Australasia | A ubiquitous technology
Drawing on global survey data, Professor Andrew Blakers of the Australian National University highlights the ubiquity and feasibility of pumped storage hydropower
the size range of 5-5000GWh at a capital cost that is five times lower than batteries (US$8-40 per kilowatt- hour) and with a lifetime that is ten times longer (150 years). A 5000 GWh PHES system can provide all the storage needs for a fully decarbonised and electrified economy relying exclusively on solar and wind energy and servicing 100 million people. Premium PHES sites usually have large head (400- 1600m height difference between the reservoirs); large water-rock ratio (a large amount of water is dammed by a small rock wall, in a volume ratio above ten) and short pressure tunnels of a few kilometres.
PHES has low impact No new dams on rivers are needed for PHES. Minimal
Above: Worldwide there are 820,000 off-river pumped storage sites with 86,000,000 GWh of storage
NEW SOLAR AND WIND generation capacity is being installed around the world five times faster than all other new electricity sources combined, which is compelling market-based evidence that solar and wind generate the cheapest electricity. As revealed by the Australian National University’s
recent comprehensive high-resolution global survey of potential pumped hydro energy storage (PHES) sites, the world has 820,000 PHES sites with a combined storage of 86M GWh - equivalent to the usable storage in two trillion electric vehicle batteries. Providing a vastly available, highly mature, lowest- cost, lowest-impact, longest-lifetime energy storage solution to support solar and wind energy, PHES constitutes 95% of global energy storage, with most of the rest being provided by batteries. Premium quality PHES provides energy storage in
mining is required compared with mining for battery metals. Reservoir walls are built by scooping rock from the bed of the reservoirs. Increasing the energy storage volume costs little: scoop more rock to make the walls a bit higher. Water requirements for PHES are very small compared with equivalent batteries (including mining and refining). Land requirements for PHES are also very small. Premium-quality PHES stores 5 to 100 GWh per km2 compared with utility batteries at around 15 GWh/km2
, .
Indeed, the land and water requirements to provide all the storage needed for an affluent and fully electrified and decarbonised economy relying on solar and wind energy are in the range of 2m2
per person
and 2 litres per person per day, respectively. Local economic content for PHES is high and includes construction of reservoirs, tunnels, powerhouses and transmission. In contrast, most countries import batteries.
Right: Class AA 500 GWh pumped storage site near Araluen, Australia
20 | December 2025 |
www.waterpowermagazine.com
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