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Plunging price of solar batteries is a ray of light


Shapshak is editor-in-chief of and executive director of Scrolla.Africa

In just three years, the cost of batteries for a solar system has dropped by two-thirds. This is just one anecdotal example of the power of Moore’s law in action – where the price of certain technologies (originally the cost of computer processors, as envisaged by Intel co-founder Gordon Moore) tends to halve every 18 months.

My in-laws live on a small horse-breeding farm outside Joburg, where they have a large array of solar panels and batteries, as well as several inverters. When they installed their solar system in December 2018, they put in eight 2.1kWh batteries. That gave them a total of 16.8kWh of storage capacity.

But they were struck by lightning in December 2021, which fried the system. The original cost of their batteries was R189,400. To replace them, they installed six 7.2kWh batteries (for a total of 43.2kWh), which cost R151,280.

The old tech cost R11,274 per kilowatt-hour. Three years later, the new batteries cost R3,502 per kilowatt-hour. In just three years the batteries had reduced in cost by more than two-thirds and, for nearly R40,000 less, my in-laws got more than a twofold boost in storage capacity.

Since the beginning of 2019, according to my father-in-law Rick’s records and calculations, the cost of Eskom’s electricity has increased 58% – and that’s before the 32% that Eskom asked for last week for its annual increase for 2023.

My wife and I took the plunge last year and installed our own solar system at home. It has saved us from Eskom’s #loadsh**ting and the stress that goes with it.

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President Cyril Ramaphosa cutting short his latest overseas travel isn’t going to solve anything. Eskom needs more power right now and the only way to get that is from ­privately owned sources. While non-practising Energy Minister Gwede Mantashe waffles on about cleaner coal or a second Eskom, the crisis gets worse.

The quickest and cheapest way to get more electricity on to the grid is through renewable projects – and, even then, there’s a two-year build process.

Instead of buying new generating capacity, we’ve burned through R8-billion in diesel so far this year. That could have bought a lot of solar panels and batteries.

Ramaphosa needs Mantashe’s support for his re-election as ANC president in December, so he’s not going to be fired. Once again, the country is secondary to the ANC’s ­internal dynamics.

Meanwhile, those who can have bought their own solar installations. Our results are compelling enough. We’ve saved money, done our little bit to help the planet and spared our family the painful rigours of #loadsh**ting, all while my wife and I manage to work uninterrupted – but for a not-­insubstantial price. If only we had got these new batteries, our capacity (14.4KWh) would also have tripled, and we could survive Stage 8.

Sadly, we have to start thinking like that. DM168

This story first appeared in our weekly Daily Maverick 168 newspaper, which is available countrywide for R25.


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  • Neven Govender says:

    Government needs to subsidise home electricity generation (like they did with solar geysers). Give suppliers a rebate on batteries or solar panels which are passed onto the consumer.

    • William Stucke says:

      Hmm. IIRC, the subsidy on solar geysers led directly to them tripling in price? They are now unaffordable.

      Nevertheless, I do agree that some sort of financial incentive makes sense, just not via the supplier. Maybe tax deductible as an expense for all households?

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