The first chart below shows irradiance and ambient temperature data for September 2019. The inverter system was offline for maintenance from Sept. 1 to Sept. 12. As a result, the analysis is based on data collected from Sept. 13 to Sept. 30.
Jinko Solar’s mono PERC, half-cut module (JKM400M-72H) was installed on Aug. 12, and Longi’s bifacial module (LR6-72HBD375) on Aug. 28.
Monthly yield figures from April to September 2019 are provided in the table below. The second chart below shows the total energy yield of all products for the month of September.
A test was set up between three Znshine modules in August. Of two graphene-coated modules (ZXP6-60-275/P), one is cleaned weekly while the other is not cleaned at all. An uncoated module (ZXP6-60-265/P), which is not cleaned, was installed as a reference.
The average energy yield of the three is shown in the third chart to the right. We observed a 1.1% energy yield boost from the coated module. As the dust continues to accumulate over time, it is expected that the energy yield boost will grow.
The overall bifacial boost for September 2019 averages 6.9%. Bifacial boost is defined as the extra energy yield of the bifacial products, compared to the average energy yield of all mono-facial products.
The chart to the bottom right shows the comparison between module technologies for September 2019. Bifacial modules are steadily performing above the average energy yield level, with multicrystalline silicon PV performing below the average energy yield level.
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.
Notes on the energy yield data:
- 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 in categories, per module type.
- The bifacial boost depends on many parameters, including the bifaciality factor, the installation geometry, the albedo of the ground, and also the sun angle and diffuse irradiance
- The ground in this case is a plastic cover simulating green grass.