Differential degradation patterns of photovoltaic backsheets at the array level.

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Limited field data exists on the degradation of non-fluoropolymer backsheets, crucial for advancing solar module technology.
• Polyethylene naphthalate (PEN)-based backsheets represent a newer class of materials susceptible to environmental factors.

Purpose of the Study:

• To document and analyze the in-field degradation patterns of PEN-based backsheets in a utility-scale solar array.
• To correlate degradation with module position, environmental factors, and array design.

Main Methods:

• Field study at a four-year-old utility-scale solar array in Maryland, USA.
• Utilized visual inspection, colorimetry, glossimetry, and Fourier-transform infrared spectroscopy (FTIR) for analysis.
• Assessed degradation based on module location, elevation, and surrounding environmental conditions.

Main Results:

• Significant backsheet degradation (yellowing, gloss loss) observed in modules at array edges and higher elevations.
• Degradation patterns linked to differential backside ultraviolet (UV) light exposure, influenced by array design (spacing, ground cover).
• No immediate correlation found between backsheet degradation and module power output or safety within the array.

Conclusions:

• Array and environmental design significantly influence non-fluoropolymer backsheet degradation, particularly UV exposure.
• Degradation may impact long-term system performance and the levelized cost of electricity (LCOE).
• Findings inform backsheet product development and solar array design for enhanced durability.