Solar Panels for Factories
Cut factory electricity bills by 40–70%. MCS-certified industrial solar with ESOS/SECR compliance support, G99 DNO management, and 100% AIA tax relief in year one.
3–5 yr
Typical payback
440,000 kWh
500kWp annual yield
91 tCO₂/yr
Carbon displaced (500kWp)
100%
AIA first-year tax relief
Commercial Solar for UK Manufacturing: The Business Case
UK factories face a structural cost challenge: electricity prices have risen 65% since 2021, and industrial tariffs on half-hourly meters include capacity charges, climate levies, and distribution use of system (DUoS) charges that inflate the unit cost well above the headline rate. For energy-intensive manufacturers — food processing, metal fabrication, plastics, automotive components — electricity typically represents 15–30% of total production cost.
Rooftop solar directly reduces that burden. A 300kWp system on a medium-sized factory generates approximately 264,000 kWh per year — enough to power the equivalent of 66 average homes. For a factory with an annual electricity spend of £500,000, a system of this size can cut the bill by 15–20% in year one, with savings compounding as electricity prices rise. The Annual Investment Allowance provides 100% first-year tax deduction on the full capital cost, reducing the effective net investment by 19–25%.
Roof Types and Mounting Options for Factory Buildings
Trapezoidal Steel Cladding (Most Common)
The standard UK industrial roof cladding profile. Standing seam and trapezoidal profiles accept T-foot or hook-and-clamp mounting systems that grip the rib of the sheet without drilling. This preserves the weatherproofing integrity of the roof and allows installers to work at pace — a competent team can install 200–300 panels per day on a clean trapezoidal steel roof. Load distribution must be checked against purlin spacing and span tables; typical solar load is 12–15 kg/m².
North-Light Sawtooth Roofs
A common feature of factories built between 1950 and 1990. The south-facing opaque pitches are ideal for solar — typically pitched at 20–30° and already facing the optimal direction. Panels mount directly to the steel purlins through the cladding using sealed penetration fixings. The north-facing glazed sections require no modification. Where asbestos cement sheets are present on south-facing pitches, these must be removed and replaced with steel cladding before panel installation.
Flat Roofs (Felt, EPDM, GRP)
Ballasted east/west portrait arrays at 10–15° tilt eliminate all roof penetrations, preserving the waterproof membrane. Ballast blocks (typically 20–25 kg/block) hold the array against wind uplift. Structural load for ballasted systems is typically 20–30 kg/m² — always requires a structural engineer's sign-off, particularly on older buildings with timber joists or lightweight steel decking.
Grid Connection and DNO Requirements
Every factory solar system above 50kWp requires a G99 application to the DNO. For factories with existing 11kV or 33kV metered supplies, the connection is managed at primary substation level and requires a relay protection study. The G99 process involves three stages: connection enquiry (free, 20-working-day response), technical assessment and offer (typically 4–8 weeks), and commissioning sign-off with DNO witness testing.
| System Size | DNO Process | Expected Timeline | Common Issues |
|---|---|---|---|
| 50–250 kWp | G99 notification + relay settings | 8–12 weeks | Existing export limitation |
| 250kWp–1MWp | G99 with engineering study | 12–20 weeks | Transformer capacity |
| 1MWp–5MWp | G100 agreement required | 6–18 months | HV connection upgrade |
| 5MWp+ | Transmission connection | 18–36 months | New substation required |
Timelines from application submission. We submit G99 at contract signature to run in parallel with procurement.
ESOS and SECR Compliance Benefits
ESOS Phase 3 (mandatory for large UK undertakings since December 2023) requires energy audits every 4 years identifying cost-effective efficiency measures. Installing solar satisfies the requirement to demonstrate action on audit findings and can be logged as an implemented measure in the Environment Agency notification. Lead assessors value solar installations as concrete evidence of energy reduction progress.
Under SECR, a 500kWp system generating 440,000 kWh displaces approximately 91 tonnes of CO₂ per year (using the 2025 grid emission factor of 207 gCO₂/kWh). This is a material improvement in Scope 2 intensity ratios. For manufacturers with supply chain decarbonisation pressures from major OEMs, Tier 1 customers, or FTSE 100 procurement teams, a documented solar installation supports supplier qualification requirements.
Case Study: 350kWp Food Manufacturing Facility, Midlands
A food processing company in the East Midlands manufacturing chilled ready meals installed a 352kWp system across two interconnected factory blocks in September 2024. The installation comprised:
- 890 × 395Wp JA Solar bifacial panels on trapezoidal steel hook-and-clamp mounting
- 3 × 110kW SMA Sunny Tripower CORE2 three-phase inverters
- 1 × 100kWh LFP battery storage system (BYD Battery-Box Premium HVS) for afternoon peak shaving
- G99 application to NGED East Midlands — approved in 10 weeks
- Full ESOS Phase 3 documentation package for lead assessor
Twelve-month performance data: 313,000 kWh generated (89% of design year). On-site self-consumption: 91%. Avoided electricity cost: £68,860 at blended 22p/kWh. SEG export revenue: £940. Total year-1 saving: £69,800. AIA saving in year 1: £62,500 (£250,000 system × 25% CT rate). After-tax payback: 2.7 years.
