SA Water answers questions about proposed KI desalination expansion

SA Water's existing desalination plant at Penneshaw on Kangaroo Island. Photo SA Water
SA Water's existing desalination plant at Penneshaw on Kangaroo Island. Photo SA Water

SA Water is continuing conversations last week with the Kangaroo Island community on plans for a new seawater desalination plant in Penneshaw, including discussing opportunities for more than 1000 residents in four local towns to connect to the local drinking water network and receive supply from the plant.

Information sessions were held in American River, Baudin Beach, Island Beach and Sapphiretown, and follow face-to-face and online meetings late last year with the wider Kangaroo Island community and businesses interested in helping deliver the project.

This includes a Wednesday night session tonight, January 13 in American River, where some residents are opposed to being made to connect to the new proposed water pipeline and its associated charges.

Residents living adjacent to any new pipeline will be charged the $271 per annum water delivery fee regardless of whether they connect or not.

Others on KI have questioned why additional desalination capacity is needed when it will only encourage more inappropriate and unsustainable development.

The construction of a new desalination plant at Penneshaw was listed by the state government as one its commitments to adapt to climate change.

The first part of the 5pm to 8pm session will be a drop-in format for the local community, with a formal presentation at around 7pm.

SA Water last month held an information night at Penneshaw to discuss the $19.8 million plan to expand the existing desalination plant.

SA Water's General Manager of Strategy, Engagement and Innovation Anna Jackson said water produced from the new plant will supplement the existing Penneshaw facility and Middle River Reservoir, and through a connected large underground pipeline, will also provide capacity to service additional properties.

"We want to hear from residents in American River, Baudin Beach, Island Beach and Sapphiretown - who currently rely on private rainwater tanks or water carters for their drinking water - to determine their interest in connecting to this new part of the network and receiving a safe, reliable and affordable water supply," Anna said.

"Their feedback will help identify where the new large water pipeline, along with smaller connecting reticulation mains, will be laid.

"As planning for the project progresses, we'll keep these residents updated, along with the wider local community and key interest groups like the Kangaroo Island Council and various progress associations.

"To inform the exact location of the new desalination plant and ensure we're able to protect and preserve the surrounding natural environment both during construction and once the plant is operational, we're also carrying out environment and geotechnical investigations in the Penneshaw area.

"The new plant will be built in the vicinity of the existing 400 kilolitre a day desalination facility at Penneshaw, which has been supplying water since 1999."

State and Federal Government funding was confirmed last year for the $47.8 million project, which through an additional climate-independent supply of drinking water, aims to improve water security for local residents and businesses, and support the Island's tourism and agriculture industries.

Subject to required development and environmental approvals, the new 700 megalitre per year desalination plant is expected to be operational by the end of 2022.

For more information on the project, visit watertalks.sawater.com.au

Questions for SA Water

The Islander submitted a list of questions to SA Water, including the new plant's location, its power usage and supply, as well as plans for its byproducts.

Q: Will people be required to connect to new pipelines, or can they opt out?

A: The new desalination facility will be built in the vicinity of the existing plant at Penneshaw. The pipeline connecting the new desalination plant to the Middle River-Kingscote network is to be a transfer main, which is typically constructed to transport bulk quantities of water from one location to another within our network.

Transfer mains are not generally part of the reticulation network that connects directly to customers. However, we are working with neighbours of the transfer pipeline to identify potential demands and opportunities for direct connection.

The new transfer main will hold sufficient capacity to develop new reticulation networks to service residents in Baudin Beach, Island Beach, Sapphiretown and American River.

We'll work together with these communities to discuss opportunities and determine interest in connecting to a new supply of safe, clean drinking water as the project progresses, informing the extent of our reticulation network.

Connections to the new reticulation main and secure water source will be optional, however rating on abuttal may apply to those who choose not to connect.

Q: What percentage of the Island's water usage is the new desal plant expected to produce?

A: The new desalination plant will produce as much as 80 per cent of Kangaroo Island's current water requirements, allowing for growth and an expected demand increase by 2022 as a result of new development

The new plant will deliver around 50 per cent of Kangaroo Island's water supply if the forecast growth is achieved.

Q: What will the anticipated annual production of the new plant be?

A: The new desalination plant will be able to produce 2 megalitres (ML) per day, or approximately 700 ML per year, with supporting infrastructure, including the new pipeline. It will be designed to sustain an ultimate capacity of 6 ML per day should forecast demand require an increased capacity in the future.

Q: What happens to the sale once it is extracted at the Penneshaw desal plant now and also in the expanded version?

A: The current desalination plant at Penneshaw, like the much larger Adelaide Desalination Plant, produces saline concentrate as one of the by-products of the desalination process, which is safely returned to the ocean using a series of diffusers.

The diffusers are designed to mix the concentrate with seawater, off-shore, to rapidly dilute it to the normal salinity levels found in both areas.

Independent reviews of each plant concluded that the discharge of saline concentrate has caused no harm to the local marine environment in the regions.

Prior to the construction of Penneshaw's new desalination plant, all relevant planning and environmental approvals and licenses will be sought.

Q: What is the annual energy consumption in kilowatt hours at the Penneshaw desal plant, now and also in the expanded version?

A: In the 2019-2020 financial year, the existing Penneshaw plant used approximately 400 MWh (megawatt hours) to produce and pump 80 ML of drinking water to our storage site and customers.

The operation of the new desalination plant is expected to require approximately 3,400 MWh of energy each year to produce and pump as much as 700 ML of drinking water across Kangaroo Island.

We will investigate alternative renewable energy sources that would enhance the sustainability of the new plant and reduce the cost of operating the plant and its supporting infrastructure.

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