WIND-POWER
For thousands of years, people have used windmills and the energy derived from wind to pump water and grind grain. Following advances in technology, wind energy can now also be used to generate electricity. Like solar energy, wind energy is a free and renewable resource that will not run out.
The amount of energy that can be extracted from wind depends on its speed. The higher the wind speed, the more energy can be harnessed to generate electricity on a large scale. However, large-scale wind generation requires substantial areas of land for the installation of sufficient wind turbines or generators, which can also produce noise.
Wind energy is most practical in areas with strong and consistent winds. South Africa has good wind potential, particularly along the coastal areas of the Western Cape and Eastern Cape.
Wind Farms
Klipheuwel Wind Farm
Eskom’s demonstration wind farm at Klipheuwel in the Western Cape was established to explore the use of wind energy for bulk electricity generation.
Of the three turbines, the smallest unit performed best under high-wind conditions during summer, while the largest turbine performed best under low-wind conditions during winter.
The wind farm produced slightly more than 4 GWh annually. It has a total installed capacity of 3.2 MW and was expected to operate at a load factor of between 20% and 30%.
The wind farm consists of three units:
- A 660 kW Vestas turbine from Denmark.
- A 1,750 kW Vestas turbine from Denmark.
- A 750 kW Jeumont turbine from France.
The blade spans are approximately 47 metres, 66 metres, and 48 metres, respectively.
The first unit began generating electricity on 16 August 2002, while the final unit began generating on 20 February 2003.
Each wind generator has its own small meteorological station installed on top of the turbine, as well as an aircraft warning light. The turbines at Klipheuwel generate electricity at wind speeds between approximately 11 and 50 km/h, with full power reached at 50 km/h.
Darling National Demonstration Wind Farm
In June 2000, the Minister of Minerals and Energy declared the Darling Wind Farm a National Demonstration Project.
The facility consists of four German-designed wind turbines, each capable of producing 1.3 MW, giving the wind farm a total installed capacity of 5.2 MW. Its annual average output was projected at approximately 13.2 GWh, representing a 28% load factor.
The Darling Wind Farm was the first grid-connected, independent wind energy power-generation facility developed in South Africa. The Darling Wind Farm Company (DWP) signed a 20-year Power Purchase Agreement (PPA) with the City of Cape Town, as well as a Power Wheeling Agreement with Eskom.
The project was developed with financial assistance from the Danish government through Danida, its funding agency, a loan from the Development Bank of Southern Africa, and investment from the Central Energy Fund and the Darling Independent Power Producer.
As a National Demonstration Project, the facility was intended to serve as a model for future public-private partnerships in electricity generation, an area that had historically been largely dominated by Eskom.
The turbines were erected below Moedmaag Hill, approximately 12 km from Darling along the road towards Yzerfontein on the West Coast. The structures are approximately 50 metres high, with blades having a span of approximately 31 metres.
Approval for the project was granted following an environmental impact assessment conducted in accordance with applicable legislation. The Department of Forestry, Fisheries and the Environment (DFFE) determined that the positive environmental impacts would outweigh the potential negative impacts.
South Africa Wind Energy Programme
The South Africa Wind Energy Programme (SAWEP) originated from the declaration by the Minister of Minerals and Energy in June 2000 of the Darling National Demonstration Wind Farm as a National Demonstration Project and the subsequent request for international assistance.