Techno-economic comparison between commercial energy recovery devices in complex Water Distribution Networks

Water Distribution Networks (WDN) proved to be viable for the exploitation of throttling hydraulic energy. Researchers often focused their attention on the study of Pumps as Turbines (PaTs) for WDNs without considering other solutions. Actually, PaTs are not the only machines that can be employed. Indeed, other solutions exists, e.g. Cross-Flow Turbines, and commercially available Energy Harvesting Control Valves. The novelty of this study regards the selection, for each node, of the best technology among these machines rather than choosing only among PaTs, in order to help the water utilities in the techno-economic decision processes. Regarding PaTs, the authors have updated and integrated PaT-ID, their proprietary decision making tool. A complex real WDN has been used as a case study, characterized by 8 reservoirs and 16 Pressure Reducing Valves (PRVs) installed to balance the network and to reduce water leakages. Although all the three considered type of devices show at least 40% of recovered available energy within the WDN, the best solution form an energy point of view not always could be feasible from an economic point of view. • Comparison among PaTs, Cross-flow turbines and Energy Harvesting Control Valves. • A complex WDN of a city is used as case study with 8 reservoirs and 16 PRVs. • A detailed economic and environmental comparison is performed for the three technologies. • At least 40% of energy recovered by the energy devices within the WDN. • The energy exploitation involves a reduction in from 25 to 160 ton CO 2 /year.