This paper analyses a steam power - two-stage binary cycle plant (SPP-2BCP), in which low temperature waste heat from a conventional steam power plant can be efficiently utilized to generate electricity by installing a bottoming binary cycle. The result from a previous calculation on the installation of binary cycle technology on a Steam Power Plant (SPP) with n-Pentane working fluid indicates an increase in plant efficiency of about 9%. The purpose of this study is to analyze the sensitivity of performance of the binary cycle system against variations in the SPP operational load and the condenser's cooling water temperature. The calculation is conducted on SPP load variations of 25%, 50%, 75% and 100%, inlet turbine pressure variations of 5 bar-30 bar, and inlet turbine temperature variations of 125 °C up to 235 °C. Each of these is also analyzed with ambient cooling water temperatures of 30 °C-37 °C. The results of the analysis indicate that the performance of this binary cycle SPP degrades slightly with SPP load, turbine inlet temperature, and turbine inlet pressure variations and with cooling water variations.