By Hügo Krüger
As South Africa aims to integrate more than 50GW of solar and wind energy into the grid within the next decade, there is a growing need to focus on energy storage solutions to prevent high electricity costs during a Dunkelflaute.
Pumped storage, often overshadowed by the hype surrounding "cutting-edge" battery technologies, is a robust technology that provides grid stability, enhanced flexibility, and efficient peak demand management. Its global success positions it as a dependable technology in South Africa’s energy transition.
Drawing inspiration from international success stories, pumped storage has demonstrated remarkable efficacy in diverse environments, notably in Switzerland, China, and the US.
The technology’s role in balancing grids, supporting renewable energy integration, and efficiently handling baseload capacity discharge underscores its versatility and reliability in real-world electricity systems. Pumped storage will bring to the grid enhanced flexibility, reliable energy supply, and grid stabilisation, making it a strategic investment.
Despite being somewhat neglected in the South African context, pumped storage technology holds immense potential, given the country's mountainous plateau. The operational 1 332 MW (21GWh) facility at Ingula in KwaZulu-Natal serves as an example of South Africa’s pumped storage potential.
Serving as the backbone of global energy supply for decades, pumped storage possesses a unique ability to store and release large amounts of electricity swiftly, effectively addressing the challenges posed by the intermittency of wind and solar energy sources.
Contrary to a prevalent misconception about its high cost, pumped storage projects exhibit an estimated one quarter of the levelised cost of electricity compared to that of grid scale batteries (T. Naude & T. Steyn). While upfront investments may seem substantial and require government funding, the life cycle benefits, that include extending operational lives surpass many alternative energy storage solutions, making it a wise investment contributing to the resilience of the energy infrastructure.
Proposed pumped storage projects like Tubatse (1.5GW), Kobong (1.2GW), Ceres (1GW), and Voëlsvlei (1GW) signify untapped potential within South Africa's topography, according to the Renew-E consulting group. The Department of Mineral Resources and Energy (DMRE) should be encouraged to advance them with the upcoming Integrated Resource Plan (IRP).
While considering these projects, it's essential to note that the expected lead time for pumped storage installations is around 10 years. However, costs and lead times are location-dependent, highlighting the need for proper feasibility studies and project planning.
South Africans should urge the Department of Mineral Resources and Energy to seriously consider advancing these pumped storage projects.
Beyond promising substantial power generation, these initiatives align with the topographical advantages of the country. Including Pumped Storage into the national energy strategy would contribute significantly to a sustainable, flexible, and resilient energy future for South Africa.
Hügo Krüger is a YouTube podcaster, writer and civil nuclear engineer who has worked on a variety of energy-related infrastructure projects, ranging from Nuclear Power, LNG and Renewable Technologies.