China has been passionately conducting its energy transition into green energy, such as solar energy. In 2018 alone, there were 43 GW PV energy devices installed. The accumulated capacity in China has also exceeded 170 GW. However, according to one study in Switzerland, China's severe air pollution might have lowered its solar power potential by 15% between 1960 and 2015.
After PV panels are installed, there are many reasons that might make power generation potential become lower than expected, such as rain, fog, and smog. In particular, smog will decrease surface radiation that reaches the ground. This factor might lower the power output of the solar panels of existing PV systems.
From solar energy companies' perspectives, lower solar power potential offsets their accumulated efforts, and does not optimize their profits. Furthermore, their future plans might become harder to fulfill because investments would pay off slower. Unfortunately, many PV devices are installed in heavily-polluted cities. Even though the long-term return on investment (ROI) for PV power is about 8%, the air pollution factor might cause potential investors to think that PV's ROI is lower than 8%.
Therefore, researchers from the Swiss Federal Institute of Technology in Zurich (ETHZ) did the following research. They collected data of solar radiation from 119 stations in China between 1960 and 2015, collected local emission data of sulfur dioxide and black carbon, and they were curious about what is the logical relationship between air pollution and PV power generation. The conclusion of the study showed that the PV energy potential dropped by 11%~15% between 1960 and 2015.
According to the team's paper in the journal of Nature Energy, if China uses strict measures to fight against air pollution, solar radiation would rise to the levels of the 1960s. In this way, PV power generation potential might increase by 12% ~ 13%, and the average solar radiation might grow by 11% nationwide.
The growth potential isn't the same everywhere in China. In Chongqing, it might grow by 26%, but in Beijing, it might only increase by 8%. If the solar radiation levels in 2016 returned to the levels of the 1960s, then the PV power generation in 2016 could rise to 14 terawatt/hour (TWh) and the matching economic benefits might amount to 1.9 billion US dollars.
When air pollution issues are completely solved and emissions from all sectors are completely eliminated, surface radiation would increase. According to existing installations and future plans, the researchers estimated that solar power generation potential in China might reach 51 TWh ~ 74 TWh and the potential economic benefits in 2030 might be 4.6 billion ~ 6.7 billion US dollars. As for the power generation potential in China in 2040, it might come to 85 to 158 TWh.
When it comes to China's air-pollution control progress, one of the researchers of ETHZ, Bart Sweerts, expressed that the current air quality level is very far from the levels of the 1960s.