1.5 MWp commercial solar PV cost in the UK (2026)
At 2026 prices, a 1.5 MWp commercial solar PV system costs £900,000 - £1,125,000 installed (excl. VAT). Typical post-tax payback: 3.3-8.3 years.
1.5 MWp cost summary
| System size | 1.5 MWp |
| Installed cost (2026, excl. VAT) | £900,000 - £1,125,000 |
| £/Wp | £0.60 - £0.75 |
| Number of panels (450W) | ~3,300 |
| Roof area required | ~8,200 m² |
| Annual generation (UK avg) | 1,425,000 kWh |
| Best fit for | big-box warehouse, large industrial site, university campus |
| Best grant stack | Full Expensing (uncapped) + IETF or PSDS + REGO + PPA structure |
Year-1 maths breakdown
| Gross capex (mid) | £1,012,500 |
| 100% Full Expensing tax saving (25% CT) | -£253,125 |
| Net effective cost | £759,375 |
| Annual self-consumption (20%) | 285,000 kWh saving £57,000/year |
| Annual SEG export (80%) | 1,140,000 kWh earning £34,200 - £171,000/year |
| Total year-1 savings/revenue | £91,200 - £228,000 |
| Post-tax payback | 3.3 - 8.3 years |
1.5 MWp commercial solar · FAQs
How much does a 1.5 MWp commercial solar system cost in 2026?
At 2026 prices, a 1.5 MWp commercial solar PV system costs approximately £900,000 - £1,125,000 installed (excl. VAT). After 100% Full Expensing tax relief for a limited company at the 25% main CT rate, net cost is around £675,000 - £843,750.
What is the payback period for a 1.5 MWp commercial solar system?
With 20% self-consumption and SEG export tariffs of 3p-15p/kWh, a 1.5 MWp system typically pays back in 3.3-8.3 years post-tax.
What size roof is needed for a 1.5 MWp system?
A 1.5 MWp system requires approximately 8,200 m² of unshaded roof area — around 3,300 450W panels.
How much electricity will a 1.5 MWp system generate?
A 1.5 MWp system generates approximately 1,425,000 kWh per year in UK conditions. Best fit for big-box warehouse, large industrial site, university campus.
Which grants apply to a 1.5 MWp system?
Best grant fit: Full Expensing (uncapped) + IETF or PSDS + REGO + PPA structure. Always use the eligibility calculator for a personalised match.
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