Green fuel for climate-neutral shipping
Methanol (Chem. CH3OH or MeOH) occurs naturally in fruits, vegetables, fermented food, beverages, the atmosphere, and even in space. It is one of the four critical, basic chemicals (alongside ethylene, propylene, and ammonia) and is used to produce many other chemical products such as formaldehyde, acetic acid, and plastics. MeOH is also used for gasoline blending (where it has been used as an oxygenated, anti-knock fuel additive and octane booster) and in the production of biodiesel and DME (dimethyl ether).
What characteristics does methanol have as a fuel?
Methanol is a colorless, water-soluble liquid with a mild alcoholic odor and with the highest hydrogen-to-carbon ratio of any liquid fuel at regular ambient conditions. As a result, it can act as a key energy carrier and be employed as an alternative fuel. Like ammonia, methanol is a low-viscosity fuel with (a) a low calorific value (at 40% that of diesel) meaning that more fuel is needed for the same power output and (b) poor ignitability, meaning that diesel pilot-fuel is required for stable engine operation.
Methanol can be used in both Diesel and Otto combustion cycles and its efficiency is similar to the fuels that are used in current dual-fuel (DF) engines. Its inherent stability allows it to be stored at room temperature and ambient pressure – which gives it an indefinite shelf life – meaning that it comes very close to fulfilling the requirements for a drop-in fuel compatible with existing infrastructure. However, the fuel has its downsides, including its toxicity and the resultant need for complex safety systems, as well as its corrosive quality.
What potential has methanol within shipping?
Methanol’s popularity as a clean-burning, low-carbon fuel is growing and methanol-fueled engines are already in use today. Its primary attraction as a shipping fuel lies in its ability to be stored as a liquid at ambient temperatures and pressures, and its favorable energy-density. While methanol’s production as a green fuel is a complex process, its handling costs are low, reducing the complexity of storage and bunkering infrastructure in port. As a cargo, methanol is already present in many seaports around the world and safe procedures already exist for its handling as both cargo and fuel.
In the main, methanol is still conventionally produced. Methanol production in 2020 stood at roughly 100 million tons per year with actual capacity 50% higher, according to the Methanol Institute. Of this, just 0.2% (200,000 tons) is produced from sustainable
sources, meaning that green, blue, and hybrid methanol production is still in their infancy. To advance the Maritime Energy Transition, the gradual development of climate-neutral methanol production from renewable green hydrogen and captured carbon
must progress.
We strongly believe in the two-stroke dual-fuel methanol engine, which has already performed well at sea for over four years.
What are the prospects for green methanol?
The first steps in using green methanol as a shipping fuel have already been taken. Shipping giant, A.P. Møller-Maersk, has announced plans to off-take green methanol from a dedicated plant in Denmark for its first carbon-neutral vessel – a 2,100 TEU feeder. Furthermore, the company has ordered eight methanol-burning MAN ME-LGIM engines in connection with the building of eight 16,200 TEU container ships. The new ships will be capable of running on green methanol and have the potential to save the company around 1 million tons of carbon emissions per year.
Additionally, this engine technology has already been proven: MAN Energy Solutions has sold some 40 two-stroke, methanol-burning ME-LGIM engines since 2016. Indeed, those engines already in service have accumulated more than 120,000 running hours on methanol alone.