Ground-mounted PV Arrays

Installation

When planning a ground-mounted array, a site survey should be undertaken. The scope of the survey will vary depending on the size of the array and the nature of the land it is to be installed on, but could include:

• Setting of a heritage asset. The installation of panels away from a listed building can often be done without any direct harm to the building’s special interest. However, consideration will still need to be given to the effect of an installation on the setting of the listed building
• Flood risk. Where a site is at risk of flooding the height of the array, inverters, isolators from ground will need careful consideration as well as the construction of the mounting frame
• Nearby vegetation. Will trees cause shading or create debris which could accumulate on the panels reducing their effectiveness. Are there any future plans for tree planting?
• Archaeology. Will the ground anchors or planned cable routes affect land with archaeological potential? It is important to assess the possibility of buried archaeology on the site. If the building or grounds are listed or scheduled, the statutory description may cover this aspect of the site
• Existing services. The location and routes of existing underground services such as gas, drainage, water, electricity, data/telephone and overhead power cables should be established
• Topography. The shape and features of the land surface will affect the array framework and spacing of rows
• Access. Is there appropriate access to the land for construction and maintenance of the array
• Security of the site. Is there a risk of vandalism or theft? Is protection of the array required?

It is important that the installation is as reversible as possible so the land can be returned to its original purpose at the end of the array's useful life.

Cabling

In such installations, a cable will need to be run from the ground-mounted PV array to the building’s electrical distribution board. This can occasionally be very costly if the installation is a long way from the building. The cable size is determined by the load it must carry as well as its length and the further the array is from the building, the larger (and more expensive) the required cable. The cable will need to be buried to a sufficient depth to avoid damage by any reasonable disturbance of the ground, such as general gardening or agricultural activities.

Where archaeology prevents a cable from being buried to a reasonable depth, an alternative route should be found. Where this is not possible, the cable can be buried close to the surface, but the duct must be sufficiently robust to protect the cable from mechanical damage.

The entry points of the cable into the building should be properly sealed to prevent water ingress, fire spread, or vermin getting into the building.

Array frame design

To ensure the framework is as reversible as possible the foundations should be minimised and the use of mass concrete should be avoided. Where possible pile driven, screw foundations, or where there is archaeology pre-moulded concrete blocks (shoes) should be used.

For statutory consent, information about the array design and frame will be required, which should include:

• The ground clearance
• Maximum height
• Row lengths
• Pitch of the array
• How the array is fixed to the ground – concrete foundations, ballasted, rammed piles, ground screws or shoes

For more information about commercial solar farms, which are typically ground mounted see our Advice Note 15, Commercial Renewable Energy Development and the Historic Environment.