TechnicalUp to date · Jan 15, 2026
Backsheet
The rear protective layer of a solar panel, typically white or black polymer film (Tedlar, TPT). Provides electrical insulation, moisture protection, and UV resistance.
Why It Matters
Backsheet failures (cracking, delamination) are a leading cause of panel degradation. Black backsheets look sleeker but run slightly hotter, reducing output by 1-2%.
Related Terms
Annual Degradation
The gradual decline in solar panel output over time, typically 0.3-0.5% per year for modern panels. After 25 years, panels still produce 87-92% of their original rated power.
Bifacial Solar Panel
A solar panel that generates electricity from both sides, capturing reflected light (albedo) on the rear face for 5-30% additional production depending on installation.