Water distribution system design with behind-the-meter solar energy under various discount rates

Abstract

Water distribution systems (WDSs) are essential parts of urban and rural infrastructure systems. The energy consumption including associated costs and GHG emissions for distributing water has increased in recent years. As a result, behind-the-meter (BTM) energy systems such as solar panels and energy storage facilities have been installed by water utilities to reduce energy consumption from the centralised energy grid. There has been a lot of research on the optimisation of the design of WDSs, however, many of these works have not considered BTM energy options or have incorporated BTM energy options in an ad-hoc fashion. Therefore, this study is proposed to optimise the design of WDSs considering BTM solar energy sources. A pressurised irrigation supply system in Victoria, Australia has been used as the case study system. In this paper, the design of a real-world WDS has been formulated as a multi-objective optimisation problem to investigate the trade-offs between the total life cycle cost and total life cycle greenhouse gas (GHG) emissions under various discount rates scenarios used to estimate the operational cost and emissions throughout the service life of the system. It has been found that both the total life cycle cost and GHG emissions have been reduced significantly when BTM solar energy is incorporated. In addition, with the same solar photovoltaic (PV) size, the optimal pipe diameters, as well as the objective function values are sensitive to the discount rate values that have been used,