African Clean Energy Developments (ACED) and EIMS Africa, in partnership with Sibanye-Stillwater, announced in April 2025 that the 89MW Castle Wind Farm had officially reached commercial operation. As the largest private-offtake wind farm in South Africa to date, the project was lauded as a significant milestone in strengthening the country’s renewable-energy sector and advancing Sibanye-Stillwater’s decarbonisation goals.
Located near De Aar in the Northern Cape, the project benefits from some of the country’s best wind resources and direct access to the main transmission corridor connecting the Cape provinces to the industrial north-east of South Africa. Castle will supply Sibanye’s South African operations via a wheeling agreement with Eskom. ACED and Sibanye-Stillwater’s early market entry secured vital grid access, avoiding current capacity constraints that limit new wind project development.
Castle Wind Farm will provide 309GWh of clean energy annually to Sibanye-Stillwater’s South African operations, reducing emissions by 321 000t CO2e per year and securing long-term energy cost savings. This project also demonstrates how private-sector-led renewable initiatives can drive energy security and economic growth.
Castle Wind Farm will provide 309GWh of clean energy annually to Sibanye-Stillwater’s South African operations…
The Castle consortium is led and cosponsored by ACED, with African Infrastructure Investment Managers (AIIM) IDEAS Fund and Reatile Renewables as shareholders. AIIM is a division of Old Mutual Alternative Investments (OMAI) and its IDEAS Fund is one of South Africa’s largest domestic infrastructure equity funds. Reatile Renewables is a strategic empowerment investor in renewables. ACED and AIIM affiliate, Energy Infrastructure Management Services Africa (EIMS Africa), will manage the project during operations.
Castle is one of two renewable energy projects that the ACED consortium and Sibanye are executing together, with the 140MW Umsinde Emoyeni Wind Farm in the Western Cape being the other one. The latter is due to reach commercial operation in late 2026.
This project brings the total delivery by the ACED and EIMS Africa teams to over 600MW of hydro, wind and solar projects to financial close and construction in a two-year period, enhancing the consortium’s collective drive to be a leader in renewable energy development and operation in South Africa and across the continent. This builds on over a gigawatt of projects it has already developed and operates via the South African Renewable Energy Independent Power Producer Procurement Programme (REIPPPP).
James Cumming, CEO of ACED, explains: “We are pleased to bring Castle Wind Farm into operation for Sibanye and the project shareholders. Projects such as these require huge amounts of collaboration and cooperation between a vast array of stakeholders and we are very grateful for the role played by all. Benefits extend way beyond ‘Buyer and Seller’, with renewables projects driving sustainable economic growth on a macro and micro level for South Africa, and we are very proud of this.”
Sunette Smith, Business Development Executive of Reatile Group, added, “Reaching COD is a testament to the hard work and dedication of the extended teams of Sibanye-Stillwater, our partners AIIM, ACED and EIMS Africa as well as our appointed contractors. We could not have done it without their commitment and expertise. We are proud to be playing our role in South Africa’s energy transition and delivering sustainable energy solutions for the country.”
