Commercial solar — your questions answered

Commercial solar means solar PV systems installed on business premises — warehouses, factories, supermarkets, offices and industrial sites — to generate on-site electricity, reduce grid demand and cut energy bills. Systems are typically 30 kWp to several MWp and sized around the building's daytime energy usage.

Commercial solar PV (photovoltaic) is the technology that converts daylight into electricity using rooftop or ground-mounted panels wired through inverters into the building's distribution board. It powers on-site loads first, with any surplus exported to the grid.

Panels generate DC electricity from daylight, an inverter converts it to AC, and it flows into your building's supply — offsetting imported grid electricity in real time. Anything you don't use is exported to the grid under an export tariff. A meter records generation, consumption and export.

For most UK businesses with a suitable roof and meaningful daytime electricity usage, yes. Commercial solar typically pays back in roughly 4–7 years, then delivers 20+ years of low-cost electricity. Worth depends on tariff, usage profile, roof condition and finance structure — the calculator gives an indicative view.

Commercial sites tend to get stronger returns than domestic because they consume more electricity during daylight hours, when solar generates. High daytime self-consumption is the single biggest driver of ROI.

As a rough guide, UK commercial solar installations land around £700–£1,100 per kWp installed, so a 250 kWp system is typically £180k–£280k. Cost varies with roof type, access, electrical works, DNO requirements and whether storage is included. A site-specific proposal gives the firm figure.

Pricing is driven by system size (kWp), roof complexity, cabling distance to the main board, scaffolding and grid connection work. Use the calculator for an indicative cost or request a feasibility review for a firm number.

Tier-1 commercial panels carry 25–30 year performance warranties and typically still produce 85–90% of original output after 25 years. Inverters are usually replaced once during the system's life (around year 10–15).

Modern commercial mono-PERC and TOPCon panels are around 21–23% efficient. In UK conditions a well-designed system generates roughly 850–1,000 kWh per kWp installed per year.

A single 450–550W commercial panel typically produces around 400–550 kWh per year in the UK. A 250 kWp rooftop system (around 500 panels) generates roughly 220,000–250,000 kWh per year.

Standard commercial panels are roughly 2.3m × 1.1m and 450–600W. A 100 kWp system needs around 180–220 panels and 400–600 m² of usable roof area.

Most large commercial roofs are suitable. Key factors: structural capacity, roof age and condition, orientation, shading, and access. Flat, south-facing or east–west pitched roofs in good condition under 20 years old are usually strong candidates. A free roof assessment confirms suitability.

From signed proposal to commissioning typically takes 8–16 weeks. The install on the roof itself is usually 2–6 weeks depending on size; DNO approval and grid connection often drive the overall timeline.

There's no nationwide grant that pays for commercial solar outright — the Feed-in Tariff closed in 2019. UK businesses typically fund solar through the 100% Annual Investment Allowance, asset finance, a PPA, or sometimes regional schemes like Scotland's SME Loan + Cashback or the Industrial Energy Transformation Fund. See our solar panel grants & funding guide for the full breakdown.

There are three main routes: outright purchase (fastest ROI, full ownership, plus 100% AIA tax relief), asset finance / lease (spread cost over 5–10 years, often cashflow-positive from year one), or a Power Purchase Agreement (PPA — no upfront cost, you buy the electricity generated at a fixed discounted rate). See the finance and grants & funding pages for side-by-side comparisons.

Typical UK commercial solar delivers an IRR of around 12–20% over 25 years, with simple payback in 4–7 years on a cash purchase. Returns improve with higher electricity tariffs and high daytime self-consumption.

Yes — owned solar systems typically lift commercial property value and improve EPC ratings, helping with MEES compliance and tenant attraction. Lower running costs also strengthen rental and resale positioning.

Savings depend on roof size, energy usage profile, electricity tariffs and finance structure. Many sites cut grid electricity costs by 40–70%. The free calculator gives an indicative figure; a full proposal refines it.

On suitable sites with the right usage profile and funding structure, yes — particularly with asset finance or a PPA where monthly repayments come in below the energy savings. Depends on site suitability and finance approval.

Not necessarily. Asset finance, PPAs and lease structures can spread or remove upfront cost, subject to lender approval.

In most cases, yes — surplus export is paid for under an export tariff (SEG or commercial PPA). Export capacity is subject to your DNO connection conditions.

Many commercial solar installations fall under permitted development, but planning may be required depending on location, listing status and scale. We review this case by case.

A formal application to your Distribution Network Operator to connect the system to the grid and confirm export limits.

G99 is the engineering standard governing how generation systems above small thresholds connect to the UK distribution network.

An export limit caps how much you can send back to the grid. Systems can still be sized effectively for self-consumption, sometimes with export limitation devices.

Often yes — but the landlord must agree, and the commercial structure (who owns the system, who benefits) needs care. We help map the right arrangement.

Roof works are sequenced around operations and electrical tie-ins are scheduled at agreed windows to minimise disruption.

Panel performance and product warranties (typically 25–30 years), inverter warranties (10–12 years) and installer workmanship warranties — confirmed in your proposal.

Options depend on ownership and finance structure. Some systems can transfer or be repurchased; we explore the right path during proposal.

Commercial solar may qualify for capital allowances including the 50% First-Year Allowance for special rate assets — confirm with your accountant or tax adviser based on your specific business and finance structure.

Yes, commercial solar installations are typically subject to VAT at the standard rate, unlike some domestic installs. VAT-registered businesses can usually reclaim it.

Not always. Batteries can improve self-consumption and resilience but add cost. Many businesses install solar first and add storage later.

Typically: recent energy bills, postcode, roof information (or photos / drawings), ownership status and an idea of your funding preference.