Integrated optimization of a regional integrated energy system with thermal energy storage considering both resilience and reliability

The regional integrated energy system (RIES) is widely adopted from the viewpoints of energy saving, emissions reduction and resilience enhancement. Especially, in case of external energy supply interruption caused by extreme events, a RIES can survive and ensure energy supply by multi-energy coupling and reserve capacity. Moreover, the resilience and reliability of a RIES can be further enhanced by employing energy storage equip-ment. In this study, an integrated optimization framework has been proposed for a RIES including thermal en-ergy storage accounting for both resilience and reliability. Firstly, a rolling optimization model is developed to calculate the minimum capacity of backup thermal energy storage at each time. Following which, the day-ahead economic scheduling is carried out based on the constraint of backup energy. The Monte Carlo method based on the Markov process is used to simulate the system reliability. The reliability model can also reflect the increase of operation costs caused by backup thermal energy. As an illustrative example, a regional energy system located in Shanghai, China has been selected for analysis. According to the simulation results, the backup thermal energy storage improves both resilience and reliability of the RIES system, and ensures the load supply in case of external energy interruption or equipment failure. There are nine load-shedding periods with improved energy satisfaction rate under external energy interruptions in summer and five in winter. Furthermore, under 10,000 days of operation simulation, the supply interruptions due to equipment failure decrease from 47 to 15 in summer and 22 to 4 in winter.