NorthStandard Loss Prevention Director Decarbonisation, Mark Smith, explores the maritime case for a sustainable biofuel that is widely used as an automotive fuel additive.

In October, the International Maritime Organization is set to adopt a legally binding framework to reduce greenhouse gas  emissions from ships over 5,000 GT, pending entry into force in 2027.

Including a new fuel standard and a global pricing mechanism for emissions, the framework is highly significant for the UN agency’s targets for global shipping to achieve net-zero emissions close to 2050, and interim carbon intensity targets for 2030 and 2040.

In the immediate term, however, ship operators looking to decarbonise by using sustainably sourced biofuels or similar alternatives could find that growing demand may outpace current supply. Ethanol, a sometimes overlooked-alternative fuel type, may therefore merit further consideration as the shipping industry  seeks additional options.

Ethanol is already an established ingredient in automotive industry fuels. Forecourt pumps and fuel filling caps on many petrol engine cars now display E5 or E10 notation to indicate ethanol content of up to 10% (E10).  New cars even have E25 on their petrol caps.  Evidently car makers are confident engines can cope with up to 25% (E25) ethanol content to create a lower carbon footprint.

Given these developments, it is worth considering the potential for ethanol to play a larger role in the maritime industry.

Ethanol (CH₃CH₂OH), also known as ethyl alcohol, is a colourless, volatile and flammable organic compound commonly used as a fuel, solvent and in alcoholic beverages. It is also used as a biofuel (bioethanol) when made from renewable resources like corn, sugarcane, or agricultural waste.  It is mostly produced by fermenting sugars derived from such crops, where yeast converts the sugars into ethanol and carbon dioxide. In principle, the carbon dioxide emitted when bioethanol is burnt is offset by the carbon absorbed in growing the plants.

NorthStandard expects to see an increase in the use of ethanol in the marine industry as demand increases for lower carbon fuels to meet FuelEU Maritime requirements and IMOs legally binding framework.

Unlike some biofuels, bioethanol can be considered both renewable and sustainable as it is sourced from widely available crops.  It burns cleaner than fossil fuels, thereby reducing CO2 emissions as well as SOx and particulate (PM) emissions. Lower GHG emissions are particularly the case when it is made from renewable sources including biomass and waste.

In addition, there is already available infrastructure for use – as ethanol is widely used in land-based transportation. Some fuelling and storage facilities could be adapted for marine use.

As in the automotive industry, ethanol can be blended with other fuels and blending with marine fuels is set to be tested shortly.

However, there are acknowledged challenges when it comes to its use in the marine sector.  As is the case with most alternative fuels, ethanol has a 50% lower energy density than fossil fuels. Its energy density is also about 40% lower than biodiesels which could have an impact on engine performance and reduce operational range as vessels may not be able to carry enough fuel without higher volume tanks.

Any lower range would likely require consideration in time charter party terms including speed and performance warranties.

Ethanol is also hygroscopic and can corrode tanks, engines, and pipelines not specifically designed for its use. Purification plants, filtration and transfer systems also need to be specifically designed to handle ethanol.

Biodiesels are more compatible with existing ship’s engine types (as “drop-in fuels”), but ethanol may require purpose built or modified ethanol-specific engines as a result. Operating these engines when built may also be a learning curve.

Crew training and safety have also to be considered.

Ethanol has a low flashpoint fuel (13-15 °C), and vapours can accumulate, increasing explosion risk if there is improper ventilation.

The fuel also creates toxicity and health risks which require scenario-based training, including vapour leakage and emergency response. Ethanol fires also develop differently to hydrocarbon fires and require specialised firefighting equipment, procedures and personal protective equipment.

Pollution and spill behaviour are also factors.

Ethanol is water-soluble and disperses quickly in the marine environment but, unlike oil, it does not form a surface slick, making physical recovery challenging. It is biodegradable, but rapid breakdown can deplete oxygen in the water leading to hypoxic (low oxygen) conditions that are harmful to marine life.

The IMO and other maritime bodies are still developing guidelines for the regulation of alternative fuels such as ethanol and further clarity will be essential to encourage investment and its adoption as part of the IMO’s Zero or Net Zero (ZNZ) emissions technology strategy.

While  ethanol may not be a perfect alternative fuel to help decarbonise shipping, short supplies of biodiesel to meet the demand created by FuelEU Maritime and the IMO ZNZ strategy suggest it can be part of the mix.

In summary, as biofuels continue to find a place in maritime decarbonisation, ethanol is a viable option worth considering for open-minded ship operators.