Technical and economic analysis of Pumps-as-Turbines (PaTs) used in an Italian Water Distribution Network (WDN) for electrical energy production

Abstract The use of renewable resources is fundamental for achieving the emissions reduction targets. Small-scale hydropower is a viable solution that has only partially been exploited so far for producing electrical energy in rural/remote zones and for recovering energy where there is availability of pressure gradients and flow rates, like in Water Distribution Networks (WDNs) or in other industrial processes. In this paper, Pumps-as-Turbines (PaTs) are studied as a potential energy recovery and pressure regulation device, considering the case study of the Egna municipality WDN, a city located in the North of Italy. An innovative analytical approach is used for selecting PaTs, depending on WDN operating data, and for forecasting the machine performance under varying operating conditions. A MATLAB® Simulink model is developed for simulating two different set-ups configurations and installation of PaTs. Finally, an economic analysis is performed by evaluating the potential energy recovery and the PayBack Periods (PBPs).