The morning started with clear skies in sunny Cape Town, but after we reached the Overberg, the mist appeared and the clouds gathered. It was raining hard and was very windy as we reached the Dassiesklip Wind Farm near Caledon; a perfect day to see a wind turbine in full action! As we entered the grounds, we were welcomed by a beautiful rainbow touching the ground on both sides with, at one end, the wind turbines. As we approached those impressive structures, we were lucky enough to see their 55m blades rotating at full capacity. One of the turbines was producing over 3000 kW.
The wind farm was constructed as a result of the first round of the REIPPPP with a budget of R80 to R100 million. Being amongst the first of its kind in South Africa, millions were spent as a results of delays. The farm consists of nine 3 MW turbines, each towering at a height of 90 m. The turbines are designed to function within a speed range of 3 to 25 m/s but maximum output is limited at 12.6 m/s, after which the blades start feathering until 25 m/s. Beyond this speed, the turbines are shut off due to safety purposes. The speed at the tip of the blade can reach just under the speed of sound with the maximum wind speed.
After an interesting talk (in the bus to stay dry!) on how the wind turbines were constructed, with some insights into the administrative and technical aspects of the whole bidding, procurement, design and construction process, we were allowed to briefly enter the turbine. For security reasons, none of us were allowed to go up to the turbine. In fact, no one, not even the engineers, has access to the top while the turbine is in use. The turbine can sway up to a 1 m radius while running at full capacity. Nonetheless, Bothokgami was allowed a very short ride in the elevator (not more than 2 m).
Completely soaked, but totally amazed, we climbed back onto the bus. We had a quick lunch at a little restaurant (Dassiesfontein Farm Stall) that had rooftop PV panels before driving back to sunny Cape Town. As a class, we would like to thank the Dassiesklip Wind Farm for allowing us the opportunity to see a wind turbine up close and to give us insight into how these farms operate. Next, to Jesse for organising the trip and finally, to Kimmy, who escorted us and bought us all coffee.
By Aumashvini Gobin & Anna Ras – Masters Students.