Ethanol, a renewable for the maritime transition?
Ethanol, an alcohol primarily derived from biomass, is chiefly sourced from corn and sugar cane. It bears the chemical formula C2H6O and is primarily utilized as an additive to gasoline. In developed countries, it is a prevalent component in gasoline, not driven by environmental concerns, but by the aim to diminish reliance on foreign oils. It emerged as the most optimal, economically viable, and renewable solution to fulfill this quest for strategic autonomy. Nowadays, it is the leading biofuel in terrestrial transportation. Conversely, the biodiesel mainly used in maritime transport is FAME (Fatty Acid Methyl Ester).
It is most regularly blended with marine diesel (MGO).
In maritime applications, the organic compound, if produced without emitting carbon dioxide, holds the potential to substantially mitigate the industry’s environmental footprint. With its clean combustion and absence of sulfur, it boasts minimal particulate emissions and lower nitrogen oxide levels compared to conventional fuels. The alcohol is currently blended with traditional marine fuels and could even function as a standalone option, providing shipowners with enhanced flexibility. However, its price in the European Continent surpasses that of MGO, standing at $982.5 per cubic meter 1, roughly translating to $1254.8 per metric ton, while MGO costs $891 per metric ton in Northwestern Europe (Rotterdam, 16.08.2023).
One of its key advantages lies in its compatibility with existing vessel engines and infrastructure, requiring minimal modifications. This facilitates its integration without demanding extensive modifications or significant investments. The financial investment associated with retrofitting and new build solutions for both methanol and ethanol is projected to fall within a similar range as the costs of implementing exhaust gas aftertreatment 2 (such as scrubber and selective catalytic reduction (SCR)) for heavy fuel oil utilization. Moreover, these investment costs are anticipated to be lower than the expenditures required for adopting liquefied natural gas (LNG) solutions. The production primarily relies on sustainable biomass sources, agricultural remnants, and dedicated crops. However, careful attention must be paid to land use and energy consumption to prevent exacerbating food scarcity issues. Notably, corn crops intended for consumption could be diverted for fuel production, compounding famine concerns.
The ethyl alcohol has a similar density to MGO at 15°C (789 Kg/M3 vs. 860Kg/M3), but its energy density is less than half of MGO’s (26.8 MJ/Kg vs. around 43 MJ/Kg). The latter translates to the need for approximately double the bunkering for an equivalent voyage. Additionally, its hygroscopic nature, absorbing water from the environment, poses challenges for storage and transportation. Finally, like any other biofuels, the lack of adequate bunkering infrastructure complicates longer voyages.
Despite these many challenges, some major companies got involved in the market. For example, Raizen, a Brazilian joint venture between Shell and Cosan, has pioneered second-generation ethanol (E2G). This innovative variant is generated from sugar cane waste left behind by 1G ethanol (E1G) production, employing enzymatic hydrolysis of pretreated sugarcane bagasse. The stock-listed company has inaugurated an E2G production facility in Brazil, utilizing sugarcane biomass, thus promoting waste reduction and circular economy principles. Although the second-generation production has yet to reach commercial scale, promising prospects are on the horizon. Projections point to its market readiness within the next five years. Encouragingly, all available quantities of this advanced ethanol generation have already been secured through forward agreements, signaling high interest and anticipation.
Forecasts by major industry players suggest marine demand could reach 32 million metric cubic meters annually by 2030. Its emission-reduction potential and compatibility with existing infrastructure position could make it a viable shipping industry solution. Despite the inherent challenge of its low energy density, characteristic of most biofuels, ethanol seems destined to serve as a transitional energy source, progressively increasing its mixture ratio with gasoline. However, the standalone option, compared to methanol or even hydrogen, seems less promising.
1 Reuters – Eurobob-ARA USD/ cbm
2 www.cummins.com/components/aftertreatment/how-it-works
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