Optimization of tilt angle for PV in China with long-term hourly surface solar radiation

The optimal tilt angle for photovoltaic (PV) systems is crucial for maximizing solar energy capture. China's diverse climate and geography pose challenges for tilt angle optimization. This study addresses the challenges by using a data-driven approach to determine grid-specific optimal tilt angles across China. Long-term ERA5 hourly solar radiation data and an optimization procedure are used to calculate the annual and monthly tilt angle that maximizes the total solar radiation received over different time periods (up to ten years) for every grid in China. Sensitivity analyses indicate that the optimized tilt angle varies by up to 10° depending on the time period considered, highlighting the importance of long-term radiation data. It is shown that four latitude-dependent schemes in China cannot accurately match the optimized tilt angles, emphasizing the need for optimization through the use of local solar radiation. The difference between our optimized tilt angles and ones via a best-performing latitude scheme makes for an estimated PV power loss of approximately 1.11 TWh/year based on China's PV installations in 2018, equivalent to the PV power generation of Philippines or Portugal in the same year. The presented data-driven framework contributes to China's PV industry by determination of optimal fixed tilt angles.