31 March 2025
On the ground at Lake King William – the centrepiece of the Tarraleah scheme – work is already underway to upgrade old infrastructure and prepare for this possible new future.
In late 2022, Hydro Tasmania kicked off a staged program of upgrade works that will support a proposed redevelopment of the iconic Tarraleah scheme.
The Federal Government is helping to fund the Tarraleah project, with up to $65M committed to support upgrades to the scheme. The program of works comprises of:
intake tower excavation
construction of the new 30-metre high concrete intake
excavation and construction of an approach channel
a 950-metre connecting tunnel and downstream portal.
The new tunnel will link the new intake at Lake King William to a future new conveyance that will feed water into Tarraleah Power Station.
The intake tower excavation is now complete. Almost a quarter of a million cubic metres of rock and soil were removed over the past 27 months to create the deep excavation where the new concrete tower will be constructed.
An innovative plastic concrete cut-off trench was designed by Entura. The trench protects the deep excavation from seepage from the mighty waters of Lake King William. It will also provide flexibility for construction and timing of future works associated with the intake excavation.
The intake tower construction is the next planned phase of work. A tender for the intake tower construction was recently released, marking another major project milestone. Other works in the pipeline are excavating an approach channel that will connect the intake to the lake.
An aerial view of the intake excavation where the new intake tower will be constructed.
A concept drawing of the proposed intake works at Lake King William
The Tarraleah scheme helps regulate water to six other hydropower stations downstream and supplies about 6.5% of Hydro Tasmania’s total annual energy generation.
Water is transported to the Tarraleah Power Station from Lake King William along a complex network of open canals, flumes, tunnels, pipelines and ponds. If you’ve driven through the Central Highlands, you will have seen the water canals that wind their way alongside the Lyell Highway.
Having a complex and lengthy way to transport water means Tarraleah is not as efficient or as flexible as it could be. Tarraleah is also not well suited to a modern electricity market where demand changes every 5 minutes!
We’ve been hard at work to reimagine the future of this mighty and iconic scheme. We analysed several options, carefully considering the social, environmental, commercial and economic risks and benefits of each. Our preferred option is a full redevelopment, including a new power station and a pressurised water conveyance. This option delivers the greatest capacity, storage, flexibility and reliability for every dollar invested, while addressing environmental risk.
Alongside the upgrade works, Hydro Tasmania has comprehensive studies underway that will help decide if this investment will bring benefits to Tasmania.
To stay up to date with the Tarraleah project, visit our project page.
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