Underground Pumped Hydroelectric Energy Storage in South Africa using Aquifers and Existing Infrastructure

South Africa is facing one of its greatest challenges in the electricity sector leading to frequent load shedding in order to prevent a collapse of the national grid. The South African government through its national electric utility Eskom, has put in place plans to build new power stations. There are pumped storage peaking stations at Drakensburg (1000MW) and Palmiet (400MW) which will be further supplemented by Ingula (1300MW) currently under construction and situated in KwaZulu-Natal Province. Underground pumped hydroelectric energy storage (UGPHES) is introduced as an alternative technology for bulk energy storage in South Africa and to contribute to the constrained electricity network with environmental and economic benefits. This paper evaluates and discusses the use of existing infrastructure for the implementation of this scheme, including the use of abandoned mines as it presents an existing underground cavern as well as large amounts of groundwater. Results obtained from studies and preliminary assessment are presented and discussed. The use of underground pumped hydroelectric energy storage as a technical alternative for bulk energy storage in South Africa, and a potential contribution to the constrained electricity network with environmental and economic benefits is proposed. The use of aquifers for the implementation of this proposed scheme is explored, with South Africa having large amounts of groundwater as well as transboundary aquifers which may be used for the proposed energy storage systems. An extensive literature review and document analysis of this alternative is carried out and results obtained from preliminary studies and assessments are presented and discussed.