Snowy Hydro 2.0’s TBM Florence is back in action after overcoming a rocky halt, marking progress in Australia’s monumental hydro project.
- The TBM Florence was stuck in hard rock for nearly two months, halting its 16km headrace tunnel excavation for the pumped hydro storage.
- High-pressure water jets were employed to dislodge the rock obstructing the TBM’s progress, allowing it to resume on 11 July.
- Despite TBM Florence’s challenges, other project elements like the 6km tailrace tunnel and 28m diameter Marica surge shaft are progressing.
- The overall Snowy 2.0 project, plagued by delays and cost hikes, aims to connect the Tantangara and Talbingo reservoirs through the Snowy Mountains.
The Snowy Hydro 2.0 project, an ambitious hydroelectric venture situated in New South Wales, has reached a critical milestone as the tunnel boring machine (TBM) Florence resumes work after being incapacitated for almost two months. The machine, crucial for cutting through the 16km headrace tunnel, had been immobilised by hard rock formations since May 2023. This marked a significant hurdle in digging the tunnel designed to facilitate pumped hydro storage.
To overcome this impediment, engineers resorted to deploying high-pressure water jets aimed at dismantling the rock obstructing the TBM’s cutter shield. After considerable efforts and a prolonged standstill, the machine commenced operations anew on 11 July 2023. However, Snowy Hydro anticipates encountering further varying ground conditions, particularly as the TBM manoeuvres through the curve leading to the main tunnel alignment, which may again affect its speed and efficiency.
Meanwhile, complementary progress on other segments of the mega project is notable. The second TBM, dubbed Lady Eileen Hudson, is advancing the 6km tailrace tunnel, having completed the 2.8km main access tunnel to the power station. This development is vital for connecting the underground power station to the lower Talbingo reservoir. Recent infrastructural additions, including a conveyor belt extension and service modifications, have been implemented to prepare for the junction of the tailrace tunnel with the Talbingo intake excavation.
The third TBM named Kirsten is tasked with excavating the 1.6km inclined pressure shaft, connecting the power station with the headrace tunnel to the upper Tantangara reservoir. This mission follows the completion of the 2.9km cable and ventilation tunnel. During the excavation, 14 trial tunnel lining rings were installed, fabricated from locally manufactured concrete segments, capable of withstanding the anticipated high water pressures.
Furthermore, the Marica surge shaft excavation is advancing, having reached a depth of 95m, and is destined to reach 250m upon completion. This 28m diameter shaft is integral for water storage and pressure relief as it will balance the water momentum during the power station startup. Excavation tasks have been executed using a combination of rock-breaking, excavation and drill-and-blast techniques.
Despite the technical progress, the project is not without its challenges. Initially budgeted at A$5.1bn, the costs soared to A$12bn as of September 2023, and the completion has been delayed to potentially December 2029. Initially set for 2027, the delays underscore the complexities and scale of the infrastructural undertaking.
Snowy Hydro 2.0’s advancements signify progress amidst challenges in the expansive hydroelectric scheme.
