Concentrating solar power (CSP) technology is one of the promising options to generate green energy. However, the cost of kWhe produced is relatively high compared to fossil resources, and can be reduced by integrating a cogeneration system exploiting waste energy. In this study a technical and economic evaluation of a 1MWe CSP plant with a condensation heat (85°C) is investigated. The temperature constraint is set to meet the thermal separation needs of the draw solution of a forward osmosis desalination process. The analysis focuses on the factors involved in reducing the cost per kWhe, which are the selection of the organic fluid used in the Organic Rankine Cycle and the optimal choice of the solar multiple according to the appropriate storage capacity maximizing the CSP thermal efficiency. The purpose of this study is to optimize the cost of kWhe produced by a Parabolic trough collector plant at high condensation temperature. It was concluded that cyclopentane provides a reduced cost compared to the other organic fluids studied and for the needs of the project the optimal storage hours and solar multiple are 8h and 1.85 respectively. Thus, in this case, the cost of kWh was found to be 23.95¢.