The short answer
A 500 kWp commercial solar system costs £375,000–£425,000 installed in the UK and generates around 475,000 kWh a year (about 950 kWh per kWp). It needs roughly 3,000 m² of clear roof — large warehouse or distribution scale — and at high daytime self-consumption can pay back in 2–5 years.
A 500 kWp system is a large commercial array — the scale of a major warehouse or distribution centre roof. It can cover a large share of a substantial industrial electricity bill, and it sits at the lower end of the cost-per-kWp range because the fixed costs are spread across so many panels. At this size the grid connection is a significant piece of work in its own right, and the planning regime above 50 kW applies. 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 500kW system?
Size a solar system to your daytime electricity use, not to how much roof you have. A 500 kWp system fits a business with a large, sustained demand through the working day — a large warehouse, a distribution centre, or a major manufacturing site. The closer your usage pattern is to the solar generation curve, the more of the output you self-consume, and self-consumed power is what makes the economics work at this scale.
Match the array to demand, not just the roof
A very large roof can host a very large array, but generation you export earns far less than the power you use on site. The strongest 500 kWp cases are operations that draw most of the output during daylight. Use the calculator for a number based on your own roof and bill.
This is large warehouse and distribution scale, so the suitability and roof-economics detail is covered on our warehouse solar installers guide. The general principles of sizing a commercial system are on our guide to solar for business.
What does a 500kW system cost?
A 500 kWp system costs £375,000–£425,000 fully installed in 2026 — roughly £750–£850 per kWp, among the lowest cost per kWp in commercial solar. That price includes the panels, inverters, mounting system, access, design and the grid connection work. The table puts it alongside the sizes below it, so you can see how the cost per kWp falls as systems scale up.
| System size | Typical installed cost | Approx. per kWp |
|---|---|---|
| 50 kWp | £63,900–£70,000 | £1,278–£1,500 |
| 250 kWp | £190,000–£230,000 | £750–£950 |
| 500 kWp | £375,000–£425,000 | £750–£850 |
The full breakdown of what sits inside a commercial solar price — hardware, labour, access, grid fees and survey — is on our commercial solar cost guide. A 500 kWp system is well above the £1m Annual Investment Allowance threshold for total spend per year, so the year-one tax treatment needs checking carefully — we cover allowances on our grants and tax relief guide.
How much will a 500kW 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 | 500 kWp |
| Typical UK yield | ≈950 kWh per kWp per year |
| Annual generation | ≈475,000 kWh per year (500 × 950) |
| Value if all self-consumed | ≈£118,750 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 a business self-consumes a share of what it generates, and at this scale a portion is often exported, earning 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. At large warehouse and distribution scale, payback typically lands in the 2–5 year range.
How much roof space does a 500kW system need?
A 500 kWp array needs roughly 3,000 m² of usable roof, working on about 6 m² per kWp (500 × 6). That is the footprint of a large warehouse or distribution centre roof. On a flat roof you usually need a little more, because panels are tilted and spaced so they don't shade each other through the day. The roof also has to be structurally sound with at least ten years of life left — a structural survey (typically £500–£2,000) confirms it can carry the load before anything is fitted.
What grid approval does a 500kW system need?
A 500 kWp system needs a full G99 connection application to your distribution network operator, and it is a substantial piece of work. At this scale the network will very likely offer a flexible, export-limited connection — permitting the system but capping how much it can push back to the grid when local capacity is tight — which is often the only practical route on a busy network. The grid application is usually the slowest single step, so it should start as early as possible.
Systems over 50 kW and prior approval
Most commercial rooftop solar is permitted development, but a system above 50 kW can require prior approval from the local planning authority before it goes ahead. Your installer normally handles both this and the grid application; our planning permission guide sets out where it applies.
Stepping down a size
500 kWp is at the larger end of rooftop commercial solar. If your roof or bill is smaller, a 250 kWp system at £190,000–£230,000 may be the better fit, and a 50 kWp system suits a single industrial unit or a larger SME. For a mid-range 100 kWp system, our sister site SolarGridCheck covers it in full: see their 100kW solar system guide.
Frequently asked questions
How much does a 500kW solar system cost in the UK?+
A 500 kWp commercial solar system costs roughly £375,000 to £425,000 fully installed in 2026, which works out at about £750 to £850 per kWp. This is among the lowest cost per kWp you will see, because the fixed costs of design, access and the grid connection are spread across a very large number of panels.
How much electricity does a 500kW solar system generate?+
A 500 kWp system generates around 475,000 kWh a year in the UK, based on a typical yield of about 950 kWh per kWp annually. Output peaks in summer and dips in winter. On a large warehouse roof the array is laid out to fill the available space efficiently rather than chasing a single ideal orientation.
How much roof space does a 500kW solar system need?+
A 500 kWp array needs roughly 3,000 square metres of clear, structurally sound roof, working on about 6 square metres per kWp. That is the scale of a large warehouse or distribution centre roof. On a flat roof you usually need a little more, because tilted panels are spaced to avoid shading each other through the day.
What size business does a 500kW system suit?+
A 500 kWp system suits a large warehouse, distribution centre or major manufacturing site with a substantial daytime electricity demand. The economics are strongest when most of the generation is used on site rather than exported. At this scale the payback is often among the fastest in commercial solar. Our calculator sizes the system to your actual roof and bill.
Does a 500kW solar system need a grid connection application?+
Yes. A 500 kWp system needs a full G99 connection application to your distribution network operator, and at this size the network will very likely offer a flexible, export-limited connection to manage local capacity. A system over 50 kW can also need prior approval from the local planning authority, so both the grid and planning side should start early.
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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.