A 1 MW (1,000 kW) commercial solar install operates at industrial-scale and is a meaningfully different engineering proposition to anything below 500 kW. Per-kW economics are at their best (we typically quote £700-£850 per kW at this scale), procurement leverage is substantial (you negotiate panels and inverters directly with the manufacturer rather than through tier-2 distributors), and the project requires a full multi-disciplinary delivery team including project manager, dedicated structural engineer, electrical principal designer to BS EN 50438 standards, and a DNO liaison through the G99 process. Capex sits at the AIA cap (£1m annual headroom), so AIA still covers the entire project for limited companies. The major distinguishing feature: at 1 MW the DNO process is no longer a paperwork exercise — it is a substantial engineering negotiation that often shapes the final project specification.
The 1 MW band is what we recommend for large factories with multi-shift production, distribution centres of 15,000+ sqm, multi-MW industrial campuses, large hospital trust sites, university campuses consolidating PV across estate, and ground-mount solar farms on adjacent land. The common thread: 6,000+ sqm of roof or land, three-phase HV-supplied transformer (typically 1,500-2,500 kVA), a daytime baseload comfortably above 250 kW, and either substantial corporation tax exposure or a board-level willingness to consider PPA structures (which is often the right answer at this scale).
What 1MW looks like physically
A 1 MW system in 2026 uses approximately 1,850 tier-1 monocrystalline panels at 540-550 Wp each (Trina Vertex, JA Solar Deep Blue, Longi Hi-MO 6 or equivalent). With higher-output 600 Wp modules the count drops to around 1,665. You need approximately 6,000 sqm of usable, well-oriented roof or land. Where rooftop space is constrained we frequently configure 1 MW as a hybrid rooftop-plus-ground-mount system, with the ground-mount portion delivered as a fixed-tilt steel-frame array (typically 25-30 degrees south-facing) on adjacent yard or paddock land. At 1 MW we always commission full structural calculations on the existing building and frequently engage the original building designer to validate. The electrical infrastructure is substantial: typically 10-20 commercial-grade three-phase string inverters (50-110 kW each — Sungrow SG-CX, Solis-S6, Huawei SUN2000 or SMA Tripower CORE) configured in parallel for redundancy. We typically specify multi-string topology because losing 50 kW when an inverter fails is materially less painful than losing 250 kW or 500 kW from a central inverter.
Cost breakdown for a 1MW install in 2026
Turnkey 2026 pricing for a properly specified 1 MW system runs £700,000-£850,000 plus VAT, working out at roughly £700-£850 per kW. The price band includes 1,850 tier-1 panels procured directly from the manufacturer, a multi-inverter topology configured for redundancy, an MCS-spec mounting system, all DC and AC cabling sized for sub-2% voltage drop end-to-end, surge protection on every string, fire-safe DC isolators, a dedicated PV main switchboard with kWh export metering and power quality monitoring, half-hourly monitoring, scaffolding and access equipment, full structural sign-off, electrical sign-off, principal designer fees under CDM 2015, full G99 connection paperwork including Type Test certificates and witness testing arrangements with the DNO, 12 months of post-commissioning support, 36-month performance warranty against modelled yield, and an O&M contract from year one.
Where a 1 MW project goes over budget tends to be one of four known knowns: asbestos-cement industrial roof removal (£90k-£250k at 6,000 sqm), HV transformer upgrade or new HV connection (£60k-£250k to the DNO), DNO reinforcement charges (£50k-£500k+ depending on area — at 1 MW these can dominate project economics), or roof reinforcement (£60k-£200k). We identify these at survey stage and quote them clearly. We do not commit major capex until the connection offer is formally accepted and reinforcement scope is fixed.
On AIA: 100% Annual Investment Allowance covers up to the £1m annual cap, so a £775,000 install is fully covered, reducing a profitable limited company's corporation tax bill by £193,750 in year one (at the 25% main rate). That drops the effective net cost to roughly £581,250 before counting energy savings. Capex above the £1m cap attracts the standard 18% Writing Down Allowance — we typically structure the project to fit within a single year's AIA where possible. The Land Remediation Tax Relief recovers an additional 50% of any asbestos-removal element through corporation tax.
