Solar Energy Yield Comparison Study Results

• An outdoor field research conducted by SPIC in China attempted to ascertain the power generation potential of various solar technologies
• Among solar modules, TOPCon followed by IBC technologies were found to have fared fare better than PERC
• The research also focused on inverters, trackers and storage solutions and their impact on overall power output
• SPIC believes these results will help the industry and the government formulate technical standards and industrial policies

A field study of various solar module technologies to determine energy yield performance, carried out by the Chinese State Power Investment Corporation (SPIC), shows TOPCon as taking the top spot followed by IBC in terms of power generation.

With modules installed in Daqing, Heilongjiang region of China, SPIC aimed to see how TOPCon, heterojunction (HJT) and interdigitated back contact (IBC) cell technologies fare in real world conditions.

The empirical experimental data results of module performance under the National Photovoltaic and Energy Storage Demonstration Experiment Platform (Daqing Base) show that in H1/2023 TOPCon and IBC modules generated 1.2% and 0.75% higher power compared to PERC, respectively.

In comparison, a year back in H1/2022, TOPCon produced 0.97% more than PERC while IBC scored 0.39% more power output, according to local media reports.

The research determined that due to different production processes of various manufacturers, the power generation among modules with same cell size differed, up to a maximum of 2.0%.

Comparing the module nameplate power and measured power capacity to calculate power generation/MW, the difference in power generation was found to be about 0.1%.

Inverters also fell under the ambit of the study with SPIC finding central inverters with low-voltage generating 4.19% less power than string inverters, under a limited power operation. However, the inverter efficiency with different technical routes reached the manufacturer's promised value, with all reaching above 98% after more than a year of outdoor operation.

The Director of the Academic Committee of the National Photovoltaic and Energy Storage Demonstrative Experiment Platform (Daqing Base) Xie Xiaoping recommended that manufacturers need to improve the efficiency of inverters under low irradiation and low load.

As for trackers, the annual power generation/MW of dual axis trackers was determined as 30.38% higher in H1/2023, while that of vertical single-axis trackers was found to be 22.22% more.

According to Xiaoping, the field research shows that the choice of trackers has a great impact on power generation with the impact range being somewhere around 30%, while the good news is trackers are increasing becoming reliable as failure rate continues to go down.

In terms of energy storage, the SPIC team found the measured efficiency of lithium batteries was over 94%, that of flow batteries was 76.32%, and the efficiency of power energy storage batteries was over 94% with all of them meeting the value promised by respective manufacturers.

SPIC expects these results to help provide scientific basis and empirical research for the industry and the government to formulate technical standards and industrial policies for new energy systems.