A holistic approach to water supply network operation – using desalination to improve cost efficiency

Seqwater is one of Australia's largest water businesses, with one of the most geographically spread and diverse asset bases. This includes 37 water treatment plants (WTPs), more than 600 km of bulk water supply pipeline, and the Gold Coast Desalination Plant (GCDP) constructed as part of the South East Queensland Millennium Drought response. The production of desalinated water has a greater unit-volumetric cost than the treatment of surface water due to high production energy costs. This paper presents the holistic approach adopted by Seqwater to find a solution for supply contingency while undertaking necessary upgrades and maintenance at the Mudgeeraba WTP. Through a process of network modelling, system risk mapping and financial analysis, it was demonstrated that operating the GCDP for 18 days would provide the best value solution due to the operating costs being offset by bulk supply network operational efficiency improvements.