Is commercial solar tax deductible? What a UK business can claim
UK commercial solar tax savings come from four mechanisms: the 50% First Year Allowance (FYA), Annual Investment Allowance (AIA), special-rate pool writing-down allowances, and Smart Export Guarantee (SEG) income. Combined, they typically deliver a 17-25% effective discount on capex for profitable trading companies — the single largest economic driver of commercial solar economics in 2026.
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Check your finance routeThe four tax mechanisms
1. 50% First Year Allowance (FYA)
Permanent for special-rate assets (gov.uk, 22 November 2023). Allows 50% of qualifying capital expenditure to be deducted from year-1 taxable profits. At 25% main rate, that's 12.5p per £1 of capex — for a £200k system, £25k of year-1 corporation tax saved. Remaining 50% goes into special-rate pool.
2. Annual Investment Allowance (AIA)
100% deduction in year 1 on the first £1m of qualifying capital expenditure per accounting period. Where AIA headroom is available (not used by other capex), claiming AIA gives stronger year-1 tax relief than FYA. £200k system at 25% main rate = £50k year-1 tax saving via AIA vs £25k via FYA.
3. Special-rate pool (SRP)
6% writing-down allowance on a reducing-balance basis on the residual capex (50% of capex if FYA claimed, 0% if AIA fully claimed). With the FYA claimed on a £200k system, the £100k balance is first written down in year two: £6,000 of allowance, or £1,500 of tax at 25%, falling by 6% a year. That is about £14,500 of tax over years 2–15 (not discounted), and the balance is never fully written off.
4. Smart Export Guarantee (SEG)
Mandatory tariff payable by large UK electricity suppliers on solar exported to the grid. Tariffs vary 3-12p/kWh depending on supplier. On typical 8% export, worth £600-1,500/year on a £200k system — additional revenue, not strictly a tax saving but contributes to total project economics.
Combined tax savings: worked example
For a £200,000 250 kWp commercial solar system on a profitable UK trading company at the 25% main rate, no AIA headroom available (AIA used by other expenditure):
| Tax mechanism | Year claimed | Tax saving |
|---|---|---|
| 50% first-year allowance | Year 1 | £25,000 |
| Special-rate pool, 6% a year on the £100,000 balance | Years 2–15 | ~£14,500 cumulative |
| Total tax savings, years 1–15 (not discounted) | Years 1–15 | ~£39,500 |
| Effective discount on capex | — | ~19.7% over 15 years |
AIA-route alternative
If AIA headroom is available for the same £200k system:
| Tax mechanism | Year claimed | Tax saving |
|---|---|---|
| AIA (100% × 25% × £200k) | Year 1 | £50,000 |
| SRP (none — fully claimed via AIA) | N/A | £0 |
| Total tax savings (PV) | Year 1 | £50,000 |
| Effective discount on capex | — | 25.0% |
AIA route delivers stronger year-1 cash than FYA + SRP route. AIA is preferred where headroom is available; FYA fills in beyond the £1m AIA cap or where AIA is exhausted by other capex.
Related questions
Can I claim FYA and AIA on the same project?
What's the corporation tax saving at 19% small profits rate?
When is the FYA expiring?
Do I lose tax savings if I use green loan or asset finance?
Can charities claim FYA / AIA on solar installations?
Continue reading
Commercial solar tax savings — complete guide 2026
Commercial solar PV installations in the UK benefit from the most favourable tax treatment of any capital investment available to UK businesses — combining the 50% First Year Allowance (FYA), the Annual Investment Allowance (AIA), and the deductibility of finance costs to create after-tax IRRs that significantly exceed pre-tax returns.
