Ethanol has emerged as a promising candidate for aiding the maritime sector in its efforts toward decarbonisation. The recent introduction of a robust fuel standard and a global emissions pricing mechanism is crucial for the United Nations’ commitment to achieving net-zero emissions in global shipping by around 2050, complemented by interim carbon intensity targets set for 2030 and 2040. However, ship operators looking to transition to sustainably sourced biofuels may experience a gap between rising demand and current supply.
In this context, ethanol, often overlooked, deserves further examination. Ethanol, known chemically as CH₃CH₂OH, is already well-integrated into the automotive fuel sector, where it is commonly blended with gasoline. Many petrol-cap labels indicate ethanol content, with E10 showing up to 10% ethanol and E25 indicating a blend of 25%.
This acceptance signals manufacturers’ confidence in the capability of engines to efficiently operate with higher ethanol ratios to reduce carbon footprints. With these advancements, the maritime industry could similarly benefit from broader ethanol implementation. Produced from renewable resources such as corn, sugarcane, or agricultural waste, ethanol can be classified as both renewable and sustainable.
It burns cleaner than fossil fuels, resulting in reduced emissions of CO2, sulphur oxides, and particulate matter. Notably, existing infrastructure from land-based transport could be adapted for marine applications. Ethanol can also be blended with other fuels, leading to upcoming tests with marine fuels.
However, significant challenges accompany ethanol’s use in the marine sector. Its energy density is 50% lower than that of fossil fuels and around 40% lower than biodiesels, potentially affecting engine performance and range. Additionally, ethanol can be corrosive to certain materials, necessitating specialized equipment and infrastructure.
The required modifications may require additional crew training to ensure safety and effective operation. Operational risks are also pertinent, as ethanol’s low flashpoint increases explosion hazards, and crew members must be trained in handling fire safety and spill response scenarios. While ethanol disperses quickly in water, its biodegradability could lead to harmful hypoxic conditions for marine life.
In summary, despite its limitations, ethanol’s potential as a viable fuel option warrants consideration for the maritime sector as it strives for decarbonisation. As demand for lower carbon fuels heightens, the integration of ethanol into the fuel mix may be essential for achieving the ambitious goals laid out by international maritime authorities.