Hydro Tasmania has reached the halfway mark of a $62 million upgrade of Lemonthyme Power Station, a key component of the Mersey-Forth Hydropower Scheme in Tasmania.
The upgrade marks further progress in a broader program to modernise all stations in the Mersey-Forth system, preparing it for long-term operation.
The scheme has a total generating capacity of 290MW, with Lemonthyme contributing up to 54MW. It supplies around 10% of Tasmania’s electricity demand.
Commissioned in 1969, Lemonthyme is undergoing its first full upgrade. The works are expected to extend the station’s operational life by 30 years. The project includes installation of a new turbine runner, main inlet valve and distributor, as well as refurbishment of the turbine relief valve and a full electrical system upgrade. The improvements are aimed at increasing efficiency and reliability.
Hydro Tasmania Executive General Manager Assets and Infrastructure Jesse Clark said Lemonthyme Power Station was an important part of the Mersey-Forth Scheme.
“Lemonthyme is an essential power station in the Mersey-Forth, connecting the Mersey River to the River Forth via a 6.5-kilometre tunnel and 1.6-kilometre penstock,” said Clark.“That vital link between the two rivers makes it a critical asset in our portfolio.”
Hydro Tasmania’s Cambridge Workshop has played a key role in the upgrade, refurbishing the turbine relief valve and machining technical parts to reduce defects.
“The level of accuracy required for these parts to work in our turbines is down to hundredths of a millimetre. In the design phase, we added some additional material to the parts we ordered to ensure we could get the fit just right,” said Clark. “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 been involved in the upgrade, providing services including steel works, platform design, transport frames and fixtures.
The Lemonthyme upgrade is scheduled for completion by the end of 2026. Work on the final station in the scheme, Fisher, is due to begin in 2027. Upgrades at Paloona, Devils Gate, Wilmot, Cethana and Rowallan power stations have already been completed.
