In the project an ORC (Organic-Rankine-Cycle) for application in gas engine-powered block-type thermal power station has been developed. The main focus has been to continue the development and optimization of the vane expander. The quantitative main objectives of the tested ORC were not achieved. The measurement results show, that the components of the ORC are not working together in an optimal manner. The pressure and heat losses in the current evaporator are too high. Based on the current level of expander development, the internal leakage is relatively high, which increases the required external power for the process. Both effects reduce the efficiency of the ORC. Regarding the durability and the maintenance costs, the ORC system is profitable for the use in genset applications whereas it is not convenient for the use in block-type thermal power stations. The project results show more clearly than it was assumed at the beginning that the ORC, involving all main components and the system harmonization, has to be designed very precisely referring to the temperature, the temperature profile and the mass flow of the ORC fluid.