Pumps as turbines for energy recovery in water distribution systems: a review

Energy recovery and pressure management are essential for achieving sustainable improvements in the development of water distribution systems. An alternative that has been studied worldwide is the use of pumps as turbines (PATs) replacing pressure-reducing valves to balance pressure control and energy production. This study aims to investigate the current and most recent literature regarding the use of PATs, addressing technical and economic implications that the technical-scientific community has studied so far. The search terms used in the Scopus and Web of Science databases were {‘pump as turbine’ AND ‘water supply network’, ‘water distribution network’ OR ‘water distribution system’}. In total, 59 papers were analysed, highlighting the operation of PATs as well as selection and location methods, along with the evaluation of electricity production, decreased leaks and especially a suitable cost–benefit ratio. This review indicates that PATs have been infrequently used in real systems. However, the application is greatly feasible from the technical and economic points of view, and in the case of a variable-speed PAT, the amount of energy produced is high. Future research should be directed towards the optimisation of new PAT settings so they can better deal with the operational variations in the systems.