Capital Allowances on Solar Panels
Commercial solar panels qualify for capital allowances — the tax relief that lets UK businesses deduct the cost of plant and machinery from their taxable profit. For most commercial solar projects, the Annual Investment Allowance delivers 100% first-year corporation tax relief on the entire installed cost. This guide explains every capital allowance that applies to solar, how much you can claim, who is eligible, and how the claim interacts with your choice of finance.
Quick answer: can you claim capital allowances on solar panels?
Yes. Solar PV is plant and machinery for tax purposes. The Annual Investment Allowance (AIA) gives 100% first-year relief on the full installed cost, up to £1 million per year — which covers the vast majority of commercial systems outright. Solar is a special-rate asset, so spend above the £1m cap attracts the 50% First Year Allowance, with the balance written down at 6% per year. A £200,000 system therefore generates roughly £50,000 of corporation tax saving in year one at the 25% rate.
The three capital allowances that apply to commercial solar
UK tax law provides three distinct capital allowance routes relevant to a commercial solar installation. Most businesses only need the first — the AIA — but understanding all three matters for large projects and for the structural building works that accompany a rooftop or ground-mount array.
| Capital allowance | Rate | Annual cap | Applies to | When it matters for solar |
|---|---|---|---|---|
| Annual Investment Allowance (AIA) | 100% in year one | £1,000,000 per year | Plant & machinery (incl. special-rate solar PV) | The default for almost all commercial solar — full relief on systems up to £1m |
| 50% First Year Allowance (FYA / full expensing special rate) | 50% in year one | No cap | Special-rate plant & machinery | Spend on solar PV above the £1m AIA limit |
| Structures & Buildings Allowance (SBA) | 3% per year (flat) | No cap | Structural and building works | Ground-mount frames, new roof structures, civil works — not the panels themselves |
Why solar panels are a "special rate" asset — and why it doesn't cost you
HMRC classifies solar PV as an integral feature of a building, which places it in the special rate pool. Special-rate assets normally attract only a 6% writing-down allowance per year — far slower than the 18% main rate. This sounds disadvantageous, but it almost never bites, because the Annual Investment Allowance overrides the pool rate: AIA gives 100% first-year relief on special-rate assets too, up to £1m per year.
The special-rate classification only matters above the £1m AIA cap. There, solar qualifies for the 50% First Year Allowance (the special-rate arm of full expensing) rather than the 100% main-rate full expensing available to ordinary plant. For the overwhelming majority of commercial solar projects — which cost between £30,000 and £900,000 — the entire cost falls within AIA and attracts 100% first-year relief regardless of the special-rate label.
Worked example: capital allowances on a £200,000 solar system
A profitable limited company installs a 235kWp rooftop solar system for £200,000 and owns it outright (cash purchase, green loan, or hire purchase). The company pays corporation tax at the main 25% rate.
| Step | Calculation | Amount |
|---|---|---|
| Installed cost (qualifying expenditure) | Full system cost | £200,000 |
| Annual Investment Allowance claimed | 100% of cost (within £1m cap) | £200,000 |
| Corporation tax saving (year one) | £200,000 × 25% | £50,000 |
| Effective net cost of system after tax relief | £200,000 – £50,000 | £150,000 |
| SEG export income + energy saving (year one) | Typical 235kWp commercial site | £30,000–£42,000 |
The £50,000 of first-year tax relief is the single largest financial lever in the entire commercial solar business case. It is also the reason ownership structures (cash, green loan, hire purchase) usually beat leasing and PPA for profitable businesses: when you lease or sign a PPA, the lessor or developer claims this £50,000, not you.
Who claims the capital allowances under each finance route?
