How to Quote and Run a Commercial Ground-Mounted Solar PV Installation

What you will learn

• Why commercial ground-mounted systems require planning permission in nearly all cases, and how to build the application process into your project programme from day one.
• How to identify and price the site-specific costs most commonly missed on ground-mount quotes: foundation type, cable run length, planning fees, and DNO application costs.
• When to submit a G99 application and how to manage DNO approval timelines without disrupting your installation programme.
• What your commissioning pack must contain to protect your MCS certification and enable the customer's Smart Export Guarantee registration.
• How to structure an O&M proposal at the quoting stage to generate long-term annual service revenue from every ground-mount installation.

Commercial ground-mounted solar PV installations represent one of the more complex project types in the renewables sector - and one of the most margin-sensitive if quoted without a full site assessment. Unlike rooftop work, ground-mounted systems almost always require planning permission for commercial scale, demand a G99 pre-approval from the DNO before a single panel is fitted, and carry groundworks and cable run costs that shift dramatically between sites. In 2026, a 50kWp ground-mounted commercial installation runs £30,000-£45,000 at current UK market rates of £600-£900 per kWp, but the difference between a profitable job and a painful one comes down to how thoroughly the site-specific variables are captured before the quote goes out.

Key Takeaways

• Why ground-mounted commercial systems require planning permission in nearly all cases, and how to build the process into your project programme from day one.
• How to structure a quote that captures the site-specific costs most commonly missed on first attempts: groundworks, cable runs, DNO application fees, and planning.
• The G99 timeline and why submitting the application before contract award protects your installation programme.
• What your commissioning pack must contain to maintain MCS certification and enable the customer's Smart Export Guarantee registration.
• How to structure an O&M proposal at the quoting stage so every ground-mount project opens a long-term service revenue stream.

Step 1: Site Survey and Feasibility Assessment

Every commercial ground-mounted enquiry starts with a site visit. Quoting from satellite imagery or customer-supplied measurements gets installers into trouble because ground conditions, shading, and boundary constraints vary enough to make ballpark figures commercially dangerous.

At the site visit, you need to establish: the available footprint and orientation (ideally south-facing at 30-40° tilt), whether the land is unshaded throughout the main generation hours, the distance from the array location to the main distribution board or connection point, and the nature of the ground itself. Foundation costs split between ground screw installations - which are faster and reversible - and concrete pad foundations, which are slower but suit difficult soil types. Stony ground can make screw pile installation impractical; soft clay can cause concrete pads to drift over time if not designed correctly. Neither situation is visible from a desk.

You also need to identify underground services across the planned cable route and array footprint. Gas, water, electricity, and telecoms runs regularly cross the areas customers expect to put ground arrays. A one-hour cable avoidance tool sweep before any groundworks quote saves a project from unexpected diversions mid-job.

Space requirements run at roughly 10m² of ground per 1kWp of installed capacity, accounting for panel spacing, maintenance access, and inter-row shading avoidance. A 50kWp system needs approximately 500m² of usable ground area. Confirm the usable area at the visit, not from the customer's estimate.

Step 2: Planning Permission - When It Applies and How to Manage It

Commercial ground-mounted systems almost universally require planning permission. The Permitted Development threshold for standalone solar structures - arrays up to 9m² and 4m high, not in front of a property, and not in conservation areas, AONBs, or listed building grounds - covers a handful of panels at most. Any commercial installation above that threshold needs a full planning application.

Applications are submitted to the relevant Local Planning Authority. The process runs 8-12 weeks for a standard decision, longer in sensitive landscape designations or where an Environmental Impact Assessment is triggered. Large commercial arrays above certain size thresholds may be classified as Nationally Significant Infrastructure Projects, which changes the application route entirely - your customer's land agent or planning consultant should confirm the applicable threshold for the site.

