Rottnest Island water and renewable energy nexus project

Client: Rottnest Island Authority
Location: Rottnest Island, Australia
Date: 2013–2017

Powering an island community through renewables for reliable electricity and drinking water at lower cost and with lower emissions.


Like many remote or island locations, the tourist destination of Rottnest Island, off the coast of Western Australia, has relied heavily on expensive and emissions-intensive diesel fuel to supply its electricity needs and power its vital water desalination plant.

An innovative and advanced integrated hybrid system was required to reduce reliance on diesel fuel while still supplying stable and reliable power to meet the current and future needs of the local community, more than half a million tourists annually and the power-hungry water desalination plant. It would also complement the island’s focus on sustainability.

The Rottnest Island Water and Renewable Energy Nexus Project (WREN) project was an initiative of Hydro Tasmania and the client, with funding assistance provided by the Australian Renewable Energy Agency to Hydro Tasmania.


The WREN project delivers both electricity and drinking water for Rottnest Island at lower cost, and with lower emissions, through innovative use of renewable energy and smart controls. 

A novel aspect of this project is its focus on controlling the timing of an energy-intensive activity – running the island’s desalination plant – to make the best use of renewable energy when most abundant.

New solar photovoltaic (PV) of 600 kW and a 500 kW dynamic resistor was integrated with the existing 600 kW wind turbine and diesel generators (including low-load diesels) by deploying an advanced hybrid control system. The smart controls manage the generation and enabling equipment as well as automating the desalination plant to operate at maximum capacity when wind and solar energy are abundant, and store treated water for use at times of lower renewable energy availability.

The project integrates education about power and water sustainability into the Rottnest Island visitor experience, through digital educational materials that allow real-time interaction with the cutting-edge power/water system, delivered via mobile apps.

The real-time performance of the system can be viewed on the Rottnest Island Water and Renewable Energy Nexus Android and iOS apps.


Rottnest Island is now almost 50% powered by renewables, and up to 95% at times of high wind and solar generation with its low-load diesels.

Running the desalination plant on renewables rather than diesel reduces the cost and emissions intensity of producing the island’s drinking water. The success of the project has strong application for remote, off-grid or island communities worldwide.