Generation and savings
A typical UK 1 MW system generates 900,000-940,000 kWh in year one. We model this in PVSyst with site-specific Meteonorm 8.2 irradiation data, panel temperature derating, inverter clipping, soiling losses, mismatch losses and shading losses derived from Lidar-resolution 3D modelling. At 1 MW we run scenario analysis for high-irradiation years (P75) and low-irradiation years (P95) as well as the central P50 estimate, because annual variability at this scale is material to the financial model. Self-consumption drives the project economics. A 1 MW system on a multi-shift factory, distribution centre with continuous refrigeration, or large industrial campus typically achieves 85-92% self-consumption — exceptional rates that drive payback below 5 years. On a single-shift business, school estate or office portfolio, self-consumption drops to 65-75%. The difference between 75% and 90% on a 1 MW system is roughly £48,000 of additional annual benefit per year — enormous in IRR terms.
At 80% self-consumption with a 24p/kWh blended import price, a 1 MW system avoids around £176,000 of grid energy purchases per year. The remaining 184,000 kWh exports to grid at the SEG rate. At a blended 8p/kWh SEG rate (we typically negotiate slightly better SEG terms at this scale through bilateral agreements rather than standard tariffs) that adds £14,720 of export income, taking total year-one benefit to around £190,000-£235,000. Simple payback on £775,000 capex (or £581,250 net of AIA) lands at 4.5-5 years. 25-year IRR is 16-21% and 25-year NPV at a 7% discount rate is approximately £3.0m-£3.9m. At 1 MW we routinely model integrated battery storage at the financial model stage — typically 500-1,500 kWh of LiFePO4 storage configured for self-consumption maximisation, peak-shaving (avoiding triad charges where they apply) and tariff arbitrage. Battery integration can lift IRR by 1-3 percentage points where the load profile and tariff structure suit it.
DNO grid connection — G99 with substantial DNO study
At 1 MW, full ENA G99 process applies and the DNO will require a substantial Connection Application study before issuing an offer letter. Standard DNO turnaround in 2026 runs 12-24 months on most networks, sometimes longer in constrained areas. The application costs £8,000-£25,000 to file. Around 30% of 1 MW G99 applications get a standard offer with no reinforcement charge; the majority face contributions ranging from £50k to £500k+ for transformer, switchgear, cable or substation upgrades. At this scale reinforcement charges frequently dominate the project economics — a £200k reinforcement charge can shift payback by 12-18 months and is often the difference between go and no-go. Our process: file the G99 application within two weeks of contract signature with draft connection scheme and Type Test data, run design and procurement in parallel. If reinforcement comes back high we re-engineer for export limiting, drop nameplate to fit local capacity, opt for self-consumption-only with battery integration, or split across two metering points. We do not commit major capex until the connection offer is formally accepted.
Best-fit sectors for the 1MW band
From our 2025 install book, the 1 MW band overweighted across five sub-verticals. Large factories with multi-shift production (food and beverage processing, drinks production, packaging, light manufacturing, plastics, automotive component manufacture) — high self-consumption rates because production load matches PV curve closely. Distribution centres of 15,000+ sqm running general distribution, ambient or temperature-controlled storage with material handling, refrigeration and lighting. Multi-MW industrial campuses (manufacturing campuses with multiple production buildings and ancillary offices). Large hospital trust sites and university campuses consolidating PV across estate. Ground-mount solar farms on adjacent land, particularly for sites with rooftop constraints (planning, structural, leasehold) where adjacent yard or paddock land is available. These map cleanly to our coverage of industrial-scale sectors.
Worked example: a Lancashire food processing facility, 22,000 sqm production hall and ambient warehouse, 24/7 operation across three shifts, three-phase 2,500 kVA HV-supplied transformer, 6,400 sqm of usable roof spread across three buildings, 4,200,000 kWh annual consumption with 320 kW continuous baseload (refrigeration plant, production lines, packaging, compressors, lighting, chargers). Quoted £775,000 plus VAT for 999.9 kW (1,850 x 540 Wp Trina Vertex, 12 x Sungrow SG75CX inverters, K2 ballasted east-west mounting at 10 degrees split across three roof areas). Connection offer included £85,000 of DNO transformer LV-side reinforcement, taking total project to £860,000 plus VAT. Modelled year-one yield 925,000 kWh. Self-consumption modelled at 92% (continuous refrigeration and process load fits PV curve almost perfectly), so 851,000 kWh avoid the grid at 25p/kWh blended (£212,750 saved) and 74,000 kWh export at 8p/kWh negotiated SEG (£5,920). Total year-one benefit £218,670. AIA tax relief £193,750 against year-one corporation tax (capex above £1m attracts WDA at 18%, but project sits at £860k so AIA covers it all). Simple payback 3.9 years, 25-year IRR 22.8%.
