Updated September 30, 2025 – Sibanye-Stillwater and the Castle consortium have marked the official launch of the 89 MW Castle Wind Farm in South Africa’s Northern Cape, following successful start of commercial operation in March 2025. The Castle Wind Farm is an integral part of Sibanye-Stillwater’s renewable energy program which is designed to reduce the Group’s reliance on Eskom as it accounts for up to 92 per cent of its total emissions. Through a 600 MW pipeline of solar and wind projects, the company also aims to displace 30% of current Eskom supply with renewable energy by 2027.
The Castle Wind Farm in Northern Cape
Castle, located near De Aar, is the largest private-offtake wind farm in operation in South Africa. It dedicates its supply of clean energy directly to Sibanye-Stillwater’s mining operations via a wheeling agreement with Eskom. Additionally, the wind farm consists of 16 turbines, each with a capacity of 6 MW, standing 100 meters hub height and reaching 183 meters to blade tip.
Since the start of operations in March 2025, Sibanye-Stillwater’s Castle Wind Farm in South Africa has already generated 56 GWh of clean energy. This has helped save Sibanye-Stillwater emissions equivalent to about 57,000 tons of CO2, and an estimated R22 million in power costs up to 30 June 2025. Additionally, Castle Wind Farm also allocates 0.6 per cent of its revenue for community development, education, health, welfare, and skills initiatives in the region.
Sibanye-Stillwater Pushes For its 600 MW Renewable Pipeline Target in South Africa
Castle Wind Farm is one of four large-scale renewable projects under Sibanye-Stillwater’s portfolio. This is alongside the 103 MW Witberg Wind Farm, the 140 MW Umsinde Wind Farm, and the 75 MW Springbok Solar PV Project. The four projects will contribute 407 MW of generation capacity by 2026 and reduce the Group’s emissions by around 1.5 million tons of CO2 equivalent annually.
Neal Froneman, CEO of Sibanye-Stillwater, also noted that the company’s renewable investments not only strengthens energy security but also provides electricity at a 15-30 per cent discount to Eskom tariffs. This, Froneman notes, further supports long-term sustainability and competitiveness.
Castle Wind Farm Project Factsheet
Location: Near De Aar, Northern Cape, South Africa
Capacity: 89 MW
Technology: 16, 6 MW wind turbines, with 100m hub height and 183m blade tip
Owner: Castle consortium
Offtaker: Sibanye-Stillwater
Commercial Operation Date: March 2025
Current Status: Fully operational
Expected Annual Generation: 224 GWh
Significance: Largest private-offtake wind farm in South Africa
Emissions Reduction: 57,000 tons of CO2 emissions annually
Castle Wind Farm Project Timeline
2022-2023: Project development and permitting phase initiated
2023: Construction agreement signed with the Castle consortium. Project financing also secured
Mid 2024: Onsite construction works begin
Late 2024: Turbine delivery and assembly commenced near De Aar, Northern Cape
March 2025: Commercial operation achieved
April-June 2025: 56 GWh Generated
September 2025: Sibanye-Stillwater and partners officially celebrates Castle Wind Farm launch
PPA Signed, Financial Close Achieved for Castle Wind Farm, South Africa’s Largest Private Wind Farm
Reported June 9, 2023 – Plans for the construction of the Castle Wind Farm, South Africa’s largest private wind farm, are moving forward. Recently, a power purchase agreement (PPA) for the project was signed and financial close attained. Sibanye-Stillwater, the project’s developer, announced this milestone. Sibanye is a platinum, gold, palladium and rhodium mining major.
The PPA was signed with state-owned utility firm Eskom. It is valid for 15 years from start of operation date. Additionally, African Infrastructure Investment Managers (AIIM) and Reatile Renewables consortium will fund, build, and operate wind farm.
AIIM is a division of Old Mutual Alternative Investments (OMAI). It is represented in the Castle Wind Farm project by African Clean Energy Developments (ACED). ACED is AIIM’s renewable energy project development and delivery platform.
Additionally, the company is invested in the project through its IDEAS Fund. The latter is one of South Africa’s largest domestic infrastructure equity funds. The financing for the Castle Wind Farm project was arranged by Rand Merchant Bank (RMB). RMB is a division of FirstRand Bank Ltd.
Development and Expectations for the Castle Wind Farm
The 89 MW Castle Wind Farm will be constructed near the town of De Aar in the Northern Cape province. Construction will start in June 2023 while commercial operation is scheduled for early 2025.
The facility will comprise of 16 6 MW Goldwind turbines. It will connect to the national grid via the Hydra main transmission station. Electricity from Castle Wind Farm will also be used to power Sibanye-Stillwater’s mining operations.
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Speaking on the project, Neal Froneman, CEO of Sibanye-Stillwater also said that this milestone marks the company’s first major step towards delivering over 550 MW of renewable project portfolio. Additionally, the CEO added that it is a significant milestone in their journey to carbon neutrality by 2040.
“The Castle Wind Farm project will not only play a pivotal role in reducing carbon emissions and mitigating climate change. It will also result in cost savings on electricity and provide energy security benefits for Sibanye-Stillwater’s SA operations. Additionally, it will contribute to addressing the electricity challenges in South Africa at large,” concluded Froneman.
