Wärtsilä Launches First Ammonia-Fueled 4-Stroke Ship Engine

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

The Finnish technology group said the solution represents a significant advancement in sustainable shipping operations, offering ship owners a viable option among green fuels. The ammonia solution is the first Wärtsilä engine to run on ammonia as a fuel and is now part of the Wärtsilä 25 engine platform, which was launched in September 2022.

Wärtsilä says it has signed a letter of intent with Viridis Bulk Carriers for the Wärtsilä 25 ammonia engine solution, targeting to sign a commercial contract in early 2024. Viridis Bulk Carriers is a partnership between Amon Maritime, Mosvolds Rederi and Navigare Logistics and is seeking to become the world’s first zero emission shipping company with a fleet of ammonia-powered newbuild vessels operating in the European short sea bulk market.

“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 André Risholm, Board member at Viridis Bulk Carriers. “We are delighted to partner with Wärtsilä on another important milestone for our ammonia-powered short sea bulk vessels.”

Håkan Agnevall, President and CEO of Wärtsilä, called the 4-stroke engine-based solution a “flagship moment” in the company’s pursuit to ensure the viability and safety of future marine fuels. “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,” he said.

In addition to the engine, the complete solution includes the AmmoniaPac fuel gas supply system, the Wärtsilä Ammonia Release Mitigation System (WARMS), and the Wärtsilä NOx Reducer (NOR) for optimal exhaust after-treatment. Wärtsilä said the solution design prioritizes safety and efficiency, incorporating a highly sophisticated automation system and maintenance agreement to ensure safe and efficient onboard operations. The company also offers dedicated training and 24/7 global support to facilitate the smooth adoption of ammonia as a new fuel for crew members.

Roger Holm, President of Wärtsilä’s Marine Power business, noted that the ammonia solution is based on the company’s well-proven LNG system.

“The Wärtsilä 25 engine has been designed for easy adoption of sustainable fuels and, now, in addition to its previous capability of operating on diesel, LNG, or on gas or liquid carbon-neutral biofuels, we are proud to add ammonia to its specifications. This makes Wärtsilä 25 a thoroughly future-proof engine platform, that combines operational efficiency with environmental sustainability,” said Holm.

Sustainable ammonia is considered one of the leading contenders for clean fuels in the shipping industry. Wärtsilä said the 25 Ammonia solution can immediately reduces greenhouse gas emissions by over 70 percent compared to a similar-sized diesel solution, surpassing both current EU targets until 2050 and the IMO target for 2040.

The Wärtsilä 25 engine running on ammonia as a fuel marks an important milestone for Wärtsilä Marine Power. They plan to add more ammonia engines to their portfolio and continue developing technologies to further reduce greenhouse gas emissions in the future.

“This is only the beginning,” said Stefan Nysjö, Vice President of Power Supply, Wärtsilä Marine Power.

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