Commercial Marine


The marine propulsion systems market is estimated to cross US$11 billion by 2026, and the market is still dominated by diesel-based engines. However, the demand for sustainable engines continues to accelerate.

This is mainly driven by the heavy push from international regulatory bodies towards reducing the environmental footprint of the shipping industry. One such regulator is the International Maritime Organization, which aims to cut CO2 emissions across international shipping by at least 40% by 2030. It has plans to gradually roll out mandatory requirements to support this goal, such as their sulfur oxide emissions cap which recently came into effect in 2020.

Cutting emissions through engines

In  order to meet these sustainability targets under a tight deadline, ship operators are looking towards updated engines that are more efficient, produce fewer emissions, and have the capability to support alternative low-sulfur fuels – without any compromise in power.  

The new mtu Series 4000 engines for tugs, ferries, push boats, and special ships address this need. It is the first high-speed pure gas engine in the high power range that can directly drive a fixed-pitch propeller, giving it dynamic acceleration capability.

From an emissions standpoint, the straightforward gas engine generates up to 11% less greenhouse gas, 90% fewer nitrogen oxides, virtually no particulates, and no sulfur dioxides, as compared to a diesel engine. This will be instrumental in reducing the impact of maritime traffic on the environment, permanently lowering emissions.

World's first LNG-Hybrid powered tugs

The innovative marine propulsion engine has already been rolling out in ships around the world. Sembcorp Marine in Singapore has installed two mtu 16V 4000 M55RN gas engines to construct the world’s first LNG-hybrid powered tugboats.  

The main propulsion system of this Sembcorp hybrid tugboat comprises twin 16-cyclinder mtu Series 4000 gas engine units equipped with multipoint fuel injection, dynamic engine control, and enhanced turbocharging, catered for dynamic acceleration capabilities and high power output with a combined total of 2984 kilowatts – delivering performance comparable to a high-speed diesel engine.  

It also utilizes an LNG-hybrid propulsion system which provides flexibility to cater for various operational modes and is able to switch between low emission liquefied natural gas (LNG) engines and zero-emission battery power. Additionally, the Series 4000 gas engines will be able to run on sustainable fuels such as e- and second-generation biofuels by 2023.

“We are very happy to be part of Sembcorp Marine’s efforts in environmental protection and adopting new green technologies in their operations. Without exhaust gas after treatment, the engines emit no sulfur oxides, only very small quantities of nitrogen oxide, and particulate mass is below the verification limit,”

Chew Xiang Yu - Head of Rolls-Royce Power Systems' commercial marine business in Asia.

With a total of 12 being built, these harbor tugs will gradually replace Sembcorp Marine Integrated Yard’s existing diesel-powered ones between now and 2025.

Rolls-Royce: Leading the path towards sustainability

This new mtu marine gas engine is part of Rolls-Royce's Green and High-Tech program which concentrates on electrification, alternative fuels, exhaust gas after-treatment, digitization, and overall system capability.  

As the global push towards sustainability continues to intensify, Rolls-Royce continues to heavily invest in developing solutions that both maximize efficiency and reduce emissions – which in turn work to reduce the impact of shipping on the environment. Find out more about Net Zero at Power Systems.

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