MAN Energy Solutions Logo
  • EN
Scroll down

Reduce your carbon footprint with the new MAN L21/31DF-M methanol GenSet

The maritime industry is decarbonizing and methanol is currently one of the leading fuels among the alternative fuel solutions. Following the market demand and rising interest, we hereby introduce the new MAN L21/31DF-M methanol GenSet - the first small-bore dual-fuel methanol GenSet in our portfolio.

MAN Energy Solutions in Frederikshavn, Denmark is home of the MAN L21/31DF-M, our first small-bore GenSet fueled by methanol.

By loading the video you agree to YouTube's privacy policy.

Load video

up to
reduction of lifecycle greenhouse gas emissions possible with e-methanol
conventional L21/31 engines in service

Proven GenSet design

The foundation of this new engine is based on the current L21/31 GenSet and its well-proven technology, which has already accumulated more than 110 million operating hours, with thousands of engines in service.

Key benefits

  • Low-emission fuel

    This engine runs on methanol or conventional fuels. When powered by green methanol, it has the potential to reduce greenhouse gas emissions. The possibility to operate GenSets on green methanol as drop-in fuel further increases the fuel-flexibility.

  • Reliability and low fuel consumption

    The new engine type keeps up the reliability and low fuel consumption of the MAN L21/31, ensuring security of power supply and handling of load steps with confidence. The power range spans 1,000-1,980 kW which makes this auxiliary engine the ideal candidate for most merchant vessels.

  • Retrofit options

    A methanol conversion will be available as retrofit for existing MAN 21/31 GenSets with delivery from 2025 onwards.

Perfect design features for efficient and reliable operation

The L21/31DF-M comes with a cost-optimised, low-flashpoint fuel supply system which makes it a competitive solution. 

Furthermore, the port fuel injection (PFI) concept provides additional simplicity and an attractive capital outlay. And it is based on proven components. 

Long time between overhaul intervals will save you time and costs on engine maintenance and will give you additional flexibility for the planning of your maintenance slots.

MAN L21/31 engine rendering

Technical specifications

DescriptionMain data


210 mm
Stroke310 mm
Speed900 / 1,000 rpm (60 Hz / 50 Hz)
Output1,000 – 1,980 kW
Cylinder configurator5 – 6 – 7 – 8 – 9
Available fuelsHFO, MDO, MGO, LSFO, ULSFO, Biofuels, MeOH
Emission limitIMO Tier III with SCR after-treatment


Optimized port fuel injection

The port fuel injection (PFI) system uses a methanol injection nozzle installed outside the combustion chamber. This simplified design removes the risk of blocked nozzles in diesel mode and reduces investment costs thanks to its easy installation and integration with standardized components.

MAN SaCoS control system and cybersecurity


MAN SaCoS ensures fast and reliable data-transfer between the engine and the power management system in the control room by easy cable connection.

The engine control system is attached to the engine and features a user-friendly color display in multiple languages. The electric speed governor enables fast response.

Perfect match for MAN B&W ME-LGIM two-stroke methanol engine


The first MAN B&W ME-LGIM came into service in 2016. Since then, we have accumulated more than half a million running hours on methanol alone, which provides a solid base for new developments. The L21/31DF-M is a perfect match for this methanol-fueled propulsion engine.

What makes the new methanol-fueled MAN L21/31DF-M GenSet special? Watch our 3D engine animation to find out more about the working principles, and also the Port Fuel Injection system.

By loading the video you agree to YouTube's privacy policy.

Load video

Service solutions for your equipment

MAN PrimeServ offers a range of modernization solutions for optimizing the reliability, availability, and economic efficiency. MAN’s upgrade and retrofit solutions are tailor-made to customers’ specific applications and equipment.

Go to MAN PrimeServ


Are you ready for green methanol?

Newbuild or retrofit? What are the costs? What are the benefits? Take the lead in sustainable shipping by contacting us today!

Contact us

Continue reading

  • PrimeServ Assist Four-stroke Brochure
    pdf, 4140 KB

Inside the making of a methanol GenSet

With the first two-stroke dual-fuel MAN B&W ME-LGIM methanol engines propelling large container ships across oceans, MAN engineers from Holeby and Frederikshavn, Denmark, are now developing the ideal match for onboard power: a small-bore GenSet capable of running on conventional fuel, biofuels and green methanol
Read the full story

Related products

  • Alternative-fuels key visual

    Alternative fuels

    Operate your in service engines with Alternative Fuels: Unleash Carbon-Free & Carbon-Neutral Solutions for MAN, B&W and S.E.M.T. Pielstick engines. Achieve Fuel Flexibility for Existing Systems!

