AbstractIn future, an additional potential of control reserve as well as storage capacities will be necessary to compensate fluctuating energy generators such as wind and solar power plants. The core objective of the joint research project “arrivee” is the integration of widely available wastewater treatment plants (WWTP) with anaerobic sludge digestion into an optimized control reserve and storage concept. Therefore the excellent technical conditions of those plants such as combined heat and power (CHP) units as well as gas storage units will be used. By means of analyzing energy consumption and production processes of existing WWTPs the potential to provide ancillary services for energy grids is investigated. Using a mathematical model of an existing WWTPs the effects of external interventions for the supply of ancillary services under different conditions are tested. Therefore, different processes will be analyzed in detail. The integration of WWTPs into a virtual power plant (VPP) is mandatory because a single plant can’t provide enough capacity to participate on energy markets. The initial results present a theoretical potential of control reserve of WWTPs in Germany focusing on a CHP/gas unit of a magnitude of 300 MWel. This results show a substantial potential of WWTPs to provide ancillary services, by reshaping the existing infrastructure in a sustainable, ecological and economic way. This may contribute significantly to a stable operation of energy grids and to further integration of renewable energy sources in the frame of energy system transition.