Professor Jamie Pittock said in a statement that if the projects were implemented, they would speed up the country's move to renewable energy. He wrote a paper on the environmental impact of such a system which was published in the Australian Environment Review.
“Estimates are that we would need about 20 big PSH facilities to back up the entire national grid. It’s partly a judgment call about how much risk you want to take in terms of the reliability of the electricity supply," he said.
PSH has two connected reservoirs and when there is excess power — for example, on especially sunny or windy days — water is pumped uphill. When the demand rises, power can be generated by releasing water back down to a generator.
These projects had a total installed nameplate capacity of 184GW with about 25GW being in the US. The round-trip energy efficiency of PSH varies between 70% and 80%, Wikipedia said, adding that there claims that this was as high as 87%.
Snowy Hydro’s Tumut 3 pumped storage hydropower station. Photo: Professor Jamie Pittock
Asked why Australia seemed to be a late entrant into using this kind of storage project, Prof Pittock told iTWire that it was probably due to cultural reasons.
The country had been used to depending on coal-fired stations for baseload power for a long time and only recently had there been a change in thinking, he added.
Prof Pittock said there was no danger that there would be a reversal of looking at PSH were the government to change at the forthcoming federal poll.
Indeed, he said, there was probably going to be more emphasis on renewable energy. But he credited the current government with having provided the necessary encouragement for looking at PSH.
Prof Pittock said: "We’re talking about more than 20 projects being assessed or built. This would put us well on the way to having a national grid that could rely almost entirely on renewables.
“It’s really a game changer. It destroys any argument that solar and wind can’t provide the baseload power needed to keep the lights on in eastern Australia.”
Prof Pittock said there were some unusual challenges involved in setting up PSH projects. "A lot of people live in rural areas because they don’t want to live next to a big industrial project, it might be a shock if somebody suddenly turns around and says they want to build a reservoir on top of the nearest mountain," he said.
Many areas that were at high elevations and were suited could not be used due to the presence of national parks or cultural sites, while other sites were too far from water or existing electricity transmission lines.
Prof Pittock said suitable sites included everything from old quarries, to doubling existing pumped hydro schemes and a “green” steel mill.
“One example is the old gold mining tunnels under Bendigo in Victoria, so [it would work by] sucking the contaminated water up to the surface and feeding it back down the mine shafts,” he said.
There was no blanket rule on where the water would be sourced, with a South Australian project proposing the use of sea water.