Civil Engineering January-February 2022 | Vol 30 No 1

Civil Engineering January/February 2022 33 Renewable Energy R oggeveld forms part of Round 4 of South Africa’s Renewable Energy Independent Power Producer Programme and feeds up to 147 MW into the national grid. At a height of 100 m, the towers support wind-powered turbines, each with a maximum generating capacity of just over 3 MW. The towers were assembled with precast concrete segments which were manufactured by Cape Town-based precast concrete producer and Concrete Manufacturers Association member, Concrete Units, in a joint venture with Spanish company Windtechnic. The latter has extensive experience in the manufacture of precast concrete wind towers and provided engineering input. On completion, some 16 500 m³ of concrete, 2 500 tonnes of reinforcing steel and 164 000 m² of shuttering had been used. Tower assembly and the supply and installation of turbines and blades was handled by Nordex Energy South Africa. In addition, a Nordex team of 20 staff members was permanently based at Concrete Units to ensure that high quality tolerances were met daily during the manufacture of the tower segments. The civils contract, which included the tower bases and the roads, was awarded to Concor, and Raubex Infra was awarded the electrical installation contract. BUILDING THE TOWERS Each completed tower comprises five 20 m tapered concrete sections, each section having been assembled with indi- vidual precast concrete segments. “The base section, T1, comprises four segments and was mounted on an in-situ concrete foundation. T2, which was mounted on T1, and T3, which was mounted on T2, were also assembled using four precast concrete segments each, whereas T4 was constructed with three segments and T5 required only two,” explains Charl Coetzee, Concrete Units Cape Town manager. “Turbines comprise a nacelle and hub which weigh a combined 140 tonnes, and Roggeveld Wind Farm – a precast concrete masterpiece Forty-seven precast concrete towers were deployed for the construction of the Roggeveld Wind Farm which is owned by Independent Power Producer (IPP) Red Rocket (formerly Building Energy) and is situated in the Western Cape close to Matjiesfontein and Sutherland in the Northern Cape. A wind tower, prior to the installation of the wind blades lying at the bottom of the tower