Analysis of energy consumption and cost distribution on a South African cement plant

Cement prices in South Africa were regulated until 1996, whereafter the industry became competitive. New local and international competition increases strain on the oversupplied market. This and rising energy costs drive cement plants to increase focus on cost effective operations. A number of energy management methods exists, but often require large capital investments. This paper investigates the typical energy source distribution of cement plants, and compares it to the energy cost distribution of a South African cement plant by means of a case study. The purpose of this investigation is to determine which energy sources should form part of an energy management system aimed at improved profitability. Previous research was used to determine the most feasible tactic. Advantages of the “plan-do-check-act” (PDCA) approach of ISO 50001 are briefly discussed to introduce it as a suggested basis for the energy management system. From the case study it was found that coal made up 88% of plant energy with electricity only contributing 12%. However, the cost of electricity is about 4.83 times higher than that of coal and thus results in electrical energy contributing 39% to the total energy cost. This motivates that the management of electrical energy is a critical component for energy management on a cement plant, even though it only contributes to 12% of the energy consumption.