Sustainable heat and power production | Assens, Denmark

Assens Fjernvarme has supplemented their existing wood chip combined heat and power plant and an existing wind turbine with a solar cell system and an air to water heat pump system. This unique combination of renewable energy sources makes it possible to combine a low price for heat consumers with the production of green electricity when the electricity market needs electricity and purchase electricity from the electricity grid when there is a surplus of green electricity in the grid. During the summer, the heat pump’s electricity consumption can be covered by electricity from solar cells and wind turbines and supply Assens with district heating. This avoids the wear and tear on the combined heat and power plant that the many starts / stops cause. During the winter, the heat pump together with the combined heat and power plant can cover the heat demand in Assens. At the same time, the heat pump helps to cool the flue gas from the combined heat and power plant from the previous approx. 45 degrees to now 25 degrees. This is done at the same time as the air coolers deliver full performance. COWI has been an advisor on the heat pump system and the solar park, as well as a complete conversion of the high-voltage system and a new 10 kV switching system. The company Innoterm has designed the heat pump system and Johnson Controls has supplied the total of 3 screw compressors that use NH3 as refrigerant.