Open Access

ARTICLE

Multi-Timescale Flexible Thermal-Electric Coupling Operation of Coal-Fired Thermal Power Units Integrated with Molten Salt Thermal Storage System

Haifeng Li¹, Xiao Li¹, Yuchen Hao¹, Tao Jin¹, Yi Cao¹, Yan Yang², Zheng Wang², Yuze Zhou², Yao Zou^3,*

1 State Grid Jiangsu Electric Power Co., Ltd., Power Dispatching and Control Center, Nanjing, 210024, China
2 Changzhou Power Supply Company of State Grid Jiangsu Electric Power Co., Ltd., Changzhou, 213000, China
3 State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing, 400044, China

* Corresponding Author: Yao Zou. Email:

(This article belongs to the Special Issue: Operation and Control of Grid-connected New Energy and Emerging Loads)

Energy Engineering 2026, 123(4), 20 https://doi.org/10.32604/ee.2025.072787

Received 03 September 2025; Accepted 28 October 2025; Issue published 27 March 2026

Abstract

The increasing penetration of renewable energy sources (RES) imposes stringent flexibility requirements on thermal power units (TPUs). Integrating molten salt thermal storage systems (MSTS) and thermal-electric coupling technologies into TPUs has the potential to improve their operational flexibility and regulation capability. However, existing research seldom investigates the combined effects of MSTS retrofitting and thermal-electric output coupling on short-term dispatchability, especially under rapid load variation conditions. This study proposes a comprehensive modeling and multi-timescale optimization framework for MSTS-retrofitted TPUs with rapid load variation capability, enabling coordinated thermal and electrical dispatch in both day-ahead and real-time stages. The TPU model incorporates steam heating, electric heating, MSTS charge and discharge characteristics, and ladder typer ramping constraints, enabling detailed representation of thermal-electric coupling interactions. The proposed scheduling framework consists of a day-ahead economic dispatch model and a minute-level intraday rolling optimization. In the day-ahead stage, the model maximizes operational revenue while considering flexibility reserve requirements, multi-period peak shaving, reserve allocation, and thermal-electric coupling strategies that coordinate steam and electric heating with MSTS charging and discharging. In the intraday rolling stage, real-time RES fluctuations and load variations are incorporated to update dispatch decisions, ensuring continuous power–heat balance and efficient use of stored thermal energy. Simulation results verify that thermal-electric coupling enhances the system’s capability to maintain real-time power balance, while MSTS operation effectively mitigates output fluctuations and supports stable, economical operation for addressing RES variation.

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Keywords

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