Design of thermal energy storage system based on molten salts for supercritical steam power plants

Abstract

In this study, a unified thermal energy storage system (UT-ESS), a novel molten salt-based thermal energy storage system, was designed for a 540 MW supercritical steam power plant. A mathematical model was developed to analyze the pressure drop and heat transfer of the UT-ESS, and simulations were performed with the developed model to derive a range of design parameters for a feasible design. Case studies were conducted on feasible design candidates using thermodynamic analysis and economic analysis to derive the optimal design. The round-trip efficiency of the UT-ESS power plant was calculated to be 0.441, and the levelized cost of storage (LCOS) was calculated to change from 139 to 250 USD/MWh as the renewable energy cost varies from 0 to 50 USD/MWh. The results of this study suggest that UT-ESS can be used to replace conventional fossil fuel-based large-scale steam power generation.