2.5 MWp commercial solar PV cost in the UK (2026)
At 2026 prices, a 2.5 MWp commercial solar PV system costs £1,400,000 - £1,875,000 installed (excl. VAT). Typical post-tax payback: 3.3-9.8 years.
2.5 MWp cost summary
| System size | 2.5 MWp |
| Installed cost (2026, excl. VAT) | £1,400,000 - £1,875,000 |
| £/Wp | £0.56 - £0.75 |
| Number of panels (450W) | ~5,500 |
| Roof area required | ~13,600 m² |
| Annual generation (UK avg) | 2,375,000 kWh |
| Best fit for | big-box logistics, multi-acre ground-mount, hospital trust portfolio |
| Best grant stack | Full Expensing (uncapped) + IETF or PSDS + wholesale PPA + REGO portfolio |
Year-1 maths breakdown
| Gross capex (mid) | £1,637,500 |
| 100% Full Expensing tax saving (25% CT) | -£409,375 |
| Net effective cost | £1,228,125 |
| Annual self-consumption (15%) | 356,250 kWh saving £64,125/year |
| Annual SEG export (85%) | 2,018,750 kWh earning £60,562 - £302,812/year |
| Total year-1 savings/revenue | £124,688 - £366,938 |
| Post-tax payback | 3.3 - 9.8 years |
2.5 MWp commercial solar · FAQs
How much does a 2.5 MWp commercial solar system cost in 2026?
At 2026 prices, a 2.5 MWp commercial solar PV system costs approximately £1,400,000 - £1,875,000 installed (excl. VAT). After 100% Full Expensing tax relief for a limited company at the 25% main CT rate, net cost is around £1,050,000 - £1,406,250.
What is the payback period for a 2.5 MWp commercial solar system?
With 15% self-consumption and SEG export tariffs of 3p-15p/kWh, a 2.5 MWp system typically pays back in 3.3-9.8 years post-tax.
What size roof is needed for a 2.5 MWp system?
A 2.5 MWp system requires approximately 13,600 m² of unshaded roof area — around 5,500 450W panels.
How much electricity will a 2.5 MWp system generate?
A 2.5 MWp system generates approximately 2,375,000 kWh per year in UK conditions. Best fit for big-box logistics, multi-acre ground-mount, hospital trust portfolio.
Which grants apply to a 2.5 MWp system?
Best grant fit: Full Expensing (uncapped) + IETF or PSDS + wholesale PPA + REGO portfolio. Always use the eligibility calculator for a personalised match.
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