Pump-as-turbine for energy recovery in municipal water supply networks. A review

Recent studies recommended the recovery of energy incorporated to water distribution networks (WDNs) of municipal water supply systems (WSS) through systems based on pumps-as-turbines (PATs). Although a simple and economically viable technology, it has received scanty attention in the literature when compared to other renewable energies, with subsequent limits in its understanding for academic and professional purposes. Current paper reviews the potential of WDNs in energy recovery studies using PAT technology and focuses on efficient management and control of pressure in networks and on the manner pressure-reducing valves (PRVs) wastes energy which may be retrieved when PAT is employed: key technical and challenging criteria of PATs in WDNs. Finally, a case study of a WDN with an estimate of 370,835.70 kWh/year recoverable by PATs is presented. It is expected that current paper will further PAT investigations and contribute towards PAT improvement and consolidation for sustainable use of water in WDNs and the recovery of clean energy.