Ammonia and Methanol as Sustainable Alternatives to Traditional Fuels
The shipping industry needs to reduce carbon emissions so that temperature increases are kept below 1.5 °C. Using alternative fuels can help reduce pollution and keep temperatures below the threshold. This means halving carbon emissions by 2030 and achieving zero emission targets by 2050. At present, the shipping industry accounts for about 3 percent of carbon emissions globally. If it were a state, this would make it the world’s sixth biggest polluting country. So, if we are aiming to reach emission targets over the next decades, carriers need to adopt greener fuels produced from renewable sources. There are several alternatives for carriers to adopt, including ammonia and methanol.
Ammonia, which releases no carbon dioxide when burned, is a compound of hydrogen and nitrogen. It is considered one of the best options for international journeys over long distances, especially for container ships. What is more, ships can carry more fuel onboard compared to hydrogen.
While it is already used in agriculture as a fertilizer, production requires energy-intensive technologies that generate significant amounts of carbon dioxide. It also generates poisonous gasses (nitrogen oxide), and vessels using ammonia need to be equipped with a selective catalytic reduction system. SCRs are used to convert emissions into nitrogen and water vapor, thus reducing the level of nitrogen oxide.
Also, ammonia is highly toxic compared to other fuels, and the shipping industry needs to adopt strict safeguarding protocols to ensure safety and environmental protection.
Methanol is an alternative to polluting diesel which can be produced from biofuels and renewable energy. According to experts, the cost of retrofitting commercial ships and building new ones is lower compared to other fuels. A further benefit is that it doesn’t have to be stored at extreme temperatures or under pressure. Methanol is safer and easier to store and can help carriers reach carbon targets.
Some carriers are already investing into using ammonia and methanol because there are no better alternatives for sea freight in Europe. Dual-fuel engines that use traditional fuels and methanol are favored by carriers, however, because methanol cannot be produced at scale at present. There are 55 dual-fuel engines currently on order and in operation, and all the major engine manufacturers have introduced methanol in their product lines. The immediate benefits are reducing nitrogen oxide by 80 percent, particulate matter by 95 percent, and sulfur dioxide by 99 percent.
According to experts, ammonia will also have a major role to play, provided that safety risks can be mitigated. A recent report highlights the fact that ammonia and methanol are best suited for long-haul journeys when used in the form of e-fuels and advanced biofuels. E-methanol and bio-methanol not only help reduce carbon emissions but require no or little engine upgrading. E-methanol is favored by freight forwarders but there are some challenges to large-scale production, including the cost and availability of captured carbon.