Considering the breakdown of a generating unit each at (a) Duvha, (b) Kriel and (c) Medupi Power Stations, and noting that delayed returns of a generating unit each at (d) Camden, (e) Kusile, (f) Komati and (g) Kendal Power Stations have worsened the current generation capacity shortages, (i) what maintenance plans does Eskom have in place for generating units and (ii) have the specified plans regularly been updated, in view of the frequent breakdowns of generating units?