Rolls-Royce hybrid propulsion systems for Liberty Lines’ newbuilds

Marine propulsion specialist Rolls-Royce has received an order from the Spanish shipyard Armon to supply nine mtu hybrid propulsion packs for nine new ships of Italian high-speed maritime passenger transport company, Liberty Lines.

The contract was signed during the SMM international shipping exhibition in Hamburg last week.

The high-speed crafts are scheduled to enter service between 2023 and 2026. The construction of an optional nine additional ships is planned for delivery between 2027 and 2030.

The concept for the fast ferries with sustainable hybrid propulsion systems has been developed in collaboration with Liberty Lines, Armon shipyard, the Rolls-Royce business unit Power Systems, the Italian ship classification society RINA and the Australian shipbuilding design company Incat Crowther.

New monohulls are part of Liberty Lines’ net zero strategy

“With this project, we are making a sustainable investment in the renewal of our fleet, with the purpose to … minimize environmental impact in order to achieve an emission-free future,” Gennaro Carlo Cotella, Chief Executive Officer at Liberty Lines, said.

“The majority of our fleet has already been successfully operating with mtu engines for decades. We are convinced we made the right choice with Rolls-Royce for the supply of the innovative mtu hybrid solutions for the renewal of our fleet on the way towards carbon neutrality.”

Quiet and emission-free into port, high performance at sea

The ships will be equipped with Rolls-Royce integrated mtu hybrid propulsion systems, each comprising two mtu 16-cylinder Series 4000M65L engines, two gearboxes, two e-motors and electric systems, two variable-speed gensets, a battery system, switchboard and electrical power management system, and an mtu hybrid automation system, which monitors and controls not only the hybrid propulsion system, but also various ship area systems.

The vessels will use different operating modes as needed: Purely electric, they can enter and leave ports quietly and with zero emissions at a speed of eight knots; in hybrid mode they can reach high speed in cruise mode when traveling across the sea whilst simultaneously charging the batteries by the two main engines and eliminating the need to operate the gensets for hotel load.

During longer stops, the batteries are charged by means of the shore power supply. Liberty Lines will have the ability to continually remotely monitor the status of the complete propulsion system via the mtu remote monitoring system.

Reducing emissions

The nine mtu Hybrid PropulsionPacks with Series 4000M65L engines will have significantly reduced exhaust particulate emissions compared to Liberty Lines’ currently operating engines, and the mtu SCR exhaust aftertreatment systems, will also greatly reduce nitrogen oxide emissions.

On a kW power output basis, the engines alone in the new hybrid propulsion system will reduce CO2 emissions by 8 percent, soot emissions by 62 percent and NOx emissions by 83 percent compared to the fleet’s current propulsion systems.

The new vessels will meet the IMO Tier III emissions standard, a very strict regulation that is not yet in force in the Mediterranean.