Build planning into your project timeline explicitly. If you quote a ground-mount for a customer expecting installation within six weeks, and planning takes ten, you have a problem before the first panel arrives. The standard approach is to price planning application preparation - or to recommend the customer's architect or planning consultant handles it - and set contract commencement at the point of planning approval, not at quote acceptance.

For agricultural land, ground-mounted solar generally requires a full planning application regardless of system size. Agricultural Permitted Development rights cover buildings and operations ancillary to agriculture but do not routinely extend to ground-mounted solar arrays. If the customer's land agent suggests otherwise, verify the position with the Local Planning Authority before building your programme around it.

Step 3: DNO Application and the G99 Process

For commercial ground-mounted systems - which will almost always exceed 16A export per phase - the DNO application runs under G99, which requires pre-installation approval, not a post-installation notification. This is a material difference from most rooftop residential work, where G98 notification after commissioning is sufficient.

Submit the G99 application as early in the project as possible. DNO processing times across UK networks vary: some straightforward G99 applications on unconstrained networks resolve in three to six weeks; others involving budget enquiries for constrained substations can run significantly longer. Regional DNO response times also vary - UKPN, NGED, SSEN, SPEN, Northern Powergrid, and NIE Networks each operate to their own timescales. If you work regularly in a specific region, understanding which substations are constrained and which network sections have available capacity is a genuine competitive advantage that lets you give customers realistic timelines at the survey stage.

Build the G99 approval date into your project programme as a dependency for installation commencement. If approval arrives later than forecast, the programme moves with it. Managing customer expectations around this clearly - and documenting it in the contract - prevents disputes when planning or DNO delays push the installation window.

Step 4: Building the Quote

A ground-mounted commercial quote has more line items than a rooftop job, and the variable ones need to be assessed from the site survey, not estimated. The fixed components - panels, inverters, monitoring equipment, isolators, and electrical materials - can be priced from the system design. The variable components are where jobs go wrong.

Variable line items to price individually per site:

1. Price foundation type and quantity individually - ground screws versus concrete pads, driven by wind load calculations for the array size and location.
2. Measure trench length and depth for the armoured cable run from array to distribution board. A 100m run costs materially more than a 20m run; longer runs also require larger cable cross-section to limit voltage drop.
3. Price fencing and security explicitly. Ground arrays are more exposed than rooftop systems; tamper-proof panel clamps are standard, but perimeter fencing is a common customer requirement that needs its own line.
4. Include planning application fees as a line item (currently £258 for standard applications in England; different in Scotland and Wales).
5. Price DNO application costs, including any budget enquiry fee for constrained networks.
6. Include groundworks reinstatement for the cable trench - reseeding, paving reinstatement, or hardstanding replacement depending on the surface the cable passes through.

Margin protection on a ground-mount starts with a contingency allowance within the groundworks section. Soil conditions discovered during foundation installation occasionally prevent the quoted approach - a provisional sum that will be reconciled on completion is cleaner than absorbing the overrun silently.

Deposit structure for commercial ground-mounts typically runs at 30-40% on contract signature to cover equipment procurement, with a further stage at planning approval or panel delivery, and the balance on commissioning. Agree the payment schedule in the contract.

Step 5: Procurement and Materials Scheduling

Once planning approval is confirmed and the G99 application is progressing, procurement can begin in earnest. The main materials for a commercial ground-mount are: solar PV modules, string or central inverters sized to the system design, DC and AC cabling, armoured cable for the trench run, conduit and cable protection, mounting frame components (rails, clamps, brackets, and foundation fittings), and monitoring hardware.

Lead times on larger panel orders and specialist inverters can run 2-4 weeks from merchant stock, longer for specific product configurations. Align delivery timing with foundation completion - panels arriving before the frames are ready creates a storage and security problem on site; frames assembled with no panels incoming creates programme dead time and a site attendance cost with no output.

