To Boost Renewable Energy, Australia Looks to Water and Gravity

Source: Nathanial Gronewold · SCIENTIFIC AMERICAN · | June 18, 2020

Pumped storage hydropower could store intermittent energy from wind and solar power to de-carbonize the nation’s electricity supply.

Pipes for a pumped-storage power plant in Tasmania, Australia. Credit: Getty Images

Fires aided by climate change wrecked havoc last year across Australia.

Now there’s a chance that water could help save the country from an even worse fate—and not just as a way to extinguish future blazes.

An Australian utility has drawn up plans that would marry the country’s renewable energy power with a decades-old trick of hydro engineering.

If successful, the design could help solve one of the biggest hurdles of renewable energy: finding a way to store excess power generated by wind turbines and solar panels. Critically for the global fight against climate change, it also could reduce Australia’s reliance on coal.

That is, if the “Battery of the Nation” ever gets built.

The concept itself is simple—use excess renewable electricity generated during low demand cycles to pump water uphill, and then release that water downhill through turbines when electricity demand is high, to both satisfy additional demand and turn a profit. General systems involve two separate reservoirs, one of them higher in elevation, connected by pumps and a tunnel. Water is cycled back up to the higher-elevation reservoir at night, using it as a storage basin.

The technology was first put to commercial use in the 1960s. The United States, Japan and Europe have been using pumped storage hydro for decades to improve the economics of nuclear power plants, because nuclear reactors can’t be easily ramped up or scaled down depending on electricity demand. A 2013 study by the Norwegian University of Science and Technology called pumped storage hydropower “the only form of renewable energy storage that is well developed and in wide commercial use today.”

Some 130 gigawatts of installed pumped storage hydro capacity exists in the world today, a third of it in Europe. It constitutes 95% of existing utility power storage in the U.S., according to the Department of Energy.