• Zignago Power

Aalborg Energie Technik a/s Biomass Combined Heat and Power Plant

Zignago Power, Fossalta di Portogruaro, Italy

Zignago Power built and now operates the biomass-fired cogeneration plant.

High Fuel Flexibility

The Zignago plant is unique because of its wide range of fuels:

  • Forestry sector: e.g. forestry wood, tree cuts, brash, trimmings, residues from sawmill and maintenance from gardens
  • Agricultural sector – residuals: e.g. wheat straw, barley straw, maize straw, grain from maize, fruit stones, nut shells and vineyard residues
  • Agricultural sector – dedicated: e.g. miscanthus, sorghum, thistle, poplar and willow.

Performance Test

The AET Biomass Boiler was successfully commissioned and handed over in the beginning of 2012. The official performance test, carried out by FORCE, showed the following performance:

  • Combustion efficiency: +99.9%
  • Boiler efficiency: 92.6%
  • In-house power consumption: only 2.3% of fuel heat input
  • Emissions below stringent, Italian standards.

All measured performances were better than the guaranteed performances by a good margin.


Upgrade With District Heating

The plant was upgraded in 2014, with a tail end heat exchanger, condenser and district heating system to supply district heating to the nearby villages and to the Zignago industrial facilities.


AET designed, supplied, constructed and commissioned the following scope:

  • AET Fuel Dosing System
  • AET Combustion System with AET Spreader Stoker and AET BioGrate
  • Oil burner
  • AET Biomass Boiler with superheaters and economisers
  • AET Combustion Air System
  • AET SNCR DeNOx System
  • AET Steam Air Preheaters
  • Condensate preheaters
  • Feed water system
  • Ash handling system
  • Flue gas cleaning with absorbent injection system
  • Flue gas system and stack
  • Tail end heat exchanger for district heating
  • Steam condenser for district heating
  • Piping in boiler house and turbine hall
  • District heating pumps and piping at the plant
  • Piping and ducting
  • Insulation
  • Structural steel for boiler house
  • Platforms and stairs
  • Instrumentation
  • PLC control and SCADA system for the full plant
  • Heat balance optimisation for the full plant.

Additional Information:

Boiler: 49 MWth
  92 bara
  522 °C

Electrical power:

≤17,9 MWe

Process energy:  

≤4,5 MWdh

The Zignago biomass-fired CHP plant in Italy - respecting nature.

3D illustration of the AET Biomass Boiler at Zignago.

Emissions from the AET Biomass Boiler.

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