Wärtsilä 34DF

The Wärtsilä 34DF 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 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

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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.

  • 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.

  • 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.

    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.

    Makuhari Power Plant, Japan

Our proudest numbers

2 min

to full load.


Electrical efficiency

1 000+

generating sets delivered.

The details

Technical data

Engine generating set
Cylinder configurations12 V, 16 V, 20 V
Cylinder bore340 mm
Piston stroke400 mm
Engine speed750 rpm (50 Hz), 720 rpm (60 Hz)
 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%
Minimun Load
Unit level10%
Plant level1%

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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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