Module Reliability Is Key for Cash Flow of PV Power Stations
The reliability of modules is critical for investors or EPC (engineering, procurement, and construction) companies, as modules with high reliability can generate reliable cash flow for the former and cut the operating and maintenance costs for the latter.
Although no comparison to the rigorous challenge of the environment in the real world, accelerated aging tests at laboratories can still generate results as basis for inferring the effect of modules’ aging mechanism on performance output, facilitating the understanding of suitable environmental conditions for the installation of different modules which can generate stable cash flow and reduce operating and maintenance costs.
In 2018, DNV GL unveiled its module scoreboard as a reference for investors or system firms in selecting modules. The following table from EnergyTrend provides the significance and suited environments for the four tests, TC600, DH2000, DML, and PID, of the scoreboard:
|
Test Explanation |
Suitable environment |
|
|
TC 600 (Thermal Cycling test) |
Heat circle test of module targets fatigue or heat-induced failure caused by repetitive changes of temperature | Drought environment with large temperature difference |
|
DH 2000 (Damp Heat test) |
Damp Heat test sequence evaluates module’s construction and resilience in preventing moisture ingression via a long term exposure in high-temperature and high-humidity environment. | High-temperature and high-humidity environment |
|
DML (Dynamic Mechanical Loading test) |
DML test sequence evaluates module’s ability to withstand cyclic mechanical deflection for wind and snow loads | Wind and snow load environment |
|
PID (Potential Induced Degradation) |
It refers to failure of power plants resulting from damage of module performance caused by electric potential difference, which in turn results from high negative voltage between PV modules and ground | Any environment |
In 2018, 22 companies worldwide took part in the tests, mainly on regular mono-si and multi-si modules manufactured in Asia and North America. Few companies passed all of the four tests, with the passage rate for DH 2000 on high-temperature and high-humidity environments reaching only 60%. In terms of the performances of the mono-si modules, JA Solar’s JAM60/PR series and SunSpark’s SST series both failed to pass the tests. Longi’s mono-si module LR60 series passed all four, testifying to its general reliability and suitability for various environments.
In 2017, mono-si modules scored significant growth in both shipment volume and share, with the latter reaching 30%. Although multi-si products retain dominant status, two leading mono-si firms Longi and Zhonghuan harbor 28 GW and 23 GW capacity plans, respectively, in 2018, as a result of which new mono-si capacity will top 60 GW in the year.
With the willingness for purchasing mono-si products increasing on the market, supply can meet the increased demands, thanks to the release of new capacities. With its quality and reliability having been affirmed by third-party certification, Longi is a good candidate for downstream system firms when it comes to choosing a reliable supplier.
Source: pv.energytrend
