Cost determination of water production in a nanofiltration desalination plant powered by a hybrid renewable energy system. Case study of Cobquecura, Chile

Abstract

This study explores a sustainable solution to address water scarcity in rural coastal areas. Using field data and simulations, the production cost of water was determined for a small-scale desalination plant designed and built by the University of Concepción. The plant employs nanofiltration technology and is powered by a hybrid system that includes solar panels, batteries, and a backup diesel generator, reducing reliance on non-renewable resources. This plant has been operational in the Cobquecura area of the Ñuble Region, Chile, since 2022. The methodology involved identifying an optimal operating profile, validated via simulations with Homer-Pro software, and calculating both the potable and irrigation water production and the average production cost of water. The results indicate an average water production cost of USD 3.19/m³, with 56 % of the cost attributed to the initial investment, 26 % to operational expenses, and 18 % to planned component replacements. This cost is significantly lower than the estimated cost of water delivered by tanker trucks, which can reach up to USD 24/m³ in the region. Additionally, tanker trucks are limited to operating under favorable weather conditions due to challenges posed by rural road infrastructure. This analysis highlights the technical and economic viability of integrating advanced desalination technologies with renewable energies, demonstrating their potential to address one of the most pressing environmental challenges in ensuring a reliable water supply for communities in remote areas. These findings offer a sustainable and innovative pathway to improve water scarcity and confirm the cost-effective application of renewable-energy-powered desalination solutions.