| New projects


duration storage by 2030, and the Government has committed $97.5 million to accelerate pumped hydro projects that could meet that target. This includes funding for private projects as well as funding to undertake site investigations for pumped hydro potential on existing WaterNSW dams.


Snowy 2.0 Another major project in New South Wales is the


Snowy 2.0 scheme. The next chapter in the Snowy Scheme’s history, Snowy 2.0 will deliver 2000MW of pumping and generating capacity and 175 hours of storage – enough to power 500,000 homes simultaneously – which will underpin thousands of megawatts of intermittent renewables. The project involves linking two existing dams,


Tantangara and Talbingo, through 27km of tunnels and building a new underground power station. In October, Snowy Hydro celebrated the completion


of excavation for its first tunnel for Snowy 2.0, with the Lady Eileen Hudson tunnel boring machine (TBM) reaching the location of the new underground power station cavern. The 11m diameter TBM has excavated 2.85km to


create the main access tunnel at Lobs Hole in the Snowy Mountains, where a workforce of more than 2200 people are building the scheme. Snowy Hydro acting CEO Roger Whitby said the tunnelling achievement was a significant milestone, with Snowy 2.0 set to underpin the nation’s transition to renewables.


“Snowy 2.0 will not only provide on-demand, quick- start generating capacity for the National Electricity Market (NEM), but a massive 350,000 gigawatt hours of energy storage,” Whitby said. “This is our first new major tunnel excavation in decades, since construction of the original Scheme, and it gives us access to the site where we will create the enormous cavern 800m underground that will house our power station. “The TBM Lady Eileen Hudson and our teams from Snowy Hydro and contractor Future Generation Joint


Venture have done a great job to complete this critical tunnelling task. “However, there’s no slowing down. Work across


the project continues to move ahead rapidly and this tunnel boring machine is now being dismantled so it can be moved to the Talbingo adit where it will be reassembled with some new components for excavation of the 6km tailrace tunnel.” While dismantling of the TBM conveyor belt gets underway in the main access tunnel, drill and blast activities are ongoing to excavate cross passages and tunnels to gain access to the power station complex, which will include a 251m-long, 52m-high machine hall cavern and 223m-long, 46m-high transformer hall cavern. Elsewhere on the project, TBM Florence continues


excavating the headrace tunnel at Tantangara following successful reinforcement works. As anticipated, the ground conditions encountered by the TBMs on Snowy 2.0 have been highly variable, ranging from soft, sandy ground to extremely hard rock. The Snowy 2.0 teams have been working


collaboratively to safely navigate the softer ground conditions experienced at Tantangara, including high groundwater inflows. As part of the tunnelling process the team probed in advance of the TBM, identifying the soft ground ahead, and then consulted with our expert design consultants to plan for stabilisation works. TBM Florence has been specifically designed to encounter these variable ground conditions. Consolidation grouting around the perimeter of the headrace tunnel, and internally, the installation of steel ribs to reinforce the concrete segmental lining in the soft zone, have been carried out to ensure stability and manage groundwater inflows. Additional instrumentation to monitor ground performance has also been installed. Successful execution of the reinforcement works by Snowy 2.0 principal contractor Future Generation Joint Venture (FGJV) is enabling the TBM to carefully thrust off the segments and move forward.


f


Left: View of the start of excavation for the Snowy 2.0 main access tunnel portal and TBM cradle upper right


www.waterpowermagazine.com | November 2022 | 23


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