Nov-2024

Propelling the maritime industry to sustainability with methanol

Sustainable methanol is emerging as a promising solution towards achieving ambitious emission reduction goals in the maritime industry.

Zinovia Skoufa
Johnson Matthey

Article Summary

The shipping industry is hard to decarbonise, but renewable methanol is emerging as a key option as maritime transport looks to reduce its greenhouse gas (GHG) emissions, transition away from fossil fuels, and make use of renewable feedstocks. Methanol engines are already available and being used on vessels, making this fuel a promising pathway for reducing emissions in maritime transportation today.

The sector is pivotal in the global economy, serving as the backbone of international trade and commerce. With more than 80% of the world’s goods transported by sea, maritime shipping facilitates the movement of raw materials, commodities, and finished products across continents and oceans. By connecting markets and facilitating trade, the industry enables businesses to access diverse markets, source materials globally, and distribute goods efficiently. This interconnectedness fosters economic growth, drives industrial development, and supports job creation worldwide.

Current impact of shipping on global emissions
The shipping industry, while indispensable to global trade, also contributes significantly to GHG emissions and environmental pollution. Accounting for around 2-3% of global emissions, it represents a substantial yet often overlooked source of carbon dioxide (CO2), nitrogen oxides, sulphur oxides, and particulate matter released into the atmosphere.

Despite efforts to improve fuel efficiency and adopt cleaner technologies, the sheer scale of shipping operations means that even incremental reductions in emissions can have a substantial impact. The reliance on heavy fuel oils and the operation of large, often inefficient vessels exacerbate the industry’s environmental footprint.

Increasing awareness of climate change and the urgency to mitigate its effects are putting growing pressure on the shipping industry to adopt more sustainable practices and driving it towards cleaner fuels, energy-efficient technologies, and alternative propulsion systems.

However, decarbonising the shipping industry presents a formidable challenge. One of the primary hurdles is the reliance on fossil fuels, particularly heavy fuel oils, which are deeply ingrained in maritime operations. Moreover, ships’ long lifespans, often spanning decades, complicate the rapid adoption of cleaner technologies. Additionally, the diverse nature of the global fleet, comprising vessels of various sizes, ages, and operational profiles, further complicates decarbonisation efforts.

Regulatory frameworks, while essential for driving industry-wide change, also pose challenges. The IMO GHG Strategy target is to reduce the carbon intensity of shipping, which is calculated based on the CO2 emissions produced per tonne-mile of cargo transported, by at least 20% by 2030 and 70% by 2040 compared to 2008 levels. By, on, or around 2050 the target is net-zero emissions. Achieving these targets requires developing and deploying zero-emission vessels powered by alternative fuels or energy sources.

Methanol and ammonia as alternative fuels
Both methanol and ammonia offer promising pathways towards reducing GHG emissions. Although both have a lower energy density compared to some conventional fuels, they can still provide sufficient energy to power large ships over long distances. This makes them a practical option for long-haul maritime routes. However, ammonia in liquid form needs to be stored in pressurised tanks or at low temperatures, adding complexity to onboard fuel storage and handling systems.

Ammonia has an established global production and distribution infrastructure. It is widely produced and used in industries such as agriculture and chemicals, facilitating its integration into the maritime fuel supply chain. Furthermore, it can be synthesised using renewable energy sources through processes like electrolysis, which produce green hydrogen that is then combined with nitrogen from the air to produce green ammonia. This green ammonia production pathway makes ammonia a sustainable marine fuel option, contributing to a significant reduction in emissions and one that will certainly support the industry in the future.

Methanol, on the other hand, has lower toxicity than ammonia, reducing safety concerns for marine habitats and during handling, storage, and bunkering operations. It also has significant advantage in the short term as methanol engines are already commercially available and in production. Like ammonia, grey methanol is widely produced today and has established infrastructure, making integrating it into existing supply chains and refuelling infrastructure easier. This existing infrastructure reduces the upfront investment required for adoption and facilitates a smoother transition for maritime operators.

Different routes to sustainable methanol
In traditional operations, methanol is primarily derived from synthesis gas sourced from fossil fuels. However, as renewable methanol production expands, it offers a viable solution for the decarbonisation of diverse transportation sectors, including shipping.

Both e-methanol and biomethanol offer renewable and lower carbon intensity pathways to decarbonise shipping. Production relies heavily on the choice of feedstock, each with its own set of advantages and limitations. One common feedstock is biomass (biomethanol), which offers the advantage of being renewable and widely available. However, if not managed properly, the use of biomass can raise concerns about land use competition, food security, water use, and biodiversity loss. The use of municipal solid waste (MSW) or waste biomass feedstocks, such as agricultural waste, mitigates the above concerns.

Using waste biomass feedstocks requires biochemical or thermochemical conversion processes. Biochemical pathways involve microorganisms fermenting organic materials, such as agricultural residues or forestry waste to produce biogas. This biogas, typically a mixture of methane and CO₂, can be reformed to produce syngas that is then converted to methanol. Thermochemical processes, such as gasification, convert biomass into syngas, which is then catalytically converted into methanol.

ohnson Matthey (JM), in partnership with MyRechemical, licences a high feedstock efficiency waste-to-methanol solution (Circular Methanol technology) that integrates waste-to-chemical technology with well-proven methanol synthesis technology and high-performance catalysts. The process uses municipal and industrial waste that cannot be mechanically recycled and chemically recycles it into synthesis gas via a partial oxidation process. The synthesis gas is then purified and conditioned, transformed into methanol, and distilled to the required purity level. Methanol can subsequently be used as a marine fuel or, further, can be converted into other sustainable fuels and chemicals. JM uses its own highly robust methanol synthesis catalyst, offering high stability and methanol productivity.