Hydro Tasmania is a step closer to completing upgrades across the Mersey-Forth hydropower scheme after reaching the halfway mark on its $62 million Lemonthyme power station project.
With a total capacity of 290MW, the Mersey-Forth scheme supplies around 10 per cent of Tasmania’s energy needs. Lemonthyme contributes up to 54MW.
As Lemonthyme’s first full overhaul since it was commissioned in 1969, the works are expected to extend the station’s operational life by a further 30 years.
Upgrades to the single-turbine station include a new turbine runner, main inlet valve and distributor, as well as refurbishment of the turbine relief valve and a full electrical upgrade to improve efficiency and reliability.
“Lemonthyme is an essential power station in the Mersey-Forth, connecting the Mersey River to the River Forth via a 6.5km tunnel and 1.6km penstock,” Hydro Tasmania executive general manager – assets and infrastructure Jesse Clark said.
“That vital link between the two rivers makes it a critical asset in our portfolio.”
Hydro Tasmania’s Cambridge workshop has played a central role in the upgrade, refurbishing the turbine relief valve and machining components to tight tolerances.
“The level of accuracy required for these parts to work in our turbines is down to hundredths of a millimetre,” Clark said. “In the design phase, we added some additional material to the parts we ordered to ensure we could get the fit just right.
“The team at Cambridge has done a fantastic job inspecting, measuring and machining the parts to ensure they are the perfect fit for the turbine.”
Around 13 local specialist contractors have also contributed to the project, delivering services including steel works, platform design, and the fabrication of transport frames, jigs and fixtures.
The Lemonthyme upgrade is expected to be completed by the end of 2026, with works on the final station in the scheme, Fisher power station, scheduled to begin in 2027.
Upgrades at Paloona, Devils Gate, Wilmot, Cethana and Rowallan power stations have already been completed.
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