Integration of hydraulic wind turbines for seawater reverse osmosis desalination

The integration of renewable energy sources to power seawater desalination is crucial to mitigate CO2 emissions and to face the increasing challenges that are stressing fresh water resources depletion. In particular wind energy is one of the most cost-effective forms of renewable energy with a high potential to reduce the seawater desalination's environmental impact. While most applications are aimed at using conventional wind technologies to produce the electricity required by the desalination processes, wind turbines with hydraulic transmission can bring new opportunities to avoid the multiple energy conversion steps and make fresh water production from wind energy more simple and cost-effective. This paper elaborates on two potential configurations, numerical modelling and possible control strategies which are able to directly combine a horizontal axis wind turbine rotor, a hydraulic transmission and a seawater reverse osmosis (SWRO) desalination unit. The integration of an ideal pressure exchanger as energy recovery devices (ERD) to increase the operating efficiency of the SWRO unit is analysed. Results are shown for the most relevant operating conditions of the integrated system in terms of wind speeds, pressures, brine salinity and fresh water productions. Intermediate results are also shown for the dynamic analysis and simulation of the wind powered direct-driven SWRO system subject to turbulent wind speed conditions.