This article presents the analytical evaluation of a central tower receiver solar thermal power plant with air-cooled volumetric receiver using exergy analysis. The energetic and exergetic losses as well as the efficiencies of a typical central tower receiver-based solar thermal power plant have been carried out under the specific operating conditions. The enhancement in efficiency of the plant from the variation in power input to constant power input achieved by thermal storage backup condition has been determined. It is found that the year round average energetic efficiency can be increased from 24.15% to 25.08% and year round average exergetic efficiency can be increased, from 26.10% to 27.10% for the selected location Jodhpur. The unit cost of electric energy generation (kWh(e)) is found to be INR 10.09 considering 30-year lifespan of the solar plant along with a 10% interest rate. The present study provides a base for the development of future solar thermal power plants in India. Copyright (C) 2013 John Wiley & Sons, Ltd.