Bio-methanol

The most sustainable feedstocks for bio-methanol include waste streams of biogenic origin, such as manure, agricultural waste, and food waste. These wastes can be converted into biogas, which can be further upgraded to bio-methanol. Additional feedstocks for bio-methanol are woody biomass and recycled carbon, which can be converted to syngas via gasification. Hybrid processes obtained by adding hydrogen to biogas and syngas are also possible and can increase bio-methanol production from biomass. The latter processes require hydrogen as an additional feedstock, which brings additional challenges.

Manufacturing biogas from waste improves waste management practices and avoids methane emissions from spontaneous rotting of waste. However, not all regulatory frameworks allow for the accounting of carbon credits for improved waste management. The ability to account for such credits could boost the biogas industry further.

According to recent estimates, the total feedstock potential for bio-methanol is abundant but also challenged by high demand across multiple industries. At the same time, existing biomass management practices are costly and do not support large-scale collection of suitable waste streams.

Methanol synthesis technology is mature. The two main routes from biomass feedstock to bio-methanol are:

1. converting/upgrading biogas or bio-methane into bio-methanol, with or without the help of hydrogen; or
2. gasification of woody biomass or recycled carbon to provide syngas for subsequent conventional methanol synthesis.

The technology for the first route is mature and commercially available. Furthermore, biogas/bio-methane is an attractive feedstock for decarbonization purposes. Processing certain biomass waste streams into biogas can significantly reduce methane emissions associated with poor waste management, thus enabling carbon credits and potentially allowing the bio-methanol to achieve a negative greenhouse gas emissions intensity (see also fuel production tile for bio-methane). The production of bio-methanol using bio-methane as feedstock requires special attention to the control of methane slip and leakages during production to ensure a positive climate impact.

Biogas is often produced in small plants, which makes stand-alone conversion into bio-methanol production unattractive due to methanol manufacturing’s pronounced economy of scale. An established strategy to aggregate bio-methane is to use the natural gas network and to trade green guarantees of origin. This practice, however, is not allowed everywhere, limiting its attractiveness outside of specific contexts such as FuelEU compliance.

Moving to the second production route, gasification technology has been demonstrated in numerous boilers worldwide for combined heat and power generation. However, biomass gasification for syngas production and chemical synthesis has shown challenges: particularly gas conditioning and biomass feeding, which have proven difficult technological areas. Solutions seem to be available but may make the overall pathway expensive.

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 potential 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 bio-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, bio-methanol can achieve close to net-zero well-to-wake CO₂ emissions. This is because the CO₂ released during bio-methanol combustion is balanced by the CO₂ originally stored in the biomass from which the fuel is derived.

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 bio-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, production standards, 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 bio-methanol. With that said, some aspects relating to the certification of bio-methanol remain to be resolved – particularly concerning fuel produced through gas grid mass balancing. Currently, if bio-methanol is made using methane from the natural gas grid with green attributes purchased from bio-methane produced outside the EU, it does not qualify as compliant for the FuelEU Maritime or EU ETS regulations. Adjusting these certification rules to recognize non-EU-sourced bio-methane could improve the supply of bio-methanol available for the shipping industry and encourage increased production, supporting a faster transition to low-carbon fuels.

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. This task may be complex, as bio-methanol’s characteristics can vary based on the feedstock and production methods used.