908MW in new private power registered in 3 months — but there is a big “ducking” problem

The National Energy Regulator of South Africa (Nersa) registered 98 new private generation facilities during the third of 2023.

These projects have a combined capacity of 908MW, coming close to the roughly 1,000MW that Eskom sheds from the grid for every stage of load-shedding.

However, the vast majority of the facilities will use solar PV without battery storage systems, so they will only be able to generate power during the day.

Nersa member responsible for electricity generation, Nhlanhla Gumede, commended the increase in generation facilities but said the lack of battery storage was problematic.

“It is concerning that most of the registered facilities are further deepening the California Duck Curve as they are not coupled with storage,” Gumede said.

“It’s recommended that registration applications for generation facilities of variable energy sources be coupled with battery storage.”

The duck curve can be seen when plotting typical solar power production over the course of a day on a graph.

It shows the imbalance in common peak electricity demand periods and peak solar power generation.

The graph below from the United Energy Information Administration shows an example of the duck curve, as illustrated by the performance of California’s own solar power fleet.

The 92 facilities without battery storage will have a maximum potential capacity of 647MW.

Most will be located in Gauteng, where 19 were approved, followed by the Western Cape and KwaZulu-Natal, with 16 and 13 approved projects, respectively.

The other six provinces account for a further 44 facilities.

Two additional solar PV projects in KwaZulu-Natal will have battery storage with a combined capacity of 0.8MW.

Nersa said solar PV technology was favoured because of its flexibility for small-scale and large-scale generation.

Two wind power plants with a combined capacity of 202MW were also approved in the Eastern Cape and Western Cape.

In addition, two projects in Mpumalanga with technology classified as “co-generation” and a total capacity of 58MW were also approved.

The Free State’s projects will have the largest total capacity — 251MW — followed by the North West with 192MW and the Western Cape with 119MW.

Nersa said the total investment value of the facilities it approved during the quarter was R17.25 billion.

The table below summarises the locations, capacities, and investment costs of the new private power projects registered by Nersa in the third quarter of 2023.

Nersa added that seven of the nine generation facilities were registered for commercial use.

These had a capacity of 140MW and an investment cost of R1.9 billion.

The addition of the 98 facilities takes the total number of approved facilities Nersa has registered since 2018 to 1,185.

These projects have a combined capacity of 5,785MW, well over the 4,800MW capacity of Medupi or Kusile, Eskom’s biggest power plants.

Their total cost of R111 billion is also less than half the estimated cost-of-completion of either of Eskom’s delay-ridden facilities.

However, it should be emphasised that it would cost billions more to equip these private power projects with enough batteries to make them capable of dispatching anywhere near the power of their maximum capacities.

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