Row to Row Shading Calculator

Inputs

Unit system Metric (m) Imperial (ft)

Switch units, then submit to recalc.

Panel length (along slope) (m)

Tilt angle (deg)

Front clearance (ground to front edge) (m)

Row pitch / spacing (horizontal) (m)

Sun altitude angle (deg)

Lower angles create longer shadows.

Row width used for area (m)

Use 1 for “per meter/foot width”.

Submit Reset

• Tilt rise: rise = L · sin(β)
• Top edge height: H = clearance + rise
• Shadow length (ground): S = H / tan(α)
• Shadow height at next row start: Hshadow = H − pitch · tan(α)
• Shaded fraction proxy: portion of module height covered above clearance.
• No-shade spacing (module): pitch ≥ (H − clearance) / tan(α)
• GCR: GCR = (L · cos(β)) / pitch

This is a fast planning model; terrain, azimuth, and backtracking trackers can change real shading behavior.

1. Select your unit system and enter the panel length along slope.
2. Enter tilt angle and front clearance to define row geometry.
3. Enter the horizontal row pitch (spacing) you are considering.
4. Choose a design sun altitude angle (often a low-angle check).
5. Submit to see shaded fraction, shadow reach, and no-shade spacing.
6. Download CSV for spreadsheets or PDF for site documentation.

Row-to-row shading can quietly reduce energy on an otherwise well-built solar site. During construction planning, teams prioritize access, foundations, and clearances, and shading is sometimes left for commissioning. A quick geometric check before procurement helps avoid avoidable losses and expensive field changes.

This calculator applies a flat-ground, fixed-tilt approximation. Your inputs define top-edge height from clearance and tilt rise, then the tool projects a ground shadow using the sun altitude angle. If the shadow is still above ground at the next row start, a shaded fraction proxy is reported to indicate potential impact. Two spacing checkpoints are also provided: a ground no-shade pitch where the shadow tip lands at the next row start, and a module no-shade pitch where the shadow height equals the clearance.

Even partial shading can trigger string mismatch and reduce inverter output beyond the shaded area. For construction teams, that means spacing decisions influence production guarantees, not just aesthetics. Capturing these checks early also reduces rework in trenching, cable management, and row alignment.

In a professional workflow, the goal is a defensible layout decision, not one “perfect” pitch. Choose a design sun altitude that represents the season you care about, then test one or two lower angles for a conservative check. Compare your current pitch to the no-shade checkpoints, and observe how shaded fraction changes. If shading remains at the target angle, consider increasing pitch, raising clearance, or reducing tilt, then re-check GCR and site constraints. Document assumptions so civil, racking, and QA teams can work from the same baseline.

Example data walk-through

Assume a 2.20 m module length at 25° tilt with 0.60 m clearance. With a 4.50 m pitch and a 20° sun altitude, review whether the shadow reaches the next row and the predicted shaded fraction. Then compare an increased pitch and a lower tilt option.

Export CSV and PDF outputs to support design reviews and field documentation. For complex terrain, confirm the final layout with terrain-aware shading tools and site survey profiles.

1) What does “sun altitude” mean?

Sun altitude is the angle of the sun above the horizon. Lower altitude produces longer shadows and is commonly checked for winter or early-morning performance risk.

2) Which spacing result should I use: ground or module?

Use “module no-shade” when you want the next row’s front edge to stay unshaded at the chosen altitude. Use “ground no-shade” when you only require the shadow tip to end before the next row begins.

3) Why can shaded fraction still be small when shadow reaches the next row?

The shadow may reach the next row but remain below the clearance height. In that case the rack is still clear, so the predicted shaded fraction stays near zero.

4) How should I choose the design sun altitude?

Pick a conservative low angle aligned with the season you care about, then test a few values. Comparing outcomes across angles helps you understand risk without overbuilding spacing.

5) Does this work for trackers with backtracking?

Trackers can change tilt through the day and reduce shading with backtracking, so real behavior differs. Use this as an early planning check, then confirm with tracker-specific modeling.

6) How does pitch affect land use and production?

Larger pitch reduces shading but increases land area and often lowers GCR. The best pitch balances energy yield, civil constraints, access, and budget.

7) Why does flat-ground assumption matter?

Slopes and uneven grades change shadow reach and clearance, especially across long rows. If your site has noticeable grade, incorporate survey profiles and validate spacing with terrain-aware tools.