Zhongning County is located in the central-western part of Ningxia Autonomous Region, covering an area of nearly 3,400 square kilometers. The towns are remote and dispersed, and schools in each town use coal-fired boilers for heating, leading to significant carbon emissions and environmental pollution from dust and gas. Based on the 'Photovoltaic + Energy Storage + Electric Heating' demonstration project at Yinchuan Manxin and Yilong Primary Schools, in 2021, State Grid Ningxia Electric Power Co., Ltd. carried out clean heating renovations in 12 schools in Zhongning County. This project is the first large-scale application of the 'Photovoltaic + Phase Change Energy Storage' clean heating model, covering a total heating area of nearly 70,000 square meters, with 2,500 kW of photovoltaic modules and 175 phase change energy storage thermal tanks.

The 'Photovoltaic + Phase Change Energy Storage + Electric Heating' clean heating system relies on Ningxia's high-quality solar energy resources. During the heating season, it converts solar energy into electrical energy during the day to drive electric boilers for heating, achieving self-consumption, while the remaining electrical energy is converted into thermal energy and stored in phase change energy storage devices. In rainy or snowy weather, the system utilizes the peak and valley electricity price policy, using electric boilers during the night low valley price period to store thermal energy in phase change energy storage devices. In the non-heating season, the photovoltaic system is connected to the grid, generating revenue and reducing operating costs, while also improving equipment utilization and addressing the issue of idle transformers in the non-heating season.

This project can reduce standard coal consumption by approximately 3,018 tons annually and decrease carbon dioxide emissions by about 7,561 tons, achieving intelligent and flexible integration and tiered utilization of photovoltaic, phase change energy storage, and electric heating. The project has operated smoothly for a complete heating season, providing a good demonstration effect for the large-scale promotion of the 'Photovoltaic + Energy Storage + Electric Boiler' clean heating model.