A quantitative and qualitative methodology to evaluate performance improvement of a coal power plant in South Africa by the virtue of energy efficiency intervention

The Industrial and Commercial sectors in South Africa consume more than 80% of the electricity generated by Eskom. The generation of electricity to meet the demand in these sectors is primarily derived from the coal thermal power plant. The goal of Eskom is to sustain the demand and equally reduce environmental pollution. Eskom has embarked on energy efficiency initiatives on their coal boiler plant in a bid to decrease the amount of coal burnt and in turn increase the electricity generated. The study focused on the analysis of the before and after outage data obtained from the unit cards in one of the Eskom's “once through” 600 MW coal boiler with a mechanical conversion efficiency of 35 % (from manufacturer specification). Multiple linear regression models were developed and built to predict the power generated and sent out in correlation with the predictors (average air heater temperature, average main stream super heater temperature, average high pressure heater temperature, the total mass of coal burnt, auxiliary power consumption, average of the cold well and hot well condenser temperature and pressure). The data obtained 3 months before and after an outage showed an average power generated of 434.95 MW and 502.08 MW respectively. The results also revealed that the cumulative energy gained was 44000 MWh. Finally, the reliefF algorithm ranked all predictors as primary factors with the high pressure heater and main stream super heater temperatures contributing the most by virtue of the weight of importance to the power generated.