PV Inter-Row Spacing and Ground-Coverage Ratio

The row layout for a ground mount, carport, or ballasted flat roof.

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Checked against published worked examples from: Greentech Renewables.

Details, formula, and sources

ScopeThe row pitch is the panel's horizontal footprint plus the shadow its top edge throws at the minimum winter-design sun angle, and the ground-coverage ratio (collector length over pitch) drives both the land area and the inter-row shading. Pack the rows tight for more kilowatts on the lot, or spread them for clean panels - a shallow tilt throws a far shorter shadow and packs nearly 50 percent more array on the same field. The profile angle is the winter sun elevation from latitude or solar-times. A layout geometry, not an annual shading-loss model.

Formula or tablerise = L x sin(tilt); base = L x cos(tilt); shadow = rise / tan(profile_angle); pitch = base + shadow; gap = shadow; gcr = L / pitch.

Source and editionNREL / Sandia PV array row-spacing geometry (pitch = L x cos(tilt) + L x sin(tilt) / tan(profile_angle), GCR = L / pitch), by name; the relations are first-principles trigonometry.

Free accessThe row-spacing geometry and the ground-coverage-ratio definition are public NREL / Sandia relations and first-principles trigonometry.

What governsEstimate. AHJ and licensed professional govern.

API field namesmodule_length_ft, tilt_deg, profile_angle_deg, rise_ft, base_ft, shadow_ft, pitch_ft, gcr

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