The monitoring of the plant showed large fluctuations in energy production. Fish silage gave a total energy production of 1623 kWh/m3 , while the dairy cow slurry produced 79 kWh/m3 slurry. Heating of new substrates required most energy during the summer, while during the winter covering for thermal energy losses from the digester and pipes required most thermal energy, even though the thermal energy consumption required for heating of new substrates was larger in the winter periods. Total energy demand at the plant varied between 26.9% and 88.2% of the energy produced.