Pvshading Loss Calculator
Our renewable energy calculator computes pvshading loss accurately. Enter measurements for results with formulas and error analysis.
Reviewed by Daniel Agrici, Founder & Lead Developer
Formula
Energy Lost = Annual Production x Effective Shading Loss %
Annual Production = System Size (kW) x Peak Sun Hours x 365 x System Efficiency. Effective Shading Loss accounts for mismatch effects in string inverter systems, where the actual loss can be 2-3x the physical shading percentage due to series connection of panels. Financial loss = Energy Lost x Electricity Rate.
Worked Examples
Example 1: Residential Rooftop with Tree Shading
Problem:A 10 kW system in an area with 5 peak sun hours experiences 15% panel shading from a nearby tree. Electricity costs $0.12/kWh.
Solution:Annual production (no shade) = 10 x 5 x 365 x 0.80 = 14,600 kWh\nDirect shading = 15% of array\nEffective loss (with mismatch) = 15% x 2.5 = 37.5%\nEnergy lost = 14,600 x 0.375 = 5,475 kWh\nActual production = 14,600 - 5,475 = 9,125 kWh\nRevenue lost = 5,475 x $0.12 = $657/year
Result:Lost: 5,475 kWh/year ($657) | 25-year loss: $16,425
Example 2: Commercial System with Minimal Shading
Problem:A 50 kW commercial system has only 5% shading from a distant chimney. Peak sun hours: 4.5. Rate: $0.10/kWh.
Solution:Annual production (no shade) = 50 x 4.5 x 365 x 0.80 = 65,700 kWh\nDirect shading = 5%\nEffective loss (with mismatch) = 5% x 2.5 = 12.5%\nEnergy lost = 65,700 x 0.125 = 8,213 kWh\nActual production = 65,700 - 8,213 = 57,488 kWh\nRevenue lost = 8,213 x $0.10 = $821/year
Result:Lost: 8,213 kWh/year ($821) | 25-year loss: $20,531
Frequently Asked Questions
What is PV shading loss and why does it matter?
PV shading loss refers to the reduction in solar panel energy output caused by shadows falling on part or all of the photovoltaic array. Shading is one of the most significant factors affecting solar system performance because even partial shading can have disproportionately large effects on energy production. When even a small portion of a solar panel is shaded, the shaded cells become resistive loads rather than power generators, potentially reducing the output of the entire string of panels connected in series. Studies have shown that shading just 10 percent of a panel array connected to a string inverter can reduce total system output by 30 to 50 percent due to electrical mismatch effects. This makes shading analysis a critical component of solar system design and site assessment.
References
Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy