Why South African Miners Are Building Their Own Renewable-Energy Portfolios

South Africa’s mining companies are increasingly becoming energy investors in their own right, as electricity costs, supply security and decarbonisation targets reshape how mines think about power.

The shift is visible across some of the country’s largest operators. Kumba Iron Ore is developing a 63MW embedded solar project at its Sishen mine. Sibanye-Stillwater says it has secured around 765MW of renewable-energy projects in South Africa. Exxaro’s 68MW Lephalale solar plant is already supplying Grootegeluk and reducing the mine’s reliance on Eskom.

The common thread is increasingly commercial. Renewable power is being used not only to lower emissions, but to manage long-term electricity costs, reduce exposure to grid risk and improve the competitiveness of energy-intensive mining operations.

Kumba designs solar around cost savings

Kumba’s Sishen Iron Ore Company signed an energy offtake agreement in July for an on-site solar photovoltaic plant expected to supply 63MW of renewable electricity to Sishen from the fourth quarter of 2027.

The company said the facility was deliberately sized to deliver the highest net present value of cost savings. Once operational, the project is expected to lift Kumba’s renewable-energy penetration to about 45%, including renewable power already wheeled to its Kolomela operation.

The Sishen project also repurposes an existing waste-rock dump for energy infrastructure, linking mine-site land use with power generation. Kumba expects the project to displace around 35% of Sishen’s current Scope 2 emissions at steady state.

Sibanye-Stillwater sees a competitiveness case

Sibanye-Stillwater’s renewable portfolio is larger. The group says it has around 765MW of renewable-energy projects secured in South Africa, with two projects already in commercial operation and additional power-purchase agreements concluded.

Its latest sustainability disclosures say 293GWh of clean electricity was generated in 2025, yielding R93 million in energy savings and avoiding more than 316,000 tonnes of carbon dioxide emissions.

The company’s 2025 integrated report goes further, estimating that contracted renewable projects could deliver annual energy-cost savings of more than R1 billion from 2028, with average electricity costs 20% to 30% below forecast wholesale Eskom tariffs at commercial steady state.

That forecast makes the strategic logic explicit. Decarbonisation is being tied directly to operating resilience and cost competitiveness.

Exxaro’s solar plant is already cutting Eskom dependence

Exxaro offers a live example. Its 68MW Lephalale Solar Project reached commercial operation in April 2026 and supplies power directly to the Grootegeluk mine through a behind-the-meter arrangement.

In its latest interim update, Exxaro said the project had reduced Grootegeluk’s reliance on Eskom power by 30%. The company expects electricity-cost savings of approximately R100 million a year. The R1.7 billion facility is also licensed for future battery-storage integration.

Exxaro remains deeply connected to South Africa’s conventional power system, including through its long-standing coal-supply relationship with Eskom. Its renewable investments therefore illustrate a diversification of energy strategy rather than a complete withdrawal from the grid.

Mining is becoming part of electricity-market reform

The broader shift is enabled by changes in South Africa’s electricity market that have made private generation, wheeling and corporate power-purchase agreements more important. Large industrial users can increasingly combine grid supply with embedded generation and power contracted from private renewable projects.

For mining companies, that creates an opportunity to treat electricity as a portfolio rather than a single-source input. On-site solar can reduce daytime grid demand. Wheeled wind and solar can diversify supply. Battery storage may eventually improve flexibility. Long-term PPAs can provide greater cost visibility.

There are limits. Renewable generation is variable, transmission capacity remains constrained in parts of South Africa and mines still require dependable power around the clock. Eskom and the national grid therefore remain central to industrial operations.

But the direction of travel is clear. For major miners, renewable power is moving from the sustainability section of the annual report into the core economics of running a mine.

Sources

• Kumba Iron Ore, Sishen solar energy offtake agreement
• Sibanye-Stillwater environmental and renewable-energy disclosures
• Sibanye-Stillwater 2025 Integrated Report
• Exxaro 2026 interim performance update
• Exxaro Lephalale Solar Project