RIYADH: Located on a dead flat piece of land about an hour-and-a-half’s drive from Upington and close to the Orange river, the curved solar collector mirrors, gleaming pipes and large molten-salt tanks of the 50 MW Bokpoort concentrated solar power (CSP) plant stand in stark industrial contrast to the vast expanse of grass and shrubs, distant rolling hills and vineyards.
Nevertheless, the R5-billion parabolic-trough plant offers a practical reference point for South Africa’s recent clean-energy progress and for the much-vaunted notion of Northern Cape’s solar radiation becoming its most valuable natural resource. Developed by a consortium led by private Saudi Arabian utility ACWA Power, the plant entered commercial operations earlier this year and, between March 18 and March 25, operated continuously for 161 hours, at a load factor of 76%, before inclement weather intervened.
Such continuous operation is made possible by 9.3 hours of molten-salt storage, acting as a massive rechargeable battery, and also differentiating the CSP plant from the more commonly known photovoltaic (PV) plants, which currently only produce while the sun is shining. Bokpoort CSP CEO Nandu Bhula expects this record to be broken as the transition from project site to operating power station gains momentum. The consortium of Acciona, Sener, TSK and Crowie has completed the engineering, procurement and construction of Bokpoort, with only a handful of Spanish-speaking contractors still on site to honour hand-over commitments.
This ability to operate when the sun does not shine is also reflected in the tariff received during the second bid window of the Renewable Energy Independent Power Producer Procurement Programme (REIPPPP), as well as the associated power purchase agreement (PPA) with Eskom. Bokpoort will receive R2.57/kWh over the 20-year PPA period.
However, Bhula notes that the tariffs associated with CSP in a subsequent bid windows has fallen, with the 100 MW Redstone power-tower CSP (being developed by ACWA Power and SolarReserve) to receive an average tariff of R1.46/kWh, inclusive of a premium of 2.7 times the base tariff if the plant sells power during peak periods. ACWA is optimistic of Redstone reaching financial close in the coming few months. Similar price declines have been recorded across all of the other renewables technologies, as well as the more recently approved CSP projects.
Besides Bokpoort, two other CSP projects are also in operation (Abengoa’s KaXu and Khi projects) while four other REIPPPP projects (Xina, Ilanga 1, Kathu Solar Park and Redstone) are under development. ACWA Power’s Southern Africa business director Chris Ehlers, who was also recently appointed as the group’s global renewables COO, tells Engineering News Online that the company is determined to increase its CSP footprint in South Africa and the region, while pursuing gas-to-power and coal initiatives in parallel.
