The technology group Wärtsilä announced the launch of the latest addition to its multi-fuel engine portfolio. The Wärtsilä 46TS-DF engine is designed with a focus on efficiency, environmental performance, and fuel flexibility signalling a new era of medium-speed marine engines. In gas fuel mode, the engine has the highest efficiency thus far achieved in the medium-speed engine market. The first order for this engine type was placed by Chantiers de l’Atlantique for Royal Caribbean Cruises in April 2021. The engines will be installed on their latest Oasis class ship ‘Utopia of the Seas’. The ship is being built by the shipyard Chantiers de l’Atlantique and will feature six Wärtsilä 46TS-DF engines with Gas Valve Units, NOx Reducer SCR systems, LNGPac and Transverse Thrusters.The overriding basis for this new engine launch is to be able to offer a future-proof solution for owners and operators to reach decarbonisation targets. The Wärtsilä 46TS-DF has a two-stage turbocharging to deliver high levels of efficiency and power density across a wide operational range for vessels in all segments of the industry. This level of efficiency reduces fuel consumption and lowers emissions, while being easily retrofittable for future carbon-neutral and carbon-free fuels as they become widely available.Development of the Wärtsilä 46TS-DF engine has been based on the extensive experience gained from the company’s Wärtsilä 46, 46F, and 50 engine families. It is available in 6 to 16-cylinder configurations, corresponding to a power output range of 7.8 to 20.8 MW at 600 rpm. It features an intrinsically modular design, which simplifies upgradability and modifications for alternative future fuels.The dual-fuel Wärtsilä 46TS-DF engine can run LNG, which dramatically reduces air pollutants as well as offering a viable platform for further decarbonisation through the use of bio- or synthetic methane in the future.