Wärtsilä 31DF

The most efficient Wärtsilä 31DF, is a four-stroke multi-fuel engine generating set.

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Wärtsilä 31DF multi-fuel engine generating set

The record-breaking efficiency and fuel adaptability of Wärtsilä 31DF has been designed for applications where energy security is significantly important and where gas network is still forthcoming. Its modular design ensures easy adaption for the engine to run on renewable fuels. Wärtsilä engine power plants can be delivered both as EPC and Equipment Delivery contracts.

Key benefits

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  • World-class open-cycle efficiency
  • Synchronises with the grid within 30 seconds from start command
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  • Ensures energy security in operation through fuel flexibility and seamless switching between fuels
  • Can be easily adapted to run on synthetic renewable fuels
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  • Supports off-grid operation and provides fast black start capabilities
  • Unparalleled load following capabilities and high part load efficiency

Our proudest numbers

2 min

to full load


Electrical efficiency


million running hours with Wärtsilä dual fuel technology

The details

Technical data

Engine generating set
Cylinder configurations 20 V
Cylinder bore310 mm
Piston stroke430 mm
Engine speed750 rpm (50 Hz), 720 rpm (60 Hz)
Performance *
Rated electrical power (kW)10 777 (50 Hz) 11 377 (60 Hz)10 777 (50 Hz) 11 377 (60 Hz)
Electrical efficiency (%)50.2 (50 Hz) 50.2 (60 Hz47.9 (50 Hz) 47.9 (60 Hz)
Heat rate (kJ/kWh)7 170 (50 Hz) 7 175 (60 Hz7 510 (50 Hz) 7 515 (60 Hz
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) < 2
Ramp rate (hot, load/min)> 100%
Minimun Load
Unit level 20%
Plant level 1%
* 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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> 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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