Snowy 2.0 Pumped Storage Power Station

Snowy 2.0 Pumped Storage Power Station or Snowy Hydro 2.0 or simply Snowy 2.0 is a pumped-hydro battery megaproject in New South Wales, Australia. The dispatchable generation project expands upon the original Snowy Mountains Scheme (ex post facto Snowy 1.0) connecting two existing dams through a 27-kilometre (17 mi) underground tunnel and a new, underground pumped-hydro power station. 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 the largest renewable energy project under construction in Australia. It includes one of the largest and deepest cavern excavations ever undertaken. It also includes the longest tunnels (at 27 kilometres in length) of any pumped-hydro station ever built.

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. It provides valuable firming capability. Snowy Hydro acts like a giant battery by absorbing, storing, and dispatching energy. Snowy 2.0 can be "switched on" very quickly. The battery is designed to operate for up to 175 hours of temporary supply. It is Australia's largest energy project, estimated to cost 12 billion Australian dollars and projected to generate 10% of the nation's energy.

The Australian grid will need about 660 GWh of storage by 2050. Claims that Snowy 2 offers more than half of this have been challenged. One analysis of actual storage capacity of Snowy 2.0 estimates capacity to be around 40 GWh when operating in full reticulation mode (no loss of water to river flows).

Construction began in 2019. By 2023, AU$4.3 billion had been spent. Snowy 2.0 has been described as a white elephant. The project is led by public company Snowy Hydro Limited. Snowy 2.0 will last for at least 100 years. When complete, it is expected to have a large impact on the price and reliability of electric power.