Wärtsilä 34DF multi-fuel engine

The Wärtsilä 34DF multi-fuel engine is a four-stroke multi-fuel engine generating set. It allows instant switching to alternative fuels, should price instability or delivery challenges affect the use of the primary fuel. It operates on the lean burn principle, which reduces peak temperatures and lowers NOx emissions considerably.

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Wärtsilä 34DF

The Wärtsilä 34DF multi-fuel engine generating set is extremely reliable as it is based on the wellproven Wärtsilä 32 engine that has a track record from the mid-1990s. The Wärtsilä 34DF features a wide power output range from 5.6 to 9.8 MW, as it is available in 12V, 16V and 20V cylinder configurations. Wärtsilä engine power plants can be delivered both as EPC and Equipment Delivery contracts.

Key benefits of the Wärtsilä 34DF multi-fuel engine

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  • Ensures energy security in operation through fuel flexibility and seamless switching between fuels
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  • Can operate on natural gas or any liquid fuel, including HFO
  • Low emissions in gas mode and meets even the most stringent emission limits with exhaust gas after treatment
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Customer stories

  • Centrica, UK

    The rapid growth in renewable energy in the UK has increased the need for flexible power to balance the electricity grid. Wärtsilä has worked closely with energy and services company Centrica to provide the changing market with flexible energy, helping tackle the issues created by intermittent renewables and supporting the transition to a low-carbon energy system.

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    Centrica power plant aerial image.
  • Kraftwerke Mainz-Wiesbaden AG

    Flexible combined heat and power plant (CHP) in Germany –enabling KMW AG to operate profitably in the increasingly volatile power market and provide climate-friendly district heating to the community.

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    Thumbnail of KMW
  • Woodland 3, Modesto, California, USA

    The state of California is known for its amazing nature and climate. Being home to beautiful beaches, sandy deserts and redwood forests alike, it is hard to find a corner of the planet with comparable natural and climatic diversity. It’s certainly called the Golden State for a reason! But to keep it golden, its inhabitants and regulators are very aware that its fate cannot be left to chance. Climate change is a real threat, and biological degradation could pose a serious risk to an agricultural region that feeds well over 100 million people.

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    Woodland 3 Generation Station - Modesto
  • Makuhari, Japan

    The growing demand for natural gas as fuel and the increasing importance of environmental values in Japan have encouraged investments in gas-fired power generation systems. The green point of view has also contributed to the rise of interest towards trigeneration energy sources.

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    Makuhari Power Plant, Japan

Our proudest numbers

2 min

to full load.


Electrical efficiency

1 000+

generating sets delivered.

The details

Technical data

Wärtsilä 34DF multi fuel engine 
Cylinder configurations12 V, 16 V, 20 V
Cylinder bore340 mm
Piston stroke400 mm
Engine speed750 rpm (50 Hz), 720 rpm (60 Hz)
Performance *
 20V34DF (50Hz / 60Hz)16V34DF (50Hz / 60Hz)12V34DF (50Hz / 60Hz)
Rated electrical power (kW)9 795 / 9 3887 830 / 7 4915 840 / 5 580
Electrical efficiency (%)GAS: 48.6 / 48.5GAS: 48.6 / 48.4GAS: 48.4 / 48.1
 LFO: 45.6 / 45.8LFO: 45.6 / 45.6LFO: 45.3 / 45.4
 HFO: 45.8 / 46HFO: 45.8 / 45.8HFO: 45.6 / 45.6
Heat rate at generator terminals (kJ/kWh)GAS: 7 404 / 7 415GAS: 7 408 / 7 438GAS: 7 445 / 7 482
 LFO: 7 898 / 7 868LFO: 7 903 / 7 893LFO: 7 941 / 7 938
 HFO: 7 856 / 7 828HFO: 7 861 / 7 852HFO: 7 899 / 7 897
Loading and unloading
 Connected to gridFull load
Regular start time (min:sec)00:30< 5
Fast start time (min:sec)00:30< 2
Stop time (min)1
Ramp rate (hot, load/min)> 100%
Minimum Load
Unit level10%
Plant level1%
* Rated electrical power and electrical efficiencies are given at generator terminals at 100kPa ambient pressure, 25°C suction air temperature and 30% relative humidity, and without engine driven pumps. Power factor 1.0 (site). Electrical efficiency with 5% tolerance. Site conditions, fuel and applicable emission limits may have an impact on performance figures. Please contact Wärtsilä for project-specific performance data. Catalyst systems are designed based on project specific requirements. Certain fuel components are poisonous for catalyst elements. Maximum amount of these components to be limited in the fuel in applications where catalyst system is installed.
Disclaimer: The information contained herein is provided for informational purposes only and may not be incorporated, in whole or in part, into any agreement or proposal. No representation of any kind is made in respect of any information contained herein and Wärtsilä expressly disclaims any responsibility for, and does not guarantee, the correctness or the completeness of the information. The calculations and assumptions included in the information do not necessarily take into account all the factors that could be relevant in a particular case. Information herein shall not be construed as a guarantee or warranty of the performance of any Wärtsilä technology, equipment or installation.


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Build your own power plant







> 500MW

Liquid fuels

Natural gas

Liquid fuels and gas

Flexible baseload (>6000 running hours annually)

Intermediate load (2000 - 6000 running hours annually)

Peaking and grid stability (<2000 running hours annually)


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