Is commercial solar finance worth it for UK businesses in 2026?
For most profitable UK trading companies, commercial solar finance in 2026 generates 14-22% post-tax IRR over 25 years on capital purchase, with the 50% First Year Allowance materially reducing year-1 effective cost. For other businesses — capital-constrained operators, charities, specific property structures — different finance structures change the answer but rarely make it negative. Here's the honest analysis.
The short answer
Yes for most profitable UK trading companies; conditionally yes for most others; no in specific circumstances. The honest framework:
- Profitable trading company, available capital, 10+ years occupation — capital purchase, 14-22% post-tax IRR. Very strong case.
- Profitable trading company, capital constrained — green loan or finance lease, 10-15% post-tax IRR. Strong case.
- Charity / not-for-profit — PPA or trading-subsidiary capital purchase, 6-10% effective return. Reasonable case but materially weaker than commercial.
- Public sector with PSDS access — bundled grant application, 75-100% covered by grant. Net positive on capital deployed.
- Loss-making business, no FYA value — typically defer until trading position recovers. Solar economics depend on tax allowance capture.
- Short-tenure occupier (under 5 years) — typically not viable for capital structures. PPA may work but contract length mismatches occupation horizon.
When commercial solar isn't worth it
Six situations where we've recommended clients NOT proceed:
- Loss-making with no near-term recovery. FYA value is contingent on having taxable profits to offset. Loss-making businesses without a clear return-to-profit plan don't capture the FYA, and economics are 17-20% worse without it.
- Tenant with sub-5-year remaining lease. Capital structures need 8+ years to break even; PPAs need 20+ years. Short-tenure tenants typically can't make the math work even with green-rent abatement structures.
- Site with very low electricity demand or weekday-only operation. If your demand profile is short hours / weekends-off, self-consumption percentage drops to 50-65%. Marginal kWh value falls toward export tariff (7p) rather than avoided cost (22p), reducing project IRR meaningfully.
- Building with imminent redevelopment plans. Solar deployments need 8-25 year horizons depending on structure. Buildings scheduled for redevelopment within 5 years should defer or do nothing.
- Highly DNO-constrained sites with no economic export option. Where DNO denies export consent and self-consumption is naturally low, project economics become marginal. Battery storage may resolve but adds capex; sometimes the right answer is "this site doesn't fit".
- Listed-building or conservation-area sensitive structures. Where conservation officer engagement makes consent improbable on visible roof slopes, project may be uneconomic on the partial-roof yield available.
Where the headline IRR comes from
Project IRR on commercial solar in 2026 typically lands 14-22% post-tax for profitable trading companies on capital purchase. The components:
- Avoided electricity cost — typically 17-19% of project IRR. The headline driver.
- FYA tax saving year 1 — typically 2-3% of project IRR uplift. Time-limited to 31 March 2026 unless extended.
- Special-rate pool relief — typically 0.5-1% of project IRR uplift over 8-15 years.
- SEG export revenue — typically 0.5-1.5% of project IRR. Material on export-heavy sites.
- Real-terms tariff inflation — typically 1-2% of project IRR if tariffs grow ahead of inflation.
Related questions
What payback period should I expect on commercial solar?
How sensitive are these returns to electricity price assumptions?
Does commercial solar still work if the FYA expires after 31 March 2026?
Are project economics the same for charities as commercial businesses?
How do I get a tailored "is it worth it" assessment?
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Is commercial solar finance worth it? — detailed analysis 2026
Commercial solar finance is worth it for the majority of UK businesses that have a suitable roof, daytime electricity consumption, and are paying typical commercial electricity rates. The question is less "is it worth it in principle?" and more "which finance structure produces the best outcome for my specific situation?"
When commercial solar finance is clearly worth it
| Scenario | Why it works | Best finance structure |
|---|---|---|
| Manufacturing or food processing (high daytime load, strong tax position) | Self-consumption 70–85%; FYA maximises tax benefit; payback 3.5–5 years | HP or capital purchase |
| Multi-site retail or logistics (portfolio, leasehold) | Operating lease at portfolio level; zero capital; immediate cash-flow positive | Operating lease |
| NHS Trust or local authority (PSDS eligible) | 67% PSDS grant; Salix 0% loan; near-zero net cost; compliance-driven | PSDS + Salix combination |
| Distribution centre (large south-facing roof, EV fleet) | High self-consumption with EV charging; FYA; strong landlord or tenant ROI | Capital purchase or HP |
| Hotel (sustainability marketing value + financial return) | GreenLeader benefit; 60–75% self-consumption; operating lease suits leasehold | Operating lease or PPA |
When commercial solar finance needs more analysis
Short lease remaining (<7 years)
If the building lease has less than 7 years remaining, the solar installation cannot be fully depreciated within the lease term. The residual asset value is low (landlord may not pay for removal). If the project IRR without lease extension is below 10%, the investment is marginal. Solution: negotiate a lease extension (even 5 years added to a 5-year remaining term transforms the economics) or choose a zero-capital PPA/lease where asset ownership risk is with the developer/lessor.
Building earmarked for sale within 5 years
Solar installations on buildings that will be sold within 5 years of installation need to be valued in the context of the sale. In the current market, solar significantly increases building value for most commercial property types — but the uplift needs to exceed the unrecovered installation cost (net of FYA). Generally, solar is still worth installing on pre-sale buildings, but the decision should be validated with a property valuer who understands the current market.
North-facing roof only (no south option)
A north-facing roof in the UK generates approximately 55–65% of the yield of an equivalent south-facing array. The economics deteriorate but are often still positive — particularly for businesses paying premium electricity rates and where the roof area is large enough to deploy a system that achieves a viable minimum size. Ground-mount or adjacent south-facing secondary buildings may be better primary options.
Financially distressed business
A business making losses cannot benefit from FYA or AIA (no taxable income to offset). Operating leases and PPAs (where the tax benefit is captured by the lessor/developer rather than the occupier) are the only viable financed options. However, a loss-making business should assess whether the electricity saving improves net margin sufficiently to justify the commitment — even a PPA at 88% of grid price provides immediate cash-flow improvement if electricity is a significant cost.
ROI benchmarks — is 15–22% worth it?
For capital purchase (own funds, 25% CT payer), commercial solar consistently delivers after-tax IRRs of 15–22% over the 25-year project life at current UK electricity prices. Compared to alternatives:
Commercial solar vs commercial property yield
UK commercial property net initial yields in 2026 range from 4.5% (prime London) to 8% (regional secondary). Onsite solar generates a 15–22% after-tax return from the same property it occupies — materially higher than the property investment return itself. For asset-rich businesses, deploying capital into own-premises solar may be more compelling than deploying it into additional property.
Commercial solar vs cash deposit
Bank of England base rate is 4.25% in Q1 2026; best commercial cash rates are 4.5–5.0%. A solar investment generating 15–22% after-tax IRR is 3–4× the risk-free cash return. The risk profile of solar is low: electricity prices are unlikely to fall to zero; the technology is proven; the panel warranty covers 25 years. The risk-adjusted case for solar versus cash is strong at current rates.
Commercial solar vs marketing/trading investment
For businesses with capital typically deployed in sales, marketing, or working capital at an incremental ROI of 10–15%, solar at 15–22% is generally a superior capital allocation. The key distinguishing factor is the predictability and liquidity of returns: solar generates a fixed annual cash flow (electricity saving) that is highly predictable, unlike most marketing or trading investments.
Want this applied to your specific situation?
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