Natural exposure testing and annual power degradation rate evaluation for photovoltaic（PV）modules—Part 5: marine environment
1Key Takeaways
This document specifies the terminology and definitions, exposure sites and test apparatus, test samples, test procedures, inspection and maintenance, test results, annual degradation performance evaluation, and requirements for test reports for natural outdoor exposure tests of photovoltaic (PV) modules in marine envi…
2Expert Interpretation
SJ/T 11828.5-2026 specifies the natural exposure test methods, annual power degradation rate, annual energy generation, and energy efficiency ratio calculations for photovoltaic modules in marine environments, as well as performance grading evaluation. It applies to crystalline silicon photovoltaic modules.
Standard Overview and Applicable Scenarios
SJ/T 11828.5-2026 "Natural Exposure Test and Annual Degradation Rate Evaluation of Photovoltaic Modules - Part 5: Marine Environment" is an electronic industry standard aimed at providing scientific methods for long-term performance assessment of photovoltaic modules under harsh marine climates. The marine environment, characterized by high salt fog, strong ultraviolet radiation, high humidity, and frequent storms, poses special challenges to the durability of photovoltaic modules. This standard applies to ground-mounted crystalline silicon photovoltaic modules, requiring the exposure test site to be located on offshore platforms or floating structures to ensure modules are tested under real marine conditions.
Core Test Process and Equipment
The test process is divided into four stages: stability testing, initial testing, one-year natural exposure monitoring, and final testing. Initial testing includes visual inspection, electroluminescence (EL) imaging, performance measurement under standard test conditions (STC), insulation testing, and wet leakage current testing. During the monitoring period, individual modules are recommended to be installed on tracking racks and continuously or periodically measured via automatic I-V testing devices (compliant with IEC 60904-1:2020); strings are installed on fixed racks and connected to the grid for power generation. Key equipment includes: irradiance monitoring equipment (Class A, uncertainty ≤±2%), ambient temperature monitoring devices (resolution 0.1℃), wind speed and direction monitoring devices, DC energy meters (Class 1 accuracy), power analyzers (accuracy 0.5%), and I-V characteristic measurement devices compliant with the IEC 61215 series standards. All monitoring devices require regular calibration.
Key Performance Indicators and Grading Evaluation
Test results primarily calculate three indicators: annual power degradation rate (ratio of the difference between initial and final STC power to initial power), annual energy generation (accumulated via continuous I-V measurement or DC energy meter), and annual energy efficiency ratio (ratio of equivalent DC-side generation hours to peak sun hours). Modules are graded based on the first-year front-side power degradation rate:
| Grade | P-type Crystalline Silicon Modules | N-type Crystalline Silicon Modules |
|---|---|---|
| A+ Grade | D1 ≤ 2.0% | D1 ≤ 1.0% |
| A Grade | 2.0% < D1 ≤ 3.0% | 1.0% < D1 ≤ 3.5% |
| B Grade | 3.0% < D1 ≤ 4.0% | 3.5% < D1 ≤ 5.0% |
| C Grade | D1 > 4.0% | D1 > 5.0% |
This grading provides a quantitative basis for module selection and warranty in marine environments.
Test Environment and Maintenance Requirements
The standard particularly emphasizes maintenance in marine environments: monthly visual inspections, cleaning modules every 90 days (using clean water and cotton cloth). Intervals may be extended in special cases (e.g., severe weather or marine organism attachment) but must be recorded. Irradiance monitoring devices also require cleaning every 90 days. Additionally, surrounding vegetation must be regularly trimmed, and bird droppings, seaweed, and other attachments must be cleared. These measures ensure the accuracy of test data.
Relationship with Other Standards
This standard is part of a series of standards, jointly forming a complete environmental adaptability evaluation system with humid heat, dry heat and sand/dust, mild climate urban, and extreme cold atmospheric environments. Referenced standards include IEC 61215 series (module design qualification), IEC 61724 series (performance monitoring), and national standards such as GB/T 33708 (DC energy meters), reflecting a technical route aligned with international practices.
Significance and Outlook
The publication of this standard fills the gap in outdoor empirical evaluation of photovoltaic modules in China's marine environment, providing a powerful tool for assessing the reliability and economic viability of offshore photovoltaic projects. With the rapid development of offshore photovoltaic power stations, this standard will play a key role in module selection, quality certification, and life prediction, promoting high-quality industrial development.