MAN ES checks off new milestone as full-scale ammonia engine runs at 100% load

German engine maker MAN Energy Solutions (MAN ES) has taken another step toward commercializing two-stroke ammonia engine by running its liquid gas injection ammonia (ME-LGIA) engine at 100% load for the first time.

The full-scale, two-stroke engine running on ammonia has been undergoing testing at Research Centre Copenhagen (RCC) facility since November 2024.

On January 30, 2025, MAN ES revealed the milestone of running the engine at 100% load as “another important step forward in the maritime energy transition”.

Ole Pyndt Hansen, Head of Two-Stroke Research & Development at MAN ES, said the company had operated the engine on ammonia from 25–100% load and validated the ammonia fuel-injection system over the full load-curve with diesel-pilot amounts recorded according to its targets.

Hansen added that the positive emission and performance characteristics from previous, single-cylinder tests has also been validated in full-scale engine operation.

MAN ES further stated that its proprietary selective catalytic reduction (SCR) was operational at all test loads to treat exhaust gases, and that all supply and safety systems worked as intended.

As informed, the next phase of testing will focus on performance and emission optimization, including injection and SCR systems as well as control strategies.

Christian Ludwig, Head of Global Sales & Promotion, Two-Stroke Business at MAN ES highlighted the ME-LGIA’s power take-off (PTO) capability and said: “The ME-LGIA concept is based on the Diesel-cycle combustion principle, which makes it eminently suitable for PTO. Prior to this round of testing, we simulated PTO on the ammonia engine with very positive results and are very happy to see this replicated in real life. We intend to support PTO on the ME-LGIA to the same degree as with the other Diesel-cycle engines in our low-speed portfolio.”

To remind, MAN ES completed the first running of a test engine on ammonia at RCC back in 2023, reporting the successful combustion had been performed on a MAN B&W two-stroke 4T50ME-X type and positive results with promising data regarding pilot-oil amount and combustion stability. 

At the time, the company said it expects to hold its delivery timeline for the first ammonia engine, with subsequent operation onboard a commercial vessel from around 2026.