Megastar is powered by three
12-cylinder Wärtsilä 12V50DF and two
6-cylinder Wärtsilä 6L50DF four-stroke
dual-fuel generating sets. While capable of running on
marine diesel oil (MDO), the engines will primarily use
liquefied natural gas (LNG) as fuel. This reduces both
sulphur oxide (SOx) and
nitrogen oxide (NOx) emissions, and allows the vessel to comply with
IMO Tier III emission limits as well as the additional restrictions of the Baltic Sea
Sulphur Emission Control Area. The gas fuel is stored in two cryogenic storage tanks which, unlike in the previous LNG-fueled cruiseferry
Viking Grace, are located inside the hull of the vessel, below the main deck. The propulsion system is
diesel-electric, meaning that instead of being mechanically coupled to the twin propeller shafts, the main engines form a power plant which produces electricity for all electrical consumers ranging from propulsion motors to auxiliary systems and hotel functions. This allows starting and stopping engines depending on power demand and improves the
fuel efficiency as the engines can run at their nominal power. The service speed of the vessel is . == Service history ==