Tunnel boring machine hits major milestone on Snowy 2.0 project

The Snowy 2.0 pumped-hydro megaproject recently marked a significant milestone, with one of three tunnel boring machines (TBM), Lady Eileen Hudson, now two-thirds of the way through its second tunnel excavation.

The TBM is approximately four kilometres into the six kilometre ‘tailrace’ tunnel, which will link the lower Talbingo Reservoir with the massive 20-storey underground power station.

TBM Lady Eileen Hudson previously completed a 2.85km main access tunnel, which is now being used by construction teams to reach the underground power station site.

Drill and blast works are also advancing at the Talbingo water intake, creating a new 700-metre tunnel between the intake structure and the tailrace tunnel.

The Talbingo intake is located in very steep terrain and following excavation of 570,000 cubic metres of material over two years, the rock face is now 110m high.

Momentum

Snowy Hydro CEO Dennis Barnes said that recent months have been some of the project’s most productive.

“Overall the project is around 60 per cent complete and there’s a strong sense of momentum, with good tunnelling progress by TBM Lady Eileen and other two TBMs performing well,” he said.

“Snowy 2.0 is one of the most complex and challenging megaprojects underway in the world. There is an immense sense of pride in what’s being achieved across the workforce of more than 3,000 people.”

Barnes said Snowy 2.0 will be the most significant addition to the National Electricity Market (NEM) since the original Snowy Scheme.

“Snowy 2.0 will have a generating capacity of 2,200 megawatts and an unmatched 160-hour storage capability, meaning it will be able to power around three million homes for a week,” he said.

“While batteries and gas are important to store the excess energy from the increasing amounts of wind and solar in the grid, only pumped hydro can offer the long-duration storage needed to keep the lights on and smooth energy price peaks during extended periods without enough sun and wind.”

Snowy 2.0 is on track to be delivered within the $12 billion budget and be complete by the end of 2028.

Progress

Progress is being made across the project.

In the underground power station complex, the caverns are more than 27 per cent excavated.

All 196 of the very large brackets that will hold the temporary construction cranes to build the underground power station have been installed in the two power station caverns.

When fully excavated, the Snowy 2.0 power station will be the equivalent of a 20-storey, 250 metre-long building, located 800m underground.

At Marica, the 28-metre wide surge shaft is excavated to 123m, or half of its final depth. The shaft will provide water storage when the power station starts up and pressure relief in the headrace tunnel when it shuts down.

TBM Florence is progressing well, excavating the 17km long ‘headrace’ tunnel that will link the upper Tantangara water reservoir to the underground power station, with more than 1,600m excavated.

TBM Kirsten is performing to plan and is now excavating the 1.6km, very steep tunnel that will link the headrace tunnel to the underground power station.

Ground conditions ahead of all TBMs are expected to be inconsistent and the performance of the machines will vary as a result.

The NSW Department of Planning, Infrastructure and Housing is currently assessing the planning modification to enable a fourth project TBM, which is required to tunnel through a challenging geological fault zone.