For most large UK businesses, commercial solar installations are worth the investment, offering average annual savings of £23,000 to £119,000, a payback period of 7 to 12 years, and a system lifespan of 25 to 30 years. When combined with the UK’s full expensing capital allowance, zero-VAT installation, and Smart Export Guarantee income, the financial case has rarely been stronger. That said, the right outcome depends on your roof, your lease, and your grid connection, all of which this guide covers in detail.
Why UK Businesses Are Going Solar Right Now?
Something shifted in UK boardrooms around 2022. Energy bills, already a manageable overhead for most large businesses, started appearing as a line item that CFOs couldn’t ignore. Com
mercial electricity rates climbed from around £0.14/kWh in 2021 to over £0.28/kWh by 2024. For a business consuming 500,000 kWh per year, that’s an extra £70,000 leaving the company annually compared to just three years prior.
That context matters, because it’s the single biggest reason commercial solar installations have surged by over 34% year-on-year in the UK. The economics that once required careful justification now almost justify themselves. But cost isn’t the only driver. Two-thirds of FTSE 350 companies have now published net-zero commitments, and on-site renewable generation is one of the fastest ways to meaningfully reduce Scope 2 carbon emissions, the electricity a company buys from the grid. For businesses with ESG reporting obligations, sustainability targets, or supply chain partners demanding carbon transparency, solar PV is fast becoming a board-level conversation rather than a facilities management one.
This guide is written for large businesses, broadly defined as organisations with 250 or more employees, annual electricity consumption above 50,000 kWh, and roof or land assets of at least 500m². If that’s you, read on. The numbers are likely to surprise you.
What Are Commercial Solar Installations? Types and System Sizes
Commercial solar installations refer to photovoltaic (PV) systems designed to generate electricity for business use, typically at a scale far beyond domestic rooftop setups. A home solar system might be 4–6 kWp. A commercial system starts at around 50 kWp and frequently exceeds 1,000 kWp (1 MWp) for larger sites.
Here’s a breakdown of the main system types relevant to large UK businesses:
The most common format for commercial solar installations. Panels are mounted on existing roof structures, typically flat roofs on warehouses, manufacturing plants, wholesale and retail stores, and office buildings.
- Typical size range: 50 kWp to 1 MWp+
- Best suited for: logistics hubs, industrial units, supermarkets, data centres, universities
- Panel types: Monocrystalline silicon (most efficient, 21–23%), bifacial panels (capture reflected light from both sides), and thin-film for specific applications
- Key advantage: No land required; uses existing structure; generally permitted development
For businesses with available land, agricultural businesses, distribution centres with large yards, or campuses with open acreage. These systems can be significantly larger and are often used for export as well as self-consumption.
- Typical size range: 500 kWp to 5 MWp+
- Note: Arrays above 1 MW may trigger Environmental Impact Assessment requirements under the Nationally Significant Infrastructure Projects (NSIP) framework
Solar panels only generate when the sun shines, which doesn’t always align with when a business is using the most power. Battery storage solves this by holding surplus daytime generation for use in the evening, overnight, or during peak tariff periods.
- Without BESS, typical commercial self-consumption: 30–40% of generated electricity
- With a correctly sized BESS: self-consumption rises to 60–70%
- Leading solutions: Tesla Powerpack, CATL, BYD, Sungrow
- Cost addition: approximately £200,000–£600,000 for a 250 kWh system
An increasingly popular dual-use option for retail parks, corporate campuses, and logistics sites with large car parks. Covered carport structures support solar panels overhead while providing EV charging infrastructure beneath, meeting two sustainability objectives with a single installation.
| System Type |
Typical Size |
Best For |
Indicative Cost Range |
| Rooftop PV |
50–1,000 kWp |
Warehouses, offices, retail |
£35,000–£700,000 |
| Ground-mount |
500 kWp–5 MWp |
Farms, distribution centres |
£350,000–£3.5M |
| Rooftop + BESS |
100–500 kWp + storage |
High-daytime-load businesses |
£270,000–£1M |
| Solar carport |
50–300 kWp |
Retail parks, campuses |
£80,000–£600,000 |
How Much Do Commercial Solar Installations Cost in the UK?
The short answer: commercial solar PV in the UK currently costs between £700 and £900 per kWp installed, including panels, inverters, mounting, cabling, and commissioning. That figure has actually fallen by around 40% over the past decade, and the trajectory continues downward as module prices drop globally.
Here’s what that means in practical terms for different business sizes:
- 100 kWp system (small factory or large office): £70,000–£90,000
- 250 kWp system (medium-sized warehouse): £175,000–£225,000
- 500 kWp system (large logistics hub): £350,000–£450,000
- 1 MWp+ system: Often sub-£700/kWp due to economies of scale
What Drives the Cost Up?
Not every quote is equal. Several factors can push a commercial solar installation beyond the baseline price per kWp:
- Roof condition and structural reinforcement. Many older flat roofs on commercial buildings weren’t designed to hold the additional load of a solar array. A structural survey is almost always required, and reinforcement work can add £20,000–£60,000 to the project cost.
- DNO connection complexity. Any commercial system above 50 kW requires a G99 application to your Distribution Network Operator (DNO). In congested grid areas, this can involve expensive reinforcement works on the local network, costs that are sometimes passed to the applicant.
- Planning permission. Most rooftop commercial solar installations fall within permitted development rights and don’t require planning permission. However, listed buildings, conservation areas, and ground-mount systems above 1 MWp typically do.
- Scaffolding and health and safety. Large commercial roofs require significant temporary works infrastructure for safe installation. This is a real cost that cheaper quotes sometimes underestimate.
