SOUTH AFRICA’S ENERGY INFRASTRUCTURE INVESTMENT REQUIREMENTS: A SYSTEMS APPROACH TO ACHIEVING NET -ZERO BY 2050

South Africa’s electricity system must simultaneously restore energy security, replace an ageing coal fleet, expand grid capacity and reduce emissions. This paper quantifies the generation; storage and gridinvestments required from 2025 to 2050 and assesses whether the associated capital can be mobilised. It applies to an adapted ‘Beyond the Gap’ framework that combines least-cost supply expansion modellingthrough Open Source Energy Modelling System (OSEMS), hourly dispatch validation through FlexTool, spatial transmission analysis, a soft market sounding, funding-gap estimation, and policy and regulatory review. Three conditional pathways are assessed: Green Industrialisation (Scenario A), Market Forces (Scenario B), and Business-as-Usual (Scenario C). Total system investment ranges from R3.586 trillion to R4.166 trillion, discounted at 8% to 2024 real terms. Scenario A has the largest and fastest buildout ofrenewable energy, storage, and grid infrastructure, but the lowest total system investment and emissions, because higher early capital expenditure is offset by lower fuel and operating expenditure. Its averageannual capital requirement is R140.1 billion from 2025 to 2030, producing estimated funding gaps of R12.5 billion per annum in 2025 to 2027 and R44.0 to R53.5 billion per annum in 2028 to 2030. The findings indicate that South Africa’s central financing challenge is not an absolute shortage of capital, but the timely conversion of available finance into a sufficiently large pipeline of bankable generation, storage and transmission projects. Regulatory certainty, credible revenue arrangements, institutionalcoordination, and catalytic risk-sharing are therefore integral to the physical energy transition. The study provides practical insights for policymakers, investors, utilities, and development finance institutionsseeking to accelerate a financially viable and inclusive transition.