As South Africa seeks to diversify its energy mix away from coal and incorporate more solar and wind power, the intermittency of these renewable sources presents a significant challenge. However grid-scale battery energy storage systems (BESS) can solve the challenge, says Gbenga Apata, Post Doctoral Research Fellow at the Department of Science and Innovation/National Research Foundation Trilateral Chair in Transformative Innovation and Sustainable Development at the University of Johannesburg and Member of the Institute of Electrical and Electronics Engineers.

BESS enhances integration of renewable energy into the grid by providing ancillary services including frequency regulation, voltage support and spinning reserves. This enables more efficient use of renewable energy resources, minimising curtailment and reducing greenhouse gas emissions.

By offering advanced grid services – such as harmonic filtering, fault ride-through capability and black start functionality – BESS ensures stable and reliable energy supply even during grid disturbances or outages.

By leveraging advanced power electronics and control systems, BESS can effectively mitigate the intermittency of solar and wind power, ensuring stable and reliable energy supply. This is especially crucial in a decarbonised energy landscape where renewable sources are becoming increasingly dominant. Integration of BESS allows for efficient use of renewable energy resources, significantly reducing greenhouse gas emissions and supporting global climate goals.

Batteries, particularly grid-scale BESS, can store excess energy generated during periods of high renewable output and release it when demand exceeds supply, effectively smoothing out variability and ensuring more reliable electricity supply.

BESS can play a transformative role in the evolution of South Africa's electricity supply industry by enabling greater integration of renewable energy sources, enhancing grid stability and supporting the shift towards a more decentralised energy system. Additional efforts are needed to expand Eskom’s battery storage project, the Hex BESS site in the Western Cape.

BESS technology provides a flexible solution for improving overall grid performance and aligns with South Africa’s commitment to a just energy transition towards a resilient and sustainable energy future.

BESS can also participate in wholesale energy markets, creating arbitrage opportunities and generating revenue streams that enhance the economic viability of renewable energy projects. By providing these ancillary services, BESS helps stabilise the grid, alleviating pressure on traditional fossil fuel-based power plants and facilitating the transition to a sustainable energy system.