Africa's energy transition is at a critical juncture, with the potential to leapfrog into a low-cost, renewable-powered future. However, a common misconception in the debate around flexibility is that battery energy storage systems (BESS) alone can provide the necessary balance for high shares of intermittent renewables. This assumption is flawed and could lead to an expensive, unreliable, and slower transition. The real question is whether storage alone is sufficient, and the answer is increasingly clear: no. Flexibility is not a single entity but a multifaceted concept, requiring multiple layers of technologies to address the varying timescales of renewable variability. While BESS excels at fast-response services, it is only one piece of the puzzle. Longer-duration balancing, which is crucial for evening peaks, multi-day renewable shortfalls, or seasonal variability, demands a different approach: dispatchable, scalable, and cost-efficient power plants, such as flexible engine power plants. These plants provide grid balancing at various time scales, stepping in when renewables and storage fall short. The cost of over-relying on storage is significant, as it often ignores the economic reality that storage costs scale with duration. Short-duration batteries are cost-effective, but extending storage to cover longer gaps becomes prohibitively expensive, especially in African contexts with rapid demand growth, weak grids, high financing costs, and reliability concerns. Combining storage with flexible engine capacity offers a more pragmatic solution, minimizing overall investment while maximizing reliability. This approach is supported by precise power system modeling, which consistently shows that an optimal mix of renewables, storage, and flexible engines delivers the lowest total cost of electricity while maintaining stability. Africa's unique starting point, with over 500 million people lacking access to electricity and weak grid infrastructure, demands a pragmatic approach. Reliability is not a marginal issue but a foundational one, crucial for industrialization, economic growth, and social development. Flexible engine capacity provides a practical solution, offering quick deployment, modular scalability, and efficient operation at partial loads, making it ideal for complementing intermittent renewables. Integrating renewables with flexible gas engines has already demonstrated cost and emission reductions compared to traditional baseload alternatives in multiple African energy markets. The concern that investing in engine-based capacity might lock Africa into fossil fuels is understandable but outdated. Modern engine power plants are designed to run on various fuels, including natural gas and sustainable fuels like green hydrogen, ammonia, or synthetic fuels, serving as a bridge to a zero-carbon future. The real risk for Africa is not deploying flexible engines but failing to deploy enough flexible capacity of any kind. Some influential narratives underestimate the system-wide value of flexible engine technology in enabling high-renewable systems at the lowest cost. A balanced approach is necessary, combining renewables, BESS, and flexible engines to create a cleaner, more affordable, and reliable energy system. Africa's energy transition should embrace a hybrid approach, recognizing the multi-dimensional nature of flexibility and the need for a diverse set of solutions.
