Load-shedding during the first quarter of 2019 would have been far worse without the contribution made to the grid by renewable energy, a study by the Council for Scientific and Industrial Research (CSIR) has found.
During March, Eskom resorted to stage 4 load-shedding, the most intensive so far, in which 4,000MW of demand was dropped from the grid. Had renewable energy not been available, stage 5 or stage 6 load-shedding would have been necessary on the days the system was most highly constrained.
There has been much public debate on the virtues of renewable energy provided by independent power producers with a lobby of trade unions, former Eskom officials and nuclear enthusiasts arguing that it is expensive and unable to alleviate SA’s power supply problem as it is variable and not available when needed most, during peak demand periods.
Jarrad Wright, principal engineer at the CSIR, says that data obtained from Eskom shows that utility-scale renewable energy — generated by solar photovoltaic, wind and concentrated solar power — produced up to 3,400MW during January, February and March, while averaging 1,400MW over the period.
During load-shedding periods, up to 2,300MW from renewables was produced, meaning that without these contributions, Eskom would have had to implement further stages of load-shedding to meet demand. The renewable fleet had also contributed to a less constrained system over the period as a whole, reducing the need for load-shedding by 46%.
“It is true that renewable energy is variable, but it is false that it does not help the system, especially when it is highly constrained. There are periods when its contribution is very low. But you can predict that and plan for it,” Wright said.
SA has a successful renewable energy procurement programme which, since 2011, has added 4,000MW of variable capacity to the grid and has seen prices plummet, making new wind and solar photovoltaic energy cheaper than new coal energy. The programme ground to a halt in 2016 when Eskom executives refused to sign power purchase agreements, on the grounds that Eskom had an excess of supply. In 2018, energy minister Jeff Radebe instructed Eskom to sign outstanding agreements with successful bidders.
Since then the situation has changed dramatically due to the deterioration of the performance of Eskom’s coal-powered fleet. Several energy analysts have advised the government to procure a new round of renewable energy with urgency as it is the quickest way to add capacity to the grid.
Radebe said in March that a new round would only be initiated after the cabinet approved the Integrated Resource Plan, the government’s long-term energy plan. This is now only likely to happen after the new cabinet is installed in May.
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