Solar PV Systems for UK Manufacturing Factories

Why solar PV makes sense for factories

UK factories and manufacturing operations represent the strongest economic case for commercial solar PV across the entire SME and lower-mid-market segment. The combination of heavy daytime process loads, large clear-span roof footprints, mature three-phase electrical infrastructure capable of accepting major generation assets, growing institutional pressure on Scope 1 and Scope 2 emissions, and access to the Industrial Energy Transformation Fund (IETF) for eligible energy-intensive manufacturers produces payback economics that materially outperform every other commercial property type we model. We routinely deliver 4-6 year simple paybacks on factory solar projects and 3-5 year post-AIA paybacks for trading limited companies — and at the upper end of the sizing range (1 MW+) the economics push into territory where solar is the cheapest source of electricity available to the manufacturer regardless of grid retail tariff. For deeper sector-specific guidance, our specialist sister site solarpanelsforfactories.co.uk covers factory solar in greater depth.

The first driver is the load profile. Manufacturing electricity demand is dominated by process loads — machining, extrusion, injection moulding, casting, finishing, surface treatment, packaging, and the supporting infrastructure of compressed air, water cooling, fume extraction, and process heating. These loads are heavily daytime-concentrated for single-shift and two-shift operations (which dominate the UK SME manufacturing sector), and they map almost perfectly to solar generation hours. Three-shift continuous-process operations have a flatter load profile but still see substantial daytime peaks driven by maintenance, cleaning, and shift-change cycles. Self-consumption ratios on factory solar installs typically run 75-90% — among the highest in the entire commercial sector.

The second driver is the roof. UK factories — particularly those built or refurbished since 2000 — typically occupy steel-portal industrial buildings with profiled metal pitched roofs ranging from 2,000 to 20,000+ square metres. The roof footprint is overwhelmingly suitable for solar PV using clip-fix mounting that requires no roof penetration. Older factories built between 1960 and 2000 have a wider variety of roof types — brick or block walls supporting timber or steel trusses with felt or metal roof finishes — and require more careful structural and condition assessment, but most are still PV-suitable.

The third driver is the three-phase electrical infrastructure. Factories typically run substantial three-phase electrical connections — 400-1,000+ kVA at 415V three-phase for smaller operations, often stepping up to dedicated 11kV connections from the local distribution network for larger plants. The mature three-phase infrastructure at factory scale means there is rarely a fundamental electrical capacity constraint preventing major solar generation deployment — though DNO connection capacity for export to grid may still need upgrading for very large systems.

The fourth driver is institutional pressure on Scope 1 and Scope 2 emissions. UK manufacturers face mounting pressure from major customers (particularly in automotive, aerospace, food and beverage, and consumer goods supply chains) to demonstrate emissions reduction across both direct combustion (Scope 1, where solar enables electrification of process heat that was previously gas-fired) and purchased electricity (Scope 2, where solar directly displaces grid imports). FTSE 100 customers running their own Net Zero programmes increasingly require Scope 3 reporting from suppliers, and a measurable on-site renewable generation figure on the supplier’s facility is the cleanest line item to put against that requirement.

The fifth driver is IETF access for energy-intensive manufacturers. The Industrial Energy Transformation Fund provides capital grants for energy efficiency and decarbonisation projects in eligible energy-intensive sectors (chemicals, steel, paper, ceramics, glass, food and drink, automotive, and others). Solar PV qualifies as an eligible measure where it materially reduces grid electricity imports, and the grant rate can run 30-70% of project cost depending on the application round and competitive scoring. We’ve supported multiple IETF applications and we coordinate the technical, financial, and emissions documentation required by the scheme as a standard part of our service for eligible clients.

System sizing for factories

The standard sizing range for UK factories sits between 250 kW and 1,500 kW, comprising 460-2,775 panels and occupying 1,500-9,000 square metres of usable roof area. A 250 kW system suits a small specialist manufacturer with annual consumption around 280,000 kWh. A 1,500 kW system suits a major manufacturing operation with annual consumption above 1,800,000 kWh. Above 1,500 kW the project enters utility-scale territory; we deliver these where the economics support it but they involve materially different connection requirements and project economics.

