5MWp PPA (ground-mount or large rooftop) — UK 2026 indicative cost & PPA tariff

2026 indicative numbers

System size	5MWp PPA (ground-mount or large rooftop)
Indicative capex (cash)	£3.5m–£4.5m
PPA tariff (year 1)	8–11 p/kWh
Annual generation	4,750,000 kWh
Indicative annual saving	£807,500+ (vs 30 p/kWh grid)
Typical audience	Industrial estates, port authorities, dairy/poultry farms with ground-mount, council portfolio aggregation.
Off-taker requirement	25 year contract, £1.5m+ annual electricity spend

Where ground-mount enters the frame

Five megawatts is the scale at which land, not roof, often becomes the answer. £3.5m–£4.5m of solar generating around 4.75 million kWh a year needs something like 15–20 acres if it goes on the ground — which is why this band suits port authorities, sprawling industrial estates, and dairy or poultry farms with spare land beside their buildings. Large rooftop schemes across a council portfolio can reach the same capacity, but ground-mount pulls planning permission and land agreements into the process.

Connection and planning are the long poles

Two consents govern the timeline. A 5MWp export connection is a substantial DNO undertaking — potentially triggering network reinforcement and a connection offer that takes months to firm up — while ground-mount almost always needs full planning consent, with ecology, landscape and glint-and-glare assessments that can run the better part of a year. Neither kills a scheme, but both belong in the programme from day one, not bolted on late.

The tariff reward for scale

The payback for that complexity is price. At 8–11 p/kWh this band sits well below rooftop-only systems, because fixed costs spread across nearly five million kilowatt-hours and construction grows more efficient at scale. Funders expect a 25-year contract and yearly electricity spend of £1.5m or more, and they will underwrite the covenant thoroughly before committing.

• Land secured, or roof area aggregated to 5MWp
• Planning route scoped for any ground-mount
• A 25-year contract with £1.5m-plus annual spend
• DNO reinforcement assessed at the outset

Getting expert funders to the table

A scheme this size wants funders who deliver ground-mount as routine. See how rates are assembled in the note on tariff build-up, weigh the options in PPA financing routes, and identify capable backers in the list of specialist providers.