Type of CHP system: Grate fired boiler
Plant owner: Owned by Tranås Energi AB, which is owned by Tranås Municipality
Status of plant: Commercial
Contractor details: Wärtsilä OY (boiler, buildings) Vaporel (turbine)
Power generation: Steam turbine
Flue gas condenser, 3,5 MW. Delivered by Radscan AB.
Main fuel: Bark
Bark75% (moist 55%), Sawdust 25% (moist 50%) , Annual consumption biomass 57 GWh
Nominal capacities & efficiencies:
Thermal input, biomass & waste: 12 MW
Total thermal input, incl. fossil fuels: 12 MW
Gross electrical output: 1,8 MWe
Net electrical output: 1,6 MWe
Heat output: 12,1 MJ/s
Electrical efficiency, gross: 15 %
Electrical efficiency, net: 13 %
Overall efficiency, gross: 116 %
Heat capacity 8,5 MW. Flue gas condensor 3,5 MW.
How is plant controlled: By heat demand
Heat backup: 20 MW biomass fired boilers, with flue gas condensors. 2×25 MW oil boilers. Electric boiler 8 MW. Landfill gas boiler 1 MW.
Heat usage: Heating only
The boiler is connected to the city of Tranås district heating system. Energy sold in the district heating system 128.000 MWh/year. 800 customers. (Approx80% to households and 20% to industries.)
District heat coverage (% of total demand in DH network): 50 %
DH inlet temperature: 70-115 °C
DH return temperature: 40-55°C
Heat storage size: Accumulation tank 2000m3 m3
Hours of full load that the heat storage can meet: 2 hours
Fuel storage: Maximum allowed storage is approx. 2.400 MWh. Approx 8 days of full load operation.
Waste water: From flue gas condenser, pH-adjustment and sandfilter. 25.000 m3/year
Ash discharge: Depony, landfill
Tranås Energi AB district heating network in Tranås is today 45 kilometers long. The new combined heat and power plant
is built next to the already existing district heating plant, which has four boilers that together produce 78 MW of district heat. Now
the combined heat and power plant is completed and the old plant will become a stand-by and peaking facility The existing
plant will also be used as a top-up facility.
Fuel feeding system: Different sorts of fuel is carried by a tractor to a 450m3 storage in the ground outside. From the storage: scrapeconveyers,1 screw,
Boiler: Wärtsilä biograte
Turbine: Tuthill Nadrowski B5-S5
Steam data: 15,2 bar, 345 degree Celcius 13,6 tons/hr
Flue gas cleaning: Elctrostatic precipitator, flue gas condenser
Staff: Daytime:3 persons, weekends daytime: 1 persons. No persons at night
Electricity sale info: Follows Nordpool spotprice (hour).
Total capital cost: € 6,400,000
Data collected and quality assured by: Swedish Biomass Association.
Contact person: Johan Vinterbäck