Commercial Solar Purchase, Finance & PPA Calculator
Compare purchasing, 3-, 5- and 7-year finance, and fixed-price 25-year solar PPAs for UK factories.
Choose your solar system size
Calculation assumptions
- Guide purchase price: £800 per kW, excluding VAT
- Finance interest: 8% nominal annually
- Annual generation: 950 kWh per kW installed (indicative; subject to site-specific solar yield assessment)
- Solar electricity consumed on site: 80%
- Initial grid electricity price: 25p/kWh
- Annual grid electricity price increase: 6.8%, compounded
- Illustrative average export revenue for purchase/finance: 10p/kWh (not guaranteed)
- Fixed 25-year PPA rate depends on system size (see PPA section)
Purchase and finance
Illustrative equal monthly repayments. Finance costs exclude fees, deposits, VAT and other lender terms.
Cash-positive solar finance
Compare the estimated first-year average monthly electricity savings and export income against each finance repayment.
Cash-positive means estimated first-year average monthly solar benefit exceeds the monthly finance repayment, before maintenance, insurance, finance fees and other costs. Solar production varies seasonally, so positive average monthly cash flow does not guarantee savings exceed repayments in every calendar month. Illustrative, not a financing offer.
Annual generation and 25-year outlook
Fixed-rate 25-year Power Purchase Agreement (PPA)
Pay for electricity consumed on site at the indicative fixed PPA rate rather than buying the solar installation. Subject to site suitability and contract.
PPA rates: 100–199 kW 19p; 200–299 kW 17p; 300–499 kW 15p; 500–999 kW 13p; 1,000 kW+ 11p per kWh. PPA pricing starts at 100 kW. No export income is attributed to the customer under the PPA model.
Year-by-year comparison
| Year | Grid price | Outright purchase | 3-year finance | 5-year finance | 7-year finance | 25-year PPA |
|---|---|---|---|---|---|---|
| 1 | 25.00p | -£59,100 | -£9,183 | £1,435 | £5,937 | £4,560 |
| 2 | 26.70p | £22,192 | -£7,891 | £2,727 | £7,229 | £5,852 |
| 3 | 28.52p | £23,572 | -£6,511 | £4,107 | £8,609 | £7,232 |
| 4 | 30.45p | £25,046 | £25,046 | £5,580 | £10,083 | £8,706 |
| 5 | 32.53p | £26,619 | £26,619 | £7,154 | £11,657 | £10,279 |
| 6 | 34.74p | £28,300 | £28,300 | £28,300 | £13,338 | £11,960 |
| 7 | 37.10p | £30,096 | £30,096 | £30,096 | £15,133 | £13,756 |
| 8 | 39.62p | £32,013 | £32,013 | £32,013 | £32,013 | £15,673 |
| 9 | 42.32p | £34,061 | £34,061 | £34,061 | £34,061 | £17,721 |
| 10 | 45.19p | £36,247 | £36,247 | £36,247 | £36,247 | £19,907 |
| 11 | 48.27p | £38,583 | £38,583 | £38,583 | £38,583 | £22,243 |
| 12 | 51.55p | £41,078 | £41,078 | £41,078 | £41,078 | £24,738 |
| 13 | 55.05p | £43,742 | £43,742 | £43,742 | £43,742 | £27,402 |
| 14 | 58.80p | £46,587 | £46,587 | £46,587 | £46,587 | £30,247 |
| 15 | 62.80p | £49,626 | £49,626 | £49,626 | £49,626 | £33,286 |
| 16 | 67.07p | £52,871 | £52,871 | £52,871 | £52,871 | £36,531 |
| 17 | 71.63p | £56,337 | £56,337 | £56,337 | £56,337 | £39,997 |
| 18 | 76.50p | £60,039 | £60,039 | £60,039 | £60,039 | £43,699 |
| 19 | 81.70p | £63,992 | £63,992 | £63,992 | £63,992 | £47,652 |
| 20 | 87.26p | £68,214 | £68,214 | £68,214 | £68,214 | £51,874 |
| 21 | 93.19p | £72,724 | £72,724 | £72,724 | £72,724 | £56,384 |
| 22 | 99.53p | £77,540 | £77,540 | £77,540 | £77,540 | £61,200 |
| 23 | 106.29p | £82,683 | £82,683 | £82,683 | £82,683 | £66,343 |
| 24 | 113.52p | £88,176 | £88,176 | £88,176 | £88,176 | £71,836 |
| 25 | 121.24p | £94,043 | £94,043 | £94,043 | £94,043 | £77,703 |
Figures show annual net cash benefit (or cost). Purchase price is deducted in year 1; finance repayments are deducted during the selected term. Figures are undiscounted.
Request your personalised factory solar proposal
Get a site-specific design, generation forecast, PPA eligibility assessment and finance quotation.
All figures are illustrative, not a quotation or guarantee. Grid electricity starts at 25p/kWh and grows at a user-adjustable 6.8% annually as a scenario, not a verified forecast. The 8% finance assumption is nominal annual interest, not a representative APR. Calculations assume constant annual solar output, consumption, export price and PPA price, and exclude degradation, maintenance, curtailment, insurance, replacement equipment, tax, VAT, financing fees and time value of money. Real PPA terms, export rights, minimum commitments and end-of-term obligations must be agreed in writing.