This section relates to the relevant consideration for the early adaption of Bio-methanol as an alternative fuel.
Sustainable feedstock for bio-methanol are waste streams of a biogenic origin such as manure, agricultural waste and food waste, which can be converted into bio-methane and further upgraded to bio-methanol. According to current estimates, total feedstock potential for bio-methane is abundant, but it is challenged by high demand across multiple industries. At the same time, existing infrastructure, established practices, and current regulatory framework do not support large-scale collection of the suitable waste streams.
Another feedstock for bio-methanol is woody biomass, which can be converted to a syngas via gasification.
Methanol synthesis technology is very mature, but currently based solely on fossil feedstocks. The two main routes from biofuel feedstock to bio-methanol are 1) by converting/upgrading a biogas mixture into bio-methanol with the help of green hydrogen using commercially available technology or 2) gasification of woody biomass to provide synthesis gas for subsequent, conventional methanol synthesis. Gasification technology is at an early stage, with several demonstration plants worldwide.
For the bio-methane pathway, special attention must be given to controlling methane slips and leakages to ensure a climate-positive impact.
Notice that processing certain biomass waste streams into biogas reduces methane emissions associated to incorrect waste management. In effect, this could make bio-methane based bio-methanol a biofuel with negative GHG emission intensity.
In the near-future, main scaling bottleneck for bio-methanol is the capacity for constructing new bio-methanol production facilities.
As a chemical, methanol is transported globally today (more than 10 million ton/year), and a mature infrastructure exists along with guidelines for bunkering. However, port infrastructure including terminals and bunkering facilities will have to be significantly expanded to meet the increased capacity requirements of potentially hundreds of millions of tons maritime fuel per year. Standards and safety requirements do not represent any new major challenges.
Methanol is liquid at ambient temperature and pressure, making it a favorable marine fuel in terms of storage and handling.
Dual-fuel two-stroke and four-stroke methanol engines are commercially available, and operational experience as marine engine has been obtained in the past decade onboard different ship types. Methanol engines are being developed and commercialized for wider size ranges and are not expected to be size restricted. PEM fuel cells may run on hydrogen from reforming of methanol, and this could be an initial option for auxiliary power. Solid Oxide Fuel Cells (SOFC) may run on methanol – perhaps with pre-reforming - but SOFCs are significantly less mature. Boilers using methanol as a fuel are in the final stage of development.
Through chemical tankers operating on methanol as a fuel, the safe handling of methanol as a low flash-point fuel on vessels is an established practice. No expected obstacles regarding onboard fuel safety and operations are present.
Dual-fuel engines fueled by methanol are in operation and no significant obstacles regarding engine emissions (NOx, SOX, and PM) remain. Onboard NOX emission reduction using known technologies is needed for regulatory compliance. Bio-methanol combustion releases the same amount of CO2 as was captured and stored in the origin biomass, effectively making bio-methanol a CO2-neutral biofuel in a well-to-wake perspective.
A necessity for large scale deployment of bio-methanol as a maritime fuel is a full implementation of the detailed methanol fuel quality specification under International Maritime Organization (IMO). For this, a life-cycle assessment and policy need to be developed, together with certification of CO2 point sources that can be considered renewable.
Life cycle assessment policy needs to be developed. Regulating the climate impact of fuel use from a life cycle perspective offers the industry the opportunity to establish sustainable fuel production and consumption patterns. By regulating the upstream (well-to-tank) climate impact, fuel users can select fuels with solid sustainability credentials. Regulation from a life cycle perspective also reduces the risk of burden shift of climate impact from the downstream (tank-to-wake) part of the value chain to the upstream. This is an important consideration for alternative marine fuels whereby much of the climate impact resides in well-to-tank activities.
Well-to-wake greenhouse gas quantification for bio-methanol has not yet developed in key regulatory bodies such as the European Union (EU) or IMO. However, the use of methanol as a fuel has been approved by IMO with issuance of Interim Guidelines and rules will soon be integrated into the IGF code where low-flashpoint fuel rules are placed.
Methanol as a marine fuel: Prospects for the shipping industry - Documentation of assumptions for NavigaTE 1.0 (2021)