Freeport & Capital Allowances: The 2026 Tax Case for Warehouse Solar

Updated July 2026.

For a UK company, warehouse solar qualifies for the £1m Annual Investment Allowance (100% first-year relief), with a 50% First-Year Allowance on spend above that - but because solar is special-rate plant and machinery, the headline “full expensing” relief does not apply to it. Units sitting inside a designated Freeport or Investment Zone special tax site can instead claim 100% Enhanced Capital Allowances on new plant. On top of the allowances, the VAT is 20% and reclaimable (there is no 0% rate for commercial), the solar and battery plant is exempt from business rates in England to 2035, and surplus export earns money under the Smart Export Guarantee. This guide sets out the whole tax case, corrects the errors most installers make, and works a full net-of-tax example on a 250 kW system.

The short version: the 2026 tax stack

If you take one thing from this page, take this: for most warehouse operators, a profitable company writes off the entire cost of a solar system against its taxable profit in the first year - but through the Annual Investment Allowance, not “full expensing”. The two get confused constantly, and getting it wrong changes the numbers.

Here is the stack that applies in 2026, all verified against government sources:

• Annual Investment Allowance (AIA): 100% first-year relief on up to £1,000,000 of qualifying plant and machinery per year. Solar PV qualifies, so a system under £1m is fully deducted from taxable profit in year one.
• 50% First-Year Allowance (FYA): for spend above £1m, a company can claim 50% in year one, with the balance going into the 6% special-rate pool.
• Why not full expensing? Full expensing (100%, uncapped) is a main-rate relief. Solar is special-rate plant, which is expressly excluded from full expensing. Do not let anyone quote you full expensing on solar.
• Freeport / Investment Zone ECAs: inside a designated special tax site, new and unused plant qualifies for 100% Enhanced Capital Allowances - an uncapped alternative to the £1m AIA ceiling.
• VAT: commercial solar is standard-rated at 20%, and a VAT-registered business reclaims it. The 0% rate is domestic-only and does not apply to a warehouse.
• Business rates: on-site solar and co-located storage are exempt from business rates in England to 31 March 2035.
• Smart Export Guarantee (SEG): surplus export (up to 5 MW) is paid at supplier-set rates.
• The IETF is closed. The Industrial Energy Transformation Fund has no open 2026 competition - ignore any advice that treats it as a live grant.

Annual Investment Allowance: the £1m, 100% route

The Annual Investment Allowance is the workhorse of warehouse-solar tax relief. It gives a business 100% first-year relief on qualifying plant and machinery, up to a permanent annual cap of £1,000,000. Solar PV is qualifying plant, so the AIA lets a profitable company deduct the whole capital cost of a sub-£1m system from its taxable profit in the year the expenditure is incurred.

The mechanics matter for the cash saving:

• The deduction reduces taxable profit, so the value of the relief is the capex multiplied by your corporation tax rate. At the main rate of 25%, £200,000 of qualifying spend written off under AIA is worth £50,000 off your tax bill.
• The £1m cap is per year, per business (with grouping rules for associated companies). Most single-warehouse arrays - a 250 kW system runs to roughly £190,000-£220,000 - sit comfortably inside it and are fully relieved.
• The relief is claimed on your corporation tax return for the accounting period in which the expenditure is incurred.

The authoritative reference is the Annual Investment Allowance guidance on gov.uk. If your project is under £1m and your company is profitable, AIA is almost always the route: 100% relief, no special-tax-site requirement, no uncapped-but-slower waiting for pool write-down.

Above £1m: the 50% First-Year Allowance

If your capex exceeds the £1m AIA ceiling in a single year - a large fulfilment or multi-site rollout, say - the excess does not simply wait years to be relieved. Solar qualifies for the 50% First-Year Allowance for special-rate expenditure:

• The first £1m is covered by AIA at 100%.
• The next tranche attracts the 50% FYA - half is deducted in year one.
• The remaining 50% drops into the special-rate pool and is written down at 6% a year on a reducing-balance basis.

