I do hope your David Gleason applies his mind to listed assets more fully than he does to renewable energy. It would appear even the basics are lost to him (Torque, June 21).

First, renewable energy, as the name implies, uses energy sources that are both perpetual and freely available, namely the wind and sun. In contrast, a coal-fired power station, as the name again implies, requires vast quantities of coal to derive energy, in addition to water. Comparing capital costs is therefore not even remotely appropriate.

What matters is the cost of electricity produced.

Medupi, when taking the cost of coal, water and maintenance into account, produces power at a cost estimated by most experts to be in the region of R1 /kWh. In contrast, the latest average wind tariff in the second round of renewable energy bidding is 89c/kWh, a discount of 11c for "rich-world energy" as Mr Gleason calls it.

This is regrettably only the tip of the ignorance iceberg. Mr Gleason also seems to believe a coal plant magically runs at 100% capacity when the more correct figure is closer to 60%. Similarly, he seems unable to grasp that one cannot compare production costs at new-generation facilities with the 62c/kWh of Eskom's depreciated fleet. Possibly in his world new cars cost less than second-hand ones?

And of course, the real depths seem to be the complete ignorance of that pesky little thing called the environment. Possibly Mr Gleason looks forward to a little global warming to alleviate wearing a bulky scarf in winter, but does he really believe noxious gases emissions and the damage of open-cast mining to be desirable if avoidable? Is there really no cost to such externalities?

Sean Friend

Via e-mail