In the 30MW photovoltaic power station built by Guodian Power in Jizhou District, Tianjin, we conducted a comparative study on the power generation performance of bifacial photovoltaic modules equipped with TOPCon and PERC cell technologies. The project site, Jizhou District, belongs to the warm temperate semi-humid continental monsoon climate. It has distinct four seasons, abundant sunshine, and rich heat. The summer is hot and rainy, while the winter is cold. The annual total solar irradiance reaches 1,450 to 1,600 KWH /m2(5,220 to 5,760 MJ/m2). The light resource conditions are excellent, which is conducive to the development and construction of photovoltaic projects.
 
Project Design
 
 
 
The rated capacity of the project is 30MW, consisting of 12 2.5MW photovoltaic power generation units. Each string is designed to be composed of 26 modules, and every 17 strings are connected to a string inverter. Each power generation unit is equipped with 11 225kW string inverters and 1 2500kVA box-type transformer. The capacity-to-power ratio of the project is 1. The bracket selection is a fixed bracket with an inclination Angle of 30°. A vertical two-row bracket scheme is adopted, and the minimum height of the component from the ground is 0.5 meters. To visually compare the power generation differences of N/ P-type modules under actual operating conditions, the project installed a total of 20MW of P-type double-glass 545 modules and a total of 10MW of N-type double-glass 560W modules.
 
Result

 
Based on the power generation performance advantages of N-type TOPCon modules, such as a lower temperature coefficient, higher bifaciality, and lower photoinduced attenuation, they can bring at least a 3% power generation gain compared to conventional P-type PERC modules under the same DC-side capacity. Based on the actual situation analysis, due to the fact that this project is located in a climate zone with a relatively high summer ambient temperature, the extreme high temperature can reach 40 degrees Celsius. Considering that the components themselves are working and heating up, the working temperature of the components can reach nearly 60 degrees Celsius. A superior component temperature coefficient can reduce the impact of temperature on the output power of the component. The temperature coefficient of the Tiger Neo series components equipped with TOPCon technology cells is as low as -0.29%/℃, which can effectively increase the power generation of the components under the same working conditions. By comparing the power generation of an N-type module array with that of two P-type module arrays, it is concluded that compared with the conventional P-type PERC modules, the single-kilowatt power generation gain of Jinko N-type TOPCon modules reaches 5.02% and 5.15% respectively, which strongly supports the outstanding performance of N-type modules in actual outdoor applications.
 
Conclusion
 
Based on the comparison and analysis of the single-kilowatt power generation of P-type PERC and N-type TOPCon modules, the outstanding power generation performance of TOPCon modules over conventional PERC modules has been fully highlighted. Generally speaking, in summer applications, as the sunlight increases, the power generation of photovoltaic modules will also increase. However, the subsequent temperature rise of the modules will reduce the power generation efficiency of P-type modules, thereby affecting the project's revenue. For this reason, the priority of using N-type TOPCon components with a better temperature coefficient for hot application environments has been further enhanced. Not only that, unlike the conventional PERC modules with boron-doped substrates, JinkoSolar's N-type TOPCon modules with phosphorium-doped substrates can effectively reduce the light-induced attenuation of the modules. Coupled with the selection of high-quality auxiliary materials, it can safeguard the customer's full life cycle power generation revenue level from the power output perspective. In terms of power attenuation performance, N-type modules have a natural advantage, with a 1% attenuation in the first year and a 0.4% linear attenuation in the year. In contrast, P-type modules have a 2% attenuation in the first year and a 0.45% attenuation in the year. Due to power attenuation, N-type modules bring an increase in power generation of approximately 1.8%. In terms of high-temperature power generation performance, it is closely related to the temperature coefficient of the module and the operating temperature of the module. The temperature coefficient of N-type modules is -0.29%/℃, while that of P-type modules is -0.35%/℃. Under high-temperature conditions in summer, assuming the operating temperature of the module is around 55℃ (ambient temperature around 30℃), The power loss of N-type modules is about 1% lower than that of P-type modules. Moreover, as the operating temperature of the modules further increases, the high-temperature power generation advantage of N-type modules will become more prominent. Meanwhile, due to the higher conversion efficiency of N-type modules, the thermal conversion of the absorbed light energy is correspondingly reduced, thereby lowering the operating temperature of the modules. This 30MW Tianjin project has also fully confirmed this point. The average operating temperature of N-type modules is approximately 1℃ lower than that of P-type modules. Combined with an excellent temperature coefficient and a lower operating temperature, the power generation of N-type modules is about 2% higher than that of P-type modules. In terms of bifacial power generation performance, the bifacial rate of N-type modules is about 80%, and that of P-type modules is about 70%. Therefore, the increase in power generation of N-type modules brought about by the bifacial rate difference (10%) is between 1% and 1.5%. Theoretically, due to its excellent power attenuation characteristics, high-temperature power generation performance, bifacial power generation performance, and low irradiation power generation performance, the theoretical power generation gain of N-type modules is about 3%. However, empirical project data shows that the power generation per watt of N-type modules is more than 5% higher than that of P-type modules, far exceeding the theoretical gain. The power generation performance of N-type modules has been fully verified. It provides certain technical basis for the selection of technical routes for photovoltaic products and the selection of component products for customers. Furthermore, this result also demonstrates the significant "four highs and four lows" advantages of N-type TOPCon modules, namely high power, high efficiency, high bifaciality and high power generation, as well as low attenuation, low temperature coefficient, low BOS and low LCOE.
 
Photovoltaic, translated from the original link: http://www.pvmen.com/article/15535.html