What commercial solar costs, by system size
Planning cost ranges, a worked payback example and building fit for four system sizes. Each example is built from published DESNZ prices and PVGIS yield, and every source is linked.
How these figures are built
No official UK statistic covers the installed cost of commercial solar above 50 kW. The cost ranges here are planning ranges. We set them between two official anchors: DESNZ's small-scale median for 2025/26, and the Arup study for DESNZ on large-scale solar. Quotes for a real building will differ.
Payback is simple payback: cost divided by yearly saving. Each example takes yield from PVGIS for a named town, and the electricity price from DESNZ's 2025 averages by size of user.
| Yearly use | Pence per kWh |
|---|---|
| 20 to 499 MWh | 28.4 |
| 500 to 1,999 MWh | 27.7 |
| 2,000 to 19,999 MWh | 25.4 |
| 20,000 to 69,999 MWh | 23.9 |
Source: DESNZ, Prices of fuels purchased by non-domestic consumers, table 3.4.1.
100kW Commercial Solar
The first step above small-scale: what it costs, and why self-use still decides payback.
Planning cost, payback and best-fit buildings for a 100kWp system, the size where MCS's small-scale standard stops applying.
- Planning cost
- £75,000 to £110,000 (£750 to £1,100 per kWp, excluding VAT)
- Simple payback
- About 4 to 11 years on the worked example, before running costs and tax relief
250kW Commercial Solar
Where daytime load still matters, while the grid application starts to decide the case.
Planning cost, payback and best-fit buildings for a 250kWp system, the size of a large warehouse or business-park roof.
- Planning cost
- £162,500 to £237,500 (£650 to £950 per kWp, excluding VAT)
- Simple payback
- About 3 to 8 years on the worked example, before running costs and tax relief
500kW Commercial Solar
Industrial roofs, where structure needs care and so does the tax allowance, since a 500kWp system uses a large share of it.
Planning cost, payback and best-fit buildings for a 500kWp system on a distribution centre, factory or cold store.
- Planning cost
- £300,000 to £425,000 (£600 to £850 per kWp, excluding VAT)
- Simple payback
- About 3 to 8 years on the worked example, before running costs and tax relief
1MW+ Commercial Solar
At a megawatt, the grid connection sets the timetable, while the roof is rarely the problem.
Planning cost, payback and best-fit sites for a 1MWp commercial system, where the network operator controls the schedule.
- Planning cost
- £550,000 to £800,000 for 1 MWp (£550 to £800 per kWp, excluding VAT)
- Simple payback
- About 3 to 7 years on the worked example, before running costs and tax relief
Which size fits your site?
Roof condition, grid capacity, tariff and load profile each move these figures, because no two sites match. A feasibility study or an ROI model gives you numbers for the actual site.