Alkimos desalination plant to cost $2.8bn

The state government has committed $2.8 billion to the construction of the first stage of Water Corporation’s Alkimos seawater desalination plant.

When announced last year, the project was expected to cost more than $1.4 billion, and a recent Metro Outer Joint Development Assessment Panel approval in September outlined a project with an estimated cost of $1.6 billion.

While today’s $2.8 billion funding commitment for stage one of Perth’s third desalination plant is almost double the estimated project cost published in the JDAP application, it is understood to cover the wider project, including a number of other major associated works.

That includes the laying of 27 kilometres of trunk mains, integration conveyence projects at more than a dozen Perth sites, and contingency costs.

The project will be funded out of the state’s budget surplus without the need for debt, with the first 50-billion-litre stage to be delivered in 2028.

Premier Roger Cook said the desalination plant would ensure the long-term water security of 2.5 million Western Australians.

“We know the globe continues to dry,” he said.

“We know that rainfall continues at around twenty per cent less than the long-term average. That’s led to an eighty per cent reduction in runoff into our dams.

“We’ve got no choice. We can either suck the water out of the ground, depleting our aquifers, or we can invest in large-scale desalination to make sure that we secure the long-term water future for WA.”

Project costings are expected to be factored into the state’s mid-year budget review.

The delivery date of the project’s second stage is to be decided, according to Mr Cook, though the JDAP application previously suggested it would take place in 2032.

Water Minister Simone McGurk said project costings had become clearer as the government worked through the finer details, incorporating factors including infrastructure project price escalations.

“As the premier said, what’s exciting is that we’ll be able to fund this from the surplus,” she said.

“This is not being funded by debt. We now know this is the complete cost of the project, including the siteworks, the construction and linking this into the surrounding water systems.”

The new plant will sit adjacent to an existing wastewater treatment plant in an area to be known as the Alkimos water precinct.

Georgiou Group has been handed a $29.8 million contract to prepare the site for construction and will sink the site into the landscape and extend a large, vegetated sand dune, thereby using the natural landscape to shield the plant from view and create a noise buffer.

The early works are expected to create around 70 local jobs.

A contract to design, construct and operate the plant will be awarded early in 2024.

Ms McGurk said the government planned for the project to have net-zero greenhouse gas emissions during its construction and throughout operation.

The facility will be Perth’s third desalination plant and will supply drinking water to households across the metropolitan region.