Ground Mounted Solar Panels

Can solar panels be mounted on the ground?

While most solar arrays are installed on rooftops, ground mounted solar panels make use of land space for optimal and high-volume generation, or in cases where a suitable roof isn’t available. As most residential homes don’t have tons of spare land, ground mounted PV is most often chosen for commercial properties or utility solar farms (though we do have information on what to consider for domestic ground mounts).

Do you need planning permission for ground mounted solar panels?

You will need planning permission for a ground mounted array if:

• it’s more than 4m high;
• it’s less than 5m from the property boundary;
• the whole array is bigger than 9m²;
• it faces onto or is visible from a highway, if in a conservation area or world heritage site;
• it’s not the first solar array on the property.

If any of these conditions are met, you need permission. This applies for both domestic and commercial installations, so commercial ground systems almost always need consent as they’re bigger than 9m².

The chance of getting permission depends on the local council’s support of solar. You’re more likely to succeed if you take these steps:

• Encourage efficient land use, using brownfield or undeveloped land over greenfield or agricultural land. Combining the space with grazing or efforts to increase wildlife and biodiversity are beneficial.
• Ensure minimal environmental impact if the system is removed at the end of its lifespan.

How are solar panels installed on the ground?

The modules need to be attached to some kind of structure, which holds them at the best angle for energy generation, while also keeping them resistant to rain, wind and snow. This structure could either be:

• a metal A-frame, which is fixed in a concrete base or on a pole that’s pile driven into the ground;
• a solar tracking system (more on this below);
• a ballasted plastic box just a few inches high;
• a wooden frame, which could double up as another structure for shading or outdoor storage.

With some of the frames, you can adjust the pitch of the panels to take advantage of the seasonal change in the angle of sunlight.

You can arrange the panels in a variety of layouts - portrait or landscape, single height or stacked. The optimum orientation in the UK is south, which of course you can choose to face when building a ground mounted system.

In terms of infrastructure, the array will require trenches for cabling, inverters and spacing between rows of panels to allow for shading.

Ground mount vs roof mount installations

To compare the predominant methods of mounting PV, let’s take a look at the pros and cons of ground mounts compared to rooftop.

Benefits of ground mounts

• A rooftop system is restricted to the size, angle and orientation of the existing roof, while ground-based offers much more flexibility to construct an optimised, bigger system.
• Some roofs may not be able to take the weight or fixings required by a solar system.
• Option of using a tracker to increase generation.
• Easy access for cleaning and maintenance.
• More ventilation around the panels than on a rooftop, which means greater efficiency.
• Easier to extend the system at a later date if your energy needs change.

Drawbacks of ground mounts

• Takes up land that could otherwise be used (unlike the dead space on a roof), however the panels can be raised higher to utilise space below for wildlife or grazing.
• Harder to find open land with no shading, restricting most usage to countryside or farms.
• Components are more vulnerable to theft than those on a rooftop.
• More labour and materials are needed to install, meaning a higher upfront cost.
• Rooftop panels protect part of the roof from weather and degradation, and add a layer of insulation.

Static ground mounts vs tracking systems

While the majority of roofs would not be able to take the extra weight of a solar tracking system, ground mounts can benefit from the uplift produced by following the sun across the sky. Trackers use a motor to tilt the panels so the sun’s rays are perpendicular to their surface throughout the day (with a single axis) or throughout the seasons too (with a dual axis). While the mechanics bring added expense and maintenance, they can increase output by over 20%.

The ecological impact

One of the concerns around ground mounted PV is its impact on the land and local ecology. But when installed under the right conditions, it can actually benefit both.

For agricultural land, the PV system will rest the soil for a long period of time, allowing for restoration of nutrients. If the system is decommissioned in the future, the land can be effectively returned to farming.

For wildlife, a ground mounted array can provide a refuge for wildlife with very little human disturbance. According to the Building Research Establishment, infrastructure in solar farms impacts less than 5% of its ground space. Solar panels create sheltered spots for insects, reptiles and ground nesting birds. They form microhabitats through shading and concentrated rain run-off, which in turn supports biodiversity.

Image source: Wikimedia.

Ground mounted bifacial panels

Bifacial panels are solar PV modules with exposed cells on the front and rear. In a ground mount setup, they can generate power from direct sunlight on the front and reflected or diffused sunlight on the back.

We investigated the output uplift from bifacial PV, and found it depends on the albedo (reflectivity) of the ground surface. On grass, the increase was about 4%, while with white pebbles it rose to 8%.

Plan your project

At Spirit we’ve installed many residential and commercial ground mount projects. Speak to one of our experts for advice, help designing your system or a free quote.