Demand response within the Irish wastewater treatment sector: Analysing flexibility potentials of the aeration process and wastewater pumping within an integrated energy–water system model

Significant amounts of electricity consumed in air and water pumping make wastewater treatment energy-intensive. This study investigates the potential power system benefits of load shifting within these pumping processes. As a case study, the Irish power system and wastewater sector are studied by using an integrated modelling approach. The results show that demand flexibility within the wastewater treatment sector can have positive effects on power system costs, electricity consumer costs and the emission intensity of electricity supply. Load smoothing happens particularly during hours with low net electricity demand. The results indicate that the process constraints of the wastewater treatment process impede the flexibility potential. This highlights the importance of modelling the technical characteristics of wastewater treatment plants (WWTP), rather than using a black-box approach which assumes a certain share of the demand as shiftable, as has been the case in the literature to date. WWTP can be a beneficial DR resource for the power system, but neglecting process constraints might yield an over-evaluation of their potential. • This study examines power system benefits of load shifting in wastewater treatment. • The novel energy system model includes wastewater treatment process constraints. • Demand response of wastewater treatment plants can lower electricity costs. • The emission intensity of the Irish power mix decreases in most scenarios.