On the use of thermal energy storage in solar-aided power generation systems

Abstract

The solar-aided power generation (SAPG) technology has been proven to be one of the most efficient ways to integrate solar thermal energy into coal-fired power plants. An open question is whether to integrate the SAPG plant with a thermal energy storage system (TES). Conventionally, most SAPG plants are not designed to include TESs due to high costs and challenges related to the intermittent nature of solar energy. To address this question, a realistic case study utilizing a 330MWe SAPG plant is investigated in this paper. The simulation shows that when the SAPG plant uses a TES with a proper regulation strategy, the energy efficiency of the SAPG can be increased by 2.5% and the levelized cost of electric energy (LCOE) can be reduced by 0.27 cents/kWh. A well-regulated TES does not deteriorate the economic performance of the SAPG plant here and has a positive impact on its operational safety (especially under sudden irradiance change). To the best of authors’ knowledge, this is the first time to study the operational strategies of TES (based on the operating characteristics of the SAPG systems) and to combine them with the TES’s size optimization to maximize the techno-economic performance of the SAPG plant.