U.K.-listed mining company, Anglo American has indicated its intent to generate electricity through renewable underground pumped hydroelectric storage (Ruphes) systems using water from flooded, abandoned mines in South Africa to power its own local mining operations with renewable energy.
By using pumped hydro storage (PHS) technology, water in deep underground mines can provide a fully integrated energy system that diminishes reliance on South Africa’s national power utility, Eskom’s, unreliable power stations.
“We’ve put a strategy to the South African Government regarding wind farms east coast, west coast, and solar energy structures in the Northern Cape,” stated Mark Cutifani, CEO of Anglo American, adding, “Then there is the use of deep underground mines that are flooded where we can use the water as a battery. We can pump the water up and let the water run back down so we have a fully integrated system that will work with Eskom and the South African system. We think companies like ours have got to be the providers of integrated solutions.”
Spokesman for Anglo American, Sibusiso Tshabalala, adds that, “There are a number of opportunities we’re exploring including an opportunity for expanding (1 GW) of the PHS to help bolster supply security of the national grid. Our plan for an integrated national/regional approach to producing clean energy around the country, drawing from natural advantages that Southern Africa possess, and wheel that energy through the grid to our operations.”
Pre-feasibility studies into Ruphes systems are currently being undertaken through a collaborative project between renewable energy solutions company, Sustainable Energy Solutions Sweden (SENS), the German uranium mining company, Wismut, and industrial solutions company, Thyssenkrupp Uhde South Africa.
“The very deep gold mines in South Africa have excellent conditions with regard to fall height and geology and thus constitute optimal places for storage of energy from pumped storage power plants,” said SENS’s acting CEO, Lise Toll. “The conditions in the gold mines mean significantly reduced costs as the necessary components for implementing pumped storage power plants are already available.”
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Pumped storage uses pump turbines to generate hydroelectricity by feeding water through an upper reservoir to a lower reservoir. This process facilitates the repurposing of abandoned mines, thus diminishing the construction period and significantly reducing the costs of hydroelectric powerplants by adapting existing reservoirs.
With approximately 6,000 abandoned mines in South Africa, the potential of converting depleted mines into Ruphes systems has garnered significant attention, with many Independent Power Producers seeking to diversify the country’s energy mix.
The South African Integrated Resource Plan 2019 outlines the country’s objective to acquire 33.8% of its power from renewable sources. In the first half of 2021, renewable energy accounted for 11% of South Africa’s total energy mix.