This business case shows the advantages of a hybrid battery energy storage system combined with a power-to-heat (PTH) solution. The installed thermal PTH system, which is already used for additional applications, provides negative power which is usually limited to the secondary reserve market. By combining both systems, the capacity of the thermal storage adds up to the installed BESS capacity. In this case only 600 kWh instead of 1000 kWh battery capacity is required. Overall this results in a reduced CAPEX of 30 - 40%.