Wärtsilä brings first ammonia four-stroke engine to market

Ammonia is one of the leading candidates in shipping’s search for alternative clean fuels with the latest projections from the International Energy Agency suggesting it will be ammonia, not methanol, that must play a major role for the industry to meet its emissions reductions targets by 2050.

Some 7.6% of the current order book are ammonia-ready vessels, with forecasts shared by S&P Global Insights projecting ammonia will have a market share of 14.7% of the alternative fuel market by 2030 and 38% by 2050.

Anticipating the uptake, engine designers have been pouring investment into developing both two-stroke and four-stroke engine technology capable of burning the carbon-free fuel.

Wärtsilä chief executive Håkan Agnevall said, “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."

Viridis Bulk Carrier operates in the European shortsea bulk market and is planning a carbon-free transport service based on a series of ammonia-powered newbuild vessels. Viridis board of directors member André Risholm said, “We are delighted to partner with Wärtsilä on another important milestone for our ammonia-powered, shortsea bulk vessels.”

Among the technical barriers to the fuel’s adoption are its combustibility. During the press conference, Mr Kytola described ammonia as a ”lazy fuel” and did not reveal exact numbers for pilot fuel requirements, only adding that it was lower than 30%. Projected GHG reductions of 70% as compared with diesel are only achievable burning green ammonia, which is produced using renewable electricity. Most of the ammonia produced to date is ‘grey ammonia’, which has higher GHG emissions than conventional marine fuels on a well-to-wake basis.

Wärtsilä Marine Power president Roger Holm said the Wärtsilä 25 engine has been designed for easy adoption of sustainable fuels including ammonia, making it what he called a “thoroughly future-proof engine platform, that combines operational efficiency with environmental sustainability.”

In addition to the engine, the Wärtsilä 25 ammonia package includes an AmmoniaPac fuel gas supply system, the Wärtsilä Ammonia Release Mitigation System, and the company’s NOx Reducer for exhaust after-treatment. 
An automation system and maintenance agreement will help ensure safe onboard operations while dedicated training and 24/7 global support will aid the adoption of ammonia as a new fuel for crew members.  

Mr Kytola explained that Wärtsilä took a modular approach to its 25 engine model that can be "built around customer values". 

"The base engine for the 25DF and 25 Ammonia is exactly the same, and only a number of components differ," he said.

Yara Clean Ammonia and a consortium of partners backed by the Norwegian government are aiming to build a container ship powered by ’pure ammonia’ by 2026. And NYK Group and Chilean mining corporation Coldelco are eyeing the construction of an ammonia dual-fuel Handymax which could potentially include over a dozen ammonia dual-fuel bulkers.

Riviera Maritime Media’s International Bulk Shipping Conference will be held 20 November 2023 in London, UK. Use this link for further information and to register your interest

Riviera Maritime Media’s Maritime Decarbonization Conference, Americas will be held 12-13 December 2023 in Houston, USA. Use this link for further information and to register your interest