Everllence Achieves Full Ethanol Operation on 21/31 Dual-Fuel Marine Engine

Everllence has successfully run its 21/31DF-M dual-fuel four-stroke engine on pure ethanol across the entire load range during tests at the company’s facility in Frederikshavn, Denmark. This achievement builds directly on the same engine platform that Everllence introduced in 2024 as the world’s first small-bore four-stroke methanol GenSet.

Several of these methanol units are already in commercial service on ships. The new ethanol tests show that the 21/31 architecture is even more flexible than previously thought. During the trials the engine not only operated without problems on ethanol, but in some conditions managed to run with a higher share of the alternative fuel than is typical with methanol.

The company has been preparing for this step for some time. Growing customer interest in ethanol as a low-carbon marine fuel prompted Everllence’s engineering teams to carry out the required design studies well in advance. The recent test campaign has now delivered the final technical confirmation: the 21/31DF can switch seamlessly between conventional diesel, methanol, ethanol, or any blend of these fuels with no hardware changes required.

This flexibility is especially valuable today, when many shipowners remain uncertain about which future fuel will dominate. By adding ethanol to an already proven methanol-capable platform, Everllence gives operators another realistic, drop-in decarbonisation option using existing engine technology.

The company stresses that ethanol is ready from a technical standpoint. What the fuel now needs is clearer regulatory recognition as a viable low-emission marine fuel and stronger market pull to drive bunkering infrastructure and supply-chain development.

With these successful ethanol trials, the 21/31DF strengthens its position as one of the most future-proof small-bore auxiliary engines on the market, offering shipowners genuine multi-fuel capability on a single, compact, and well-established platform.