Performance analysis of photovoltaic residual electricity thermal conversion and storage system in solar energy enrichment areas

The Tibetan Plateau is characterized by abundant solar energy resources, providing excellent conditions for centralized solar photovoltaic power generation applications. Traditionally, the electricity generated by photovoltaic systems is mainly utilized through grid connections or battery storage. However, constrained by grid standards and regional dispatching, power surplus waste is common in high-altitude areas. In this regard, integrating storage systems are generally accompanied by increased costs. To address this, an innovative regional photovoltaic residual electricity thermal energy conversion and storage system is proposed and evaluated in this paper. A system simulation model is developed in Trnsys, and the load characteristics of surplus electricity are simulated and evaluated under different photovoltaic capacities. On this basis, the heat storage system capacity is obtained. The simulation results showed that the energy utilization rate of the system increased relatively by 6% to 54%, with the exergy efficiency in the range of 12.55%–23.56%, when implementing the proposed solution. The levelized cost of energy exhibited a trend of initially decreasing and then increasing. Furthermore, a performance comparison was conducted against traditional photovoltaic systems and solar centralized heating systems. The proposed system's operational benefits and investment costs are evaluated and analyzed. The results highlighted that the system not only effectively utilizes the abundant solar energy resources in the Tibetan Plateau, realizing efficient energy conversion and storage, but also demonstrates significant economic and environmental benefits. And the findings of this study contribute to the efficient utilization of solar energy resources in the Tibetan Plateau.