Rolls-Royce has disclosed that it is working alongside UK luxury performance yacht builder Sunseeker International, to produce the first yacht fitted with an MTU-branded hybrid propulsion system.
Speaking in mid-January 2019, Knut Müller, head of marine and government business at MTU, said: “The combination of diesel engines and electric motors, in addition to batteries and their variable areas of application, offer significant benefits. Silent cruising, combined with low vibration and emission levels, offers tremendous gains in terms on onboard comfort.” He added: “The yacht industry’s future focus will be more and more on smart, innovative system solutions, rather than just on the power output level.”
He was echoed by Sean Robertson, Sunseeker sales director, who said: “The way owners are using their boats continues to evolve, with efficiency and noise reduction now as important as features and volume, which all contribute to their ultimate purchase decision.”
The yacht is planned for completion in 2020, although technical particulars were unavailable at time of writing. However, a spokesperson for Rolls-Royce tells Ship & Boat International: “MTU will supply the whole hybrid propulsion system, including the lithium-ion batteries.” The yacht will be fitted with two 12-cylinder MTU Series 2000 diesel engines, each rated approximately 1,432kW, plus battery modules with a combined capacity of 30kWh.
The MTU serial hybrid system will also comprise: one E-propulsion unit per shaft; one gearbox per shaft (if required); one DC link per shaft; one battery per shaft; one AC/DC converter per shaft; one local operation panel per shaft; a remote-control monitoring system; and a local monitoring system.
The hybrid system, still partly in development, will enable the owner to select from six distinct operating modes. The first mode, whereby both diesel engines are engaged and no electric power is used, is described as ‘Mechanic’ mode. The spokesperson says: “[In this mode], the ship will deactivate all hybrid components and tune the ship to conventional plant.”
In ‘Electric’ mode, propulsion and onboard power are supplied continuously by the generators, “providing optimisation of fuel consumption and onboard comfort for long and overnight passages,” the manufacturer adds. In ‘Silent’ mode, the ship relies solely on battery power. Rolls-Royce elaborates: “Up to 40 minutes of propulsion and 120 minutes of onboard power are available with each pair of MTU batteries installed, with no emissions produced whatsoever.”
‘Smart Hybrid’ mode is described as an “automated mode with focus on propulsion performance”, in which all onboard power sources (ie, diesel engine, batteries, gensets) are made available. The MTU hybrid controller manages and switches between these propulsion and energy sources “without active selection by the captain.” Rolls-Royce adds: “The only exception is the main diesel engine, which has to be manually started and switched off by the operator.” The company adds: “In this mode, both propulsion power and onboard power are generated by the main diesel engines if possible, reducing total fuel consumption.” However, should the engine’s power reserve and the batteries’ state of charge be too low, the gensets will kick in.
Next up, ‘Charge Hybrid’ mode is reportedly “very similar to ‘Smart Hybrid’ mode,” only with an emphasis on charging the battery modules rather than on boosting performance and reducing fuel consumption. This mode uses all available power to charge the batteries as quickly as possible, and is chiefly intended, Rolls-Royce says, “to prepare the ship for an overnight stay or for a longer mooring period”.
The company adds: “The details of the sixth mode are not completely fixed [and are] still in development.”