RUPHES

thyssenkrupp Uhde South Africa wins study and signs an agreement with Pumped Hydro Storage Sweden AB

• Storage of renewable energy at low cost with high efficiency

• Pre-feasibility study for a project together with Wismut Gmbh

thyssenkrupp Uhde Africa together with Wismut Gmbh has been appointed to execute a pre-feasibility for study for a “Renewable Underground Pumped Hydroelectric Energy Storage” (RUPHES) project on a specific site with a South African mining company. thyssenkrupp Uhde South Africa is collaborating with international specialist companies to facilitate mine repur-posing. Already last year thyssenkrupp Uhde had signed a cooperation agreement with min-ing rehabilitation specialist Wismut GmbH in Germany. The international cooperation was now recently expanded by an agreement with Pumped Hydro Storage Sweden AB.

With the increase in renewable energy generation there is an increased need for energy stor-age. Renewable Underground Pumped Hydroelectric Energy Storage (RUPHES) in repur-posed mines – coupled with solar and wind power – can reliably provide green energy when it is needed. Repurposing of depleted gold mines for RUPHES enables short construction schedules and significantly reduced costs. The main reason: Gold mining has already creat-ed the underground water storage reservoirs that commonly are the mostly costly compo-nents of pumped hydro plants. They just have to be adapted to their new purpose.

This is exactly what Pumped Hydro Storage Sweden does. It is part of the company Sustain-able Energy Solutions and is currently developing a 2 MW / 8 MWh underground pumped energy storage project in an abandoned iron mine in Aland, Finland. The project has the support of both the European Commission and Swedish Energy Agency, and they are looking to commission the project in December 2023. This project demonstrates the reduced con-struction schedules and costs associated with utilizing mining infrastructure for pumped ener-gy storage as did a similar project at the Kidston gold mine in Australia.

Well-proven, cost-competitive solution serving a major trend in Africa

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. Just for comparison: In June 2021, a South African gold mining company announced that they are able to produce electricity from solar power at USD’21 1.1c/kWh. This pricing is nearly on par with the best international solar pricing USD’21 1.04c/kWh, achieved in competitive bidding in Saudi Arabia. The fact that South Africa has world-class solar and wind resources is gaining traction in 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.