Aalborg Energie Technik a/s - Biomass Cogeneration Plant

Verdo Production, Randers, Denmark

After two retrofits, carried out by AET, the district heating plant in Denmark's sixth largest city, Randers, was reborn as a biomass cogeneration plant. It can now be fired by 100% biomass fuel or 100% coal - and any combination of these.

The original CHP plant was built in 1982 and has provided Randers city with electricity and district heating for more than 20 years. The plant was originally commissioned as a spreader stoker coal-fired plant by Aalborg Industries.

In 2002-2003 and 2007-2009, two retrofits were carried out by AET:


First Retrofit: Co-firing of Coal and Biomass

In 2002-2003, AET retrofitted the cogeneration plant with an AET biomass dust-firing system. The plant was then able to operate in co-firing mode with min. 50% coal and max. 50% biomass fuel or 100% coal in single mode - and any combination in between.

The biomass fuel system was designed for a variety of granulated biomass products such as meat and bone meal (MBM), olive stones, shea nuts, sunflower pellets, biopellets and others.

Second Retrofit: 100% Biomass or 100% Coal

In 2007-2009 a substantial retrofit was carried out by AET enabling the plant to fire 100% biomass or 100% coal or any combination in between e.g. 70% biomass and 30% coal. This is possible with the AET Combi Spreader Stoker.

A redesign of the two boilers was caried out, taking into account the narrow available space. The CHP plant is now able to burn uncontaminated wood chips as well as dusty fuels.


AET Scope of Supply

AET handled the retrofitting of the two boilers as a delivery consisting of:

  • Feasibility study
  • Fuel handling
  • AET fuel dosing and transport system
  • AET Combi Spreaders (coal and/or biomass)
  • Boiler refurbish of furnace, superheater and economiser
  • AET Dust firing system
  • AET Combustion air system
  • Ash handling system
  • Erection of equipment
  • Design of electrical system
  • Instrumentation
  • Engineering of control system
  • Commissioning.

Note that Verdo Production was previously Energi Randers.


Additional Information

Boiler: 2x95 MWth
  111 bara
  525 °C

Electrical power:

≤52 MWe

Process energy:

≤110 MWdh

The CHP plant in Randers changed name from Randers Energi to Verdo in order to signalise that they are now using renewable energy.

The AET dust firing system.

The AET Combi Spreader Stoker.

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  • Aalborg Energie Technik a/s
  • Alfred Nobels Vej 21 F
  • 9220 Aalborg East, Denmark
  • Tel +45 96 32 86 00
  • aet@aet-biomass.com