The short answer
A 50 kWp commercial solar system costs £63,900–£70,000 installed in the UK and generates around 47,500 kWh a year (about 950 kWh per kWp). It needs roughly 250–300 m² of clear roof and suits a business with a £1,500–£3,000 monthly electricity bill and strong daytime use.
A 50 kWp system is a common size for an SME with a decent roof — a single industrial unit, a larger shop or office, a workshop or a small warehouse. It is large enough to make a real dent in a mid-size electricity bill, but small enough to sit comfortably within the £1m Annual Investment Allowance, so most businesses can deduct the full cost from year-one profits. This page sets out the numbers for this size specifically. For a figure tailored to your roof, the calculator takes about a minute.
Who needs a 50kW system?
Size a solar system to your daytime electricity use, not to how much roof you have. As a rule of thumb, a 50 kWp system fits a business spending roughly £1,500–£3,000 a month on electricity, with much of that demand falling during daylight hours. The closer your usage pattern is to the solar generation curve — busy through the working day — the more of the output you self-consume, and self-consumed power is what makes the economics work.
Bill banding is a starting point, not a quote
The £1,500–£3,000 monthly range is a guide for matching system size to demand, not a precise rule — your actual bill, tariff and how much you use during daylight all move the figure. Use the calculator for a number based on your own roof and bill.
If your bill is consistently below that range, a smaller system is usually the better fit; if it is well above, you may have the demand for something larger. The general principles of sizing are covered on our guide to solar for business.
What does a 50kW system cost?
A 50 kWp system costs £63,900–£70,000 fully installed in 2026 — roughly £1,278–£1,500 per kWp. That price includes the panels, inverters, mounting system, scaffolding, design and the grid connection paperwork. The table puts it alongside the sizes either side, so you can see how the cost per kWp falls as systems get bigger.
| System size | Typical installed cost | Approx. per kWp |
|---|---|---|
| 25 kWp | £31,950–£35,000 | £1,278–£1,400 |
| 50 kWp | £63,900–£70,000 | £1,278–£1,500 |
| 100 kWp | £80,000–£95,000 | £800–£950 |
The full breakdown of what sits inside a commercial solar price — hardware, labour, scaffolding, grid fees and survey — is on our commercial solar cost guide. Because the 50 kWp price sits within the £1m Annual Investment Allowance, most businesses can write off the entire cost against year-one profits; we cover the tax treatment on our grants and tax relief guide.
How much will a 50kW system generate?
Output depends on UK yield, which we take as a typical 950 kWh per kWp per year — a fair mid-point for a commercial rooftop in Britain. On that basis:
| Measure | Figure |
|---|---|
| System size | 50 kWp |
| Typical UK yield | ≈950 kWh per kWp per year |
| Annual generation | ≈47,500 kWh per year (50 × 950) |
| Value if all self-consumed | ≈£11,875 per year at 25p/kWh |
Yield is higher on a south-facing, unshaded roof and in the sunnier south of the country, and lower with shading or an east–west split. The savings figure above assumes every unit is used on site; in practice most businesses self-consume 60–80% of what they generate, and exported units earn far less than the 25p you avoid by using power yourself. That balance is why a daytime-heavy demand profile matters so much, and it is what decides payback — our payback and ROI guide works through it, with typical UK commercial payback landing in the 4–7 year range.
How much roof space does a 50kW system need?
A 50 kWp array needs roughly 250–300 m² of usable roof, working on about 6 m² per kWp. The lower end suits a clean pitched roof where panels sit flush; the upper end is more realistic on a flat roof, where panels are tilted and spaced so they don't shade each other. The roof also has to be structurally sound with at least ten years of life left — re-roofing before installing is common, and a structural survey (typically £500–£2,000) confirms it can carry the load.
Does a 50kW system need grid approval?
Yes. A 50 kWp system that exports to the grid needs a G99 connection approval from your distribution network operator, which typically takes 8–12 weeks. Your installer normally prepares and submits the application. It is usually the slowest single step in a commercial project, so starting it early is the most effective way to keep the overall timeline — typically 5–9 months end to end — under control. Planning permission is a separate matter: most commercial rooftop solar is permitted development and needs no application, which we cover on our planning permission guide.
Stepping up or down a size
50 kWp is one point on a range. If your bill is smaller, a 25 kWp system at £31,950–£35,000 may fit better; if it is larger, the next common step is 100 kWp, then a 250 kWp system for a factory or mid-size warehouse and a 500 kWp system for large distribution roofs, where the cost per kWp drops sharply.
Looking at a 100kW system?
A 100 kWp system is a different size class with its own economics. Our sister site SolarGridCheck covers it in full — see their 100kW solar system guide. For the price of every size in one place, see our commercial solar cost guide.
Frequently asked questions
How much does a 50kW solar system cost in the UK?+
A 50 kWp commercial solar system costs roughly £63,900 to £70,000 fully installed in 2026, which works out at about £1,278 to £1,500 per kWp. The price covers panels, inverters, mounting, scaffolding, design and the grid application. Bigger systems cost less per kWp, so the rate falls as you scale up.
How much electricity does a 50kW solar system generate?+
A 50 kWp system generates around 47,500 kWh a year in the UK, based on a typical yield of about 950 kWh per kWp annually. Output is higher in summer and lower in winter, and a south-facing, unshaded roof performs best. Your actual figure depends on location, roof pitch and orientation.
How much roof space does a 50kW solar system need?+
A 50 kWp array needs roughly 250 to 300 square metres of clear, structurally sound roof, working on about 6 square metres per kWp. Flat roofs usually need a little more because panels are spaced to avoid shading each other. The roof also needs at least ten years of life left before re-roofing.
What size business does a 50kW system suit?+
A 50 kWp system suits a business spending roughly £1,500 to £3,000 a month on electricity with significant daytime use. The aim is to match generation to what you consume on site during the day, because self-consumed power saves far more than exported power. Our calculator sizes the system to your actual bill.
Does a 50kW solar system need grid approval?+
Yes. A 50 kWp system that exports to the grid needs a G99 connection approval from your distribution network operator, which typically takes 8 to 12 weeks. Your installer normally manages the application. It is the slowest part of the project, so starting it early is the best way to keep the overall timeline down.
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Updated June 2026 · By Taro Schenker, founder of Business Solar Check. We're independent — we don't install solar. Figures are indicative UK averages; your site survey confirms the numbers for your roof.