Clean energy is set to be a major contributor to a global and sustainable energy system and wind energy is becoming one of the lowest-cost sources of clean energy, Mineral Resources and Energy Minister Gwede Mantashe said during the eleventh Windaba Conference, in Cape Town, on October 12. He noted that the conference was being held at a time when South Africa was experiencing frequent loadshedding owing to challenges with the performance of its existing coal-fired power generation plants.