Shading Calculator: Output Loss

How much output do you lose from shading?

Solar shading impact — quantified for common UK scenarios: CHIMNEY SHADOW (covers 1-2 panels for 2hrs/day): String inverter: 3-8% annual output loss (£30-£80/yr). With optimisers/micro: 1-3% loss (£10-£30/yr). TREE LINE (blocks morning sun until 10am): String: 15-25% loss (£150-£250/yr). With optimisers/micro: 5-10% (£50-£100/yr). NEIGHBOURING BUILDING (shadows bottom 2 panels afternoon): String: 10-18% loss (£100-£180/yr). With optimisers/micro: 3-7% (£30-£70/yr). SELF-SHADING (rows too close on flat roof): String: 5-10% loss. Solution: adequate spacing (minimum 1.5× panel height between rows). SEASONAL: Shading impact is 2-3× worse in winter (lower sun angle) vs summer. Annual figure is weighted toward summer (when most generation occurs). MITIGATION COST vs BENEFIT: Micro-inverters add £800-£1,200. If shading causes >8% loss: micro-inverters pay for themselves in 5-8 years. Sources: PVsyst shading methodology, manufacturer bypass diode performance data, academic studies.