Raise purchase orders against confirmed system specifications, not against the quote-stage design. Where the planning application has required design changes from the original layout - setback adjustments, array reorientation to satisfy visual impact conditions - confirm revised specifications before ordering.

Step 6: Groundworks, Foundation, and Cable Installation

Foundation installation is typically the first physical activity on site. Ground screws - spiral steel piles driven 1-2m into the ground using specialist equipment - are the most common choice for commercial ground-mounts where soil conditions permit. They can be installed in a single day for most commercial-scale arrays, require no cure time, and are reversible at end-of-life. Concrete pad foundations take 3-7 days to cure sufficiently to carry frame loads; build this into the programme when specifying this foundation type.

The cable trench from the array to the property connection point runs at 600mm depth as a standard minimum, with armoured cable in conduit. Trench installation is most efficient when coordinated with foundation work - a single groundworks mobilisation covering both reduces cost and minimises site disruption. Confirm underground service positions before any excavation using a cable avoidance tool, and record the cable route on as-built drawings for the handover pack.

Frame assembly follows foundation installation and sets the array tilt angle. Confirm the design angle against the site-specific shading analysis before assembly. Panels are mounted to rails using tamper-proof end clamps as standard on commercial ground-mounted work. All DC wiring within the array - panel-to-panel string connections, string cabling to the inverter, and lightning protection where specified - is completed under qualified electrician supervision to BS 7671.

Step 7: Commissioning and MCS Certification

Commissioning follows the same electrical testing disciplines as rooftop work, but the documentation requirements are more extensive. The commissioning stage covers: DC string testing (open circuit voltage, short circuit current, and insulation resistance per string), AC-side testing to BS 7671 requirements, inverter commissioning and monitoring system configuration, and performance verification against the design output model.

MCS certification requires the installation to have been completed by an MCS-certified contractor and documented to current MCS standards. The MCS certificate is the customer's primary document for Smart Export Guarantee registration with their energy supplier - without it, they cannot access SEG payments. Provide the MCS certificate, electrical installation certificate, and as-built drawings to the customer at handover. The G99 confirmation notification to the DNO is submitted following commissioning, confirming the system is operational within the approved parameters.

Step 8: Handover, O&M Proposals, and After-Commission Revenue

The handover pack for a commercial ground-mounted installation should contain: the MCS certificate, electrical installation certificate, as-built drawings including cable route and foundation positions, DNO G99 confirmation documentation, inverter commissioning report and monitoring login credentials, warranty documentation for panels, inverter, and mounting system, and a maintenance schedule.

Ground-mounted systems have lower per-visit maintenance costs than rooftop equivalents because panel access requires no scaffolding, but they carry additional vegetation management requirements. Grass and scrub growth inside and around the array footprint causes shading if left unmanaged, and vegetation regrowth against panel lower edges creates shading-related hot spots over time. An annual maintenance contract covering visual inspection, panel cleaning, vegetation control, and electrical testing represents a genuine service value for the customer and a recurring revenue line for the installer.

Propose the O&M contract at the quoting stage when the customer is already thinking about long-term system costs, not just at handover when the project feels concluded. A fixed annual fee for inspection, cleaning, and vegetation management - structured to the site's specific access and scale requirements - is a natural extension of the installation relationship.

Ground-mounted commercial solar PV rewards preparation more than most renewables project types. Installers who invest time in thorough site surveys, start DNO and planning processes early, and build complete quotes from site-specific data rather than standard allowances consistently protect their margin from the job types that look straightforward until they are not.

Sources

• How to Install Ground-Mounted Solar in the UK 2026Spectrum Energy Systems · accessed 2026-07-24
• Agricultural Solar Panel Installers UKSolarPanelsForFarms.uk · accessed 2026-07-24
• Ground Mounted Solar Panels - Complete UK GuideMidland Solar · accessed 2026-07-24
• UK surpassed 2 million solar installations in MarchSolar Power Portal · accessed 2026-07-24

See it in Zigaflow