Present and future fuels in the shipping industry: Methanol

A shipping vessel at sea
An introduction to methanol and the role it can play in the shipping industry’s shift away from traditional fossil fuels.

Over the past couple of months, we’ve looked at the most common fuels used in the marine industry as it shifts towards a net-zero future. We’ve already looked at the pros and cons of diesel and LNG as more traditional options, but methanol can also play an integral part in the move towards greener shipping. Read on to discover more about what methanol has to offer. 

Methanol is an organic chemical and alcohol, made up of four parts hydrogen, one part oxygen and one part carbon. It can be created from natural gas, biomass or recycled carbon dioxide, and its versatility, abundance and cost-effectiveness make it a possible option when it comes to replacing diesel in the shipping industry.

The benefits of methanol

Methanol is already available today in small quantities based on biological feedstocks as a green fuel. This means that implementation from a well-to-wake perspective can be realised much earlier than other alternative fuels such as ammonia.

As with LNG and the other future fuels we’ll be looking at, one of the main benefits of methanol is the fact it has considerably lower emissions than traditional heavy fuel oil. That includes emissions such as sulfur oxide, nitrogen oxide and particulate matter, making it a suitable option for shipping as the industry works towards IMO 2050. It’s not carbon-free, although it is a lot cleaner than diesel.

Methanol can be used in a variety of engines, including traditional internal combustion engines and fuel cells, with the humble turbocharger continuing to play a supporting role in boosting efficiency, making it a cost-effective choice for ship owners and operators. It is also non-corrosive, reducing the risk of damage to fuel tanks and other ship components over time.

The challenges of using methanol

Although currently available in small quantities, there are challenges to producing methanol on a large scale. Methanol can either be produced from biological sources, which are limited, or using green hydrogen and a large-scale CO2 capture system, which we’re still several years away from realizing. Once the infrastructure is established, however, it’s likely to preserve methanol as a marine fuel of the future.

Energy efficiency also remains a challenge, and just like other alternative fuels, methanol features a lower energy density than diesel. This means more fuel is required to travel the same distance, with greater fuel costs as a result. Lower energy density means that solutions such as methanol, ammonia, LNG and hydrogen require larger fuel tanks than diesel, which reduces cargo space and increases weight.

How methanol compares to other fuels

Compared to LNG, ammonia and hydrogen, methanol delivers the best compromise when it comes to space and complexity of fuel storage and supply. It has a higher volumetric energy density than ammonia and hydrogen, although slightly lower than LNG, but the fact it can be stored at ambient temperatures works in its favor.

It is also more flammable than traditional marine fuels, which increases the risk of fire and explosion on ships. As with LNG, this means that additional safety precautions are required when handling and storing methanol.

Ultimately, the decisive factor for the widespread use of methanol in the shipping industry will depend the ability to produce methanol on a large scale. That means embracing green hydrogen and CO2 capture technologies, which remain an unknown factor in terms of large-scale implementation, energy requirements and costs.

Image credits: Shutterstock / Aun Photographer