In November 2021, the Chinese Government entitled SPIC (State Power Investment Corporation) invested approximately 6 billion yuan in Daqing City to establish an empirical experimental area for four types of products including
Photovoltaic modules, inverters, brackets, and energy storage. There are about 640 empirical experimental plans for planning and deploying photovoltaic power generation systems. Since then, CPIC has held academic meetings every quarter to report on trial reports. After the base's test platform has been running smoothly for 18 months, on September 17, 2023, the Daqing base released the latest data report.
This issue’s data report has the following highlights:
Solar Panel Section
Backside irradiance of photovoltaic array in different application scenarios
Under the typical climate conditions of Daqing, the proportion of backside irradiation received by the double-sided photovoltaic Solar panels used in the experiment will show different trends depending on the application scenario, different months, and different heights. Among them, in terms of application scenarios, the highest proportion of backside irradiation is 50-60% in snow scenes, and the lowest proportion is about 10-12% in conventional land. Statistics are available for other site conditions such as tall glass land and short grass land. Data are as follows:
Chart: Backside irradiation of bi-facial solar modules in different field conditions
| Field Conditions | Backside irradiation (2022 data) | Backside irradiation (2023 data) | Total Irradiation of Both Sides |
| Snow fully covered | 50%~60% | | 100% |
| Thin snow covered | | 27%~30% | 100% |
| tall grass land | 15%~17% | | 100% |
| Short grass land | 13%~14% | | 100% |
| Bare mud land | 10%~12% | 15%~16% | 100% |
Power generation capacity performance of solar panels of different technologies
In the comparison of the power generation of N type TOPCon, P type PERC, N type IBC, and N type HJT, the test results verified that under the same conditions, the order of power generation is N type TOPCon, P type PERC, N type IBC, N type HJT . It can be seen from the data released in the first half of 2023 that the power generation patterns of different technology types in 2023 are consistent with the same period last year. In 2023, TOPCon and PERC were 1.28% and 1% higher than IBC respectively. HJT is 2.63% lower than IBC.
Other comparisons of data for solar modules of different technologies, include:
● N-TOPCon modules not only have the best power generation, but also have a higher bifacial ratio and lower operating temperature;
● The bifacial ratio of N-IBC modules is low, and the gain of power generation on the back side is low;
● N-HJT components operate at higher temperatures and suffer greater temperature losses;
● N-HJT has excessive oxidation of the solder ribbon due to high operating temperature, and the power attenuation is high, as shown in the figure:
The long-run operating current of the solar modules at the test site is higher than the nominal current value
It is worth noting that according to empirical data, the measured operating current of the component on site is higher than the nominal current for a long time, and can reach 115% Imp at the highest. When the current is too high, on the one hand, the components will generate a lot of heat and the operating temperature of the components will be too high; on the other hand, whether the AC and DC side supporting equipment can meet the requirements needs further verification. The next step will focus on tracking the operating current changes of large-size components.
Silicon Cell Size influents the electricity yielding insignificantly
The size of the cell has little impact on the power generation of the module. Overall, the power generation of large-size cells is relatively high, but there are differences in the power generation of cells of the same size from different manufacturers. As can be seen from the figure below, the highest and lowest megawatt power generation capacity comes from 158mm cells, which means that there are still differences in the processes of different manufacturers. Differences in the manufacturing process of different manufacturers will cause differences in the power generation of modules, with the maximum difference being only 2.0%.
Solar Inverter Section
String inverters have the highest power generation, distributed inverters have the lowest power generation
Regarding inverters, the power generation pattern of inverters of different technology types in 2023 is consistent with the same period last year, and the difference in power generation compared to the same period last year is within 0.5%. For distributed inverters, the low-voltage side of box-type inverters did not reach 1.1 times due to strategic reasons in 2022. In power-limited operation, the power generation is 4.19% lower than that of the string inverter; after the strategy is optimized in 2023, the power generation is 1.14% lower than that of the string inverter.
According to the empirical data of inverters, string inverters have the highest power generation, distributed inverters have the lowest power generation, string inverters have higher inversion efficiency, and distributed inverters have not reached the 1.1 times fixed value. Limited power. From the perspective of overload capacity, most inverters meet the overload requirement of 1.1 times, and some inverters can reach 1.13 times overload in a short period of time. When some inverters are overloaded 1.03 times, power limit operation occurs.
