A ground mount gives you freedom that a roof does not: you can choose the location, orientation, tilt, row spacing, and service access.
That freedom also creates more decisions. The best-looking spot may have a long cable run. A steep winter tilt may increase wind loading. Tight row spacing saves land but creates morning and winter self-shading.
The right layout is a compromise between energy, structure, maintenance, land, and electrical cost.
1. Choose orientation and tilt for the job the array has to do
For a fixed array in the Northern Hemisphere, facing near true south is a useful baseline for annual production. It is not automatically the best answer.
You might intentionally rotate or change tilt because of:
- morning or afternoon loads,
- terrain and tree shading,
- snow-season priorities,
- available land,
- inverter clipping,
- utility rate structure in a grid-connected system.
Rules such as “tilt equals latitude” or “latitude plus 15 degrees for winter” can be useful first estimates, but they should not be presented as an optimum.
Run a few candidate orientations through PVWatts or a more detailed model and compare the season you care about, not just annual kWh.
A steeper array can also shed some snow more readily, but snow release depends on weather, module surface, frame geometry, accumulation, and lower-edge obstruction. Do not count on automatic clearing.
2. Row spacing is a shadow-design choice
There is no single correct multiple of panel height for every ground mount.
A useful starting relationship for a simple cross-section is:
But row-to-row design also depends on solar azimuth, slope, module tilt, row orientation, and which hours you are willing to shade.
That last point matters. Trying to eliminate every possible shadow from sunrise to sunset would require impractically large spacing.
Instead, choose a design window—for example, protecting a useful block of winter midday production—and model the actual site geometry.
NREL’s SAM can account for row geometry through parameters such as ground coverage ratio and self-shading. That is more defensible than saying every site at 35–45°N needs 2.5–3 times a particular height.
3. Let local loads and soil drive the foundation
Wind and snow design values vary substantially by location. Foundation performance also depends on soil, frost, groundwater, slope, and the racking system.
Common approaches include:
- concrete piers,
- driven or helical piles,
- ground screws,
- engineered ballasted systems.
None is automatically the “gold standard.”
Use the racking manufacturer’s engineering requirements together with the applicable local design loads. In the U.S., ASCE 7 hazard data is commonly part of that process; other jurisdictions use their own structural codes.
A taller rack or steeper tilt can improve access or winter geometry while also increasing structural demand. Treat those effects together.
4. Plan the electrical run before the array location is final
A beautiful clearing 250 feet from the power equipment may be expensive once trenching, conductor size, disconnects, and voltage drop are included.
Decide early whether the design carries:
- higher-voltage PV DC back to the power equipment,
- inverter-produced AC from equipment located near the array,
- or another architecture permitted by the equipment and local code.
Burial depth is not one number for “PVC,” “UF,” or “metal conduit.” Requirements vary with the wiring method, voltage, location, vehicular traffic, concrete cover, and adopted code edition.
Where the NEC applies, use the relevant underground-wiring table and installation conditions rather than copying a single depth from an article. Other countries and provinces may differ.
Then check voltage drop over the complete conductor length with our DC Voltage Drop Calculator.
5. A practical site-selection checklist
Before ordering racking, confirm:
- year-round shade pattern,
- seasonal energy objective,
- module tilt/orientation candidates,
- row spacing and maintenance access,
- wind and snow design loads,
- soil/foundation assumptions,
- frost and drainage conditions,
- cable/trench route,
- conductor voltage drop,
- equipment location and service access,
- setbacks, permits, and local electrical/structural requirements.
A good ground mount is not the one with the most “optimal” tilt. It is the one that produces the energy you need while remaining structurally, electrically, and operationally sensible.