Australia's abandoned mines could solve renewable energy storage problem, study finds - E&T Magazine

Australia’s abandoned mines could solve renewable energy storage problem, study finds | Engineering and Technology Magazine

Jack Loughran— Thu 29 Feb 2024

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Researchers have identified 37 former mining sites in Australia that present the ideal conditions for installing pumped hydro facilities as a way to store renewable energy.

Pumped-storage hydroelectricity is effectively a way of storing energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation.

Low-cost surplus off-peak electric power is typically used to run the pumps. During periods of high electrical demand, the stored water is released through turbines to produce electric power.

Due to Australia’s sizeable mining industry, there are a significant number of mining pits that could be transformed into reservoirs to make mass energy storage a reality, according to a team of researchers from the Australian National University (ANU).

On a global basis, they identified 904 sites in former mining areas, known as brownfield, with a combined potential storage of 30 TWh. The team developed an algorithm that identified mining pits, pit lakes and tailings ponds that were located near other reservoirs that could form a suitable pair.

Brownfield sites typically have advantages for pumped storage projects including existing transmission infrastructure, water pumping infrastructure, road access and reduced environmental impact for development on disturbed land.

There are currently only four pumped storage sites in the UK and just one in the Republic of Ireland (pictured above).

Solar and wind energy comprised approximately three-quarters of global generation capacity additions in 2022. If the trend continues, huge amounts of energy storage will be needed to make the most use out of it.

While grid-scale storage with lithium-ion batteries holds immense potential for enhancing grid reliability and integrating renewables, high costs and a need to improve capacity has made it difficult to roll out at scale.

According to the researchers, pumped hydro energy storage is generally cheaper than battery storage at large scales while having a minimal environmental footprint.

Australia has set a goal of reaching 82% renewable electricity by 2030, although the Australian Energy Market Operator has estimated that by 2050, the nation will need about 640 gigawatt-hours of “on-demand” storage to support the extra solar and wind capacity.