July 9, 2021
by Erik Johnston, P.Eng.
Marine traffic emits roughly 1,000 million tonnes of CO2e (carbon dioxide equivalent) annually (and growing) – enough to make the industry a top 10 emitter if it were its own nation. The IMO agreed at MEPC 75 to accelerate aspects of its plan to reduce CO2 emissions from the maritime sector, so continuing to burn fossil fuels indefinitely is not an option. But which future fuel is the right choice? That depends on many factors, which are unique to each application, so there is likely no “one-size-fits-all” approach.
Hydrogen and ammonia are both making many headlines as potential carbon free fuels. However, both have their technical challenges to overcome to be suitable for workboats. Methanol, while less in the public eye, shows serious promise as a future fuel, as discussed in the recent DNVGL report “Maritime Forecast to 2050”.
Methanol, a clear, colourless liquid, offers similar emissions reductions as natural gas, and has many benefits over other alternative fuels, including ease of handling, availability (in 100+ ports globally), lower CAPEX, moderate energy density, and low toxicity. Most methanol engines do not need exhaust aftertreatment to satisfy IMO Tier III or EPA Tier 4 emissions limits. Additionally, when green methanol is produced from bio waste or carbon capture, it becomes a carbon neutral fuel, with no modifications to an existing methanol-fueled vessel.
Robert Allan Ltd. is actively building on knowledge gained from using natural gas (methane) as a marine fuel to develop other low flashpoint fueled vessels. In a recently completed project, supported by the Carbon Trust and the Offshore Wind Accelerator, a methanol-fueled wind farm Crew Transfer Vessel (CTV) was proven to be a viable alternative to the diesel-fueled versions in the current fleet. Vessel performance was maintained, with only a modest increase of bunkering frequency to one or two times per week.
Taking lessons learned from the methanol CTV project, Robert Allan Ltd. is now investigating the modifications necessary to operate a tug on methanol. Spoiler alert: the amount of change is less than one might think. Watch the news in late 2021 for details about this exciting new development.