“…Currently, more than 40 per cent of the world's electricity is generated at coal-fired power stations [1]. This figure does not seem that high, but many countries -such as South Africa (93%), Poland (92%), China (79%), India (69%), and the USA (49%) -rely primarily on coal for electricity generation [2]. The unpredictable demand for electricity, along with the uncertainties related to inventory replenishment and coal quality, places great emphasis on accurate and effective inventory planning at coal-fired power stations.…”