LETTER: It's simply impossible to replace coal power in a decade

At last, the cold, hard truth. As the writer Samuel Johnson said, “A hanging in a fortnight concentrates the mind”.

Eskom COO Jan Oberholzer has concentrated the minds of the governing ANC by pointing out that we need to retire over 20GW of coal power in the next decade or so. To replace this with sun and wind power would require 60GW.

This is simply impossible. Sun and wind power are ideal, but inefficient as they are accessible for only a third of the day. The sun shines only eight hours a day. The wind blows only eight hours a day on average. So to provide 20GWh of power a day, we need 60GW of installed (so-called nameplate) capacity. This we cannot achieve in a decade.

Oberholzer is not explicit as to what form of (relatively) “small” power projects should be built, as this is the province of government. My reading of the situation is that we need a considerable number of new baseload gas power plants. Powerships will not be nearly enough. We will need numerous Ankerlig-type, land-based gas power plants (Ankerlig uses diesel, but gas is more efficient). Such plants can be built in under two years.

Where will all this gas come from? We are of course exploring for offshore oil and gas. There is, in addition, a robust global market in gas. Most of the power generated today in developed countries comes from gas. Renewables are at present only a small component. Yes, the gas will be costly — but not as costly as a death sentence over the economy.

Willem Cronje

Cape Town

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