Running an island sustainably
Discover how a Class A Reserve creates its own water and power.
The story of Wadjemup/Rottnest Island doesn’t start and end on the famous shoreline or threaded bike paths. Rottnest Island is also an example of sustainable tourism. And, it all starts with the island’s water and energy systems.
Thanks to a team of engineers, the water you drink at Rottnest actually comes from a desalination plant on the island. The sweeping, white semi-circle of Longreach Bay not only holds the dappled water of your morning swim, but the saline (salty) water that’s collected by beach bores for filtering. This water is then pressurised to separate out the salt, forming a fresh, drinkable version that keeps the island hydrated without the need for groundwater.
A natural way to produce power
Just like the water you drink, the energy you use when you’re here also comes from the island — it’s a return to the natural cycle of things. And as you walk the well-worn trails, bike the quiet paths, and even submerge into the waves, you are part of this.
Rottnest Island has two amazing natural resources — the strong Western Australian sun and the wind of the Indian Ocean. These resources are not just free, they’re renewable. It’s a truly natural system, where our life-sustaining resources are constantly replenished, but the island remains whole.
To manage fluctuations in the supply, Rottnest runs on an advanced hybrid energy system that combines wind and solar power with a local power generation plant using low-load and standard diesel.
The transformation of wind into light
You might have seen our wind turbine spinning on Mt Herschel. Even from the shores of Perth, the gentle motion is visible against the horizon. Essentially, it’s a little generator; as the wind turns the blades, the kinetic energy (energy that comes from movement) is converted into direct current (DC) electricity. From there it’s transmitted to a transformer, which converts it to alternating current (AC) electricity and increases its voltage. And from there it’s directed to the powerhouse and spread around the island.
How does the sun play its part?
Well, it works much the same as the wind turbine, except it’s sunlight that’s converted into electrical energy. The solar panels in our solar farm are made up of what are called photovoltaic (PV) cells. When the sun hits them, they absorb the light and release electrons. When the free electrons are captured, they produce an electrical current that can be converted into DC electricity. From there, the DC electricity is converted into AC electricity and distributed, just like the wind.
When darkness sets in and the wind lies still
The solar farm can only produce power during sunlight hours and even though wind can occur 24 hours a day, it does lull at times. That’s when the hybrid energy system kicks in — it tells us how much energy is being generated outside and if it isn’t enough, energy from our diesel generators fills the gap.
Sometimes we have the opposite problem though. Strong winds and hot days often provide us with an excess of renewable energy. We don’t want these precious resources to go to waste, so we partnered with Hydro Tasmania, ComAp, and the Australian Renewable Energy Agency to create the Rottnest Island Water and Renewable Energy Nexus.
The Nexus takes the excess energy from the wind turbine or solar farm and directs it to the desalination plant to produce more clean water. The fresh drinking water can then be stored here in tanks, ready to be used as soon as needed.
The wind turbine and solar farm provide up to 45% of the island’s energy needs, so we’re using diesel less and less. So far, we’ve achieved a reduction of around 1,600 tonnes in CO2 emissions each year – the equivalent of taking 350 cars off the road. And it’s about to get better. With new government investments coming into effect, the reduction in emissions will increase to an estimated 4,000 tonnes and the island will run off 75% renewable energy.
Read the full article published on rottnestisland.com