The district energy system serving the Swedish city of Falun is the best in the world according to the International District Energy Association (IDEA) and Euro Heat and Power. The municipality-owned district energy, waste management, and water utility, Falu Energi & Vatten AB (FEV), was presented last year with the prestigious “Award of Excellence-Municipal Scheme serving more than 10 000 Citizens-Modernization” by the IDEA at its annual Global District Energy Award gala.
The City of Falun has around 56 000 inhabitants. The heart of the FEV energy system is its Västermalmsverket combined heat and power (CHP) plant. The plant has an installed capacity of 130 MW thermal and 18 MW electric and consists of two biomass boilers, two oil, and two gas boilers for start, peak, and backup.
The plant uses locally sourced forest and wood industry residues to produce around 300 GWh heat and 60 GWh of electricity per annum. The energy system also includes a gas-fired CHP that uses sewage gas from a wastewater treatment plant (WWTP) as well as three wind turbines and five hydropower stations.
Pellet production too
What makes the Västermalmsverket unique is the integration of a 45 000 tonne-per-year wood pellet plant in 2011. Using district heat from the CHP for the drying the pellet plant operates from March through to October when the demand for district heating is low.
The pellet plant uses sawdust sourced from several large sawmills in the region but it is also configured to be able to use small diametre roundwood and logging residues as feedstock. The pellets are primarily used in other boilers operated by the company.
This enables more efficient usage of the CHP during the warmer season and enables us to store energy in the wood pellets to be used during the colder period. In 2012 we used over 16 GWh of district heating in the pellet plant which meant we could produce 4 GWh more electricity, explained Bengt Gustafsson, CEO of Falun Energy & Vatten AB.
Network expansion
The FEV district heating network is 180 km in total including three smaller local networks. To further improve CHP production the network is being expanded another 18.4 km to connect with the district heating network of neighbouring city Borlänge.
Due to be commissioned this autumn the SEK 117 million network-connect project is in partnership with another municipality-owned utility, Borlänge Energi. Borlänge Energi operates a waste-fueled CHP plant as well as use waste heat from paper and steel industries for its district heat production.
The network connection has a heat transfer capacity of 30 MW heat and is expected to transit 120 GWh of energy annually between the cities with a temperature loss of only 1 degree Celcius. The companies will have joint production optimisation with the direction of the water flow determined by which fuel is most profitable to use.
The companies have shared the project costs equally and the collaboration between the two is expected to result in further advantages involving staff as well as maintenance and purchasing.
Facts
About FEV district heat
Network: 180 km ≈ 2 500 properties & 2.6 million sq.m of buildings/facilities. Over 90 percent in urban areas & over 50 percent of households.
Climate impact: 20g CO2e/kWh
Fuel: 99 percent biomass (wood chips, bark, logging residues, sawdust & pellets), 1 percent landfill gas (LFG) and liquefied natural gas (LNG)
