Wärtsilä’s Ammonia Engine Achieves Up to 90% GHG Emissions Reduction in Latest Tests

Wärtsilä’s 4-stroke ammonia engine, part of the Wärtsilä 25 platform, has achieved up to 90% reduction in greenhouse gas (GHG) emissions compared to diesel engines, following extensive testing since its commercial introduction in November 2023. With a 95% ammonia energy share, the engine demonstrates an 18% improvement in emissions performance, measured on Well-to-Wake and Tank-to-Wake bases.

Utilising a low-pressure Otto cycle design, the engine matches the efficiency of dual-fuel LNG engines while offering robust combustion and safety. Enhanced safety features, an AmmoniaPac fuel system, Wärtsilä Ammonia Release Mitigation System (WARMS), and Wärtsilä NOx Reducer (NOR) ensure optimal performance and reliability. Ammonia is a promising sustainable fuel, critical for achieving the International Maritime Organization's net-zero emissions target by 2050, as it addresses up to 73% of shipping emissions not covered by existing efficiency measures. First engine deliveries are scheduled for 2026.

May 27 2025