One of the most important topics in the field of thermal engineering is the possibility of making the performance of thermal units to be at the best possible and more efficient. This is due to the high cost of energy and the depletion of fossil fuel resources. The objective of the present work is to conduct a field study through daily follow-up of AL-Hartha power station in Basrah City-Iraq, under operation for a full year of 2016. This is to discover the reality of the station capacity, to consider its real performance and to identity the locations through the station components of useful loss/destroyed energy and exergy for restoring it to enhance the efficiency. To achieve this goal, a presence co-location was performed together with the station employers to get all the information related to the station and to follow up its daily operation along one year. A mathematical model was constructed and verified to simulate all thermal processes anywhere in the operating unit. This simulation was based on the energy and exergy analysis. The complete computer coding and graphing were performed using Engineering Equation Solver (EES) software. It is noticed that AL-Hartha Station of four roduction units, is currently operating with one unit only. This unit actually operates at 60% of its design capacity, generating 120 MW. Results showed that the actual overall thermal efficiency of this unit is 33% with an exergitic efficiency of 30.6%. The actual thermal energy lost at the condenser alone is 51% of the fuel energy (low grade energy at a 23°C to 41°C), 0.88% in the blow down, 7 % at the exhaust gases (high grade energy at 151°C). The total amount of the destroyed exergy is 253.6286 MW and the lost exergy is estimated to be 18.712 MW. The most important sites affecting the exergitic performance is the boiler sector which caused 90.3% of the total destructed exergy mainly at the boiler coils and then at the fuel burners. The second component in the order that affect the station performance is the turbine sector, which caused 5.475% of the total destructed exergy.