Is Eskom facing another financial disaster over its multi-billion-rand-losing derivatives? In its financial year to 31 March 2009, Eskom, the South African state-owned power monopoly, scored losses of 11.9bn South African Rand on its derivatives book, and warned that such losses were “not sustainable”. Last week, BHP Billiton, the world’s biggest diversified resources company, announced that it had agreed to “review” its power supply agreements with beleagured Eskom, which faces a build programme for new power stations that will cost hundreds of billions of rands a year for some years to come.