Financing a 1MW system
All three financing routes are commercially viable at 1 MW, and at this scale the choice often comes down to balance sheet treatment and tax position rather than headline economics. Cash plus AIA delivers the strongest IRR for any limited company with corporation tax exposure — the £193,750 year-one tax relief shortens payback by around 18 months versus a finance route. Asset finance over 7-10 years (around £9,500-£11,500 per month over seven years on £775k capex) is common where capital allocation is the binding constraint. Hire purchase preserves AIA; operating lease forfeits it. PPA structures are highly competitive at 1 MW. A 15-25 year fixed-rate PPA at 15-20% below current grid retail with end-of-term ownership transfer is straightforward to arrange — the third-party setup costs that diluted PPA returns at smaller scale are negligible at 1 MW. PPA is often the right answer for charities, schools, NHS trusts, multi-tenant estates and any organisation where the asset would impact balance sheet metrics, and handles tenancy questions cleanly. We model all three routes in your finance options assessment, and our grants and funding guide covers any sector-specific schemes that apply.
Next steps
If you want to know whether a 1 MW system makes sense for your specific business, the fastest route is a free desk-based feasibility against your half-hourly meter data — turnaround is ten working days for the desk pass, plus a multi-disciplinary site survey for fixed-price proposal. Request a quote with your address. For broader cost benchmarking across system sizes see our cost guide, browse all our services, or compare adjacent sizes — step down to 300 kW for sites where 1 MW is more capacity than the load profile justifies. Common questions are covered on our FAQs page. For policy detail see Ofgem's market guidance on the SEG, grid connection process and embedded generation, and gov.uk's AIA guidance for tax treatment.
Common questions
How big a roof do I need for a 1MW system?
Plan for around 6,000 sqm of usable roof area for a 1 MW (1,000 kW) install. That accommodates 1,850 panels at 540-550 Wp each. Most large factories, distribution centres and multi-MW campuses have ample roof at this scale, often spread across multiple buildings. Where rooftop space is constrained we frequently configure 1 MW as a hybrid rooftop-plus-ground-mount system or a pure ground-mount solar farm on adjacent land.
How much will a 1MW system save me per year?
A typical 1 MW commercial system in the UK generates 900,000-940,000 kWh in year one. With self-consumption above 75% and a blended import price of 24p/kWh, expect annual benefit of £190,000-£235,000 (energy avoided plus SEG export income). Multi-shift industrial sites, distribution centres with refrigeration, and multi-MW campuses with substantial year-round daytime baseload sit at the upper end where self-consumption can exceed 90%.
What is the payback on a 1MW commercial solar install?
Simple payback for a 1 MW industrial install in 2026 typically lands at 4.5-5 years. 25-year IRR is 16-21% with NPV at a 7% discount rate of around £3.0m-£3.9m. AIA covers the first £1m of capex, dropping effective net cost from around £775k to £587k for a profitable limited company in the year of capex. Strong per-kW pricing and high self-consumption profiles drive the fastest paybacks at this scale.
How long does a 1MW install take?
Contract to commissioning typically runs 12-24 months. Most of that is the G99 process and DNO study running in parallel with detailed design, procurement and site prep. Physical install is 60-100 working days. We file the G99 application within two weeks of contract signature so DNO timing aligns with delivery and any reinforcement requirements are known early in the project.
What size business needs a 1MW system?
The 1 MW band suits large factories with multi-shift production, distribution centres (15,000+ sqm), multi-MW industrial campuses, large hospital trust sites, university campuses, ground-mount solar farms on adjacent land, and food and beverage processing facilities at industrial scale. The common thread: 6,000+ sqm of roof or land, three-phase HV-supplied transformer, daytime baseload of 250-400 kW, annual electricity bill above £250k.
Can I get finance for a 1MW system?
Yes. Asset finance terms for £775k capex are typically 7-10 years at 6-8% APR, giving monthly payments of around £9,500-£11,500 over seven years. The monthly bill saving on a 1 MW system typically substantially exceeds the finance payment from month one. PPA structures are highly competitive at 1 MW and are frequently the preferred route — a 15-25 year fixed-rate PPA at 15-20% below current grid retail with end-of-term ownership transfer is achievable, particularly for organisations with limited corporation tax position or where the asset would otherwise impact balance sheet metrics.