In integrated steel works, blast furnace gas, coke oven gas and converter gas are produced during the process of crude iron and steel production. A power plant complex in an integrated steel works is mainly used to deal with the cogeneration gases and using them to supply saturated steam and electricity for the production process. A power plant needs to use gasometers and adjust operation parameters continuously to guarantee an uninterrupted operation due to the fact that the processes in steel works are discontinuous. Nowadays the additional objective in operating those power plants is to use an economic and technical efficient way to lower costs for natural gas and electricity. For this reason the software of the project “Energieeinsatzoptimierug” was developed. This system based on Evolutionary Algorithms provides a recommendation for operation modes of the next two hours to help the personnel. The complex model of an integrated steel works and its energy network is depicted in a simplified way regarding the gas and steam network. For modelling all power station units a developed thermodynamic correct model is used. This thesis is dedicated to evaluate the optimization system for creating thermodynamic correct recommendations to operate power plants in integrated steel works. Beginning with the determination of the stability of the optimization process using the same input data several times and going through changes based on different limitations in calculation time. Another issue is a sensitivity analysis to figure out which parameters have the greatest influence on the outcome of the optimization system. Essential points to investigate are the effects of varying balancing energy prices on the behavior of the system and the stability of the calculation process. To complete this work, an examination of the financial potential is made by comparing the monetary outcome of the optimization system and the actual operation mode.