Thyssenkrupp Uhde Africa and Wismut GmbH will do a pre-feasibility study into a renewable underground pumped hydroelectric energy storage (RUPHES) project with a South African mining company.
Facilitating mine repurposing is a new focus area for construction engineering company thyssenkrupp Uhde, which last year signed a cooperation agreement with mining rehabilitation specialist Wismut GmbH in Germany. The international cooperation was also recently expanded by an agreement with Pumped Hydro Storage Sweden AB.
As renewable energy generation increases globally, the need for energy storage increases. Coupling renewable underground pumped hydroelectric energy storage (RUPHES) in repurposed mines with solar and wind power generation is one way to provide green energy when needed.
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Pumped storage hydropower ideal for clean energy systems
Repurposing a depleted gold mine for RUPHES means shorter construction schedules and significantly reduced costs. Gold mines create underground water storage reservoirs as a matter of course. These reservoirs are the most costly component of pumped hydro plants. Adapting an existing reservoir is the cheaper option.
Pumped Hydro Storage AB is part of the company Sustainable Energy Solutions and is currently developing a 2MW / 8MWh underground pumped energy storage project in an abandoned iron mine in Aland, Finland.
That project has the support of both the European Commission and the Swedish Energy Agency, who want to commission the project in December 2023. This project would demonstrate the reduced construction schedules and costs associated with utilising mine tunnels for pumped energy storage, just like a similar project at the Kidston gold mine in Australia.
Pumped hydro storage at mines in Africa is the new gold
As probably the most mature energy storage technology currently available, pumped hydro accounts for 97% of the global storage capacity.
Exceptionally high hydraulic heads and stable hard rock geology render ultra-deep gold mines ideal for implementing the concept, and for producing internationally cost-competitive, reliable green electricity as well as green hydrogen and green ammonia.
In an online press statement, thyssenkrupp said South Africa’s world-class solar and wind resources are being noticed by both government and industry “and the fact that it is cheaper to provide electricity from South African renewables than it is to provide power by importing foreign gas.
“Just for comparison, in June 2021, a South African gold mining company announced that they are able to produce electricity from solar power at $1.1c/kWh. This pricing is nearly on par with the best international solar pricing $1.04c/kWh, achieved in competitive bidding in Saudi Arabia.”