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UK Solar PPA Savings Calculator 2026
Model your indicative PPA savings — year-1 net saving, 15-year cumulative and contract-term total. All inputs adjustable. Includes self-consumption, SEG income and escalator scenarios.
PPA savings calculator
Model your indicative year-1 saving, 15-year cumulative saving and NPV vs CapEx. All inputs adjustable.
Typical commercial: 100-1000 kWp
UK average 950; South 1050; Scotland 850
Your current commercial import tariff
9-18 typical for on-site PPA in 2026
% of generation used on-site (rest exported)
2-15 typical from licensed suppliers
0% fixed, 2.5-3% typical RPI-linked
15-25 typical UK
£0
Year-by-year breakdown
Annual generation— kWh
Self-consumed @ PPA rate— kWh
Exported (SEG)— kWh
Year-1 grid bill avoided£0
Year-1 PPA cost£0
Year-1 SEG income£0
Year-1 net saving£0
15-year cumulative net saving£0
Contract-term cumulative saving£0
Indicative only. Assumes constant grid tariff and constant generation; in reality grid tariffs rise and panels degrade ~0.5%/year. Run real provider numbers via the quote form for a binding tariff.
FAQs
Calculator FAQs
How accurate is the calculator?
Directionally accurate within ±15%. It assumes constant grid tariff and constant generation (in reality grid tariffs rise and panels degrade ~0.5%/year). For a binding tariff use the quote form — we return real provider numbers within one working day.
What's a typical UK yield?
UK average is ~950 kWh per kWp per year. Southern England can reach 1,050; Scotland sees 800-900. Local irradiation data from PVGIS gives postcode-specific numbers.
Why is self-consumption % so important?
Self-consumed kWh save you grid-import cost (~30 p/kWh); exported kWh only earn the SEG rate (3-15 p/kWh). High self-consumption means high savings. Factory daytime load = 80-90%; office Mon-Fri = 60-75%; school term-time = 50-65%.
Should I set the escalator to fixed (0%) or RPI?
Run both scenarios. A fixed 0% escalator gives higher year-1 tariff but lower 25-year cost; an RPI-linked escalator looks cheaper in year 1 but cumulates higher. See our escalator comparison.
Why include SEG income?
Most PPAs leave the SEG income with the off-taker (you). For systems with significant export (low self-consumption sites), SEG can add £2-15k/year. Some PPAs route export differently — confirm in your contract.
What this calculator doesn't model
The calculator gives an indicative year-1 and contract-term picture but doesn't include:
- Panel degradation (real-world ~0.5%/year)
- Grid tariff escalation (which can be substantial)
- Performance ratio guarantee make-good payments
- Buy-out price at contract end (if you exercise that option)
- NPV / DCF — i.e., the time value of money
- Site-specific costs like roof refurbishment or DNO upgrades
For a full DCF model run by your finance team, see our 25-year DCF comparison. Or send us your site data and we'll model in real provider scenarios via the quote form.
Run real provider numbers
A 60-second form gives us enough to match you to PPA providers and return real binding tariff ranges.
Get an indicative PPA tariff
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