So a £1.4m system is relieved as: £1m fully written off (AIA), plus 50% of the remaining £400,000 (£200,000) in year one under FYA, with the final £200,000 written down at 6% per annum thereafter. The capital allowances framework on gov.uk sets out the first-year rules. The key point for planning is that the great majority of the relief still lands in year one, even above the AIA cap.

Why full expensing does NOT apply to solar

This is the single most common tax error in warehouse-solar sales material, and it is worth being precise about because it changes what you can claim.

Full expensing is the 100%, uncapped first-year deduction the government made permanent for companies - but it applies only to main-rate plant and machinery. Solar panels are classed as integral features / special-rate expenditure, which is specifically excluded from full expensing. For special-rate assets the analogue is the 50% First-Year Allowance, not full expensing.

In practice, for a warehouse operator this means:

• Under £1m: you use AIA to get to 100% first-year relief. (AIA is category-agnostic - it covers special-rate plant, so the special-rate exclusion from full expensing does not cost you the 100%.)
• Over £1m: the excess gets the 50% FYA, not 100% full expensing.

If a proposal claims you can “fully expense” a solar array, treat the whole document with caution - it has the tax classification wrong. The correct framing is: AIA to £1m at 100%, then 50% FYA above, with solar as special-rate plant.

Freeport & Investment Zone Enhanced Capital Allowances

For the minority of warehouses that sit inside a designated special tax site, there is a more generous option than AIA: the Enhanced Capital Allowance (ECA). A company investing in new and unused plant and machinery for use primarily within a designated Freeport or Investment Zone tax site can claim 100% first-year relief with no £1m cap.

The eligibility rules are strict, and this is where sites go wrong:

• Designated tax site only. ECAs apply only inside the specific designated sub-areas of a Freeport - not the whole Freeport outer boundary, and not the surrounding travel-to-work area. You must confirm your unit’s location against the published tax-site maps.
• New and unused plant. Second-hand or transferred equipment does not qualify.
• Time-limited windows. The relief is available for English Freeport tax sites to 30 September 2031, and for Scottish and Welsh Freeport sites and Investment Zone tax sites to 30 September 2034.

The designated English Freeports include Felixstowe & Harwich, Humber, Liverpool City Region, Teesside, Thames, Solent, East Midlands (with East Midlands Airport / DIRFT logistics land), and Plymouth & South Devon - several of which sit squarely in prime logistics geography. Check your eligibility against the Freeport enhanced capital allowances guidance on gov.uk before assuming you qualify. Bonded, customs and Freeport warehousing is precisely where this bites - see our bonded, customs & Freeport warehousing page for the operational picture.

For a company already at or above the £1m AIA ceiling, an ECA on a tax-site array is materially better because it is uncapped. For a sub-£1m project, AIA and ECA both deliver 100% in year one, so the ECA route mainly matters at scale.

VAT: 20% and reclaimable - not 0%

A second frequent error: the 0% VAT rate does not apply to a warehouse. Zero-rating for solar is a domestic relief. Commercial solar - anything installed on a business warehouse - is standard-rated at 20%.

The practical position for a VAT-registered operator:

• You pay 20% VAT on the installed cost.
• You reclaim it as input VAT through your normal VAT return, assuming the system serves taxable business activity.
• The net cash cost of the system is therefore the ex-VAT figure - but the VAT is a genuine cash-flow item between payment and reclaim, so build it into your funding plan.

Any quote showing 0% VAT on a warehouse install is wrong and should be queried. The correct number is 20%, reclaimable.

Business rates exemption and the Smart Export Guarantee

Two further reliefs sit alongside the allowances.

Business rates exemption. On-site renewable generation and co-located battery storage plant are exempt from business rates in England from 1 April 2023 to 31 March 2035. This removes a recurring running-cost objection: adding solar to a rated warehouse does not add a rateable value line for the generating plant during the exemption window. See the business rates overview on gov.uk.

