A new report shows ethanol could become a major fuel source for ocean-going vessels, potentially creating billions of gallons in new demand while helping the shipping industry cut emissions.
The National Laboratory of the Rockies released “Evaluation of Ethanol Use in Marine Shipping”, finding that ethanol offers technical, economic, and environmental advantages as a marine fuel. The report was prepared with support from Growth Energy and the U.S. Grains & BioProducts Council.
“This report makes it clear that the American ethanol industry could have a potentially transformative impact on the maritime sector,” said Growth Energy CEO Emily Skor. “The things that make ethanol such an attractive option as a fuel for ships are the same things that make it vital as a fuel for light-duty vehicles—lower emissions, cost competitiveness, and scalability.”
The research identifies several advantages that position ethanol as a practical marine fuel option. Large dual-fuel methanol engines can operate on ethanol with no changes to the equipment, according to the report. Engine manufacturers including Everllence, WinGD, and Wärtsilä have successfully tested ethanol in engines originally designed for methanol.
Environmental benefits stand out among ethanol’s advantages. U.S. corn ethanol produces approximately 51.4 gCO2eq/MJ, about 46% lower than petroleum fuels, with potential for further reductions through carbon capture technology. Ethanol also produces lower sulfur and particulate matter emissions compared to conventional marine fuels.
In spill scenarios, ethanol presents fewer environmental risks than traditional marine fuels. The report notes ethanol’s rapid dissolution in water and low bioaccumulation reduce long-term environmental persistence compared to conventional oil spills. The fuel also has lower human toxicity than alternatives.
Supply availability favors ethanol adoption. The United States currently has about two billion gallons per year of idled production capacity, nearly six million metric tons. This existing infrastructure could support marine fuel demand without requiring major new investments in production facilities.
Ethanol offers approximately 35% higher energy content than methanol, meaning ships would need to carry less fuel to achieve the same range. This energy density advantage reduces onboard storage requirements, a critical consideration for vessel design.
The market potential appears substantial. The report estimates that the current fleet of 112 methanol dual-fuel ships could consume roughly two billion gallons of ethanol annually under high-substitution scenarios. This represents significant new demand for ethanol producers.
“The marine fuel market is important for new growth for ethanol,” said U.S. Grains & BioProducts Council President and CEO Ryan LeGrand. “Even modest adoption could create billions of gallons of new demand, providing another long-term market for corn growers while helping the shipping industry reduce emissions.”
Current methanol-capable ships operate primarily on conventional fuel oil, but infrastructure is developing. As of June 2026, about 48 ports worldwide offer commercial methanol bunkering, with methanol available in more than 120 ports globally. This existing methanol infrastructure could support ethanol with minimal modifications.
“Ethanol has advantages that few other potential marine fuels do,” said NLR Senior Research Fellow Robert McCormick, who authored the report. “Its robust compatibility with methanol infrastructure, its overall scalability, and its environmental benefits make it uniquely suited to help the shipping sector achieve its goals.”
The shipping industry faces increasing pressure to reduce emissions under international maritime regulations. The report suggests ethanol could help vessel operators meet these requirements while maintaining operational flexibility through dual-fuel systems that can run on either ethanol or conventional fuels.
Container ships represent the most likely early adopters, with ultra-large container vessels and Panamax container ships showing strong interest in alcohol fuels, according to the research.
