Definition
Ground Coverage Ratio (GCR) is the ratio of total PV module area to total ground area of a solar installation. Higher GCR fits more modules per acre but increases inter-row self-shading and reduces bifacial gain.
GCR Formula
GCR = (module area) / (land area)
= (rows × modules per row × module area) / (rows × row pitch × row width)
= (modules per row × module length) / (row pitch)For tracker with horizontal axis:
GCR = module_chord_length / row_pitchDesign Tradeoffs
- High GCR (0.50+): more modules/acre, lower land cost/W, but 4–8% energy loss to self-shading.
- Low GCR (0.30): less self-shading, higher bifacial gain, but 30–40% more land needed.
- Backtracking (trackers): mitigates inter-row shading at low sun angles, allowing higher GCR.
Worked Example — Tracker
- Module: 2 m × 1 m, mounted in a string of 28 modules per row.
- Row chord length: 2 m (single-axis horizontal).
- Row pitch: 6 m → GCR = 2/6 = 0.33.
- Land area for 100 MW = ~100 MW / GCR-density ≈ 480 acres.
Key Takeaways
- GCR = module area / land area.
- Typical: fixed tilt 0.40–0.55; tracker 0.30–0.40; bifacial tracker 0.30–0.38.
- Higher GCR = more density but more self-shading.
- LCOE-optimal varies by latitude, tariff, land cost.
- Backtracking on trackers allows higher GCR without proportional shading loss.
Frequently Asked Questions
5 commonly searched questions about GCR (Ground Coverage Ratio).
What is GCR?
Ground Coverage Ratio — module area divided by land area. Expresses how densely modules are packed on the ground.
Typical GCR values?
Fixed tilt: 0.40–0.55. Tracker: 0.30–0.40. Bifacial tracker: 0.30–0.38 (lower for max bifacial gain).
Why not maximize GCR?
Higher GCR = more self-shading between rows at low sun angles = energy loss. Bifacial gain also reduced.
How is GCR optimized?
PVsyst sweep across GCR 0.30–0.55. LCOE-optimal GCR balances energy gain per acre vs. additional land cost.
Does GCR vary by latitude?
Yes. Lower-latitude sites (sun high) tolerate higher GCR. Higher-latitude sites need lower GCR for less self-shading.
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