Summary of tax saving mechanisms
| Tax saving mechanism | Timing | Applicable entity | Amount (25% CT rate) |
|---|---|---|---|
| 50% First Year Allowance (FYA) | Accounting period the expenditure is incurred | Companies paying corporation tax only (not LLPs or sole traders) | 12.5% of system cost in year 1 |
| Annual Investment Allowance (AIA, 100%) | Accounting period the expenditure is incurred (up to £1m) | CT-paying entities | 25% of system cost in year 1 (on amount within AIA limit) |
| Special-rate pool WDA (6% reducing balance) | Years 2–25+ on unrelieved balance | CT-paying entities | Continues to reduce taxable profit each year |
| Finance interest deduction | Annual (if debt-financed) | CT-paying entities | HP/loan interest × 25% CT saving per year |
| SEG income (taxable) | Annual on export income | CT-paying entities | SEG income adds to taxable income; not a saving |
| Electricity cost reduction (deductible) | Annual | Any business | Avoided import cost reduces trading expenses — always fully deductible |
Worked example: full tax benefit calculation
A profitable UK manufacturing company installs 500kWp of rooftop solar. System cost: £500,000. Corporation tax rate: 25%. Finance: capital purchase from own resources.
Year 1 tax effect
FYA claim: £250,000 (50% of £500,000). CT saving: £250,000 × 25% = £62,500. Electricity saving: 450,000kWh × £0.24/kWh = £108,000 (reduces taxable income; taxable at 25% = saves £27,000 of tax but increases net profit by £108,000 × 75% = £81,000 after tax). Combined year-1 benefit: £62,500 FYA relief + £81,000 after-tax electricity saving = £143,500.
Year 2–7 tax effect
Remaining pool after FYA: £250,000 entering the special-rate pool (solar is special-rate plant). Year 2 WDA: £250,000 × 6% = £15,000 allowance = £3,750 CT saving. Year 3: WDA on £235,000 = £14,100 = £3,525 CT saving. The WDA continues each year on the diminishing pool. Over the first 10 years of writing-down, cumulative WDA CT relief on the £250,000 pool = approximately £28,800 (at 6% the pool is never fully written off: about 23% is still unrelieved after year 25).
25-year total tax saving summary
FYA (year 1): £62,500. Cumulative WDA (years 2–25): ~£48,300. Total capital allowance CT relief: ~£110,800. Finance interest deductions (if debt-financed): additional relief dependent on interest cost. Total tax benefit as % of system cost: ~22% — over a fifth of the system cost returned as direct CT relief over the project life, in addition to the electricity cost savings.
Tax planning considerations
Year-end timing: when the expenditure is incurred
The FYA and the AIA are given for the accounting period in which the expenditure is incurred (Capital Allowances Act 2001 s5; HMRC CA11800), not the period in which the system is first used. Expenditure is generally incurred when the obligation to pay becomes unconditional, for example on completion or acceptance under the contract, even if payment is made later; if payment is not due until more than four months after that, it is incurred when payment is due. Hire purchase has its own rule (s67). On a £500k system, a contract that becomes unconditional just before the year-end rather than just after it brings £62,500+ of CT relief forward by 12 months. Agree the contract terms with your tax adviser at the start; an obligation made unconditional early only to pull relief forward is treated as incurred on the payment date instead (s5(5)).
Group company considerations
If the business installing the solar is a member of a corporate group with multiple entities, the AIA £1m limit applies per group (connected persons) — not per entity. A group spending £3m on solar across three companies in the same year has only £1m of AIA to allocate (not £3m). The allocation should be to the entity with the highest taxable profits in the year, maximising the immediate tax relief. FYA has no monetary cap, so it can be used for the remaining expenditure above the AIA limit.
Loss-making businesses: when tax benefits don't apply
Businesses that are loss-making or not paying UK corporation tax (charities, public sector, international businesses with no UK CT liability) receive no direct benefit from FYA or AIA — the allowances reduce a taxable profit that doesn't exist. These organisations should instead use operating leases, PPA structures, where the tax benefit is embedded in the lease rate by the lessor rather than claimed directly.
VAT and Stamp Duty Land Tax
VAT: 20% on commercial installations (reclaimable)
Commercial solar installations are subject to 20% VAT at the standard rate. VAT-registered businesses reclaim this as input tax in the VAT return period following the tax point (date of supply). For a £500,000 system, this represents £100,000 of VAT — a material cash flow item for 30–90 days until the VAT repayment is processed. Cash flow planning should account for the VAT payment timing.
