Commercial Solar – Is Your Site Suitable?
Most commercial properties can support a solar installation, but viability hinges on the roof, energy demand, and grid connection. The real determinants are the structural load capacity of your roof, the actual usable space free of obstructions, your daytime power consumption, and the hard limits imposed by your local network operator. A detailed upfront assessment prevents expensive project revisions. It defines the optimal system size from day one.
What Our Surveyors Look For in a Viable Commercial Solar Site
A prime site is not just about having a large roof. It is a combination of good solar exposure, a structurally sound building, and a significant on-site electricity demand to consume the power generated. The local DNO’s capacity and your building’s planning status are equally critical. We evaluate how these factors interact to determine true feasibility.
Roof Orientation and Tilt
South-facing roofs with a pitch between 10 and 40 degrees are textbook perfect. However, the flat composite panel or standing seam roofs common on modern UK warehouses are ideal for east-west systems. This configuration broadens the generation window across the working day, better matching business consumption patterns.
Roof Size and Usable Area
Large, uncluttered roof surfaces simplify design and maximize output. HVAC units, rooftop ducting, skylights, and mandatory maintenance access routes all reduce the available area. We perform a detailed layout to calculate the net usable space, which dictates the maximum array size.
Structural Integrity and Load Capacity
Solar PV systems introduce a dead load of 15-20 kg/m² and significant wind uplift forces. Our structural engineers must verify the roof’s capacity. A recent survey on a 1970s industrial unit in Yorkshire revealed its concrete deck required no reinforcement, while a similar-era building needed targeted strengthening.
Shading and Obstructions
Adjacent buildings, mature trees, or even your own parapet walls can cast shadows that cripple output. Partial shading on a single panel can degrade the performance of an entire string. On a recent project in Manchester, we specified SolarEdge inverters with individual panel optimisers to mitigate shading from a neighbouring new-build.
Roof Condition and Remaining Lifespan
Installing a 25-year solar system on a roof with only 10 years of life remaining is a false economy. The cost of removing and reinstalling the entire array during a future re-roofing project is significant. We always assess the roof membrane’s condition and advise on refurbishment needs beforehand.
Analysing Your Energy Usage Profile for Maximum ROI
Commercial solar generates the best returns when the electricity is consumed directly on-site, offsetting your retail-rate power purchases. Your operational patterns are key to sizing a system for financial performance. High daytime usage is the goal; it maximises self-consumption and insulates you from low export tariff rates.
Daytime Electricity Consumption
Businesses with a standard 8 am to 6 pm operational window are prime candidates for solar. Manufacturing sites, cold storage facilities, and office buildings often have consumption profiles that align almost perfectly with the solar generation curve.
Half-Hourly Meter Data and Load Patterns
Your half-hourly (HH) meter data is the single most important document for system design. It shows us your baseline load and peak demand periods with precision. A steady daytime demand supports a larger system, whereas a business with sharp, brief peaks may achieve lower self-consumption rates.
Single Site Vs Multi-Site Portfolios
A single-site installation is straightforward. A portfolio of properties, for instance across a retail park or industrial estate, allows for phased rollouts and bulk procurement discounts on panels from brands like Trina or JA Solar. Each site still requires its own independent grid connection assessment.
Matching System Size to On-Site Demand
Oversizing a system to maximise export is rarely profitable due to low Smart Export Guarantee (SEG) tariffs. We “right-size” the PV array to match your typical daytime demand. This strategy maximises your savings for every kilowatt-peak (kWp) of capacity installed.
The Realities of Grid Connection and Electrical Infrastructure
The local grid’s capacity is a hard constraint on your system’s export potential. Even if you plan to use 100% of the energy on-site, your Distribution Network Operator (DNO) dictates the rules. Engaging the DNO early is critical to uncover technical limitations and connection costs.
Existing Supply Capacity
Properties with a large existing authorised supply capacity can typically integrate solar with fewer complications. Sites with limited import capacity might trigger costly upstream network reinforcement works by the DNO.
Distribution Network Operator (DNO) Approval
Any system over 16A per phase (3.68kW) requires a formal grid application, with larger systems over 50kW needing a detailed G99 application. This involves submitting technical designs for review by your regional DNO, whether it’s UK Power Networks in London, ScottishPower in Central Scotland, or Western Power Distribution in the Midlands.
Export Limits and Curtailment
Many parts of the UK grid are constrained, and DNOs may impose a zero-export limit or require export limitation devices. These devices monitor the site’s connection and throttle the inverters to prevent any surplus power from flowing back to the grid, ensuring compliance.
On-Site Infrastructure and Switchgear
Your main switchboard, transformers, and site cabling must be rated to handle the additional fault level from a solar generator. We inspect this infrastructure to ensure it meets current BS 7671 and MCS standards, as older equipment often requires an upgrade for safe integration.
