[2] It is expected to supply 2.2 gigawatts of capacity and about 350,000 megawatt hours of large-scale storage to the national electricity market.

It is designed for grid stabilization; to be a backup at times of peak demand and for when solar and wind energy are not providing sufficient power.

Snowy Hydro acts like a giant battery by absorbing, storing, and dispatching energy.

[15] The current project originated as the centrepiece of Malcolm Turnbull's climate change policy in 2017.

[18] The first tunnel that was completed by October 2022, was a 2.85 kilometre section that provided main access at Lobs Hole.

[20] It is 2.93 kilometre long, 10 metres in diameter and will be used for power station ventilation and high-voltage cables.

[16][7][4] Delays have been caused by the COVID-19 pandemic, global supply chain disruptions, complex design elements and variable site and geological conditions.

[9] The delays have raised concerns that Snowy Hydro will not be ready in time for new solar and wind projects coming online as five coal-fired power stations close.

[4] The project is currently expected to be fully operational by the end of 2028 and generating power as early as late 2027.

[16] One of the machines, called Florence was stuck for 19 months after encountering soft rock near Tantangara.

[23] Florence is excavating the 16 km headrace tunnel, which will connect the underground power station to the upper Tantangara reservoir.

[26] By 11 July Florence was clear of the hard rock after using ultra-high pressure water jetting.

[36] The construction of overhead power lines by TransGrid has been opposed by community advocacy groups.

[37] Landholders desire to see the transmission line built underground have been opposed due to prohibitive costs.