Category: Economics
PPA vs Rooftop Lease: 25-Year Cashflow Compared
Two very different deals: PPA pays you in cheap kWh; rooftop lease pays you in cash. 25-year DCF model for a 500kWp roof.
Two very different deals
Rooftop lease: you rent your roof to a generator for £5-15k/MWp/year. PPA: you buy the kWh for 11-16 p. Same roof, totally different outcomes.
25-year DCF model
For a 500kWp roof generating 475,000 kWh/year at 75% self-consumption:
| PPA | Rooftop lease | |
|---|---|---|
| Year-1 cash inflow | £0 | £3,750 (£7.50/MWp/yr × 500 kWp) |
| Year-1 cash outflow saving | £82,000 (vs 30p grid) | £0 — you still buy from grid |
| Year-1 net benefit | £82,000 | £3,750 |
| 25-year cumulative (DCF 5%) | £1.05m | £52k |
| Best for | Sites that use kWh | Roof-rich, low-power-use |
When rooftop lease wins
- Small electricity user with huge roof (warehousing tenant, lorry park, self-storage)
- Site sells to a buyer who wouldn't want a PPA
- Strict no-OpEx constraint
- Risk-averse — fixed annual rental cleaner than per-kWh variable
When PPA wins
- Any site that uses 50%+ of the generation
- Strong daytime load profile
- Want to reduce Scope 2 emissions
- Need MEES / ESOS / TCFD evidence
See what tariff your site qualifies for
A 60-second form gives us enough to match your site to providers and return an indicative tariff range within one working day.
Get an indicative PPA tariffLeasing the panels themselves is a different deal again, and our solar lease vs PPA comparison sets out how it differs.
Related reading
Get your site assessed for a solar PPA
PPA vs Rooftop Lease: 25-Year Cashflow Compared — tell us about your site and we'll return an indicative p/kWh tariff for it. Reply by email within one working day.