-emissions electricity is required to generate hydrogen via electrolysis at an industrial scale. However, the build-out of low-emissions electricity is constrained by issues like the expansion of electricity grids, availability of raw materials such as copper, and competition from other sectors.

Efficient e-methanol synthesis requires a certain scale, which in turn requires large quantities of renewably sourced CO₂ (see also feedstock availability tile for e-methanol) at a centralized location. Such CO₂ sources typically come from industrial waste streams like flue gas. The industrial plants that produce these waste streams are often located where it is not possible to build adjacent CO₂ capture and e-methanol production infrastructure. As a result, transportation of CO₂ feedstock from its source to a methanol production facility presents logistical challenges, which can increase the well-to-wake environmental impact of the resulting fuel.

Therefore, the primary challenges in the advancement of e-methanol synthesis lie in expanding low-emissions electricity infrastructure, securing renewable CO₂ for e-fuel production, and increasing the manufacturing capacity of electrolyzer stacks.

Methanol is an emerging maritime fuel, with the number of dual-fuel vessels capable of operating on methanol reaching double digits as of 2024. The associated infrastructure for methanol transportation, storage, and bunkering is also available in some locations. The next step is to scale up infrastructure to make methanol more available as a maritime fuel.

Methanol is a liquid at ambient temperature and pressure, making it a favorable marine fuel in terms of storage and handling. Dual-fuel two- and four-stroke methanol engines are commercially available and operational. The industry has also gained operational experience of these engines on board different ship types in the past decade. Methanol dual-fuel engines are now being developed and commercialized for a wide range of vessels.

In 2023 Maersk launched the first methanol dual-fuel container vessel, Laura Maersk, which has undertaken several voyages on green methanol. By 2024, over 100 dual-fuel methanol new builds have been contracted with yards, and many projects for methanol dual-fuel retrofits have been announced.

In the future, fuel cells may offer another possible fuel conversion solution for shipping. Proton-exchange membrane (PEM) fuel cells can run on hydrogen obtained by reforming methanol, which could be an initial option for auxiliary onboard power. Solid oxide fuel cells (SOFC) can run on methanol – perhaps with pre-reforming – but SOFC are significantly less mature than PEM. Boilers using methanol as fuel are in the final stage of development.

Through experience with e.g. container carriers, passenger ferries, and chemical tankers operating on methanol as a marine fuel, the safe handling of methanol as a low-flashpoint maritime fuel is a demonstrated and established practice. No significant barriers regarding onboard fuel safety and operations are present.

Prescriptive rules for methanol as a fuel (International Maritime Organization interim guidelines for methanol) are underway (see also regulation and certification tile for e-methanol).

Dual-fuel engines fueled by methanol are already in operation, and no significant obstacles regarding engine emissions (including nitrogen oxides,NO_x, sulfur oxides, SO_X, and particulate matter, PM) remain. Onboard NO_x emissions reduction in accordance with current regulations can be achieved using existing technologies.

While methanol combustion releases CO₂, e-methanol produced with renewably sourced carbon can achieve close to net-zero well-to-wake CO₂ emissions. This is because the CO₂ released during e-methanol combustion is balanced by the CO₂ used as a feedstock to produce the e-methanol.

A detailed methanol fuel quality specification has not yet been implemented by the International Maritime Organization (IMO). However, guidelines for methanol as a fuel are available, and in 2025 the IMO will initiate work on including these in the text of mandatory regulations such as the International Code of Safety for Ships Using Gases or Other Low-flashpoint Fuels (IGF Code) and the International Convention for the Safety of Life at Sea (SOLAS). With methanol-fueled vessels now sailing globally, increasing industry experience with this fuel should allow a timely inclusion of methanol in mandatory text.

At the same time, the IMO is advancing its development of well-to-wake-based regulations to promote the use of sustainable fuels, including e-methanol. Regulating the climate impact of fuel use from a life-cycle (well-to-wake) perspective offers the industry the opportunity to establish sustainable fuel production and consumption patterns. Such regulation can help mitigate the risk of shifting climate impact from the downstream (tank-to-wake) segment of the value chain to the upstream (well-to-tank). This is a crucial consideration for alternative marine fuels, as a significant portion of their climate impact is associated with upstream activities (see also tiles for feedstock availability and fuel production). However, many elements of these regulations remain to be discussed and finalized, including certification, sustainability criteria, rules for electricity production, and implementation in the IMO mid-term measures.

The European Union (EU) has made progress with the introduction of the EU Emissions Trading Scheme (ETS) and the FuelEU Maritime regulation, which may promote the uptake of e-methanol. With that said, some aspects relating to the certification of e-methanol remain to be resolved.

The International Organization for Standardization (ISO) has also progressed in developing standards for methanol. However, some issues with physical properties and engine compatibility persist. In addition, fuel quality standards and their associated certification procedures need to be further developed.