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 not whether storage is needed, but whether it is sufficient. The answer is no, as flexibility is multifaceted and requires multiple layers of response. Battery storage is excellent for fast-response services, but longer-duration balancing demands dispatchable, scalable, and cost-efficient power, which is where flexible engine power plants come in. 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 high, as extending storage to cover longer gaps becomes prohibitively expensive, especially in African contexts with rapid demand growth, weak grids, and high financing costs. Combining storage with flexible engine capacity optimizes investment and reliability. This approach is supported by precise power system modeling, which shows that the 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 foundational, and a system that cannot guarantee power during low-renewable periods will hinder industrialization, economic growth, and social development. Flexible engine capacity provides a practical solution, offering quick deployment, modular scaling, and efficient operation at partial loads. It complements intermittent renewables, reducing costs and emissions compared to traditional baseload alternatives. The concern that investing in engine-based capacity locks Africa into fossil fuels is outdated. Modern engine power plants are designed to run on various fuels, including natural gas and sustainable options like green hydrogen and 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. Influential narratives often underestimate the system-wide value of flexible engine technology in enabling high-renewable systems at the lowest cost. Policymakers must design systems based on a balanced understanding of flexibility, combining renewables, storage, and flexible engines to create a cleaner, more affordable, and reliable energy transition. This hybrid approach recognizes the multi-dimensional nature of flexibility and the need for a comprehensive solution.
