Report examines ethanol as a potential marine fuel for ocean-going vessels

A new report from the National Lab of the Rockies (NLR) has examined the technical, economic and environmental potential of ethanol as a lower-carbon fuel for ocean-going vessels.

The report, titled “Evaluation of Ethanol Use in Marine Shipping,” was prepared with support from Growth Energy and the U.S. Grains and BioProducts Council (USGBC). It assesses ethanol’s compatibility with existing marine fuel technologies, emissions profile, supply availability, energy density and potential demand from the shipping sector.

Ethanol compatibility with methanol-fuelled engines

According to the report, ethanol’s molecular characteristics are similar to methanol, which could allow certain existing methanol-fuelled marine engines to operate on ethanol without major modifications.

The report states: “Large dual-fuel methanol engines can operate on ethanol with no changes.”

NLR Senior Research Fellow and report author Robert McCormick said: “Ethanol has advantages that few other potential marine fuels do. 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. We hope this research paves the way for greater collaboration between ethanol producers and shippers, and that it encourages further study to fully grasp the impact ethanol could have in maritime applications.”

Ethanol emissions and environmental profile

The report highlights ethanol’s potential emissions benefits compared with conventional petroleum-based marine fuels. It cites a study estimating the lifecycle carbon intensity of U.S. corn ethanol at approximately 51.4 gCO2e/MJ, around 46% lower than petroleum fuels. The report notes that further reductions could be possible through carbon capture and sequestration.

It also identifies ethanol’s lower human toxicity compared with some other marine fuels. In the event of a spill, the report says ethanol’s rapid dissolution and low bioaccumulation could reduce its long-term environmental persistence compared with conventional oil spills.

Ethanol supply and energy density

The report also points to available U.S. ethanol production capacity as a factor supporting its potential use in marine applications. It estimates that the United States has around two billion gallons per year of idled production capacity, equivalent to nearly six million metric tonnes.

Ethanol also has a higher energy content than methanol. According to the report, ethanol has approximately 35% higher energy content than methanol, which could offer an operational advantage when comparing the two fuels.

Marine shipping could create additional ethanol demand

The study identifies marine shipping as a potential additional market for ethanol producers. Under high-substitution scenarios, the report estimates that the currently operating fleet of methanol dual-fuel vessels could consume approximately two billion gallons of ethanol annually.

Growth Energy CEO Emily Skor said: “This report makes it clear that the American ethanol industry could have a potentially transformative impact on the maritime sector. 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. We thank NLR for its critical work outlining the ways in which ethanol can meet the needs of today’s shipping sector and look forward to working with our members and the entire industry to secure ethanol’s global future as a marine fuel.”

USGBC President and CEO Ryan LeGrand said: “The marine fuel market is key to new growth for ethanol. 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.”

The report indicates that further research and collaboration between ethanol producers, engine manufacturers and shipping companies will be needed to assess the practical deployment of ethanol as a marine fuel.

SOURCE: Growth Energy