By George Touloupas

This article was originally published in pv magazine – September 2024 edition. Learn more about the pv magazine test here.

George Touloupas, senior director of technology and quality at Clean Energy Associates (CEA), analyzes the September 2024 results from the pv magazine test outdoor installation in Xi’an, China. 

View previous PV Magazine Test Results

We are excited to announce that pv magazine test will undergo a significant revamp in 2025, with new partners. The pilot run at a new test field will start in Dec. 2024 and many of our existing product types, provided by new partners, will be installed. We will announce more details as the launch date approaches.

Due to system downtime, four days of data have been excluded. The Risen HJT product has been removed and will be replaced in the new field. The average bifacial boost is 7.53% for September 2024. Bifacial boost is defined as the relative advantage in average specific energy yield of all bifacial products compared to the average of all monofacial PERC products.

There are changes in the bifacial TOPCon ranks this month, as Longi’s product climbed to the top together with Astronergy’s product, and Runergy’s new product. Certain n-type products started at the top rank, but have fallen lower after only a few months in operation. We need longer observation time to draw conclusions on the causes of this.   

Notes on the energy yield measurements:

• The energy yield comparison among various technologies, including bifacial boost, analyzes products installed since the beginning of 2019.

• The energy yield is given in Wh/Wp and is 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 solar module type.

• The bifacial boost depends on a number of parameters: the bifaciality factor, the installation geometry, the albedo of the ground, and the sun angle and diffuse irradiance. The ground in this case is gray gravel.

Test cooperation

pv magazine test is a cooperative effort involving pv magazine, CEA, Gsolar and Hoymiles. 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.