US Ethanol Could Fuel 300+ Methanol-Capable Ships, Study Finds

The United States holds roughly 2 billion gallons of unused ethanol capacity — enough, in theory, to supply 1% of global shipping's annual fuel consumption by mass — according to a study published Wednesday by the Maritime Ethanol & Methanol Alliance (MEMA).

The report, Marine Ethanol: Unlocking the US Opportunity, argues that ethanol can run in existing methanol dual-fuel engines and bunkering infrastructure with relatively minor modifications. That claim lands in front of a growing installed base: more than 300 methanol-capable vessels are already operating or on order worldwide.

How big is the supply?

US ethanol plants have an annual production capacity of approximately 18.5 billion gallons, against actual output of 16.4 billion gallons in 2025. The country produces slightly more than half of the world's fuel ethanol and exports to roughly 80 countries, with Gulf Coast terminals sitting near major bunkering hubs.

The arithmetic is straightforward at the entry level. Supplying 1% of shipping's annual fuel consumption by mass would take about 1 billion gallons — comfortably inside existing spare capacity. A 5% market share by the mid-2030s, however, would require around 5 billion gallons annually, forcing either additional production or a shift in existing demand. That second scenario is where the study's confidence thins; it names the gap without pricing it.

What has actually happened so far?

Ethanol has already moved beyond demonstration projects. In September, A.P. Moller-Maersk completed the first publicly announced commercial ship-to-ship ethanol bunkering of a deep-sea containership in the United States, delivering US-produced corn ethanol to the dual-fuel Tangier Maersk in Houston.

Engine developer WinGD subsequently confirmed the vessel sailed from Houston to New York on ethanol — the first in-service operation of its X-DF-M/E alcohol-fuel engine platform on the fuel. The study rates ethanol's technology readiness at level 8–9: the engineering is mature, but commercial deployment remains at an early stage.

The emissions case is narrower than it first appears. Ethanol virtually eliminates sulfur oxide emissions, cuts nitrogen oxides by 40% to 94% depending on engine technology, and reduces particulate matter by 90% to 99% — figures that cover combustion only, not lifecycle greenhouse gas intensity, which depends on feedstock and supply-chain emissions.

Can it compete on cost?

The study puts ethanol's net production cost, after co-product revenue, at less than $1 per gallon. That figure is not a delivered marine fuel price, and the report concedes as much. Widespread adoption also requires consistent fuel specifications, reliable certification and traceability systems, and compliance with emerging environmental regulation — none of which exists at scale yet.

"Ethanol is moving beyond pilots, and this study shows the United States has the production base and export infrastructure to supply shipping at scale," said Clarence Woo, managing director of the Singapore-based Global Centre for Green Fuels, MEMA's parent platform.

"The next challenge is consistency. As international bunkering grows, shipping needs standardised and fungible marine fuel specifications, together with traceable feedstocks and a robust chain of custody, so that ethanol from different producers and regions can be used with confidence," Woo said.

Classification society ABS provided technical analysis as a knowledge partner; US producer Marquis Energy contributed industry input. The findings are MEMA's own.

What happens next?

For shipowners, the appeal is access to an established fuel supply chain without waiting for renewable methanol output to expand. For US ethanol producers, marine bunkering offers a new demand stream. For forwarders and carriers weighing fuel strategies, the study's projections remain illustrative — competitiveness will turn on delivered cost, lifecycle carbon intensity and regulatory treatment, none of which is settled.

The policy clock is running. The IMO's Marine Environment Protection Committee meets November 30 to December 3, with a resumed extraordinary session provisionally planned for December 4, pending confirmation. Those talks could determine how alternative fuels are assessed and rewarded under the Net-Zero Framework — and whether ethanol earns a place at the table.