Commercial Solar Finance Case Studies
Reviewed by the Commercial Solar Finance editorial team (we take no installer or lender commissions). Last reviewed: June 2026.
The best way to understand commercial solar finance is to see the numbers worked through. Below are four illustrative case studies showing how different UK businesses fund solar and what each route delivers on cost, tax and cashflow. These are illustrative worked models built from representative 2026 market figures, not named client accounts — we publish them so you can see the mechanics transparently before requesting figures for your own site.
What these case studies show
Four scenarios — a green loan, a hire purchase, a PPA, and a past public-sector PSDS project — each with the system size, finance terms, year-one tax relief, and net cashflow. Use them to see which financing route behaves how, then compare finance companies for your own quote.
Case study 1 — Midlands manufacturer, 250kWp, green loan
Illustrative model. A profitable precision-engineering business installs a 250kWp rooftop system to cut a rising electricity bill and shelter taxable profit.
| Metric | Figure |
|---|---|
| System size / cost | 250kWp / £212,500 |
| Finance route | Green loan, 7% APR over 8 years (100% funded, £0 upfront) |
| Year-one AIA relief | £53,125 (100% AIA × 25% CT) |
| Annual energy saving (yr 1) | ~£78,000 (at 35p/kWh, 75% self-consumption) |
| Annual loan repayment | ~£33,900 |
| Net year-one cashflow | Positive after AIA + saving exceed repayment |
| Outcome | Owns the asset, keeps 100% of savings + SEG, full tax relief |
Why a green loan: the business keeps the Annual Investment Allowance (worth £53k in year one) that a lease or PPA would hand to the provider, while paying nothing upfront.
Case study 2 — Logistics operator, 600kWp, PPA
Illustrative model. A distribution business with a very large warehouse roof and steady daytime load wants solar with zero capital and zero maintenance responsibility.
| Metric | Figure |
|---|---|
| System size | 600kWp on a single distribution-centre roof |
| Finance route | 25-year Power Purchase Agreement, £0 capital |
| PPA rate | ~10p/kWh (vs ~30p grid import) — ~30% discount |
| Annual saving (yr 1) | ~£90,000 on consumed solar units |
| Capital outlay | £0 — developer owns, installs and maintains |
| Tax position | Developer claims allowances; saving is the unit-price discount |
| Outcome | Zero capital, zero risk; lower lifetime return than owning |
Why a PPA: at 600kWp the developer's return is predictable, so the rate is keen; the operator gets a large bill reduction with no balance-sheet impact. See commercial solar PPA rates.
Case study 3 — SME retailer, 80kWp, hire purchase
Illustrative model. A mid-size retailer with one large unit wants to own the system and claim the tax relief, but spread the cost.
| Metric | Figure |
|---|---|
| System size / cost | 80kWp / £80,000 |
| Finance route | Hire purchase, 8% APR over 7 years, 10% deposit |
| Year-one AIA relief | £20,000 (claimed on completion of HP) |
| Annual energy saving | ~£26,000 |
| Annual HP instalment | ~£13,000 |
| Outcome | Owns on final payment; AIA + savings outweigh instalments |
Why hire purchase: ownership and the full AIA, with the cost spread — the HP buyer claims the allowance even before the final payment.
Case study 4 — NHS trust, 300kWp, PSDS era (past scheme)
Illustrative past-scheme model. While PSDS was open, a public body could fund most of a project with a grant; PSDS closed to new applications in November 2024, so this route is not available for new projects.
| Metric | Figure |
|---|---|
| System size / cost | 300kWp / £300,000 |
| Funding | PSDS grant 80% (£240,000) + trust capital 20% (£60,000) |
| Net capital cost to trust | £60,000 from the capital programme |
| Annual saving | ~£95,000 |
| Outcome | Owns the system; the £60,000 is recovered from savings inside the first year |
Why PSDS (past example): no commercial route beat a grant covering 80% of cost. See PSDS eligibility and application.
About these models: figures are illustrative, built from representative 2026 UK market rates and the standard tax rules (AIA 100% to £1m; 25% corporation tax; special-rate solar). They are not records of named clients and are provided to show the mechanics transparently. Your actual figures depend on your site, load profile, tax position and the live finance market.
The four routes side by side
Reading the four illustrative models together shows the central trade-off in commercial solar finance: ownership routes (green loan, hire purchase) deliver the best lifetime value because you keep the capital allowances and 100% of the savings, while capital-free routes (PPA) trade some of that value for zero risk and zero balance-sheet impact. The public-sector PSDS route sat apart while it was open; it closed to new applications in November 2024.
| Model | Upfront | Owns asset | Keeps AIA | Best when |
|---|---|---|---|---|
| 1 — Green loan | £0 | Yes | Yes | Profitable, want best lifetime value |
| 2 — PPA | £0 | No | No | Large load, want zero risk |
| 3 — Hire purchase | 10% deposit | Yes (on completion) | Yes | SME wanting ownership + spread cost |
| 4 — PSDS era (closed 2024) | £0 | Yes | N/A (public body) | NHS, council, school, university |
How to read these models for your own site
Three variables move the numbers most for any business. Self-consumption rate — the share of generation you use on site — is the biggest: a 24/7 operation captures far more value than a weekday-only office. Your import tariff sets the saving per unit; a site on an expensive contract saves more per kWh than one already on a cheap fixed deal. And your tax position decides whether the AIA is worth keeping — a loss-making business cannot use it this year, which can tilt the decision toward a lease or PPA where the provider monetises the relief instead. Change any of these and the "best" route can change with it, which is why a model built for your specific site beats any generic rule of thumb.
Every figure here is illustrative and built from representative 2026 market rates. To turn them into real numbers for your building, the inputs we need are simple: roof area or target system size, your current electricity price, your operating hours, and your tax position. From those we model all six financing routes and show you the after-tax, after-finance outcome for each.
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