Modelling the impact of energy management on long-term decarbonisation outcomes in South Africa’s gold mining sector

South Africa’s mining sector faces regulatory and operational pressure to reduce greenhouse gas emissions while maintaining production. Energy efficiency is an option for reducing electricity use and emissions in deep-level gold mining, however the associated savings are not inherently persistent. This study evaluates the long-term impact of an ISO50001-aligned energy management system across a major gold mining group. Using internally-verified data, three scenarios were modelled: continued implementation with a tapering savings target, maintenance of existing savings only, and full discontinuation. Scenario 1 produced 12.7 TWh in cumulative energy savings, 7.1 MtCO 2 e in avoided Scope 2 emissions, and $1.4 billion in cumulative cost savings by FY44. Scenario 2 preserves the accumulated savings through continued maintenance. Scenario 3 reverses these gains, ending in a net cumulative real loss of $6.6 billion and net present value of −$449.9 million by FY44. One-at-a-time and Monte Carlo sensitivity analyses confirm the outcomes across the parameter ranges. Results show the value of energy management is realised only while the system is sustained, and that discontinuation imposes substantial financial and environmental risk. These findings support integrating sustained energy management into mining decarbonisation planning, aligning with SDGs 7, 12 and 13.