Unfortunately, the study is very flawed.  For instance, there are several models of 7-day supply/demand balances.  In one, there is no drop in demand on Saturday and Sunday; in another, there is such a drop in three days out of seven.  In all, the morning peak in demand is often higher than the late afternoon peak, something rarely seen in South Africa.  They hope to balance things out with combined cycle gas turbines [CCGT] by 2020, but it is nearly 2018 and there is no sign of any gas, let alone any CCGT stations. Although the authors are German, they take no account of the German experience, which is having to build 19 new coal-fired power stations to balance their grid even though they have extensive interconnections to the rest of Europe.  We have no such level of connectedness. And Germany nearly lost control last winter when there was no wind for two weeks, and only great efforts by their neighbours saved them.  Beware the Germans bearing gifts!