Energetic flexibility on wastewater treatment plants.

In the future, an additional potential of control reserve as well as storage capacities will be required to compensate fluctuating renewable energy availability. The operation of energy systems will change and flexibility in energy generation and consumption will rise to a valuable asset. Wastewater treatment plants (WWTPs) are capable of providing the flexibility needed, not only with their energy generators but also in terms of their energy consuming aggregates on the plant. To meet challenges of the future in regard to energy purchase and to participate in and contribute to such a volatile energy market, WWTPs have to reveal their energetic potential as a flexible service provider. Based on the evaluated literature and a detailed analysis of aggregates on a pilot WWTP an aggregate management has been developed to shift loads and provide a procedure to identify usable aggregates, characteristic values and control parameters to ensure effluent quality. The results show that WWTPs have a significant potential to provide energetic flexibility. Even for vulnerable components such as aeration systems, load-shifting is possible with appropriate control parameters and reasonable time slots without endangering system functionality.