A wind farm cluster near Impofu Dam in the Eastern Cape is utilizing 1425 locally manufactured keystones. Nordex, a wind energy specialist, built a custom concrete casting tower that is being used to cast the keystones, an integral part of this project.
“This custom-built factory, located 52 kilometres from the wind farm site, is a key investment in the region’s renewable energy infrastructure and we are pleased to be able to announce that the facility is ready to ramp up in line with the construction milestones,” explained David Moncasi Hortet, Head of Sales for Africa at Nordex Energy South Africa.
David Moncasi Hortet, Head of Sales for Africa at Nordex Energy South Africa.
Each wind turbine concrete tower comprises 25 individual keystones, with the heaviest keystone cast weighing over 57 tonnes, measuring 20 metres in length and over 5 metres in width. In addition to concrete, rebar is a crucial structural component, ensuring the strength of the keystones by absorbing tensile forces that concrete cannot withstand on its own. Rebar installation is completed in one day, followed by a 4-5 hour casting process, and the keystones are cured for 7-10 days to achieve the necessary strength for transport.
The concrete cast is cured for 7 days before being sent to the site
“Considering the local content contribution, including steel rebar, concrete, and aggregate—each sourced locally—the production of the towers not only supports job creation but also provides an additional boost to the South African economy,” added David Moncasi Hortet.
Given the size and weight of the keystones, 13 of the 25 required for each turbine tower will need police escorts for transportation. With the factory’s proximity to the wind farm site, the logistical process is streamlined, ensuring smooth delivery of these essential components.
Developed as part of a broader strategy to stimulate the local economy, the facility is creating approximately 350 ongoing jobs and spans nearly 10 hectares. Its strategic location near the Port of Ngqura supports efficient logistics for both the manufacturing and transport of the keystones, further cementing the Eastern Cape as a renewable energy hub. This cluster of wind farms is a significant milestone in South Africa’s renewable energy efforts, with the casting of the first keystone marking a crucial step in the project’s construction progress. As manufacturing accelerates, the project will continue to contribute to the country’s clean energy goals and bolster the local economy.
The keystones are integral to the structural integrity of the wind turbine housing
