Aquasure Desalination Plant, Australia

Delivering Real Resilience.

The total average water inflow into Melbourne’s water storage facilities between 1997 and 2009, during the most severe drought ever recorded in the State of Victoria (Victoria), was less than two-thirds of the historical average between 1913 and 1996. Over the period of the drought, Melbourne’s population grew by 20% - from 3,336,088 to 4,031,787 – adding to downward pressure on reserves from consumption. Hence, between 1998 and 2007, Victoria’s water storage facilities decreased to around a third of maximum capacity leading to multiple years of water restrictions.

Against the backdrop of drought, the Victorian Government released a water management strategy, “Our Water Our Future” in June 2007. As part of the plan, the government announced its intention to develop a seawater reverse osmosis desalination plant to "augment Melbourne's water supply, as well as other regional supply systems."

The Victoria Desalination Project was procured as a public-private partnership (PPP) between The State of Victoria and AquaSure, the company contracted to finance, design, construct, operate and maintain the project for 30 years. The capital cost was AU$3.5 billion and involved the construction of 29 buildings, including the building housing the reverse osmosis equipment as well as an 84 km undergound transfer pipeline and 87 km underground power supply.

With commissioning completed in December 2012, the plant represents a rainfall-independent source of water capable of supplying up to 150 billion litres of water a year. This is equivalent to around one third of Melbourne's annual water consumption. Desalination therefore provides an insurance policy against future dry conditions by supplementing Melbourne's existing supplies from water catchment.

The world class design includes Australia's largest living green roof and a 2,250,000 sqm revegetated ecological reserve for public use. Long intake and outlet tunnels protect the coast and marine environment. Ongoing environmental management is a key project focus.

Desalinated water is piped from the plant at Wonthaggi to Cardinia Reservoir, which serves Melbourne via an 84 kilometre underground pipeline and directly into the water network. The pipeline consists of more than 6,200 lengths of pipe, with each pipe 1.93 metres in diameter, 13.5 metres long and weighing around 13 tonnes. The pipeline is capable of transporting up to 200 billion litres of water a year and connects into the existing water supply network in Berwick, an outer suburb of Melbourne.

Seven water delivery points along the pipeline connect local communities to the desalinated water supply while a booster pump station helps maintain enough pressure to keep the water moving on its journey from the desalination plant to Cardinia Reservoir. The pipeline is two-way so it also connects some regional areas to Melbourne’s catchment supplies when desalinated water is not being used. 

Under the PPP contract, Victoria is entitled to order water in set block increments up to 150 billion litres per annum. The plant proved that it is capable of producing water to the quality and quantity required by delivering 23 billion litres of high quality water to the Melbourne network as part of its commissioning process. Good rainfall levels have meant that Victoria has not ordered water from the plant since 2012; however, as the project was procured as an availability based concession, Victoria makes regular availability payments, irrespective of whether it places orders for water.