The ammonia-based 4-stroke engine

Wartsila has introduced the marine sector’s first commercially available 4-stroke engine-based solution for ammonia fuel.

The new solution enables a significant advance in sustainable shipping operations – during a time in which ship owners are seeking viable options among green fuels.

The ammonia solution is now commercially available as part of the Wartsila 25 engine platform, which was launched in September 2022.

Viridis Bulk Carriers, zero emission shipping company, is intended to be the first shipowner to benefit from the new ammonia solution.

"The maritime industry must significantly reduce its emissions if we are to succeed in reaching the goals set in the Paris agreement. The adoption of new technologies and ammonia as a carbon free fuel is central to this," said Andre Risholm, Board member at Viridis Bulk Carriers. "We are delighted to partner with Wartsila on another important milestone for our ammonia-powered short sea bulk vessels."

Hakan Agnevall, President and CEO of Wärtsilä said: "Wartsila is a leader in shaping the decarbonisation of marine and energy industries. This industry-leading solution is yet another flagship moment in Wartsila’s extensive programme to ensure future marine fuels are both viable and safe. Working in partnership with Viridis Bulk Carriers, we take the next step in our decarbonisation journey, enabling the transition to greener fuels and accelerating towards net-zero emissions shipping."

In addition to the engine, the full solution includes an AmmoniaPac fuel gas supply system, the Wärtsilä Ammonia Release Mitigation System (WARMS), and the Wärtsilä NOx Reducer (NOR) for optimal exhaust after-treatment. Safety and efficiency are central to the solution design, maximised by a highly sophisticated automation system and maintenance agreement to ensure safe and efficient onboard operations.

The safe and smooth adoption of ammonia as a new fuel for crew members is further supported by dedicated training and 24/7 global support. Sustainable ammonia is one of the leading candidates in shipping’s search for alternative clean fuels.

This new Wartsila 25 Ammonia solution can immediately reduce greenhouse gas emissions by more than 70 percent, compared to a similar sized diesel solution, meeting current EU targets until 2050 and even exceeding the IMO target for 2040.

"The Wartsila 25 is the first Wartsila engine to run on ammonia as a fuel, and while we are planning for additional ammonia engines in our portfolio over time, we are committed to further developing and testing of technologies and solutions to support the industry with reducing greenhouse gas emissions even further in the future," Stefan Nysjo, Vice-President of Power Supply, Wartsila Marine Power, said.