Navigating Planning Permission and Regulatory Hurdles
Most commercial rooftop installations are covered by permitted development rights, but there are important exceptions. Your building’s location and classification determine the specific planning pathway.
Permitted Development For Commercial Buildings
On industrial and commercial buildings, rooftop panels generally fall under permitted development rights, provided they don’t protrude more than 20cm from the roof plane and the visual impact is minimal.
Listed Buildings and Conservation Areas
Properties with listed status or located within a conservation area face significant scrutiny. Any proposal will require a formal planning application and consultation with the local authority’s conservation officer. We recently navigated a successful application for a Grade II listed farm building by specifying roof-integrated panels on a non-visible roof slope.
Land-Based Solar and Change of Use
Ground-mounted solar arrays almost always require full planning permission. The land’s agricultural classification and visual impact on the landscape are key factors that the local planning authority will assess.
Building Regulations and Compliance
All installations must adhere to UK building regulations, covering both structural and electrical safety. Full compliance, certified through the Microgeneration Certification Scheme (MCS), is essential for the system to be insurable and bankable.
Commercial Solar Site Suitability Checklist
A structured review highlights technical, operational and regulatory constraints before detailed design. The table below summarises core assessment areas and typical next steps.
| Assessment Area | What To Check | Why It Matters | Typical Constraints | Next Step |
|---|---|---|---|---|
| Roof Structure | Load capacity and condition | Ensures safe installation | Weak decking or ageing roof | Structural survey |
| Usable Area | Clear roof space | Determines system size | Plant, skylights, access zones | Measured layout design |
| Energy Demand | Daytime usage levels | Drives self-consumption | Low weekday load | Analyse half-hourly data |
| Grid Capacity | Export permission | Limits system size | DNO export cap | Submit grid application |
| Planning Status | Building designation | Affects approval route | Listed or conservation area | Confirm with local authority |
A rigorous checklist ensures decisions are based on hard data, not assumptions. If you need a quick primer before working through the checklist, review commercial solar basics and getting started to understand the key terms and early-stage decisions.
Financial and Commercial Viability
Financial performance is a function of upfront cost, electricity price inflation, your funding method, and operational savings. A clear-eyed evaluation of each variable clarifies the return on investment.
| Factor | What It Affects | Typical Threshold Or Consideration | Impact On Return |
|---|---|---|---|
| Capital Cost | Upfront investment | £700–£1,200 per kWp typical range | Higher cost extends payback |
| Daytime Usage | Self-consumption rate | 60% or higher improves savings | Greater usage increases ROI |
| Grid Limits | Export revenue | Low export tariffs reduce value | Oversizing lowers returns |
| Funding Model | Cash flow profile | Capex vs PPA structure | Influences internal rate of return |
| Electricity Price | Bill offset value | Higher unit rates increase savings | Strong driver of payback speed |
A project becomes commercially compelling when strong technical suitability meets high on-site consumption and volatile energy markets.
When A Site Is Unlikely to Be Suitable
Identifying red flags early prevents wasted expenditure on detailed design work.
Severe Shading or Limited Roof Space
Heavily shaded roofs or fragmented areas may not generate enough power to justify the fixed costs of mobilisation and installation.
Low Daytime Electricity Use
Businesses that operate primarily at night or on weekends, like theatres or certain clubs, will export most of their generated power at a low value, undermining the business case.
Structural or Access Limitations
A fragile roof requiring complete replacement or a site with prohibitive access for cranes can add costs that make the project financially unviable.
Short Lease Terms or Uncertain Tenure
If your lease term is shorter than the project’s payback period (typically 5-8 years), the investment risk is too high. Landlord consent is a mandatory prerequisite.
How Our Professional Site Survey Process Works
Our survey process is designed to replace assumptions with certainty, providing the data needed for a confident investment decision.
Desktop Assessment
Engineers begin with a remote analysis of satellite imagery, your submitted half-hourly data, and DNO network maps. This initial screening identifies any immediate showstoppers before a site visit is scheduled.
On-Site Technical Survey
Our surveyors physically inspect the roof material and condition, take precise measurements, and assess the existing electrical room and cable routes. This hands-on verification of the desktop data is non-negotiable.
Yield Modelling and Performance Estimates
Using industry-standard software like PVSol or PVSyst, we model the system’s expected annual generation. This model accounts for your specific location’s irradiation, panel orientation, and any shading factors to produce a bankable performance estimate.
Feasibility Report and Recommendations
You receive a comprehensive report summarising all constraints, system design options with specific hardware (e.g., Longi panels and Solis inverters), and detailed financial projections. We provide clear, actionable next steps and firm costings.
Conclusion
The majority of commercial properties with unshaded roof space, a solid structure, and significant daytime power demand can host a profitable solar PV system. Grid capacity, planning status, and property tenure are critical variables that our initial assessment process clarifies quickly. A structured, data-driven review confirms whether a site is straightforward or requires specific mitigation, ensuring your solar investment delivers reliable performance and financial returns for decades.