SDLT: no SDLT on solar installation
Solar panel installations are not a transfer of land or property and do not trigger Stamp Duty Land Tax. The installation of solar panels on a property does not constitute a new lease, easement, or other SDLT-chargeable interest. SDLT implications only arise if the property itself changes hands.
Commercial solar tax savings: a full worked guide for UK businesses in 2026
Commercial solar tax savings in 2026 operate across four distinct HMRC mechanisms that interact to reduce the real net cost of a solar installation to 40–75% of the gross installed price. Understanding how each mechanism works — and how they stack — is the single most important financial modelling task before committing to any solar finance structure. The four mechanisms are: (1) Annual Investment Allowance (AIA), (2) 50% First Year Allowance (FYA, the first-year allowance for special-rate assets such as solar), (3) Climate Change Levy (CCL) exemption on self-consumed solar energy, and (4) Smart Export Guarantee (SEG) income treatment for exported electricity.
Tax savings by mechanism: what each is worth in 2026
| Mechanism | Rate of benefit | Year of benefit | Typical value on £200k system | Who qualifies |
|---|---|---|---|---|
| Annual Investment Allowance (AIA) | 25% of expenditure in year 1 (at CT25%) | Accounting period the expenditure is incurred | £50,000 tax reduction in year one | UK limited companies and unincorporated businesses paying income tax; 100% of expenditure up to £1m AIA limit |
| 50% First Year Allowance (FYA, the first-year allowance for special-rate assets such as solar) | 50% in year 1; 6% WDA on the balance each subsequent year | Year 1: 50%; from year 2: 6% WDA on the reducing balance | £25,000 in year 1; £1,500 in year 2; £1,410 in year 3 (etc) | Limited companies subject to corporation tax only; sole traders use AIA |
| Climate Change Levy (CCL) exemption | No CCL (0.801p/kWh from 1 April 2026) on solar electricity used on site | Annually from commissioning | About £1,500/yr (about 190,000 kWh used on site) | Businesses whose electricity supply carries CCL |
| Smart Export Guarantee (SEG) income | Export income 3–24p/kWh depending on tariff; treated as trading income | Annually from commissioning | £500–£4,000/yr (size and rate dependent) | Any business exporting to grid under a licensed SEG tariff |
Tax savings by business type: worked examples
| Business type | System size | Gross cost | AIA saving (year 1) | CCL saving (annual) | SEG income (annual) | Net cost after tax | Effective payback |
|---|---|---|---|---|---|---|---|
| Manufacturing (25% CT) | 200kWp | £180,000 | £45,000 | £1,400 | £1,200 | £132,400 | 4.5–5.5 years |
| Retail business (25% CT) | 100kWp | £90,000 | £22,500 | £700 | £600 | £66,200 | 4–6 years |
| Logistics (25% CT) | 500kWp | £420,000 | £105,000 (AIA cap £1m) | £3,600 | £2,500 | £308,900 | 4–5.5 years |
| Small business (income tax, not CT) | 50kWp | £45,000 | AIA at income tax marginal rate (20–45%) | £350 | £400 | £24,000–£35,250 | 4–7 years |
The AIA timing rule: why year-end purchases matter
AIA is given for the accounting period in which the expenditure is incurred (CAA 2001 s5): generally the date the obligation to pay becomes unconditional, not the date the invoice is paid or the date the system is first used. A contract that becomes unconditional on 31 March (the last day of a 31 March year-end) counts against that year's profits; one that becomes unconditional on 1 April falls into the next period, so its relief arrives 12 months later. If payment is not due until more than four months after the obligation becomes unconditional, the expenditure is incurred on the due date. For a business with a profitable year about to end, agree the contract and completion dates with your accountant before signing the finance contract.
