pv magazine test: June 2021 Results
By George Touloupas
This article was originally published in pv magazine – August 2021 edition. Learn more about the pv magazine test here.
pv magazine test involves a range of indoor tests, as well as an outdoor performance test in Gsolar’s test facility in Xi’an, China. Some of these tests are standard in the industry, while others are innovative and provide data on important module quality and performance issues.
June 2021 Test Results Explained
Figure 1 below charts the meteo station data (irradiance and ambient temperature) for June 2021. A new product from LONGi was added in the field (#37).
Daily Temperature and Irradiance Data
Figure 1: Daily meteo station data - June 2021
Energy Yield Ranking
Table 1: Energy yield ranking - June 2021
Total Energy Yield
Figure 2: Total energy yield - June 2021
Generation data of May and June show that products 12 and 17 had unreasonably low performance compared to samples with similar technology. After reviewing the meter data records, abnormal current values were detected. As these data are considered suspect, we will conduct further investigations to identify the root cause. In the meantime, the yield data of these 2 products have been removed from our analysis of bifacial boost and relative yield below.
The average bifacial boost is 9.3% for June 2021. Bifacial boost is defined as the extra energy yield of the bifacial products compared to the average energy yield of all mono-facial mono PERC products.
Bifacial Boost
Table 2: Bifacial boost - June 2021
Figure 3 shows the comparison between different PV module technologies for June 2021. Bifacial modules are steadily performing above all the other technologies, with monofacial cast monocrystalline PERC modules having the lowest yield.
Relative Yield of Different Technologies
Figure 3: Relative yield of different technologies – June 2021
Notes on Energy Yield Measurements
The energy yield comparisons, including bifacial boost, will be analyzed using products installed after the beginning of 2019.
The energy yield is given in Wh/Wp and calculated by dividing the energy produced by the module by the Pmax at STC of the module. This Pmax is the maximum STC power after a process of stabilization.
The results are grouped per module type.
Bifacial boost depends on the bifaciality factor, the installation geometry, the albedo of the ground, the sun angle, and diffuse irradiance. The ground in this case is gray gravel.
George Touloupas is CEA’s Senior Director, Technology and Quality
Test Cooperation
pv magazine test is a cooperative effort involving pv magazine, CEA, and Gsolar. All testing procedures are carried out at Gsolar’s test laboratory in Xi’an, China. CEA supervises these tests and designed both the indoor and outdoor testing procedures.