Renewable energy sources (RES) are abundant in South Africa – and they are the fastest way to reduce load-shedding if a RES curtailment framework is in place. The persistent load shedding crisis in South Africa is caused by a power generation deficit of at least 6 GW. RES can be a cheap and fast remedy to this crisis. To ensure system security in the mid and long term, the substantial growth of RES will need to be accompanied by accelerated investments in grids and flexible, fast resources for their successful integration into the power systems. However, grid planning and expansion takes time and will only become effective in five to ten years from now. In the very short term (immediate action), significant amounts of RES in the order of magnitude of several gigawatts could be deployed even within the constrained areas of the existing power grid infrastructure, if only a certain operational framework – RES curtailment – gets implemented. This framework is laid out in this paper and could become effective within weeks. It could make a substantial contribution in the shortest possible time (2 years or less) to sustainably mitigate load shedding. “Curtailment” means making optimal use of existing power grids to accommodate maximum RES. It refers to the active control (reduction) of the output of RES plants as response to system security needs or temporary transmission capacity constraints. Preliminary analysis of ESKOM’s strategic grid planning confirms that by accepting a reasonable share of no more than 10% curtailment, the RES hosting capacity for the Western Cape Region could be almost doubled. Round about 4 GW of additional RES capacity could be connected to the grid almost immediately, and more than 90% of these RES plants’ electricity production could be safely integrated into the grid.

The study was done by Elia Grid International (EGI) in cooperation with the South African integrated electricity producer and TSO ESKOM. Elia Group is parent company of the North-eastern German TSO 50Hertz (grid region with 18 million people, 100 TWh annual load), which is one of the European frontrunners for the integration of variable RES – more than 60% on an annual average. At 50Hertz, like many other TSOs, curtailment has been a standard operation procedure for more than a decade. It has proven to be a highly efficient and effective way of grid operation with high shares of RES as it minimizes system expenditure, maximizes RES uptake and increases the speed of RES uptake. The study was commissioned by Climate Neutrality Foundation.

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