This research deals with Energy and Exergy analysis of Sapele steam power plant in Nigeria. The key point in this paper is to identify areas where energy losses are occurring and develop a model that will ensure efficient and effective improvement in a thermal power station. This was accomplished by conducting energy analysis of the overall plant and determination of the efficiencies and energy losses of all the major parts on the power plant in light of experimental data collected from Sapele power plant in Nigeria. Areas where energy losses are being experienced in the plant were pinpointed. It was deduced that energy losses occurred fundamentally in the boiler where 105KW was lost to the surrounding while just 15.7 KW was lost from the condenser system. The rate proportion of the exergy destruction was discovered to be greatest in the boiler system (105.9%) trailed by the turbine (86.53%), and after that the condenser (62.5%). Moreover, the exergy efficiency of the power plant was 11.003% for boiler, 30.315% for turbine and 59.8% for condenser. For a moderate change in the reference environment state temperature, no exceptional change was seen in the execution of major components and the principle conclusion continued as before; the boiler is the significant wellspring of irreversibilities in the power plant. Synthetic response is the most noteworthy wellspring of exergy destruction.