IS METHANOL THE SUPERIOR CHOICE IN GREEN SHIPPING FUELS?

With the maritime industry producing 3% of all global greenhouse gas (GHG) emissions¹ and International Maritime Organisation (IMO) setting a shipping emission reduction target of 70% by 2050, methanol is emerging as a promising green alternative fuel.

As per experts, its versatility, coupled with advancements in how we handle methanol storage and transportation, places it in a unique position to become the mainstream renewable fuel across the international shipping industry.

However, methanol isn’t the only low-emission fuel option. Alternatives like ammonia and, to a lesser extent, hydrogen are also being explored as potential pathways to decarbonising the shipping sector.

Methanol – the Fuel of the Future

The advantages methanol offers as an alternative, low-carbon fuel type are clear. Shipping companies are already adopting it, with over 20 dual-fuel methanol tankers in operation.

Additionally, compliance with the IMO’s Interim Guidelines for The Safety of Ships Using Methyl/Ethyl Alcohol As Fuel (MSC.1/Circ.1621) ensures that safe practices to handle methanol are in place, paving the way for more methanol-powered vessels to sail the open seas.

But what makes methanol stand out compared to other low-emission fuels? And are there any challenges, such as specific methanol storage rules, that shipping companies need to address?

 

Protects the planet and people

Methanol is a biodegradable fuel that poses fewer climate and environmental risks compared to traditional fuels.
Unlike diesel and gasoline, pure methanol combustion emits no sulphur oxides, reduces nitrogen oxides (NOx) by up to 60% depending on the engine, and produces minimal particulate matter and CO2². Additionally, injecting water into the combustion chamber can further lower NOx emissions further by lowering peak combustion temperatures and diluting oxygen.

Methanol’s storage and handling also provide environmental advantages. It is biodegradable and dissolvable in water, with a half-life of just 1-7 days, which significantly reduces the risk of environmental pollution in the event of a spill³. By contrast, ammonia has drawbacks. Despite its lower CO2 emissions, ammonia generates high nitrous oxide outputs upon combustion, resulting in high greenhouse gas emissions⁴.

Above all, ammonia is highly toxic and potentially deadly to humans. Incorrect handling and leakage incidents can endanger the crew as even air concentrations of 30 parts per million (ppm) can cause respiratory problems in a short amount of time. Significantly higher concentrations can cause irreversible damage or death⁵.

 

Proper Methanol Storage and Handling is Crucial

Methanol is extremely flammable. It has a low flashpoint of roughly 9-10°C, making it highly ignitable and susceptible to spark or flame-related explosion incidences⁶. Its high vapor pressure, around 13 kPa at 25°C, also increases the risk of evaporation and flammable vapor buildup at room temperature. By comparison, ammonia is non-flammable but can ignite at temperatures exceeding 600°C or in the presence of other substances.

Given these risks, it is crucial to ensure correct practices to handle methanol during storage and transportation. This includes proper ventilation, advanced valve systems, and compliance with IMO guidelines for safe storage. The same precautions apply to alternative fuels like ammonia and hydrogen.

By adhering to the proper methanol storage tank requirements, vessel owners can virtually eliminate risks of casualties or accidents on board.
But what are the costs of preparing a ship for methanol use?

 

Cost Considerations – Retrofitting for Methanol Storage

Nearly half of all operational vessels must be retrofit for methanol and other zero-emission fuel use to achieve complete shipping decarbonisation by 2050. And considering there are other carbon reduction targets before 2050 and a typical vessel’s lifespan is 25 years, widescale retrofitting needs to start as soon as possible⁷.

But transitioning from high-emission fuels to low-emission methanol comes with some additional costs.

According to a recent report, the upfront cost of converting a high-emission fuel oil vessel to a methanol-enabled one is roughly 10-16% the cost of a newbuild tanker, amounting to USD 15-24 million depending on the preparation level. Comparatively, retrofitting vessels for ammonia is 19-26% (USD 47.5-65 million)⁸.

 

Choosing the Right Safety Valves for Methanol Storage

Installing the right safety valves offers long-term protection for shipowners, their crew and their vessel, including their methanol storage systems.
But it all comes down to which valve solution they choose. Choosing the correct valve solution and maintaining compliance with the IMO’s MSC.1/Circ.1621 rules for valve specifications on methanol ships are key to safe operations.

Many inline pressure-vacuum (P/V) valves cannot prevent the passage of flames or function effectively without a flame arrester, posing a risk of toxic methanol fume leakage into storage or living areas and potentially endangering the crew.

Our end-of-line high-velocity valves combine pressure-vacuum release devices and flame arresters into a single solution. They are designed to disperse toxic methanol fumes upwards, away from the vessel, preventing obstructions or leaks into storage or living areas.

Each valve outlet functions at least three metres above-deck, six metres above a gangway and ten metres away from living areas, ignition sources and other openings in accordance with MSC.1/Circ.677. This design minimises the risk of dangerous methanol leakage and explosion-related incidences.

What’s more – our valves are a cost-effective solution as they have undergone endurance burn testing and are certified to meet IMO MSC/Circ.677 standards, as well as amendments outlined in MSC.1/Circ.1324 and MSC/Circ.1009.

 

Adopting Methanol as a Green Fuel

Methanol is gradually emerging as the leading fuel option for shipping and marine companies compared to other low-emission fuels like ammonia and hydrogen, thanks to its minimal carbon output, reduced environmental pollution and lower upfront retrofitting costs compared to ammonia.

Limited technological advancements and the lack of comprehensive IMO guidelines for ammonia further position methanol as the preferred choice for shipowners.

However, we should keep in mind that strict measures that need to be in place for methanol storage and handling due to its high flammability. Proper ventilation and advanced valve systems are key to minimising risks and ensuring safe operations.

 

¹ https://ec.europa.eu/research-and-innovation/en/horizon-magazine/emissions-free-sailing-full-steam-ahead-ocean-going-shipping

² https://www.methanol.org/wp-content/uploads/2020/04/IMO-Methanol-Marine-Fuel-21.01.2016.pdf

³ https://www.methanol.org/wp-content/uploads/2016/06/White-Paper-The-Fate-Transport-of-Methanol-in-the-Environment-1999.pdf

⁴ https://www.sciencedirect.com/science/article/pii/S1743967122002069

⁵ https://www.ncbi.nlm.nih.gov/books/NBK207883/

⁶ https://www.icheme.org/media/9915/xviii-paper-32.pdf

7 https://www.globalmaritimeforum.org/content/2022/03/Insight-brief_Retrofitting-ship-engines.pdf

⁸ https://cms.zerocarbonshipping.com/media/uploads/publications/Preparing-Container-Vessels-for-Conversion-to-Green-Fuels.pdf