The Steam Power Plant (PLTU) is a power plant that controls the kinetic energy of steam to produce electricity. The PLTU is one of the most constrained operational plants because the energy conversion process in the PLTU is quite long and in each process the ability to deal with changes in load is not the same. The process is carried out by filling the water into the boiler then the water gets heat from the combustion of coal which will later get superheater vapor with high temperature and high pressure to be able to drive turbines and generators. Therefore, in the process of energy conversion, a power plant is expected to be able to deal with changes in load so that it can minimize wasful in the use of fuel so the result is is better efficincy. In this Final Project the method that used is Calculation of Turbine Heat Rate, Calculation of Efficiency Boiler, Calculation of Gross Plant Heat Rate, and Thermal Efficiency Gross Calculation. From the calculation and analysis, it is found that the highest generator efficiency is at a load of 400 MW, which is 42.7940%, which is the maximum load.