Get a Factory Solar Survey
Our industrial solar team surveys your roof structure, existing metering, and DNO connection capacity. We manage G99 applications and ESOS documentation as part of every project.
Book Factory Solar SurveySolar Plus EV Charging: The Industrial Package
Factories operating delivery vehicle fleets can stack solar savings with EV charging by using midday surplus generation to charge vehicles during loading bay downtime. A 500kWp solar system with 100kWh BESS can deliver approximately 80–120 kWh of free charging per day — enough for 3–5 medium-range electric vans. The Workplace Charging Scheme (WCS) offers £350 per socket (up to 40 sockets) for employer-funded EV chargepoints, further improving ROI.
We design integrated solar + BESS + EV charging packages for manufacturing sites as a single project scope, managing all DNO notifications and MCS certification under one contract.
Related Factory and Industrial Solar Pages
- Solar Panels for Warehouses
- Commercial Solar Panels Nottingham
- Solar Panels for Businesses
- Commercial Battery Storage
- Commercial EV Charging
Frequently Asked Questions
What size solar system does a factory need?
Most UK manufacturing facilities consuming 500,000–5,000,000 kWh/year install between 100kWp and 1,000kWp of rooftop solar. A rule of thumb is 10kWp per 10,000 kWh of annual consumption if the aim is 25–30% offset, or 25kWp per 10,000 kWh if aiming for 60–70% offset with battery storage. The practical ceiling is set by roof area and your DNO connection capacity. We assess both during a free roof-and-grid survey.
Does factory solar require ESOS compliance documentation?
ESOS Phase 3 (active 2023 onwards) requires all large undertakings to audit their energy use and identify cost-effective improvements every 4 years. Installing solar does not satisfy the ESOS audit requirement, but it does constitute an ESOS-qualifying energy efficiency measure. Your lead assessor can document the solar installation as an implemented action in the ESOS notification, improving your compliance position and potentially satisfying the Environment Agency that you are acting on the audit findings.
How does factory solar affect our SECR report?
Under Streamlined Energy and Carbon Reporting (SECR), companies with turnover over £36m, 250+ staff, or balance sheet over £18m must report Scope 1 and Scope 2 emissions annually. Rooftop solar reduces your purchased electricity (Scope 2) and can be quantified using the carbon intensity factor of grid electricity (approximately 207 gCO₂/kWh in 2025). A 500kWp system generating 440,000 kWh/year displaces approximately 91 tonnes of CO₂ — a material SECR improvement that strengthens ESG reporting.
How is a factory solar system connected to the grid?
All factory systems above 50kWp (above 11kWp per phase on three-phase supplies) require a G99 application to the DNO. This includes protection relay settings, export limitation, and in some cases reactive power control. Large systems above 1MW require a G100 agreement. For factories already connected at 11kV or 33kV, the connection process is managed at the Primary Substation level and timeline can be 3–6 months. We manage the full G99/G100 application and commissioning process.
Can solar reduce our demand charges and capacity charges?
Yes. Factory electricity bills include a Maximum Import Capacity (MIC) charge based on the peak demand you declare to your DNO. If solar plus battery storage reliably shaves peak demand by 10–20%, you may be able to negotiate a lower MIC on contract renewal, reducing the standing charge component of your bill. This is particularly valuable for manufacturers with predictable afternoon peak loads — the most common factory demand profile. Our energy analysts model demand-charge reduction as part of every commercial assessment.
What roof types are suitable for factory solar panels?
The most common factory roof types — north-light sawtooth, trapezoidal steel cladding, and built-up metal — are all excellent solar substrates. Sawtooth roofs with south-facing glazed sections achieve the best orientation. Trapezoidal steel profiles accept hook-and-clamp or T-foot racking without penetrations. Flat felt or EPDM roofs use ballasted aluminium frames. The only roof types that require additional engineering are aged asbestos cement (ACM) sheets and roofs with wind-uplift ratings below 1.2 kPa. We conduct structural assessments as standard.
How long does a factory solar installation take?
A 200–500kWp factory installation typically takes 2–4 weeks on-site. Scaffold erection accounts for 2–3 days; panel installation runs at 15–25 panels per operative per day; inverter wiring and commissioning adds 2–4 days depending on the MV/LV switchgear layout. The most common programme delay is DNO G99 approval — budget 8–12 weeks from application to approval for systems above 200kWp. We submit G99 applications at contract signature to run the DNO process in parallel with procurement.
What is the ROI for a 500kWp factory solar system?
A 500kWp rooftop system on a Midlands factory installed for approximately £330,000 generates around 440,000 kWh per year. At a blended electricity tariff of 22p/kWh and 70% on-site self-consumption rate, avoided electricity costs are approximately £67,760/year. SEG export revenue adds approximately £3,520/year. With AIA tax relief saving £82,500 in year one (at 25% Corporation Tax), the net after-tax outlay is £247,500 — giving a payback of 3.4 years and a 25-year net benefit exceeding £1.4 million.