Commercial solar installation in the UK is a specialised discipline distinct from residential PV. Roof scale (500-30,000 sqm), structural loading considerations, sprinkler clearance compliance with LPC standards, DNO grid connection at G99 scale, customer audit alignment with retailer Scope 3 programmes, and lease/landlord engagement all demand dedicated commercial-installer experience. We cover distribution, fulfilment, cold chain, last-mile, port, manufacturing, and retail distribution sub-sectors, matching each project to MCS-certified commercial installers.
Commercial vs residential solar installation
Commercial solar installation differs from residential in five ways: (1) Scale — commercial systems run 50 kW to 5 MW (vs residential 4-10 kW). (2) Mounting — commercial uses ballasted or mechanically-fixed industrial systems on flat or low-pitch profiled steel/membrane roofs; residential uses pitched-roof tile-hook systems. (3) DNO connection — commercial above 3.68 kW (16 A) per phase requires G99 application (vs G98 notification for residential). (4) Customer audit — commercial includes audit pack for retailer programmes (Amazon, Tesco, M&S, ASOS, JLP, Sainsbury's) which residential doesn't need. (5) Compliance — commercial includes LPC sprinkler clearances, insurer pre-design review, structural loading analysis, BS EN 1991-1-4 wind loading.
5-stage commercial solar installation process
Stage 1: Free desk feasibility (1 week) — half-hourly meter data analysis + roof drawing analysis, PVSyst yield modelling, 25-year DCF, recommended financing route. Stage 2: Structural and electrical survey (1-2 days) — engineer site visit confirming roof condition, structural loading reserve, electrical infrastructure, sprinkler clearances. Stage 3: Permits, DNO, and insurer (4-8 months parallel) — G99 grid connection application, planning where required, insurer pre-design review, lease addendum where tenant. Stage 4: Install and commission (4-10 weeks) — on-site delivery scheduled around your operational windows. Stage 5: Audit pack handover.
Equipment specification
Installers should be manufacturer-independent. Standard specification: Tier-1 monocrystalline modules (Trina Vertex, JA Solar Deep Blue, LONGi Hi-MO, Jinko Tiger Neo) at 405-560W per panel. String inverters: SolarEdge, Huawei FusionSolar, SMA Sunny Tripower, Fronius Symo. Mounting: K2 Systems, Schletter, Renusol (ballasted) or HellermannTyton MIRO Solar (mechanically fixed). Monitoring: vendor-native (SolarEdge ONE, Huawei FusionSolar) plus an independent third-party PV monitoring layer for vendor-neutral audit-ready exports.
Common questions about commercial solar installation
How long does commercial solar installation take?
Total project: 9-14 months from first contact to commissioning. DNO grid connection (4-8 months for sub-1 MW; 6-14 months for >1 MW) is usually rate-limiting. Install + commission itself: 4-10 weeks on site.
Will commercial solar installation disrupt our operations?
No. Roof installation happens above operations. Only operational impact is final grid synchronisation (4-8 hours) which the installer schedules for a planned shutdown or weekend.
Do you handle the DNO grid connection?
Yes. The G99 application should be submitted immediately after structural survey. The installer manages the entire process — technical study, connection offer review, contestable connection works coordination, G99 commissioning.