Wall Street Journal | By: Rhiannon Hoyle | November 11, 2022

Pumped-storage hydropower at abandoned pits could help make wind and solar power available anytime

ADELAIDE, Australia — Mining operations that contributed to greenhouse-gas emissions could soon help to cut them.

Around the world, companies are seeking to repurpose old mines as renewable-energy generators using a century-old technology known as pumped-storage hydropower. The
technology, already part of the energy mix in many countries, works like a giant battery, with water and gravity as the energy source. Water is pumped uphill to a reservoir when energy supply is plentiful. It is released and flows downhill through turbines generating hydroelectric power when electricity demand is high or there are shortages of other types of power. Finally, the water is captured to be pumped uphill again in a repeated cycle.

Surface and underground mines hold potential as reservoirs for the water, and could be developed with a lower environmental impact and upfront costs than building such
plants from scratch, experts say.