Nationwide assessment and turbine selection for energy recovery in water distribution networks using fuzzy AHP – VIKOR method

In water distribution networks (WDNs), excessive hydraulic pressure caused by elevation differences is commonly dissipated through pressure reducing valves (PRVs), resulting in significant energy loss. This study suggests replacing PRVs with hydropower plants (HPPs), enabling simultaneous pressure regulation and renewable electricity generation. To address the lack of integrated turbine selection tools in existing literature, this study develops a novel, real-data-driven nationwide assessment framework. Hydraulic and operational data from 129 sites were obtained from the National Water and Wastewater Engineering Company of Iran. The analysis follows a systematic 8-step process: first filtering sites for hydraulic compatibility using real-world specific speed equations, and then ranking feasible alternatives through a two-stage Multi-Criteria Decision-Making (MCDM) approach. The Fuzzy Analytical Hierarchy Process (FAHP) was used to determine criteria weights based on expert judgments, and the VIKOR method was employed to rank alternatives. Energy generation was estimated under three capacity factor scenarios (0.4, 0.6, and 0.8). The analysis indicates that Iran’s WDNs can generate up to 53.3 MW of electricity with an investment of €26.2 million, reducing annual CO2emissions by up to 0.246 million tons. Pelton (36.4%), Turgo (26.4%), and Francis (20.2%) turbines were identified as the most suitable options. This research provides a validated decision-support tool that bridges the gap between theoretical potential and practical manufacturer specifications for urban energy recovery.