ROI and Savings: What Can Your Business Actually Expect?
This is the question that matters most, so let’s work through it with real numbers rather than vague promises.
Annual Energy Savings
A well-designed commercial solar installation generates roughly 850 kWh per kWp per year in the UK (this varies by location, orientation, and shading, the South East performs better than the North West, but not dramatically so). At a commercial electricity rate of £0.28/kWh:
| System Size |
Annual Generation |
Annual Saving (self-consumed) |
| 100 kWp |
~85,000 kWh |
~£23,800/year |
| 250 kWp |
~212,500 kWh |
~£59,500/year |
| 500 kWp |
~425,000 kWh |
~£119,000/year |
These figures assume 100% self-consumption of generated electricity. In practice, the proportion you actually use on-site depends on your operational hours and energy profile. A factory running 24/7 will consume more of its solar generation than an office building that’s empty at weekends.
Challenges and Practical Considerations
No guide on commercial solar installations would be complete without an honest account of where projects go wrong or take longer than expected.
Grid Connection Delays (G99 Applications)
This is the most common cause of project delays. Any system above 50 kW requires a G99 application to the local DNO, and in congested grid areas, the queue can stretch to 6–24 months. In some parts of the UK, DNOs are requesting expensive reinforcement works before they’ll grant a connection.
The mitigation is straightforward: engage your DNO as early as possible, ideally before you’ve finalised your installer. Some specialist connection facilitation services can manage this process on your behalf.
Structural Surveys and Roof Remediation
A surprising number of commercial rooftop solar projects hit delays or cost overruns because roof structural surveys reveal issues that weren’t anticipated, such as corroded steel purlins, degraded roof membranes, or insufficient load capacity for panel ballast.
Budget for a structural survey as part of your due diligence before appointing an installer, not after.
Planning Permission Nuances
While most rooftop commercial solar installations fall within permitted development, there are important exceptions:
- Listed buildings require prior approval before any external alterations
- Buildings in conservation areas may have restricted permitted development rights
- Ground-mount systems above 1 MWp may require a full Environmental Impact Assessment
Your installer should flag planning requirements early in the feasibility stage. If they don’t ask about your building’s listed status, that’s a red flag.
Maintenance and Long-Term Performance
Solar panels degrade slowly, typically around 0.5% per year, and most manufacturers offer a performance guarantee of at least 80% output at 25 years. However, systems do require maintenance:
- Annual O&M contract: £3,000–£10,000 for a 500 kWp system (cleaning, monitoring, inverter checks)
- Inverter replacement: Every 10–15 years; budget £5,000–£20,000 depending on system size
- Panel replacement: Rarely required, but budget for occasional damage from extreme weather
A monitoring system (most modern inverters include cloud-based dashboards) is essential for catching performance drops early.
Leasehold and Landlord Consent
If your business occupies a leased property, you’ll need your landlord’s written consent before installing solar PV. This is increasingly straightforward with the growth of green lease clauses, standardised lease provisions that encourage both landlord and tenant to pursue energy efficiency improvements.
If your landlord is reluctant, a PPA model can sometimes be more palatable, since the solar developer, not the tenant, owns the asset and therefore carries the lease risk.
How to Choose a Commercial Solar Installer in the UK?
The commercial solar market in the UK has matured considerably, but it still contains a broad spectrum of installer quality. Here’s how to filter for the right partner.
Accreditations to Verify
- MCS (Microgeneration Certification Scheme): Mandatory for Smart Export Guarantee eligibility. Any installer who can’t demonstrate MCS certification should be disqualified immediately.
- NICEIC or NAPIT: Electrical installation competence certification.
- CHAS or Constructionline: Health and safety compliance, particularly important for large rooftop projects.
Questions to Ask Before You Sign Anything
- Do you handle the G99 DNO application as part of your service?
- What annual yield do you guarantee, and how is underperformance compensated?
- Which monitoring platform do you install, and do we get direct access to the dashboard?
- What does your post-installation O&M contract include?
- Can you provide contact details for three comparable commercial installations you’ve completed in the past two years?
The Numbers Don’t Lie, But Only If You Act on Them
The honest answer to whether commercial solar installations are worth it for large UK businesses is this: for the vast majority, they are, and the case is stronger now than it has ever been.
Energy prices are elevated and unlikely to return to pre-2021 levels. The UK tax treatment of solar investment is genuinely generous. The technology is mature, bankable, and warrantied for 25 years. And the ESG benefits are increasingly valued by tenants, investors, lenders, and customers alike.
That doesn’t mean every project is straightforward. Grid connections take time. Roofs need surveying. Leases need reviewing. But none of these are insurmountable obstacles, they’re project management tasks that a good installer and a switched-on energy team can handle.
The businesses benefiting most from commercial solar right now are the ones that started the conversation twelve months ago. The best time to start yours is today.
Ready to See What Solar Could Save Your Business?
Every commercial site is different, with roof area, grid capacity, energy profile, and financing preference all shaping the outcome. The fastest way to get a clear picture is to speak with a specialist who’s done this before, many times over. Get a Free Solar Assessment from Evo Energy.
Our team will assess your site, model your projected savings, and walk you through financing options, with no obligation and no hard sell. Most businesses have a detailed feasibility report in their hands within two weeks.
Want to Learn More First? If you’re not quite ready to talk to someone and want to dig deeper into rooftop solar specifically, how systems are designed, what the installation process looks like, and what ongoing performance looks like in practice, our rooftop solar page has everything you need. Explore Our Commercial Rooftop Solar Solutions!