Annual consumption is the sizing starting point. UK factories in 2026 typically consume 100-400+ kWh per sq m of floor area per year, varying enormously with manufacturing process — light assembly at the lower end, heavy machining and extrusion in the middle, energy-intensive smelting and forming at the upper end. We pull 12 months of half-hourly meter data and decompose it by shift pattern, process cycle, and seasonal variation, with particular attention to peak demand periods that drive the maximum demand and capacity charges layered on top of unit rates.

Roof area is rarely the binding constraint for factory PV — most factories have substantially more usable roof than their consumption profile would justify. We typically size to approximately 60-80% generation against annual consumption to optimise self-consumption economics, with the remaining roof either reserved for future expansion or specified for SEG export at the operator’s preference.

DNO connection capacity is often the binding constraint above 750 kW. Many factories sit on dedicated 11kV connections with substantial existing demand, and adding a 1 MW solar generation asset that exports surplus may require connection reinforcement. We submit DNO scoping enquiries immediately and present connection cost transparently — typical reinforcement costs at factory scale run £40,000-£250,000 with 9-18 month timelines.

Self-consumption ratio for factories typically runs 75-90% without batteries. Continuous-process plants with refrigeration or freezing achieve the very upper end. Battery storage is sometimes cost-justified for factories with substantial overnight load (24-hour cooling, water treatment, automation) — payback on a 500-1,000 kWh battery typically lands at 7-9 years versus 4-5 years for the underlying PV.

Cost and payback for factories

A 250-1,500 kW factory solar system in 2026 costs between £190,000 and £1,275,000 installed. Cost per kilowatt sits at £750-£950/kW for systems between 100 and 500 kW, falling to £700-£850/kW for systems above 500 kW. Factory projects benefit from the largest economy of scale in commercial solar — the per-kW cost on a 1.5 MW factory install is typically 30-40% lower than on a 100 kW office install on the same site type.

Worked example. A specialist engineering manufacturer operating from a 12,500 sq m steel-portal factory with annual electricity consumption of 2,400,000 kWh on a 24p/kWh contract spends £576,000 a year on electricity. Two-shift operation, six-day week. A 1,200 kW clip-fix PV system on the profiled metal pitched roof, costing £960,000 installed, generates around 1,104,000 kWh in year one. Self-consumption modelled at 85% (heavy daytime process load through both shifts plus support infrastructure): 938,400 kWh self-consumed at 24p saving £225,216. The 165,600 kWh exported delivers £23,184 of SEG income at 14p/kWh. Total annual benefit: £248,400. Simple payback: 3.86 years before tax relief.

Under 100% AIA, a profitable limited company at 25% corporation tax deducts the £960,000 in year one for £240,000 of tax relief. Post-tax effective net cost: £720,000. Post-tax simple payback: 2.9 years. Modelled 25-year IRR: 30%.

If the manufacturer qualifies for IETF grant funding (eligible sector, sufficient energy intensity, successful application round) and is awarded 40% of project cost, the IETF grant of £384,000 reduces the post-grant net cost to £576,000 with no impact on year-one AIA tax relief on the full £960,000. Post-grant post-tax effective net cost: £336,000. Post-grant post-tax simple payback: 1.35 years. Modelled 25-year IRR: 47%.

Financing route. Cash purchase suits cash-rich manufacturers with strong retained earnings — many established UK manufacturers fall into this bracket given the typical operating margin of the sector. Asset finance over 7-10 years suits operators preferring to preserve working capital for capital equipment refresh — finance payments typically run materially lower than bill savings from month one. PPA suits operators wanting zero capex and zero balance sheet impact — PPA structures for factories typically deliver 30-50% off grid retail tariff over 15-25 year contracts. We model all four (cash, finance, PPA, IETF-supported cash) for every factory quote. Compare the financing options at our cost page and grants and funding.

Compliance and regulation

Most factory solar PV installations fall under Permitted Development rights under Class A Part 14 of the GPDO 2015. Industrial estate locations rarely sit in conservation areas or have listed status. Larger systems above approximately 1 MW may trigger Environmental Impact Assessment screening depending on local authority interpretation, but EIA is rare for rooftop PV.

