Developing and maintaining a policy-focussed, comprehensive, energy systems model in a developing country context: The case of SATIM in South Africa

South Africa faces a myriad of energy-related challenges, including severe constraints in electricity supply, a rising cost of electricity to consumers, high levels of energy poverty, and a reliance on coal in both energy supply and demand sectors. These challenges exist in a context of significant development imperatives and commitments to decarbonise. This paper presents the South African TIMES model (SATIM), a comprehensive energy systems model developed and maintained over two decades, which has proved useful in informing energy and climate policy in South Africa. We explore how SATIM has been adapted to overcome data limitations and address unique and complex policy, development and broader socio-economic challenges faced by developing countries. The model's evolution, structure, and applications are discussed, highlighting its role in providing evidence-based insights for critical policy decisions. We argue that SATIM's long-term development, flexibility, and integration with other models offer valuable lessons for energy systems modelling in developing country contexts.