    More info



    The MAN B&W ME-LGIM is a two-stroke, dual fuel engine that runs on both methanol and conventional fuels.

    More info

  • MAN-L23-30DF-28-32DF

    MAN 23/30DF - 28/32DF

    The dual fuel MAN L23/30DF is based on the popular and robust MAN L23/30H GenSet, and is available for new buildings as well as an economical retrofit solution.

    More info


Related News

Monday, January 22, 2024

MAN Cryo Wins Approval for Ammonia Fuel-Supply System

Latest collaboration with Yada Green Energy Solutions gets seal of approval from classification societies

MAN Cryo has announced that its design for an ammonia fuel-supply system to safely provide ammonia to marine-engine applications has been awarded an Approval in Principle from classification societies, DNV and Bureau Veritas.

Part of MAN Energy Solutions and a leading expert in the field of storage and handling of LNG and natural gas, MAN Cryo developed the system in cooperation with Chinese company, Yada Green Energy Solutions, with whom the company has previously cooperated to provide equipment for LNG and methanol marine fuels.

Xiang Guangqing, Chairman, Yada Green Energy Solutions, said: “Facing the climate-change issue, no one can solve it alone and we firmly believe that cooperation is a powerful means of achieving this. YADA and MAN Cryo are customer-centric operators, providing high-quality, dual-fuel system solutions and continuously achieving new breakthroughs in handling methanol and ammonia.”

He continued: “Yada Green Energy Solutions has set ambitious goals to accelerate the green transformation of the global-transportation industry. Working together to support global development, understanding and anticipating customer needs is an important driving force for our daily work. MAN Cryo and YADA will unite with industry peers, embrace innovation and cooperation, and jointly move towards the sustainable future of global shipping.”

Henrik Malm, Managing Director, MAN Energy Solutions Sweden said: “We are pleased to announce the successful achievement of a significant strategic milestone for MAN Cryo in cooperation with Yada Green Energy Solutions. This accomplishment underscores our unwavering commitment to our global customer base as we collectively work towards a decarbonised world. The establishment of a secure and reliable fuel-supply system for future ammonia engines marks a pivotal development.”

Malm added: “Ship owners can rest assured that MAN Cryo, in cooperation with Yada Green Energy Solutions, is delivering a market-ready solution adhering to the highest security standards and embodying world-class engineering. Once again, MAN Cryo has demonstrated pioneering leadership in the engineering of fuel-supply systems for emerging fuel solutions. This achievement further solidifies our position as industry innovators, dedicated to advancing cutting-edge solutions in response to the evolving landscape of sustainable energy.” 

About YADA

Yada Green Energy Solutions provides customers with one-stop, full lifecycle services including principle design, stress analysis, production design, optimisation design, component manufacturing, pipeline prefabrication, module integration, installation and commissioning, safety monitoring, global operation and maintenance.

About MAN Cryo

MAN Cryo offers system design and engineering solutions for the storage, distribution and handling of liquefied gases and has a pioneering reputation within the marine sector. It supplied the world’s first LNG fuel-gas system for the ‘Glutra’ ferry in Norway in 1999, while in 2013 it supplied the world’s first LNG bunker vessel – the ‘SeaGas’ – with operations in Stockholm, Sweden. More recently, MAN Cryo delivered the first liquid-hydrogen fuel-gas system to be installed below deck aboard a ship.

Contact:Kristoffer Lorentsson – Sales & Project Manager, MAN Cryo


  • PR MAN Cryo Yada_EN
    PDF, 281 KB English


  • Cargo ship in the sea at winter time
    JPG, 858 KB English


Nils Søholt

Trade Press Marine

Group Communications & MarktingMAN Energy SolutionsTeglholmsgade 412450 Copenhagen SVDenmark

t +45 33 85 26 69

Available languages

Set course to net zero with methanol GenSets - MAN L21/31DF-M

Watch the recording of our MAN ExpertTalk, where we introduced our new engine type: the small-bore four-stroke MAN L21/31DF-M GenSet for methanol operation.

You can look forward to hearing about this new GenSet type, the Port Fuel Injection (PFI) concept, the fuel gas supply system and the possibility to operate these GenSets on green methanol and biofuel oils.

    Register now