grid electricity
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By Andrew Kenny, a Cape Town-based mechanical engineer qualified in nuclear physics

Two energy disasters menace South Africa. One is happening, the other looms before us. The first is the functional troubles at Eskom. The second is the possible large-scale adoption of solar and wind for grid electricity.

Eskom, which once provided the world’s cheapest electricity very reliably, is crumbling. In 2007, it failed to provide enough electricity for the growing economy (despite slow growth), delivering a blow to our economy from which it has not yet recovered. Since then we have had blackouts, station breakdowns and massive debt, which Eskom cannot manage. Eskom’s failure has been caused by incompetence, corruption, questionable coal procurement, over-staffing, failure to build stations when needed, and the bad design, construction and procurement for Medupi and Kusile.

Renewables (usually meaning solar and wind) will be even worse if they are implemented on an even larger scale, which is just what our IRP2018 had planned. (The Integrated Resource Plan is the plan for energy sources of electricity until 2030). Every country using wind or solar for grid electricity has seen electricity costs rising and electrical failures. Our own REIPPPP (Renewable Electricity Independent Power Producers Procurement Programme) has forced upon South Africa the most expensive electricity in her history and the worst.

Solar and wind have wonderful applications for off-grid energy. But they are useless for grid electricity. The reasons lie with nature, not man.

Electricity must be consumed at the instant it is produced. Electricity is useless unless it can be provided on demand for as long as necessary. The brakes in your car are similar: unless they work every time they are needed for as long as they are needed, they are useless – or worse than useless. If the power from the electricity utility does not match demand, the frequency and the voltage will change, and the grid will be upset.

Solar and wind are intermittent and unpredictable. They cannot match demand. The Sun does not shine when electricity demand is highest, at dinner time on winter nights. The wind seldom blows at full strength and is highly unpredictable. To incorporate them into the grid, the operator (Eskom) must pay a fortune for “system costs”. Here is the most important equation for costing renewable electricity:

Cost of solar & wind power = price the utility pays for them + the system cost.

The system costs are the huge costs of incorporating the violent fluctuations of wind and solar into the grid to keep frequency and voltage stable. They include back-up generators, spinning reserve (generators running below optimum power), wasted capital, extra transmission lines, wear and tear on generators forced to ramp up and down rather than run steadily, and extra fuel used by these generators. Eskom is forced to pay for these system costs. The wind and solar PV (photovoltaic) companies pay nothing; they just collect profits.

Graph compiled by Willis Eschenbach from Eurostat Data.

System costs explain a paradox. The greens and renewable companies keep telling us the price of solar and wind electricity is coming down, down, down but, all around the world, countries that are increasing solar and wind see the costs of electricity going up, up, up.

Eskom’s latest annual report, for the year ending 31 March 2019, showed that Eskom paid 207 cents/kWh for solar and wind electricity. This compares with its average selling price of about 82 cents/kWh.  If this seems crazy, it’s actually far worse because it ignores the system costs.

The true cost of solar and wind for Eskom is probably closer to 400 or 500 cents/kWh – with system costs about 200 to 300 cents/kWh. An indication is given by the one renewable technology that does pays its own system costs, namely solar CSP with storage (Concentrated Solar Power uses the Sun to heat molten salt stored in a tank. On-demand, this heat is used to raise steam for a turbo-generator). The latest CSP with storage charges Eskom 500 cents/kWh at peak times.

IRP2018, drawing on the CSIR, suggested the “least cost” option for South Africa is solar, wind and a “flexible” power source – meaning imported natural gas, since we have little ourselves. In fact, this is not only the “highest cost” possible but a proven disaster. Australia, which had cheap reliable electricity from coal, started changing towards renewables. Costs rose steeply.

In South Australia, they coincidentally adopted the CSIR plan, moving heavily into wind, with some solar, backed up with natural gas, which Australia has in abundance. The result was soaring electricity prices and two total state blackouts. At one point in July 2016, the price of electricity in South Australia reached R140/kWh – 150 times Eskom’s selling price.

In Germany, the energiewende initiative, the phasing out of clean, safe, cheap nuclear and replacing it with wind and solar, has resulted in soaring electricity prices. It has also resulted in an increase in CO2 emissions. If you want to reduce CO2 (which I do) nuclear is the best technology. Solar and wind are not, because the flexible power essential to support them is usually fossil-fired. Denmark, with the world’s highest fraction of wind power, has about the most expensive electricity in Europe. Britain, ploughing a fortune into wind, onshore and offshore, has seen a steep rise in electricity costs and in electricity failures. On 9 August 2019, there was a massive blackout in England and Wales, caused by the failure of an offshore wind farm and a gas generator.

Storage seems the last desperate hope for grid renewables. But it has failed spectacularly so far, and nothing indicates future success. After the blackouts in South Australia, Elon Musk, at a huge price, installed the world’s biggest battery, with the world’s latest technology to help them. It might help smooth out electricity instability but it is useless for storage, with only enough stored energy to provide the South Australian grid for four minutes.

The best possible future energy source for South Africa is nuclear. It has the best safety record of any energy source and is clean, sustainable, reliable and economic. Koeberg, which started up in 1984, has been a wonderful success, and now provides us with our cheapest electricity. All around the world, you can see that countries with a lot of nuclear on their grids have economic electricity.

There have been construction delays and cost over-runs with companies with a broken record of nuclear construction but those with a continuous record (such as in Russia, China and South Korea) build stations on time and on budget. If we chose a proven reactor design and built in a programme of two reactors a time, this would be our most affordable electricity. Nuclear was unfortunately mired in the suspicion of corruption during the Zuma years (South Africa’s president from 2009 to 2018) but the record of nuclear here and abroad is one of economic and environmentally sound electricity.

Recently, Mineral Resources and Energy Minister Gwede Mantashe announced the latest IRP 2019 plans for energy provision for South Africa, going into the future. It can be described as an extremely sensible plan, bearing in mind the constraints now bringing pressure to bear.

The Minister has allowed latitude to make sensible decisions. Nuclear power is firmly in the plan, “at a pace and price that the country can afford”. That is eminently sensible; no nuclear professional ever advocated anything else, other than fiscal and engineering good sense. We need a rational, responsible plan for our electricity future that will be free of vested interests and ideology and simply provide the best for our people and our environment.


1. REIPPPP prices from Eskom’s annual report for the year ending 31 March 2019.

2. The author has all the production figures and graphs for the REIPPPP since its inception in 2015 until this year. “They are appalling. The load factor for wind, about 35%, is actually good for wind but terrible compared with nuclear, coal, gas etc. But the unpredictable fluctuations make it a nightmare for the grid operator.”

3. Report on South Australia electricity price surge from the Australian, Judith Sloane, 19 July 2016.

4. To see how nuclear and hydro reduces CO2 for electricity generation and wind and solar does not, please go to

5. Elon Musk’s colossal battery in South Australia can produce a maximum power of 100MW and has the maximum storage of 1.29MWh. “This is hopeless for supplying even the small grid there.”