AIA vs FYA: which delivers more tax savings for your business?
| Factor | AIA wins when... | FYA wins when... |
|---|---|---|
| Taxable profit availability | Company has sufficient CT25% profit to absorb 100% of cost in year 1 | Company is in a tax loss position in year 1 or has low taxable profits |
| Business structure | Limited company or unincorporated trade | Limited company only (FYA not available to sole traders/partnerships) |
| System cost | Under £1m (full AIA available); over £1m, split AIA+FYA | Any size — the 50% first-year allowance for special-rate assets has no cap |
| Year-end timing | System commissioned in accounting period with high profits | Profits uncertain; spreading relief over 2–4 years reduces timing risk |
| Property sale plans | No plans to sell within 5–7 years | Either route can give a balancing charge on a sale; take advice before selling |
| Typical verdict for UK commercial solar | AIA preferred in 70–80% of cases | FYA preferable when profit timing is uncertain or disposal risk is high |
CCL: a small saving that adds up over 25 years
The Climate Change Levy (CCL) is charged on business electricity supplies at 0.801p/kWh from 1 April 2026 (0.775p/kWh in 2025–26; gov.uk, Climate Change Levy rates). Solar electricity generated and used on site is not a taxable supply, so it carries no CCL. This is often presented as a 5% saving, but the value depends on your tariff: if your business pays 35p/kWh all-in and the CCL component is 0.801p/kWh, the saving is 2.3% of the bill on self-consumed solar. Over 25 years on a 200kWp system generating 180,000 kWh/year of which 80% is self-consumed (144,000 kWh), the CCL avoided at the 2026–27 rate adds up to about £28,800, before any future rate changes.
SEG income: tax treatment and optimising the rate
| SEG provider | Commercial tariff (2026 indicative) | Payment method | Best for |
|---|---|---|---|
| Octopus Energy (Outgoing Octopus) | Variable (Agile Export tracks half-hourly prices — short peaks can be high, long-run averages are far lower); fixed SEG tariffs are typically low single-digit p/kWh | Monthly settlements | Businesses with Octopus supply contract; Agile rate tracks wholesale price |
| OVO Energy | 15p/kWh fixed | Monthly | OVO commercial customers; transparent fixed rate |
| EDF Energy | 12–15p/kWh | Monthly | EDF commercial customers |
| E.ON Next | 12–14p/kWh | Monthly | E.ON commercial customers |
| British Gas (Centrica) | 10–13p/kWh | Quarterly | BGas commercial customers; competitive for larger systems |
| Scottish Power | 10–12p/kWh | Quarterly | SP supply area; limited to SP commercial customers |
| Minimum (default market rate) | 3–5p/kWh | Variable | Fallback — switch to competitive provider to maximise SEG income |
SEG income is taxable trading income — but the rate is favourable
SEG income received by a UK limited company is treated as trading income and subject to corporation tax at 25% (for companies with profits above £250k) or the small profits rate of 19%. This means the effective after-tax SEG income on a 12p/kWh tariff is 9p/kWh (at 25% CT) or 9.72p/kWh (at 19% CT). Even at the after-tax rate, SEG income from a 100kWp system exporting 20% of generation (approximately 18,000 kWh/year) produces £2,025–£2,187 in net annual income. Over 25 years at a modest 2% annual electricity price escalation, the cumulative after-tax SEG income from a 100kWp commercial system is approximately £56,000 — a meaningful contribution to total project return.
Capital allowances tax relief is one of the capital allowances available on commercial solar. For the complete picture — how AIA, the 50% First Year Allowance and the Structures & Buildings Allowance fit together, who can claim, and how to claim — see our parent guide: Capital Allowances on Solar Panels.
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The complete picture on solar panel capital allowances, including landlord and tenant claims, sits in the parent guide.
The rating side is often missed: business rates and solar panels — the England exemption runs to 31 March 2035.
The short answer is no, and what applies instead is set out in is there a business tax credit for solar panels.
Every allowance is worked through, with the HMRC sources, on capital allowances on solar panels.
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