Steam Power Plant’s Loads and Efficiency of the Subcritical Pulverized Coal Boiler: A Case in Kendari City

Steam Power Plant (PLTU) is a type of thermal power plants widely used nowadays due to its high in efficiency. PLTU Moramo is an Independent Power Producer (IPP) that supplies electricity to PT PLN and has two generating units which produce 2 x 50 MW of electricity. The main goal of this research is to investigate effect of the steam power plant’s electricity loads on efficiency of the Subcritical Pulverized Coal (PC) Boiler and to determine values of the boiler’s efficiency based on the three vary loading capacity which are 30 MW net, 40 MW net, and 50 MW net respectively. Method applying to calculate the boiler efficiency in this research is an indirect method or heat loss method of calculation based on the heat loss value for each parameter, then the boiler efficiency is determined. Results obtained in this research showed that by using indirect method or the heat loss method, thermal efficiency of the boiler decreases as the boiler’s loading capacity is increased. Based on this research, thermal efficiency of the boiler is 81.15 % for the loading capacity of 30 MW net and decreasing to 80.20 % and 79.20 % for 40 MW net load and 50 MW net load respectively