Snowy Hydro’s beleaguered tunnel boring machine, Florence, seems to be regularly stuck between soft rock and a hard place.
But that has not deterred enthusiasts for pumped hydro as a key part of Australia’s transition off fossil fuels.
Progress on the headrace tunnel within Snowy’s $12bn project to link two big dams stalled for a year after Florence hit “soft ground conditions” sooner than anticipated. Two months ago, it got wedged in “extremely hard and abrasive rock” but crews are confident “hydro blasting” will permit boring to resume within days.
When completed – assuming no catastrophic incident occurs – the venture will be able to run water through its 2.2-gigawatt turbines for a week, a handy power source especially during still, dark wintry days. Water would get pumped up to the higher dam when electricity prices are low.
That the basic hydro technology has been known for a century is one reason similar schemes will play a significant role in helping Australia – and many other nations – reach net zero emissions. Of six projects recently given fast-tracked planning approval in New South Wales, three were pumped hydro ones.
Elsewhere, Genex, a listed firm being bought for $380m by Japan’s J-Power, hopes its Kidston pumped hydro plant at an old Queensland goldmine will switch on by the first quarter of 2025. Retailer Zen Energy hopes to tap into Sydney’s main water dam for a $4bn project to power the city’s fast-growing west while renewables investor North Harbour will soon announce a venture without tunnels.
Andrew Blakers, an emeritus engineering professor at the Australian National University, says Snowy’s woes might have been reduced had the Turnbull government studied alternative sites to 2.0. These locations could one day become Snowy 3.0, 4.0 or more.
“There’s a whole flock [of prospective sites] just to the west” of Talbingo reservoir that will serve as Snowy Hydro’s lower dam, he says, citing ANU’s online atlas that has identified more than 600,000 suitable pumped hydro sites globally.
“You can put in anything from two up to 1,500 gigawatt hours [of storage]. You’ve got so many good sites.”
Snowy itself identified four pumped hydro sites as part of a Snowy Mountains Scheme Augmentation Ranking Study back in 1991, as noted in 2.0’s environmental impact study, although what these were has never been revealed.
The atlas, though, reveals one site of a similar scale but requiring a tunnel just one-eighth of the 27km now being drilled for 2.0. Proceeding with it could make use of existing workers, machines, transmission and even Talbingo dam, Blakers says.
The ANU tool reveals many sites, such as near the Illawarra to Sydney’s south, where there’s a sharp vertical distance and access to water sources such as the ocean. Blakers says he was “quite proud” the Queensland government used it to locate its proposed 5GW Pioneer-Burdekin pumped hydro project, potentially the world’s largest.
Pumped hydro has its critics. Friction and other losses means the round-trip efficiency is typically only about 75%.
Tumbling lithium prices, down more than three-quarters since late 2022 because of Chinese oversupply, means batteries offer storage competition that can be built rapidly – especially compared with the decade needed for pumped hydro.
Bruce Mountain, head of the Victoria Energy Policy Centre, says the gap is “growing ever wider”.
“Chemical solutions seem to be eating ever more into the supply of longer duration [more than four hours] supply,” Mountain says. “The vast bulk of possible [pump hydro sites have] a small market and is facing ever stiffer competition.”
Big battery installations are growing rapidly even before the collapsing price of lithium really takes effect. Australia's additions are starting to pick up too.
— @phannam@mastodon.green (@p_hannam) July 11, 2024
(Source: @BloombergNEF ) pic.twitter.com/KpJVmjg5Pk
While AGL Energy and EnergyAustralia – backers of two of the three projects granted NSW critical state significant infrastructure status – are proceeding, Origin Energy opted not to extend its existing pumped Shoalhaven hydro plant south of Sydney.
“Due to higher-than-anticipated pricing estimates from construction contractors, Origin made the decision not to progress plans for the Shoalhaven pumped hydro expansion at this time,” a spokesperson said.
“[It] remains an advanced development option and Origin continues to take steps to secure the necessary environmental and regulatory approvals and will re-test pricing at a future opportunity when economic and market factors may have changed.”
Deb Frecklington, who may become Queensland energy minister should the LNP win the 26 October elections, has vowed to scrap the $12bn-plus Pioneer-Burdekin venture. “The massive cost blowouts on this project will unavoidably drive up the price of power in Queensland,” she said in June. “This is a project with no direct funding, no approvals and no social licence.”
But CSIRO rates pumped hydro as a viable option in all states but Western Australia, according to its 2023 storage roadmap report.
“Internationally, [pumped hydro] is a commercially competitive technology deployed extensively across the world,” it said.
Indeed, Australia’s Department of Foreign Affairs and Trade has been promoting the technology – and ANU’s atlas – to help neighbours from Nepal to Vietnam decarbonise economies to combat global heating.
“Australia’s support on pumped hydro energy storage is enabling partner countries to assess the potential of pumped hydro as a part of their transitions to clean energy and make informed decisions on their most appropriate transition path,” a spokesperson says.
Jamie Pittock, an ANU professor who recently took part in one project meeting inside the generator cabin of one of Thailand’s three pumped hydro plants, says that country is proposing six more, including three close to a decision. Cambodia and Vietnam are also considering three such plants.
“One of the advantages for developing countries is that most of them have the engineering capacity to lead in doing these projects, and most of the capital investment is spent in-country on civil engineering works,” Pittock says. “So they keep a lot more of the value than they do by importing a technology like batteries.”
Since many of them have centralised power networks, “when the transition happens in south-east Asia, it will happen very, very fast”, he says.
For Australia, the estimated 65,000 abandoned mine sites – according to CSIRO – offer many combinations of both disturbed land and the necessary vertical drop needed for pumped hydro.
Zen Energy’s venture, for instance, would use a discarded washery deep with 50m of coal dust and spoil as its upper reservoir. It has approval from WaterNSW to begin feasibility studies on a 3km tunnel linking it with Lake Burragorang that could support 1GW – half Snowy 2.0’s size – and power a third of Sydney’s homes from 2031.
“We’d hope that this comes in under $3m/megawatt,” says Zen’s chief executive, Anthony Garnaut. “At current pricing that’s competitive with a six-hour battery”, he says, adding pumped hydro has a “likely life of 80 years” compared with 25 or fewer for lithium.
Tony Schultz, North Harbour’s managing director, says his firm has a couple of such ventures in the works, including one worth hundreds of millions of dollars to be made public soon.
That one will use pipes rather than tunnelling to save costs and lower risk. Water loss will only be through evaporation and it “actually solves a water quality problem as well”, he says. Approvals and construction should take five years.
“It’s a great technology, and it’s a proven technology, and it has its place in the energy system of the future,” Schultz says.
“The scale of the challenge in terms of the ultimate closure of thermal or coal-fired generation is much, much larger than what Snowy 2.0 is going to be able to provide.”
