Energy Storage Start up Strategies for Concentrated Solar Power Plants With a Dual Media Thermal Storage System

Abstract

A concentrated solar power (CSP) plant typically has thermal energy storage (TES), which offers advantages of extended operation and power dispatch. Using dualmedia, TES can be costeffective because of the reduced use of heat transfer fluid (HTF), usually an expensive material. The focus of this paper is on the effect of a startup period thermal storage strategy to the cumulative electrical energy output of a CSP plant. Two strategies—starting with a cold storage tank (referred to as “cold startâ€‌) and starting with a fully charged storage tank (referred to as “hot startâ€‌)—were investigated with regards to their effects on electrical energy production in the same period of operation. An enthalpybased 1D transient model for energy storage and temperature variation in solid filler material and HTF was applied for both the sensible heat storage system (SHSS) and the latent heat storage system (LHSS). The analysis was conducted for a CSP plant with an electrical power output of 60 MWe. It was found that the cold start is beneficial for both the SHSS and LHSS systems due to the overall larger electrical energy output over the same number of days compared to that of the hot start. The results are expected to be helpful for planning the startup operation of a CSP plant with a dualmedia thermal storage system.