SOUTH Africa is once more experiencing periodic power cuts. These typically take the form of scheduled supply interruptions, for two to four hours a day, whenever the country’s electricity system is overloaded. Such overloading currently happens on 40-50 days a year. HARTMUT WINKLER, Professor of Physics, University of Johannesburg Eskom, the country’s power utility, recently admitted that such interruptions are likely to persist for as long as the next five years. This is because of the increased down-time of the rapidly ageing fleet of coal plants. But it is also due to delays in setting up new power plants. The…