This case study of the Rottnest Island Water Renewable Energy Nexus (WREN) Project describes the practical integration challenges for hybrid renewable energy power systems. It was presented by Hydro Tasmania at the 2017 World Renewable Energy Congress.
Hydro Tasmania has been engaged by the Rottnest Island Authority to design and implement an advanced hybrid off-grid system on Rottnest Island, Western Australia. This project was funded by the Australian Renewable Energy Agency (ARENA). The system achieves a higher level of annual renewable energy contribution through the innovative integration of wind and solar generation with the demand-side management of reverse osmosis desalination and a dynamic load bank.
The project aims to increase renewable contribution from 30% to 45% per annum, via the addition of: a new hybrid control system incorporating demand management of the reverse osmosis desalination system as a form of ‘energy storage’; 600 kWp DC solar for additional renewable power generation; and a 500kW dynamic resistor for increased security of supply at high instantaneous penetration levels.
This paper provides a summary of the process of utilising water desalination as a method of ‘energy storage’ to increase renewable energy contribution and assist in addressing and leveraging the opportunity that exists from the existing water / energy nexus. It outlines solutions deployed to meet the practical challenges of implementing a high renewable contribution hybrid project in the absence of significant enabling technologies such as flywheels and batteries. Also highlighted is the importance of operator involvement and performance tools to maximise diesel savings.