Techno-economic assessment of vertical axis wind turbine driven RO desalination with compressed air energy storage for remote communities

Abstract

Renewable energy desalination is gaining much attention in remote off-grid communities facing challenges in accessing clean water. Typically, batteries ensure the continuous operation of small-scale renewable reverse osmosis (RO) desalination systems; however, they are expensive and have relatively shorter lifespans. This study investigates the implementation of a compressed air energy storage (CAES) system coupled with a vertical axis wind turbine (VAWT) to directly drive small-scale RO desalination, potentially replacing batteries and reducing energy conversions. A Simulink model was developed to simulate the performance of a VAWT-driven CAES operating RO units, adaptable for both technical and economic assessments. Parametric studies have identified the optimal configuration. The most cost-effective configuration, utilising eleven VAWTs and a pressure exchanger (PX), achieves a levelised cost of water (LCOW) of 1.63 US$/m 3 and an annual water production of 9400 m 3 . The normalised daily water production per square metre of turbine swept area at the study site is 0.19 m 3 /m 2 /day at an average wind speed of 5 m/s. While this configuration has a higher initial capital cost, it yields the lowest LCOW. The CAES system effectively addresses the intermittency challenges of wind energy. This study presents a novel, battery-free VAWT-CAES-RO system as a sustainable desalination solution for remote communities, offering a promising approach to address water scarcity in an environmentally friendly manner. • Using VAWTs to mechanically drive RO via a compressed air system was investigated. • Replacement of batteries with compressed air storage reduced water production cost. • VAWT with a compressed air system is economical, addressing wind intermittency. • Examined scenarios with varying VAWT numbers with or without energy recovery for the study site. • Parametric studies resulted in an optimal LCOW of 1.63 US$/m 3 for an off-grid system.