An answer to South Africa’s load-shedding problem is right in front of us

South Africa is facing a unique challenge: balancing its energy demands with its sustainable development and environmental goals.

Yet, Professor Marco van Dijk and Dr Louis Coetzee from the University of Pretoria’s (UP) Department of Civil Engineering believe that the country can effectively meet these demands with the help of pumped storage schemes.

Currently, coal accounts for roughly 80% of its electricity generation, yet the country has committed to moving towards sustainable energy by integrating varied renewables.

Seen through its Just Energy Transition (JET) Plan, South Africa is looking to diversify its mix driven by the need to reduce carbon emissions and enhance energy security.

“In this context, pumped storage schemes offer a viable solution to balance supply and demand, integrate renewable energy sources and provide ancillary services to the grid,” said Van Dijk and Coetzee.

Very broadly, pumped storage schemes are a form of energy storage that uses two reservoirs at different elevations to store and release water, generating electricity when needed, acting like a “giant battery” for the electricity grid. 

“It offers reliable, flexible, and low-carbon electricity,” wrote Van Dijk.

Currently, South Africa has four major pumped storage schemes: the Drakensberg, Palmiet, Ingula and Steenbras.

These facilities help stabilise the grid by storing surplus energy during low demand and releasing it during peak periods.

However, despite existing projects, the experts say that substantial untapped potential remains for additional pumped storage schemes nationwide — particularly through integration into existing water infrastructure.

Utilising existing infrastructure and improve policy

The Hydropower Research Group at UP, in collaboration with the Geoinformatics division, developed the South African Hydropower Atlas (SAHA) using ArcGIS Online.

This web-based GIS tool identifies potential sites for hydropower projects, including pumped storage schemes.

It identifies that South Africa’s varied topography presents numerous opportunities for new developments.

The country sports over 4,450 dams, including 1,269 classified as large (30m+ wall height), primarily built for water supply, irrigation, and flood control.

The experts say that by integrating hydropower into these structures — utilising ecological reserve or irrigation releases — the country can optimise water resources, enhance infrastructure value, and create additional revenue streams.

Utilising existing infrastructure reduces the need for new construction, which is resource-intensive and disruptive to ecosystems.

Additionally, small-scale and distributed hydropower projects can bring clean energy to remote and underserved areas, supporting local development.

“Integrating hydropower into existing water infrastructure aligns with sustainable energy principles,” wrote the experts.

Currently, energy recovery at wastewater treatment works (WWTWs) is often overlooked, with very few pilot plants developed, said Van Dijk

“Electricity generated at WWTW outlets can be directly utilised within the facility, offsetting operational costs associated with water treatment.”

Small hydropower and pumped storage schemes are also important.

“Small hydropower systems can be integrated into existing water infrastructure by retrofitting non-hydropower dams and weirs, and exploring unconventional avenues such as conduit hydropower and turbine installations at WWTW outlets and potable water systems,” said Van Dijk.

With that said, the experts say that a supportive policy and regulatory framework is essential for integrating hydropower into existing water infrastructure.

Van Dijk emphasised aligning South Africa’s energy and water policies to support multipurpose projects.

“The most viable pumped storage solutions involve utilising existing water infrastructure,” he said.

The pros, cons and future of pumped storage

Given the high capital investment and geographic constraints of pumped storage, the experts emphasise the need to evaluate technical, legislative, environmental, social, and economic factors before feasibility assessments.

The viability of a pumped storage scheme depends on key factors such as available head, flow rate, reservoir capacity, and the distance between reservoirs.

Development costs include civil infrastructure, electromechanical equipment, licensing, environmental mitigation, grid integration, and maintenance.

Despite these expenses, Van Dijk and Coetzee assert that pumped storage remains a valuable investment due to its role in grid reliability and renewable energy support.

A key advantage is its ability to stabilise the grid, adjusting quickly to fluctuating energy demand while aiding frequency regulation and load balancing, thereby reducing blackout risks.

By storing excess wind and solar energy, pumped storage mitigates intermittency issues, enabling greater renewable energy integration.

Additionally, these projects create jobs, stimulate local economies, and ensure long-term economic benefits.

Compared to fossil fuels, pumped storage has a lower environmental impact, producing no direct emissions and minimising ecological disruption.

However, challenges such as high initial costs and regulatory barriers remain. While generally eco-friendly, these projects can still impact local ecosystems and communities.

Ongoing research aims to mitigate these challenges. Advancements in hydropower technology can further enhance feasibility and efficiency.

The UP’s Hydropower Research Group is developing technologies for the country’s environmental and infrastructural conditions.

Innovations such as modular hydropower systems, low-head turbines, and advanced control systems enable more flexible and cost-effective projects.

“The future of pumped storage in South Africa looks promising, with multiple projects under consideration,” said Van Dijk and Coetzee.

“Government support for renewable energy expansion and grid stability creates a favorable environment for growth.

“As the country increases renewable energy capacity, pumped storage will play an essential role in balancing the grid. Integrating these schemes with wind and solar farms provides a comprehensive solution for energy storage and grid management,” they added.