Savon Voima Oyj and Calefa Oy have started a cooperation project in which heat pumps utilise waste heat from the flue gas scrubber of the Joensuu biomass power plant. In the summer, when the power plant and scrubber are shut down, river water is used as the heat source for the heat pumps. The solution is the first of its kind in Europe.The capacity of the heat pump plant is 6 MW in the winter and 3,7 MW in the summer. The heat is utilised in the district heating network.