South Africa model shows 45 GW wind-solar system still needs winter firm power

Seriti Green engineering modelling suggests South Africa could meet most residual demand with renewables if it adds a balanced 45 GW mix of wind and solar, supported by roughly ten hours of battery storage. July 2026 was the stress case: a winter wind drought cut residual renewable penetration to 53.5%, required an 18 GW gas peak, and showed why extra batteries alone cannot solve multi-day renewable shortfalls.