Excavation breakthrough for Snowy 2.0 transformer hall

One of the four tunnel boring machines for Snowy 2.0 (breakthrough)
One of the four tunnel boring machines for Snowy 2.0 (Image: Snowy Hydro)

Snowy Hydro is celebrating a major breakthrough at the Snowy 2.0 pumped-hydro project, with successful excavation of the final three metres of the power station’s enormous 223m long transformer hall cavern crown.

Related article: Government says Snowy 2.0 still viable despite cost blowout

The Snowy 2.0 delivery team began excavating the transformer hall and machine hall caverns in June 2023. The Snowy 2.0 power station will be located approximately 800m underground at Lobs Hole in the Snowy Mountains. When completed, the machine hall will be 251m long and 52m high and the transformer hall 223m long and 46m high. Together they will form one of the largest and deepest caverns in the world—big enough to fit the Sydney Opera House inside.

So far, about 17,000 cubic metres of material has been excavated from the central heading of the transformer hall cavern crown. The heading has been advanced in 3-4 metre rounds from either end of the cavern for a total of 77 blasts.

The machine hall cavern crown breakthrough will take place in coming weeks, and widening of both cavern crowns, known as side slashing, is ongoing and planned for completion in coming months. Excavation of both power station caverns is set to continue through 2024.

The breakthrough of the transformer hall cavern crown represents another important milestone for the Snowy 2.0 pumped-hydro project, which will significantly expand the existing Snowy Scheme and will provide an added 2.2GW of on-demand power and 160 hours of large-scale renewable energy storage for the National Electricity Market.

Related article: I’m not an apologist for the Snowy 2.0 hydro scheme—but let’s not obsess over the delays and cost blowouts

Snowy Hydro CEO Dennis Barnes said, “The breakthrough of the transformer hall cavern crown is a really pleasing milestone for the Snowy 2.0 team, reinforcing that we’re making good progress with our underground drill and blast excavation activities. We are well on our way to delivering the largest single project that will help ensure Australia’s secure and reliable transition to renewable energy.”

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