This article deals with comparative energy and exergetic analysis for evaluation of natural gas fired combined cycle power plant and solar concentrator aided (feed water heating and low pressure steam generation options) natural gas fired combined cycle power plant. Heat Transfer analysis of Linear Fresnel reflecting solar concentrator (LFRSC) is used to predict the effect of focal distance and width of reflector upon the reflecting surface area. Performance analysis of LFRSC with energetic and exergetic methods and the effect, of concentration ratio and inlet temperature of the fluid is carried out to determine, overall heat loss coefficient of the circular evacuated tube absorber at different receiver temperatures. An instantaneous increase in power generation capacity of about 10% is observed by substituting solar thermal energy for feed water heater and low pressure steam generation. It is observed that the utilization of solar energy for feed water heating and low pressure steam generation is more effective based on exergetic analysis rather than energetic analysis. Furthermore, for a solar aided feed water heating and low pressure steam generation, it is found that the land area requirement is 7 ha/MW for large scale solar thermal storage system to run the plant for 24 h. (C) 2011 Elsevier Ltd. All rights reserved.