Smart Export Guarantee. Under the Smart Export Guarantee (Ofgem), an MCS-certified system up to 5 MW is paid for surplus electricity it exports to the grid. Rates are set by suppliers (they must be above zero), not fixed by Ofgem - typically a few pence to around 15p/kWh on flat commercial tariffs, and negotiable at scale. For genuine daytime warehouse operations, export is small because self-consumption dominates; for low-base-load or shift-only sites (self-storage, single-shift ambient) a competitive SEG tariff becomes a meaningful part of the return. These figures are indicative and should be confirmed with suppliers before you model them.

Worked example: a 250 kW warehouse system, net of tax

Here is the whole tax case pulled together on a representative 250 kW rooftop array for a profitable UK company paying corporation tax at the 25% main rate. All figures are indicative planning-grade and rounded; a fixed position follows a roof and meter survey and should be confirmed with your accountant.

Assumptions

• System size: 250 kW
• Indicative installed cost (ex-VAT): £210,000
• VAT at 20%: £42,000 - paid, then reclaimed through the VAT return (net-neutral over the cycle)
• Corporation tax rate: 25% (main rate)
• Funding: cash purchase, project under the £1m AIA cap
• Annual generation: ~225,000 kWh (≈900 kWh/kWp)

The tax relief (standard site - AIA route)

Line	Amount
Qualifying capex (ex-VAT)	£210,000
AIA first-year deduction (100%)	£210,000
Corporation tax saved (25% × £210,000)	£52,500
Effective net-of-tax capital cost	£157,500

So a £210,000 array costs a profitable company an effective £157,500 once the year-one AIA relief is taken - roughly a 25% reduction in the real cost of the asset. The VAT is reclaimed separately and nets out.

If the same unit sits in a designated Freeport tax site

The relief is the same 100% in year one here (because the project is under £1m, AIA already delivers 100%), so the ECA changes nothing on a project this size. The ECA advantage appears only above the £1m AIA cap, where the 100% ECA beats the 50% FYA. For a single 250 kW system, AIA and ECA are equivalent - the Freeport benefit is a scale benefit.

What the reliefs do not do

They do not change the energy economics - the ~£40,000-£50,000 a year of avoided electricity cost (driven higher by the ~60% TNUoS network-charge rise in April 2026) and any SEG export income sit on top of the tax saving. The allowances simply cut the effective capital cost of getting there. Combine the year-one tax relief, the business-rates exemption, and the avoided energy cost, and a well-sized warehouse array typically pays back in roughly 3-6 years self-funded. See our cost page for the full per-kW pricing ladder and payback modelling, and our grants and funding page for the complete funding picture including PPA and asset-finance routes.

A note on the IETF - and on “grants” generally

You may still see the Industrial Energy Transformation Fund (IETF) cited as a solar grant. It is closed - there is no open 2026 competition and no announced successor - so do not build a funding plan around it. For warehouse solar in 2026, the real levers are tax reliefs, not cash grants: the AIA/FYA allowances, the Freeport/Investment Zone ECAs where eligible, the business-rates exemption, VAT reclaim, and the SEG. That is a good-news story for a profitable company, because tax relief is faster and more certain than a competitive grant round.

If you operate on a lease and cannot use the capital allowances yourself, a Power Purchase Agreement moves the asset (and the allowances) to a third-party funder and you simply buy the daytime power below grid price - the tenant route covered on our grants and funding page and relevant to most 3PL and contract logistics operators.

Get the numbers for your site

The tax case is strong in 2026 - but every figure above is a planning-grade indicative number, and the reliefs depend on your profitability, your tenure, and whether your unit sits in a designated tax site. We model cash, asset finance and PPA side by side, with the year-one allowance, the VAT position, the business-rates saving and the SEG income shown for each, and we check Freeport/Investment Zone eligibility for every applicable site.

Get a warehouse solar quote with a full net-of-tax breakdown for your unit - sized from your half-hourly data, priced to your roof, and modelled against the 2026 tax stack.

This guide is general information, not tax advice. Confirm your specific position with your accountant or tax adviser before committing capital. All figures are indicative and planning-grade.