The single most important rule: only the legal owner of the asset can claim capital allowances. Your finance structure therefore decides whether you or the finance provider captures the relief.
| Finance route | Who owns the system | Who claims capital allowances | Your AIA benefit |
|---|---|---|---|
| Cash / capital purchase | You | You | Full 100% AIA |
| Green loan | You (from day one) | You | Full 100% AIA |
| Hire purchase | You (on final payment) | You (from contract start, once in use) | Full 100% AIA |
| Finance lease | Lessor | Lessor | None — reflected in lower rental |
| Operating lease | Lessor | Lessor | None — reflected in lower rental |
| Power Purchase Agreement (PPA) | Developer | Developer | None — reflected in discounted kWh rate |
Key planning point for profitable businesses
If your business has taxable profit to shelter, an ownership route (cash, green loan, or hire purchase) lets you keep the Annual Investment Allowance — worth 25% of the system cost in year-one corporation tax relief. On a £500,000 system that is £125,000. Leasing and PPA give this relief away to the finance provider. Only choose a lease or PPA when zero capital, off-balance-sheet treatment, or simplicity outweighs the lost tax relief — or when your business is not currently profit-making and cannot use the allowance.
How to claim capital allowances on solar panels
Capital allowances on solar: frequently asked questions
Can you claim capital allowances on solar panels?
Yes. Solar PV qualifies as plant and machinery, so a UK business that owns the system can claim the Annual Investment Allowance — 100% first-year corporation tax relief on the full installed cost, up to £1m per year. Spend above the cap attracts the 50% First Year Allowance with the balance at 6% per year. You must own the asset to claim: buy outright, use a green loan, or use hire purchase.
Are solar panels plant and machinery or a building structure?
The solar PV panels, inverters, cabling and mounting system are plant and machinery (special-rate pool) and qualify for AIA/FYA. Only genuinely structural elements — a new roof, ground-mount foundations, or civil works — fall under the Structures and Buildings Allowance at 3% per year. On a typical rooftop installation, almost the entire cost is plant and machinery, so AIA covers it.
Can a sole trader or partnership claim capital allowances on solar?
Yes. Capital allowances apply to income tax payers (sole traders, partnerships) as well as corporation tax payers. A sole trader claims the AIA against trading profit on the self-assessment return. The relief reduces income tax and Class 4 National Insurance. The same ownership rule applies — you must own the system, not lease it.
What if my business isn't making a profit yet?
If the AIA claim creates or increases a trading loss, you can carry the loss back one year (or forward indefinitely) to obtain relief against other profits. For groups, the allowance can shelter group profits. If your business genuinely cannot use the relief, a finance lease or PPA — where the provider claims the allowance and passes the benefit through a lower rate — may be more efficient than buying outright.
Is commercial solar tax deductible?
Yes — commercial solar is tax deductible in two distinct ways, and businesses frequently confuse them. The capital cost of the system is relieved through capital allowances (AIA at 100% in year one, as set out above). Separately, the ongoing running costs — operations and maintenance contracts, monitoring, insurance, and any loan or lease interest — are deductible as normal revenue business expenses against trading profit.
This dual deductibility is why the after-tax cost of commercial solar is substantially lower than the headline price. A profitable company buying a £200,000 system claims £50,000 of capital allowance relief in year one, then deducts maintenance and any financing interest annually thereafter. If the system is financed with a green loan, the loan interest is also deductible — so the business claims the full AIA on the asset and writes off the interest on the borrowing used to buy it. Leasing and PPA structures are deductible as operating expenses but do not give you the capital allowance, as the finance provider owns the asset.
There is no separate "solar tax credit" in the UK comparable to the United States Investment Tax Credit. UK relief comes through the capital allowances system — principally the AIA — plus the deductibility of running costs and the Climate Change Levy exemption on self-generated electricity. Combined, these reliefs typically recover 25–30% of the lifetime cost of a commercial solar system through the tax system.
Explore each capital allowance and tax relief
- Annual Investment Allowance (AIA): 100% first-year relief
- 50% First Year Allowance: spend above the AIA cap
- Commercial solar tax savings: AIA, FYA & CCL combined
- All commercial solar incentives and tax reliefs
- Green loans: borrow and still claim 100% AIA
- Hire purchase: spread cost, keep the allowance
- Public sector? PSDS grants instead of allowances
- All six commercial solar financing routes
Maximise your solar capital allowances claim
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