People who appoint themselves public commentators on SA’s electricity supply options must really try harder to keep abreast of new developments. The somewhat clichéd and incorrect assessment of the potential of wind (Wind not up to scratch, February 14) provides a good example in the comment "engineers reckon that 100% standby power is needed on line at all times to back up turbines if we want a reliable grid". Not to mention the tactic of the pseudo-authoritative statement "engineers reckon …".

The CSIR showed in 2016 that a mix of about 85% variable renewables (solar PV and wind) and 15% flexible supply (such as gas) could have satisfied SA’s actual electricity needs in the period 2010-2012. This was based on actual wind and solar PV data. This is possible because wind is spread across the country. The cost of generation was about R0.90/kWh or less (2016 rand, with 2016 technology), somewhat lower than the recent independent power producer programme numbers of R1.03/kWh for new coal.

The credibility of the CSIR finding is enhanced by the fact that the Department of Energy has included a scenario based on this approach in the recent draft Integrated Resource Plan for electricity.

Dave Collins

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