Pumped storage hydropower a 'game-changer'

Pumped storage hydropower a “game-changer”
Snowy Hydro’s Tumut 3 PSH project. Credit: Jamie Pittock, ANU

A series of Pumped Storage Hydropower (PSH) projects planned across 5 states could triple Australia's electricity storage capacity, according to a new study by a researcher at The Australian National University (ANU).

Professor Jamie Pittock says if the projects go ahead, they will accelerate our transition to renewable energy.

"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," Professor Pittock says.

"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."

PSH works by having two connected reservoirs. When there is excess power, (for example, on especially sunny or windy days) it's used to pump water uphill.

During times of greater demand, power can then be generated by releasing water back down to a generator.

Professor Pittock's paper outlines the environmental implications of this system. He says it does throw up some unusual challenges.

"A lot of people live in 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."

A lot of high elevation areas that would otherwise be suitable have to be ruled out because of national parks or cultural sites. Other sites are too far from water or existing electricity transmission lines.

Professor Pittock says the sites which could soon be home to PSH projects include 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 sucking the contaminated water up to the surface and feeding it back down the mine shafts," Mr Pittock said.

In South Australia, another project proposes the use of sea water to generate power.

This means there's no blanket rule when it comes to sourcing the water needed for PSH.

"In South Australia for example, one project will buy water entitlements out of the Murray Darling Basin system."

"Then you've got Snowy Hydro, whose operators say legally nothing changes, we're using the same , we're just recycling it."

Mr Pittock says despite the complexity, a number of the proposed sites are really promising, and more than enough to back up the grid.

"Estimates are that we would need about 20 big PSH facilities to back up the entire national grid. It's partly a judgement call about how much risk you want to take in terms of the reliability of the electricity supply."

The research has been published in Australian Environment Review.

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More information: Jamie Pittock. Are we there yet? The Murray-Darling Basin and sustainable water management, Thesis Eleven (2019). DOI: 10.1177/0725513618821970
Citation: Pumped storage hydropower a 'game-changer' (2019, March 25) retrieved 22 October 2019 from https://phys.org/news/2019-03-storage-hydropower-game-changer.html
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Mar 25, 2019
"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."

Yes and no.

It's easy to triple your capacity when you have essentially none to start with. The question is, how many megawatt-hours are you going to build?

The Dinorwig Power Station in the UK holds 9.1 Gigawatt-hours, being one of the largest pumped storage sites in the world, but in context of the whole UK grid it has a capacity of about 15 minutes. In the Australian grid that would be 21 minutes (25.5 GW year-round average).

For pumped storage of renewables to count as baseload, you can start by averaging over the solar energy production of a single day. Suppose 6 hours of peak production, followed by running 18 hours of reserves as a rough simplification - that would be pretty much two Dinorwigs for every 1 GW of "baseload" you intend to have, and you're pumping a whole lake of water every day.

Mar 25, 2019
Wind power is trickier to turn into baseload, because you can have a full week of calm and reduced output, and then a week of high winds - it only starts to average out properly on a timescale of weeks to a month.

Though you still get a variation of 30-50% between summer and winter months, and year-to-year variations, so you also have to think about seasonal storage schemes, and that runs into the Terawatt-hours which simply isn't feasible with pumped storage, or just about any storage - except that one crazy German concept of coring out a kilometer wide plug of bedrock and using it as a hydraulic piston. Good luck with the earthquakes.

Meanwhile, turning renewable energy into gas (methane), and pumping it into pipes and gas bells easily stores hundreds of Terawatt-hours of energy, and runs your cars and kitchen appliances just fine.

Mar 26, 2019
Wind/Solar plus Pumped Storage don't work even in small-scale, worse yet in large-scale.
"The absolute best form of storage is pumped hydro; but when it is used with wind turbines and solarPV the energy returned on energy invested drops below the breakeven point."

"100% renewables fail. This small island of El Hierro has been attempting to power itself with wind, solar, and pumped hydro for 3 years, but the diesel back is still the mainstay electricity generators."

"Storage systems are incredibly expensive in the case of batteries—and geographically limited in the case of pumped hydroelectric"

"A mix of hydro and nuclear works. Hydro happens to fall into the "renewables" category. And is alternately included and excluded, in the data when convenient by RE fans."

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