Bifacial Solar Gain Estimator

Quantify the bifacial boost on annual production by blending DC capacity, site-specific yield, surface reflectivity, and rear irradiance exposure. Use it to validate plant models and communicate expected kWh gains with prospects and asset owners.

Enter the DC nameplate size of the bifacial array in kilowatts
Use the specific yield from your production model or historical plant data
Ratio of rear to front current (0 to 1) published on the module datasheet
Average reflectivity of the surface beneath the array; snow can exceed 60%
Percent of diffuse light that reaches the back of the module after accounting for row spacing and tilt

Examples

  • Commercial rooftop: 5.4 kW array, 1,650 kWh/kW·year yield, bifaciality 0.72, concrete albedo 40%, rear view 88% ⇒ 10,539.70 kWh per year
  • Ground-mount in grassland: 12 kW array, 1,500 kWh/kW·year yield, bifaciality 0.60, grass albedo 20%, rear view 70% ⇒ 21,456.00 kWh per year

FAQ

What is bifaciality?

Bifaciality is the ratio of rear-side current to front-side current under identical irradiance. Modern glass-glass modules often publish values between 0.65 and 0.80.

How do I measure ground albedo?

Reference published tables for surfaces like asphalt, vegetation, or snow, or deploy a portable albedometer on site during commissioning.

Does the calculation include shading losses?

No. Evaluate row-to-row shading, trackers, and obstruction losses separately with layout software or the Solar Panel Count and Solar Panel Wind Load calculators.

Additional Information

  • Rear-side gain scales with reflective surfaces such as white membranes, sand, or seasonal snow packs—refresh the albedo input for winter and summer scenarios.
  • Pair the output with the Solar Panel Count calculator to validate nameplate sizing and ensure inverter loading ratios stay in range.
  • Check the Solar Panel Wind Load tool before widening row spacing to improve the rear view factor on open-field sites.
  • Document modeled gains in proposals and O&M handbooks to educate clients on how soiling or snow removal influences bifacial performance.

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