Structural assessment is the most consequential factory compliance step. We commission a chartered structural engineer’s report on every factory install above 200 kW, modelling the existing portal frame and cladding for compliance with BS EN 1990 Eurocodes under the new combined load case. Where reserve capacity is insufficient (occasionally encountered on pre-2000 factories with original cladding), we specify structural strengthening — typical cost £15,000-£60,000 — costed transparently in the proposal.

Asbestos compliance: pre-2000 factories occasionally still have asbestos cement (AC) roof sheeting. The Control of Asbestos Regulations 2012 require an asbestos refurbishment survey before any roof work. Where asbestos is present, our standard responses are overcladding (new metal sheet over the existing AC) or full removal and re-roofing — both costed transparently.

Process integration is the most factory-specific compliance area. The PV electrical system must integrate cleanly with existing factory power infrastructure, respecting protection coordination, harmonics, and any sensitive process equipment. Where the factory runs sensitive electronic process equipment (CNC machining, precision metrology, semiconductor processes), we run a power quality study and may specify additional filtering or isolation transformers. Where the factory runs welding, induction heating, or arc-furnace equipment that itself produces harmonic distortion, the solar inverter selection must be appropriate to the existing power quality environment.

Fire safety is critical. Factories carry significant fire load (raw materials, work-in-progress, packaging, oils and solvents in many manufacturing processes), and rooftop PV must respect fire-service access strips, smoke vents, and any roof-mounted fire suppression infrastructure. We design every factory install to BAFE SP203-1 standards with fire-alarm-integrated DC isolation and arc-fault detection.

CDM 2015 Construction Design and Management Regulations apply to all factory installations exceeding 30 person-days — virtually all 250 kW+ jobs. We appoint a Principal Designer and Principal Contractor accordingly.

DNO connection: factory systems above 100 kW use G99 with DNO turnaround typically 6-18 months. Larger systems (above 500 kW) often require connection reinforcement at the local 11kV substation. IETF applications require detailed grid connection documentation as part of the application package.

A typical factories install scenario

A specialist precision engineering manufacturer operating from an 8,400 sq m steel-portal factory constructed in 2009 in a regional manufacturing hub. The site runs CNC machining, surface finishing, assembly, and test bays across two-shift operation Monday-Friday plus reduced single-shift Saturday. Steel-portal construction, profiled metal pitched roof, gross roof area 7,200 sq m with 5,800 sq m usable after excluding fire-service access strips, rooflights, edge zones, and the central apex strip.

Annual electricity consumption: 1,560,000 kWh, dominated by CNC machining (38%), compressed air system (16%), surface finishing including chrome plating and anodising (14%), HVAC and process cooling (12%), lighting (8%), and miscellaneous including ICT and quality control (12%). Current electricity bill: £374,400 a year on a 24p/kWh fixed contract. Site has a dedicated 1,500 kVA 11kV connection. Manufacturer qualifies for IETF as an eligible energy-intensive engineering operation under the relevant scheme guidance.

The system specified: 1,050 kW PV array using 1,945 panels installed in clip-fix configuration on the profiled metal pitched roof. Three string inverters totalling 1,000 kW (DC-to-AC ratio 1.05). DC isolation integrated with the building’s fire alarm panel, fire-service access strips maintained per BAFE SP203-1. DNO scoping confirmed 11kV connection capacity sufficient for the proposed export profile. Power quality study confirmed compatibility with the existing CNC machine portfolio without need for additional filtering. Total installed cost: £840,000 inclusive of all hardware, scaffolding, structural assessment, DNO fees, and commissioning.

Funding layered: IETF grant £294,000 (35% of project cost, awarded under a 2025 application round supported by full carbon-savings calculation, energy-intensity documentation, and grid connection evidence) plus AIA tax relief on the full £840,000 (£210,000 at 25% corporation tax). Post-grant post-tax effective net cost: £336,000.

Year one results: actual generation 968,000 kWh, self-consumption 87% delivering £202,118 of cost avoidance at the 24p/kWh contracted retail tariff, plus £17,621 of SEG export income at 14p/kWh on the 125,840 kWh exported. Total year one benefit: £219,739. Post-grant post-tax simple payback: 1.53 years. The manufacturer referenced the install in customer audit submissions to two FTSE 100 supply-chain partners in the year following commissioning, and the project was used as a reference site for two further IETF applications by sister manufacturing operations in the same parent group.

