GCR (Ground Coverage Ratio)
GCR is the ratio of module area to ground area in a multi-row plant — collector length divided by row pitch. Higher GCR packs more capacity per acre but increases row-on-row shading.
Design baseline keeps rows shadow-free at winter-solstice noon; GCR up to ~0.45 is conservative, 0.45–0.6 balanced. Beyond that, simulate annual shading losses before committing to a generation guarantee.
In More Depth
GCR matters for arrays installed in rows — ground-mount and flat-roof plants. At a fixed tilt, a lower GCR means wider gaps and less shading but more area per kW; a higher GCR fits more capacity into the same area at the cost of morning and evening shading losses. On rooftops, where area is the constraint, designers often accept a higher GCR and some shading loss — simulate it rather than guessing.
Use our row spacing calculator to find the pitch that keeps rows shadow-free at the winter-solstice noon design condition.
Frequently Asked Questions
- What is a good GCR for solar?
- There is no single best value. As a rule of thumb, up to about 0.45 is conservative with little row shading, 0.45–0.6 is balanced, and beyond that you should simulate annual shading losses before committing to a generation guarantee.
- How do I calculate GCR?
- Divide the collector (module row) width by the row-to-row pitch: GCR = collector width ÷ pitch. For example, a 2 m row on a 4.5 m pitch gives a GCR of about 0.44.
Related Terms
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