Solar Engineering P2 Reference 4 min read Reviewed July 8, 2026 Nimesh Katariya Nimesh Katariya

Albedo

Albedo is the reflectance of the ground surface beneath PV modules. Critical for bifacial gain calculation and ground-mount design.

Definition

Albedo is the fraction of incident solar radiation reflected by the ground surface beneath PV modules. Albedo values range from 0.05 (dark asphalt) to 0.85 (snow), critically affecting bifacial gain and rear-side energy.

Albedo Values by Surface

SurfaceAlbedo
Snow (fresh)0.70–0.85
Snow (old)0.40–0.60
White gravel0.25–0.35
Sand (light)0.30–0.40
Concrete (new)0.30
Concrete (aged)0.20
Tan TPO roof0.25–0.35
Wet vegetation0.20
Dry vegetation0.25
Black EPDM0.05
Dark asphalt0.05–0.10
Water0.05–0.10

Design Decisions

For bifacial ground-mount projects, the choice of ground surface materially affects yield:

  • White gravel: +5–8% bifacial gain vs. vegetation.
  • Concrete pad: similar to gravel.
  • Painted white surface: similar to gravel.
  • Sand: +3–5% over vegetation in hot climates.

Surface treatment cost ($0.10–0.50/W) often pays back via 3–5% additional bifacial gain.

Key Takeaways

  • Albedo is the ground reflectance, from 0.05 (asphalt) to 0.85 (snow).
  • Critical input for bifacial gain calculation.
  • Use monthly profile in PVsyst for accurate modeling.
  • High-albedo surfaces (gravel, concrete, sand) boost bifacial gain 5–10%.
  • Site-specific measurement preferred for bifacial bankable projects.

Albedo rarely gets analyzed on its own — it feeds directly into the bifacial gain and rear-side irradiance figures that show up in a project’s yield model. If you’re building that model, the PVsyst tracker yield study methodology walks through where the monthly albedo profile actually enters the simulation chain, and the broader question of which platform to run it in is covered in solar simulation software picks for 2026. Because a wrong albedo assumption quietly understates or overstates bifacial gain, it also shows up as a swing factor in P50/P90/P99 yield report uncertainty — lenders scrutinize the ground-surface assumption for exactly this reason. On the design side, ground albedo works alongside GCR and DHI as one of the core irradiance-and-layout inputs our Solar 3D Pre-Design team validates before a bifacial ground-mount layout is locked.

Frequently Asked Questions

5 commonly searched questions about Albedo.

What is albedo?
The fraction of solar radiation reflected by a surface. Ranges from 0 (perfect absorber) to 1 (perfect reflector). Critical for calculating bifacial module rear-side gain.
Typical albedo values?
Snow: 0.70–0.85. White gravel: 0.25–0.35. Sand: 0.25–0.40. Concrete: 0.20–0.30. Grass: 0.15–0.25. Wet soil: 0.10. Dark asphalt: 0.05–0.10.
Why does albedo matter for solar?
Bifacial modules harvest rear-side reflected light. Higher albedo = more rear-side irradiance = higher bifacial gain (up to 25%).
Does albedo change seasonally?
Yes. Vegetation albedo varies with growth. Snow cover dramatically raises winter albedo. Use monthly albedo profiles in PVsyst for accuracy.
How is albedo measured?
Portable albedometer (paired up/down pyranometers). Site-specific measurement is the gold standard for bifacial bankable projects.

Need engineering-backed solar designs?

Heaven Designs delivers PE-stamped solar design packages, structural calculations, electrical engineering, and utility-compliant permit plans.