Opportunity and Economic Feasibility of Inline Microhydropower Units in Water Supply Networks

Abstract

Small-scale hydropower is emerging as a decentralized source to satisfy local demand for electricity. In water supply systems, microhydropower can be used for energy recovery associated with excessive pressure control. However, there is a lack of specific solutions for applications within networks where discharges are highly variable and there are limitations of pressure. An arrangement of microturbines specially conceived for water supply networks is proposed, based on a recently tested microturbine for inline installation in pipes. The installation of up to four turbine units is possible within a buried chamber created around an existing pipe. The location of the chambers is analyzed using an optimization algorithm that considers two objective functions: energy production and economic value. The feasibility of the proposed arrangement for a microhydropower plant was assessed through a case study of a subgrid of the water supply network of Lausanne, Switzerland. A detailed analysis of the cost breakdown revealed that further to the electromechanical equipment, the number of isolation valves required in each layout may have an important role on the investments.