Methanol (Marine Fuel)

Methanol is emerging as one of the leading alternative fuels for a shipping industry under pressure to cut its emissions. It is a simple alcohol that is liquid at ambient temperature and pressure, which gives it a major practical advantage over gaseous fuels such as LNG: it can be stored and handled with equipment much closer to that used for conventional liquid fuels, without the deep refrigeration or high pressure that gases require. Burned in suitably designed engines, methanol produces very little sulphur oxide and particulate matter and lower nitrogen oxides than heavy fuel oil, so it helps ships meet the air-quality rules on sulphur and NOx.

The greater interest in methanol, however, is its potential to reduce carbon emissions. Methanol made from fossil sources still releases carbon dioxide when burned, but methanol produced from renewable feedstocks, so-called green or e-methanol, made from biomass or from captured carbon dioxide combined with hydrogen from renewable electricity — can offer a substantial or near-complete reduction in net carbon emissions over its life cycle. Because a ship built to burn methanol can in principle run on either fossil or renewable methanol, it allows owners to invest in the capability now and switch to lower-carbon supplies as they become available, which is attractive given the long life of a ship.

Adopting methanol involves trade-offs and challenges. It carries less energy per unit volume than conventional fuel oil, so ships need larger tanks for the same range; it is toxic and, being readily miscible with water, demands careful handling and safety precautions; and the availability of green methanol at the scale and price the industry needs is still developing. Even so, a growing number of ships, notably in the container sector, are being ordered or converted with dual-fuel engines able to run on methanol, making it, alongside LNG, ammonia and others, a significant part of the industry's search for the fuels that will power low-carbon shipping.