Three times cost: Snowy 2.0 was never going cheap, but much cheaper than relying on batteries for storage

Cost and completion timeline

Snowy 2.0 will convert the original Snowy hydroelectric scheme into a large pumped hydro storage project. Its final estimate is A$22–25 billion, and completion is scheduled for late 2029.

When the project was announced in 2017, then-Prime Minister Malcolm Turnbull gave a rough estimate of $2 billion and said it could be completed in four years. Engineering problems, stalled tunnelling machines and rising construction costs contributed to major overruns. The project is now about 80% complete and is likely to finish within three years.

Storage as coal retires

Renewables provide about 50% of electricity in the National Electricity Market, while the government’s target is 82% by 2030, mostly from solar and wind. More storage will be needed because over half of electricity demand occurs overnight, from 4pm to 8am, when solar output is minimal or absent.

Coal plants currently meet most overnight demand, but Australia’s ageing fleet is expected to close almost entirely over the next ten years. Wind, gas and stored energy are among the options for keeping power available overnight and on cloudy days; the article describes wind as intermittent and gas as expensive and high-emitting.

Batteries and pumped hydro

Batteries are increasingly affordable for short-term storage, covering minutes to hours, and can help meet brief demand spikes. The article says they are more expensive for longer periods, such as overnight or cloudy days.

Pumped hydro stores energy by pumping water uphill when power prices are low, then releasing it through turbines when prices rise. The latest CSIRO GenCost figures show it can store and release electricity more cheaply than batteries, with that advantage expected to remain over the next 10 and 20 years as battery cost declines taper off.

Long life and storage scale

Once operating, Snowy 2.0 will roughly quadruple Australia’s total rechargeable electricity storage. Its upper reservoir, Tantangara, has a 45-metre-high wall and can hold up to 254 gigalitres of water, about half the 500 gigalitres in Sydney Harbour.