Assessment of Integrating Solar Energy Technology with Combined Cycle Power Plants

Abstract

The integration of solar energy technology with the conventional combined cycle is considered as a promising technology to produce electricity due to its valuable and unique benefits. Also, adding thermal energy storage (TES) is a key issue in the development of solar thermal power plants (STPP) in the future.In order to select the suitable working heat transfer fluid (HTF), a comparative study was carried out using the system advisor model (SAM) software on six different HTFs: Nitrate Solar Salt, Caloria HT 43, Therminol VP-1, Hitec, Dowtherm Q and Dowtherm RP. Therminol VP-1, which is a synthetic heat transfer fluid designed to meet the demanding requirements of vapor and liquid phase systems, was selected as the suitable HTF for the parabolic trough system and Hitec Solar Salt was selected as the storage medium. In this study, a technical, economic and environmental analysis for two proposed power plant designs was carried out to find out which integration option has the best technical performance and economic benefits in terms of levelized cost of electricity (LCOE) value, carbon footprint and fuel savings. Detailed energy and exergy analyses were carried out and the efficiency values were obtained based on the average and maximum values of monthly global beam irradiance. The results showed that the ISCC with 12.5 hours storage capacity had the lowest LCOE after the conventional combined cycle with a LCOE value ranging from 3.46 Cents/kWh to 4.76 Cents/kWh, which makes it the least cost feasible choice among the proposed integration options. Finally, it was found that utilizing thermal energy storage with maximum storage capacity of 12.5 hours led to more greenhouse gas reduction potential while reducing the amount of fossil fuels consumed by the power plant.