Sector-specific FAQs

How does solar interact with our heavy machining and process loads? Cleanly, with appropriate engineering. The solar inverter is grid-tied and synchronises with the existing factory power infrastructure, providing electrical output that integrates seamlessly with the existing distribution. Where the factory runs sensitive electronic process equipment (CNC machines, precision metrology, semiconductor or pharmaceutical processes), we run a power quality study before specification and may specify additional filtering, isolation transformers, or harmonic mitigation as appropriate. Where the factory itself produces harmonic distortion (welding plant, arc furnaces, induction heating), we select inverters rated for the existing power quality environment. We’ve never seen a factory solar install cause a process-equipment fault — but the engineering work to ensure that is a meaningful part of the design phase.

Are we eligible for IETF funding? IETF eligibility depends on sector classification (energy-intensive manufacturing including chemicals, steel, paper, ceramics, glass, food and drink, automotive components, and others — the eligible sector list is published by the scheme), energy intensity threshold (typically 50+ GWh of energy per year or specific energy intensity per unit output, depending on scheme phase), and project type. We help manufacturers self-assess eligibility, gather the documentation required by the scheme, and develop the technical and financial case for application. IETF is competitive — not all applications succeed — and the scheme runs in periodic application rounds with strict deadlines. We’ve supported multiple IETF applications across the manufacturing client base. For sites that don’t qualify for IETF, the underlying economics of factory solar still produce 5-7 year payback on AIA-backed cash purchase, so the project case is strong with or without grant funding.

Our factory runs three shifts continuous — does solar still work? Yes, in some respects better. Continuous-process factories have a flatter load profile than single or two-shift operations, which means the daytime peak is less pronounced — but it also means the always-on baseload is much higher. Solar generation captured during daylight hours offsets that baseload kilowatt-for-kilowatt, and the overnight load remains served from grid imports. Self-consumption ratios on continuous-process factory PV installs typically run 85-95% — among the very highest in any commercial sector. Where the operator wants to maximise self-consumption further (toward 100% renewable supply), batteries to capture daytime surplus into overnight load become economically interesting at this scale — but typically the financial case favours additional PV capacity rather than batteries until the roof is saturated.

What about fume extraction, dust collection, and compressed air? These are large factory loads that solar serves well. Fume extraction and dust collection systems run continuously during operating hours and align with solar generation. Compressed air systems are particularly well-suited — many factories run compressed air at 30-40% of total electrical consumption, with the compressors cycling under load through the working day. Solar generation directly powers compressor cycling during daylight, with surplus exporting under SEG. Some compressed air systems can be optimised further by adding compressor scheduling to favour daytime operation (where production allows), shifting more load to solar-generated electricity. We model these optimisation opportunities alongside the underlying PV economics.

Can we add EV charging for our employee fleet and HGVs? Yes, and this is increasingly common at factory sites. Employee EV charging integrates straightforwardly with the existing solar infrastructure — typically 4-30+ x 22 kW AC chargers in employee parking. HGV electrification (where the factory operates outbound logistics) requires substantially more infrastructure — 150-500 kW per vehicle for fast turnaround — and often drives DNO connection upgrades that we factor into the design. We design the AC distribution and grid connection sizing with future EV and HGV charging in mind. For deeper sector guidance see our specialist sister site solarpanelsforfactories.co.uk. Compare also with the warehouses sector for adjacent industrial-scale solar economics and the solar carports sector for car park canopy options.

Next steps

The honest first step is a free desk feasibility study. Send us your last 12 months of half-hourly meter data, the factory build year, roof type, gross roof area, your existing grid connection capacity, your shift pattern, and your manufacturing sector classification. Within 7-14 working days we’ll model an indicative system size, generation forecast, self-consumption ratio, financial DCF, IRR, and IETF eligibility assessment if applicable. If the numbers work, we’ll arrange a structural survey, electrical survey, roof condition assessment, asbestos refurbishment survey if applicable, DNO scoping enquiry, and power quality study where process-sensitive equipment is present. We’ll then issue a fixed-price proposal with full PVSyst modelling. We’re MCS-certified for commercial, NICEIC-registered, RECC and TrustMark licensed. To get a quote tailored to your factory, visit our quote page, review typical costs and payback, or check grants and funding.