Techno-economic design and placement tool for energy recovering pressure regulating turbines in water distribution systems

Water distribution systems present poor energy efficiency due to the significant amount of energy that dissipates in the form of excess water pressure. Besides energy losses, excess pressure increases water losses due to leakages and may result in pipeline damage. The employment of micro-turbines that concurrently harness excess energy and achieve pressure management is proposed by many researchers as potential replacements to the currently used pressure reduction valves. This work relies on previous work that determines the optimal design and operating point of such turbines integrated in the power distribution system, in order to develop an algorithm that considers the economic viability of such projects. The suggested algorithm has been applied to a simulated large-scale WDS in Kentucky that contains several locations where pressure regulation is currently performed or planned due to immense local pressure. Involving the economic viability of pressure regulating turbines within the design optimization process improves pay-back period and levelized cost of energy by more than 10 % and 20 %, respectively, compared to when their design is optimized solely for pressure regulation and maximum energy yield. The application of this approach to a typical WDS allowed more than 161 MWh/year of clean energy to be produced.