An exploration of transition pathways for South Africa’s coal-to-liquids complex under long-term national greenhouse gas emissions constraints

Coal-based industries represent a critical challenge for long-term energy transitions: their strong economic and energy-security benefits come with the disadvantage of high greenhouse-gas (GHG) emissions. South Africa’s Coal-to-Liquids (CtL) complex in Secunda, which is responsible for around 12 % of national GHG emissions, illustrates these tensions, where rapid or unplanned shutdown could impose substantial economic and energy-security risks. This study evaluates alternative decarbonisation strategies and transition pathways for this CtL complex using an enhanced version of the South African TIMES national energy-system optimisation model. Three pathways are examined: a Baseline case; a Roadmap-Aligned pathway reflecting near-term efficiency with renewable energy integration measures; and a Structural Decarbonisation pathway in which low-carbon technologies are deployed under a national long-term emissions constraint (LTEC). The Roadmap-Aligned scenario reduces facility-level emissions by ∼ 26 % by 2030, decreasing carbon intensity from 0.18 to 0.15 Mt CO 2 PJ −1 . Structural Decarbonisation under a national Long-Term Emissions Constraint of 8.5 Gt achieves deeper cuts of 45 % by 2030, 56 % by 2040 and 62 % by 2045, ultimately lowering carbon intensity to 0.097 Mt CO 2 PJ −1 . While a structural transition is feasible, decarbonisation remains partial. Demand-side electrification, especially uptake of electric vehicles, ease fuel demand and CO 2 constraints, while transition timing is primarily governed by costs of renewable energy and policy ambition, with oil-price dynamics playing a secondary role. Lower oil prices narrow profit margins and reduce Fischer–Tropsch output and Scope 1 emissions, yet result in earlier hydrogen deployment, whilst higher oil prices have the opposite effect. The findings provide strategic insights for policymakers and planners designing industrial transition pathways in carbon-intensive economies.