However, empirical data on inverters found that inverters in the Daqing base operate at low load for a long time after starting up and before shutting down. The low load operation time accounts for a large proportion. The inverter efficiency is relatively low when running at low load. The next step will focus on Study how to improve the efficiency of the inverter under low load conditions.
PV Bracket Section
Empirical data on brackets show that among different bracket types, biaxial power generation is the highest. Vertical single-axis and full-dimensional brackets have higher faults and lower power generation. Compared with fixed brackets, flat single-axis power generation is higher in January and February with fixed brackets. , after March, the power generation of flat single-axis brackets is better than that of fixed brackets, and the difference is getting bigger and bigger. In addition, the power generation capacity per megawatt of different types of supports is basically consistent with the irradiation trend.
It is worth noting that from the empirical data of the bracket, it is found that the photovoltaic power station design theoretical calculation software only supports fixed + double-sided and flat single-axis + double-sided systems, and does not support the simulation of other tracking bracket + double-sided systems. The deviation between the measured data and the theoretical calculation data of the fixed bracket is small, and the deviation between the measured data and the theoretical calculation data of the flat single-axis bracket is large. In addition, there are also differences in irradiation at different tilt angles. Increasing the sub-array spacing can increase the proportion of back irradiation, reduce morning and evening shading times, and help increase the matrix power generation; there are differences between back irradiation and back irradiation proportions at different spacings. The larger the overall spacing, the higher the proportion of backside irradiation.
Energy Storage System Section
The energy storage product demonstration section of the Daqing base covers 7 different energy storage technology types from 6 manufacturers, including electrochemical energy storage, electromagnetic energy storage, and mechanical energy storage, covering lithium iron phosphate, ternary lithium, lithium titanate, All-vanadium flow, supercapacitor, hybrid capacitor, flywheel energy storage. From the perspective of system efficiency, the energy storage battery system has high efficiency and can reach the promised value. After the energy storage system increases the losses of PCS and power conversion devices, especially after the air conditioner or pump consumes power, the system efficiency will be low.
Through the empirical study of energy storage products in the Daqing base, it was found that there is a lack of outdoor testing standards for measured energy storage products. The next step will focus on conducting research on outdoor testing methods and testing standards for energy storage products. Different energy storage batteries perform differently in different weather and application scenarios. The next step is to focus on finding out the operating characteristics and adaptability of different energy storage products and photovoltaic power stations in different weather.
The demonstration of the energy storage system focuses on three application scenarios: simulated energy transfer, local power grid covered by a large power grid, and local power grid with adjustment and support capabilities. Among them, energy transfer means configuring a certain proportion of photovoltaic and storage power generation systems with energy transfer functions in large power grids to smooth the combined photovoltaic and storage operating curves. Among them, the combined photovoltaic and storage output curves of single PCS and dual PCS energy storage systems are smoother, and the combined output curves of hybrid storage systems are smoother. The combined output curve of energy systems with light and storage fluctuates greatly; configuring a certain proportion of light and storage power generation systems with fast frequency regulation functions in large power grids can reduce local power and frequency fluctuations.
solar panel
Monocrystalline solar Panels
Polycrystalline solar Cells
HJT Half Cut solar Panels
TOPCon solar Panels
PERC Silicon solar Panels
Perovskite tandem solar Cells
Flexible Thin-Film ETFE solar Panel
Bifacial Solar Panel Vertical Module Cell dual double glass 600W ~ 700W
solar Lighting
JLA solar Street Lights
JLB solar Street Lamps
SPX solar Flood Lights
SPH solar Flood Lamps
SPD solar Spot Light
Small Mini Portable
10V 10W Portable
10W-30W Emergency
solar Energy Storage
JSG Portable solar Light kits
JPB Portable solar Power
JBD Home solar Battery
JBL 48V solar Lithium Battery
JBH Modular solar Battery Stack
Outdoor Camping Battery
500W Portable Solar
Independent Off Grid
solar inverters
JMC Micro Inverter
JMN Off-grid MPPT Solar Inverter
JBW On-grid Hybrid Solar Inverter
JND Low Frequency Solar Inverter
JNT Single Phase PV Inverter
JPM Three Phase Solar Inverter
Configured Solar System
JSS Solar Power kit setup
JBP Balcony Solar
Solar Powered Refrigerator
Solar Powered DC freezer
Solar DC Fan
Solar Fabrication Accessories
Solar Panel Glass
Solar Module Backsheet
Encapsulation Film
Solar Module Frame
JM Profile
