A solar plant complex with battery storage has come online in the deep Karoo. It isn’t very impressive.
What with everyone being on holiday last month, the mainstream news media appears to have ignored the most exciting thing to happen to renewable energy since solar-operated pocket calculators. Only the trade publications carried the news.
‘World’s largest solar + battery project comes online in South Africa,’ read the headline on 12 December 2023 in Emerging Technology News, about a new renewable energy plant in the remote Karoo town of Kenhardt, built by Norwegian solar specialists Scatec.
‘The Kenhardt project symbolises not only a technological triumph but a commitment to shaping a sustainable future,’ Scatec CEO Terje Pilskog told Engineering News.
‘Scatec’s hybrid power project comes on line in South Africa,’ read the more matter–of-fact story in Power Technology.
It wasn’t until a month later that MyBroadband picked up on the news, under a headline that said: ‘South Africa’s biggest solar battery now online — with more power than an old Eskom coal power station’.
This notion, that it’s better than coal, was floated by Pilskog back in September, too, when he called Kenhardt an ‘inpirational site’, which ‘is poised to demonstrate the competitiveness of solar and batteries relative to conventional dispatchable technologies that take far longer to deploy’.
So, let’s have a look at this world-beating solar and battery hybrid power plant – this ‘triumph’ – and what it demonstrates.
Dispatchable power
The site at Kenhardt comprises three vast solar photovoltaic fields, with a total nominal capacity of 540MW.
Its battery storage can nominally deliver up to 225MW of power.
In practice, what this all adds up to is a 20-year contract with Eskom to supply 150MW of dispatchable power consistently between 05:00 and 21:30 throughout the year. ‘Dispatchable’ means that it can be switched on or off, or ramped up or down, depending upon demand.
The project cost is in the region of $1 billion, which at the time of writing amounted to roughly R19 billion.
Scatec describes this project as ‘innovative and large-scale’.
It certainly is ‘large-scale’ in terms of land use. The company reports that it ‘[spans] 879 hectares and [measures] 10 km north to south’. This sounds inconsistent, since 879 hectares is 8.79 square kilometres, which would make the entire thing only 879 metres wide from east to west, but in terms of land use, this almost exactly matches the 883-hectare site on which the Medupi coal-fired power station was built.
So, let the comparisons begin.
More expensive
Medupi, a 4 800MW six-unit monster, produces 5.4MW per hectare. Kenhardt achieves 0.17MW/ha, so per unit of land, Medupi is 32 times more efficient.
Medupi was originally budgeted to cost R80 billion, but since that was in 2007, and both inflation and project costs have since escalated, I’m going to use the most recent and the highest cost-to-completion figure I can find: R234 billion.
At that price, the cost-overrun disaster of Medupi comes in at R49 million per megawatt, while the Kenhardt plant costs R127 million per megawatt. The solar-battery-hybrid is, therefore, 2.5 times more expensive than a grossly overpriced coal-fired power station.
Taking into account Medupi’s energy availability factor of about 70% and Kenhardt’s inability to produce electricity 24 hours a day does not change this calculation by much, and not in Kenhardt’s favour, anyway.
A coal-fired power station does, of course, need coal, which balances the scales somewhat in favour of the solar plant, but 1.5 times the price of Medupi buys a hell of a lot of coal.
On the downside for the Kenhardt plant, Medupi will last 50 years. The typical lifespan of solar photovoltaic panels is 20 years, and the typical lifespan of grid-scale batteries is perhaps 10 years.
When MyBroadband said the Kenhardt plant produces ‘more power than an old Eskom coal power station’ it was being rather disingenuous. It refered to the last unit (of nine) at the more than 60-year-old Komati power station, which at the time of its decommissioning in 2022 produced a mere 121MW. The entire station used to produce 1 000MW, and with more modern coal-fired (or nuclear) power stations, each unit can produce nearly that much on its own.
Grid connections
Medupi is built on the coal fields of the Waterberg, where existing grid infrastructure is abundant. Kenhardt is a tiny town in the deep Karoo. The Scatec plant itself is about 91km due south of Upington, which is the closest town with more than 50 000 people. It is almost 600km from Cape Town, as the crow flies, and about 750km from Johannesburg.
The length of high-voltage connections to the grid, the rights-of-way, and the line losses, all favour power plants other than this solar installation.
To match a single large coal-fired power station, we would need 32 plants such as the Scatec plant at Kenhardt, most of which will be situated in remote locations far from available grid connections, to take advantage of the high levels of solar irradiation of hot, arid regions.
The latest Integrated Resource Plan published by the Department of Mineral Resources and Energy, IRP 2023, pencils in the equivalent of only 25 of such ‘battery energy storage systems’ between now and 2050, for a total of a mere 3 743MW.
It also makes the government’s views on renewables clear: ‘[Renewable energy] pathways do not provide security of supply while carrying the highest cost to implement.’
Displacing coal
Of course, coal-fired power stations are heavily polluting, and they’re also controversial over their contribution to carbon dioxide emissions.
That doesn’t mean, however, that solar plus battery plants are an adequate substitute. With the short projected lifespan of the technologies involved, the permanently toxic waste of panels and batteries will also mount as the decades pass.
A few dozen 150MW plants are not going to displace coal in South Africa. The country’s first priority, as the new IRP makes clear, should be simply to rehabilitate the existing coal fleet.
Down the line, a far more adequate mix to replace coal would be to combine modern nuclear power stations – such as those being built right now in countries with similar levels of development as South Africa – with natural gas peakers.
I have written over and over and over and over and over again in favour of nuclear power in particular. I’m a long-standing proponent of building out a domestic natural gas industry, too.
Each of these sources have advantages over solar-and-battery plants, from far more limited land use, to equivalent or even lower pollution levels, to relative safety, to reliability and dispatchability, to better locations, and to sheer scale. And each can be made cost-competitive with solar, or even with South Africa’s abundant, cheap coal.
The plant at Kenhardt is certainly state-of-the-art, but it does not ‘demonstrate the competitiveness of solar and batteries relative to conventional dispatchable technologies’.
The views of the writer are not necessarily the views of the Daily Friend or the IRR
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Image: Part of Scatec’s solar power plant, with the battery storage facility in the foreground, at Kenhardt in the Northern Cape. Photograph courtesy of Scatec.