Ground-mounted solar panels in Perth: when they make sense and what they cost

Ground-mounted solar panels sit on a frame installed at ground level rather than on a roof. For Perth households with large blocks, poor roof orientation, or limited roof area, ground mount systems can capture more solar energy than a roof installation allows — at higher installation cost.

When ground mount makes sense

Poor roof orientation or heavy shading: A house with a predominantly east-west roof pitch, significant tree shading, or a roof covered by skylights, chimneys, and HVAC units may have limited suitable roof area. A north-facing ground mount in an unshaded area of the property solves the orientation problem.

Large property, high electricity use: Rural or semi-rural Perth properties (Serpentine-Jarrahdale, Swan Valley, Chittering) with large blocks and high electricity use from pumps, sheds, workshops, or farming equipment may benefit from arrays larger than any roof can accommodate.

Preferred panel angle: Ground mount frames can be set to the optimal tilt angle (31° in Perth for maximum annual generation) rather than accepting whatever angle the roof pitch provides. This generates 5–8% more than a typical 15–25° roof installation.

Bifacial panels: Ground-mounted systems can take advantage of bifacial panel gains (see our bifacial panels guide). Over light-coloured gravel or concrete, a bifacial ground array can achieve 10–20% more generation than the front-face rating suggests.

Future expansion: Ground arrays on large blocks can be expanded by adding more frames and panels, without the complexity of adding panels to an existing roof installation.

When ground mount does not make sense

• Limited yard space: A ground array requires clear unshaded area for the panels AND the frame footprint — typically 1.5–2× the panel area for access and sun angles
• Small suburban blocks: Most Perth metro blocks (600–800m²) have limited yard space; a ground array competes with gardens, lawns, and living space
• Cost sensitivity: Ground mount costs 20–50% more than an equivalent roof installation; the frame, concrete footings, and extra cabling add significant cost
• Standard roof: If your roof has good north-facing space and minimal shading, a roof installation almost always makes more economic sense

Types of ground mount systems

Fixed-angle frame (most common): Aluminium or steel frames set at a fixed tilt — typically 25–35° for Perth. Simple, low maintenance, no moving parts. Panels face north.

Manually adjustable tilt: Frames that can be adjusted seasonally — steeper in winter (up to 50°) for lower sun angles, shallower in summer. Provides 10–15% more annual generation than fixed-angle in Perth conditions. Requires periodic manual adjustment (2–4 times/year).

Single-axis tracking: Motorised frames that track the sun east-to-west throughout the day. Can generate 20–35% more than fixed-angle systems. Significantly higher cost ($1,000–$3,000 per kW more) and requires ongoing maintenance. More common in commercial applications; occasionally installed on large rural residential properties.

Pole-mounted: Single central pole with a panel array mounted on top. Used when excavation for a frame base is difficult, or for compact arrays. Often used for smaller off-grid applications (water pumps, remote shed).

Building approval and setbacks in Perth

A ground-mounted solar structure requires a building permit from your local council. Requirements vary, but generally:

• Setbacks: Ground-mounted solar frames are often treated as a "structure" — setback requirements (typically 1m from side/rear boundary) apply
• Height: Most local planning schemes have height limits for structures (typically 2.4m–4m depending on zone and location on the block)
• Heritage or character areas: Additional design constraints may apply
• Western Power NCN: A new NCN must be lodged for a ground-mounted system (same as roof-mounted)

Most Perth local councils have planning officers who can advise on ground mount permit requirements before you engage an installer.

Installation: what's different from roof mount

Footings: Ground mount frames require concrete footings. The footing depth depends on soil type (deeper in sandy soils, shallower in clay/rock). Typical residential Perth block: 4–6 footing bores of 300–450mm diameter at 600–900mm depth.

Cabling: Cabling runs from the ground array to the inverter (which is typically installed on the house). Underground conduit is standard — adds cost depending on cable run distance.

Access: Unlike roof-mounted panels, ground-mounted panels are accessible without ladders — making cleaning, inspection, and maintenance easier. Bird-proofing mesh is less necessary (no roof cavity below panels) but pest access may differ.

Wiring routing: Ensure the cable run from the ground array to the house is factored into the quote — 20m of underground conduit with trenching adds $500–$1,500 depending on distance and ground conditions.

Cost comparison: ground mount vs roof mount in Perth

For a 6.6kW system:

Roof mount: $5,500–$8,000 installed (depending on roof type, height, access)

Ground mount: $7,500–$12,000 installed (depending on footing requirements, cabling distance, frame type)

The premium is approximately $2,000–$4,000 for a residential scale. This premium is justified when:

• Roof-mounted alternative would generate significantly less due to orientation/shading
• The property already has the clear ground space available
• Future expansion is planned (adding more panels to ground array is easier than roof)

Maintenance and mowing

Ground-mounted panels need grass or vegetation management underneath. Options:

• Gravel or rock mulch under and around the array (eliminates mowing, prevents mud splash)
• Regular mowing around the frame perimeter
• Ground cover planting that stays below panel clearance height

Mud splash from rain on bare soil can dirty panel undersides and reduce bifacial gain — gravel is the preferred ground treatment for bifacial installations.

For most Perth metro homeowners, roof-mounted solar remains more cost-effective. Ground mount solar is the right choice for properties with poor roof orientation, large land areas, or high electricity demand that exceeds available roof space.