Ethanol is back on the maritime fuel shortlist as a candidate pathway to lower shipping emissions, gCaptain reported this week, adding a biofuel alternative to the methanol, ammonia and LNG options that have dominated recent newbuild orderbooks.

The renewed attention comes as carriers, charterers and engine manufacturers face tightening pressure from regulators and customers. The International Maritime Organization's 2023 greenhouse gas strategy commits the industry to net-zero by or around 2050, with indicative checkpoints of a 20% reduction by 2030 and 70% by 2040 against 2008 levels. The European Union's FuelEU Maritime regulation, in force since January 2025, layers an additional compliance requirement on voyages touching EU ports.

For bunker buyers and charterers, the practical effect has been a wave of biofuel-blended marine gas oil trials and the gradual appearance of green premium clauses on long-term contracts. Several major container lines have launched methanol-fuelled services on the Asia–Europe trade lane during 2025, raising the prospect of differentiated bunker pricing across the same route.

What makes ethanol different?

Ethanol already moves at industrial scale — global production runs above 100 billion litres a year — and burns with lower particulate and sulphur emissions than conventional marine gas oil. For shipowners weighing near-term action, the fuel requires a shorter ramp than hydrogen or ammonia, both of which need new bunkering infrastructure, crew training and dedicated engine designs.

It also sits in a transitional category: less disruptive than ammonia or hydrogen, but more demanding than drop-in biodiesel or marine gas oil. Engine makers including Wärtsilä and MAN Energy Solutions have run alcohol-fuel platforms, with methanol currently the lead commercial deployment. Maersk's 18 large methanol-dual-fuel container newbuilds and CMA CGM's expanding methanol-ready fleet are the most visible commitments.

Commercial questions remain

Ethanol's energy density sits below conventional bunker fuel, so a vessel would need larger bunker tanks or more frequent refuelling to match existing range profiles. Feedstock sustainability also matters: ethanol derived from sugarcane, corn or cellulosic feedstocks carries a different lifecycle emissions profile, and any surge in marine demand would compete with road transport, aviation and food markets for the same supply.

Pricing remains a moving target. Biofuel blends have traded at premiums of 30–50% over conventional VLSFO during 2024–2025, depending on feedstock and certification, while green methanol variants remain several times more expensive than fossil alternatives. Ethanol, depending on source and certification, sits between the two on a cost curve that could narrow as production scales.

Bunker suppliers — traditional oil majors and renewable-fuel specialists alike — face a fragmented calculation. No single alternative fuel will dominate the deep-sea fleet in the 2030s. The likely outcome is a portfolio: LNG and methanol on the newbuild orderbook, biofuels blended in the existing fleet, and ethanol, ammonia and hydrogen scaling where infrastructure permits.

What does it mean for shippers and forwarders?

For shippers, the proliferation of fuel options translates into uneven exposure to green surcharges and contract clauses. Most major liner services now apply some form of emissions pass-through, and as the fuel mix diversifies, the basis for those surcharges will become harder to standardise across trade lanes.

Carriers will choose by trade lane economics. Long-haul Asia–Europe and transpacific services will gravitate toward higher-energy-density fuels — methanol, ammonia or LNG — while short-sea, regional and inland operators have more flexibility. Ethanol's strongest near-term case sits in those latter segments, particularly in Northern Europe where production, blending and regulation already align.

If gCaptain's framing holds, ethanol's next test is whether engine makers, regulators and bunker suppliers can align on a workable commercial pathway before the IMO's 2030 checkpoint forces fleet-level decisions across liner, bulker and tanker segments.