In this study, a thermodynamic analysis of a Rankine cycle reheat steam power plant is conducted, in terms of the first law of thermodynamic analysis (i.e. energy analysis) and the second law analysis (i.e. exergy analysis), using a spreadsheet calculation technique. The energy and exergy efficiencies are studied as 120 cases for different system parameters such as boiler temperature, boiler pressure, mass fraction ratio and work output. The temperature and pressure values are selected in the range between 400 and 590 degreesC, and 10 and 15 MPa, being consistent with the actual values. The calculated energy and exergy efficiencies are compared with the actual data and the literature work, and good agreement is found. The possibilities to further improve the plant efficiency and hence reduce the inefficiencies are identified and exploited. The results show how exergy analysis can help to make optimum design decisions in a logical manner. Copyright (C) 2001 John Wiley & Sons, Ltd.