Commercial solar · 500 kWp

500 kWp commercial solar system — cost, size and payback (UK)

A 500 kWp system is the entry point to large-format commercial solar in the UK — big-box distribution, national retailer roll-outs, tier-1 manufacturers, multi-site hospital estates. Full G99 DNO approval is required, and network reinforcement is a common cost consideration.

500 kWp at a glance

System size
500 kWp
Panels
~1,000 panels (500 W each)
Roof area
50,000–75,000 sq ft (~4,650–7,000 m²)
Annual generation
~475 MWh/year (475,000 kWh)
Installed cost
£360,000–£420,000 installed
After Full Expensing
£270,000–£315,000 after Full Expensing
Annual saving
£90,000–£120,000/year
Payback
3.5–4.5 years after Full Expensing

Best fit business types

  • Big-box distribution and fulfilment centres
  • National retailer roll-out sites
  • Tier-1 manufacturers and process plants
  • NHS hospital estates and university campuses
  • Large agricultural / poultry sites

Design and spec notes

  • Central inverter architecture, single-point DNO G99 connection.
  • Network reinforcement fee possible — factor £30–£100k contingency.
  • PPA and corporate offtake models routinely available at this size.
  • Battery storage (500 kWh–1 MWh) opens flexibility market revenue.

Related reading

FAQ — 500 kWp systems

Does 500 kWp trigger extra planning steps?

Rooftop is still Permitted Development in England up to 1 MWp. Ground-mounted 500 kWp needs a planning application.

What's the DNO connection cost?

Standard G99 approval on an already-fed site is £3–£10k. Network reinforcement (needed on ~15% of 500 kWp+ sites) can add £30–£150k.

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