Commercial Solar Grants and Tax Relief in 2026

What support actually exists for commercial solar in 2026

There is a persistent myth that UK businesses get a cheque in the post for installing solar. That is not how commercial solar grants work. The real support in 2026 is a mix of tax relief, export income and a handful of targeted grant schemes aimed at specific sectors. Get the mix right and the effective cost of a system falls sharply, often by a quarter or more before a single kilowatt-hour is generated.

This guide sets out every route worth knowing, what each is actually worth, and who qualifies. It uses real figures, not sales talk. If you want the full pricing picture alongside the funding, our cost guide breaks down per-kWp rates across the 30 kW to 1 MW range, and every route below is covered in more detail on the grants and funding page.

100% Annual Investment Allowance: the biggest lever

For most profitable companies, the single most valuable form of support is not a grant at all. It is the 100% Annual Investment Allowance (AIA). Solar PV counts as plant and machinery, so a business can deduct the full capital cost from its taxable profit in the year the system is installed, up to the £1m AIA cap per year.

Because the deduction reduces taxable profit rather than the price, the value depends on your corporation tax rate. For a profitable limited company paying the main 25% rate, AIA effectively knocks roughly 25% off the net cost of the system. A £200,000 warehouse array reduces taxable profit by £200,000, saving around £50,000 in corporation tax. Most commercial installs sit well below the £1m cap and are fully expensed in year one. Companies spending above the cap can use Full Expensing as an alternative route.

Two caveats matter. AIA only helps a business that is making a taxable profit, so a loss-making company or a charity gets no benefit from it. And the timing follows the accounting period, so it is worth speaking to your accountant about when the system is commissioned relative to your year end.

VAT: reclaimable, not zero-rated

This is where commercial and domestic solar are commonly confused. Homeowners currently pay 0% VAT on solar because of a domestic-only relief. That relief does not apply to businesses.

For a VAT-registered business the position is different but still favourable. You pay VAT on the installation and then reclaim it through your normal VAT return, in the same way you reclaim VAT on any other business asset. The net effect for a fully taxable business is that the system costs the ex-VAT price. Businesses that are not VAT-registered, or that are partly exempt, cannot reclaim in full and should factor the irrecoverable portion into their model.

Smart Export Guarantee: getting paid for surplus

Not every unit a commercial system generates is used on site. A daytime-occupied building typically consumes 55% to 75% of its solar directly, and buildings without round-the-clock demand, such as offices, retail and schools, export 25% to 45% of what they generate.

The Smart Export Guarantee (SEG) is the mechanism that pays for that surplus. Any MCS-certified installation up to 5 MW exporting to the grid qualifies. Tariffs vary by supplier and typically pay between 4p and 15p per kWh. That is a wide range, so shopping the SEG tariff is worth real money. For a building that exports a meaningful share of its output, a competitive SEG rate is a genuine part of the economics rather than a rounding error. You can model export income properly with our savings calculator.

Sector-specific grants that actually pay out

Beyond tax relief and export income, a small number of grant schemes provide direct funding. They are targeted, competitive and open and close in windows, so the right one depends entirely on what kind of building you run.

• Industrial Energy Transformation Fund (IETF). Aimed at energy-intensive manufacturing and industrial sites in England, Wales and Northern Ireland. Grants start from around £100,000 and run in competitive phases. Best suited to larger factory and process-heavy installs. Check the current open window before you plan around it.
• Public Sector Decarbonisation Scheme and Salix. The primary route for schools, the NHS, colleges and councils. It provides grant funding and interest-free loans covering solar and wider decarbonisation, and it is applied for centrally by the public body rather than by the installer.
• Regional and combined-authority business grants. Authorities such as GMCA, WMCA, WYCA and LCRCA periodically run SME decarbonisation grant rounds, typically worth £5,000 to £50,000 per business. These open and close without much notice, so it is worth checking your combined authority or Growth Hub before committing to a funding route.

If you run an energy-intensive plant, the IETF plus AIA combination is the strongest hand available. Our manufacturing and factories page covers how that stacks up alongside the high self-consumption these sites enjoy. Public bodies should read the public sector and education page for the Salix and PSDS process.

Grant and relief routes compared

Different mechanisms suit different organisations. This table sets out who each route helps and what it is broadly worth.

Route	Who it suits	Rough value	Applied for by
100% Annual Investment Allowance	Profitable companies paying corporation tax	About 25% of capex saved in year one	Your business, via tax return
VAT reclaim	VAT-registered businesses	The full VAT element, recovered	Your business, via VAT return
Smart Export Guarantee	Any MCS install exporting surplus	4p to 15p per kWh of export	Your energy supplier
Industrial Energy Transformation Fund	Energy-intensive manufacturers	Grants from £100,000 upward	Your business, competitive bid
Salix and PSDS	Public sector, schools, NHS, councils	Grants and interest-free loans	The public body centrally
Regional SME grants	Small and medium businesses by region	£5,000 to £50,000 typically	Your business, via the authority

Funding the rest: cash, finance or PPA

Grants and tax relief rarely cover the whole project, so the remaining capital has to be funded somehow. There are three routes, and an honest installer models all three side by side rather than pushing one.

• Cash purchase. You own the system outright from day one, capture the full AIA benefit, and see the fastest return. Simple payback for a daytime-occupied building is typically 5 to 8 years, after which the system delivers 15 to 20 years of near-free power under its 25-year performance warranty.
• Asset finance. The cost is spread over 5 to 7 years. In most cases the finance payment is smaller than the bill saving it replaces, so the project is cash-flow positive from month one, and you own the system at the end.
• Power Purchase Agreement (PPA). A funder installs and owns the system and you simply buy the power it generates at a fixed rate below grid. It needs zero capex, though the funder rather than your business captures the tax relief.

The comparison below shows the trade-offs.

Funding route	Upfront capex	Captures AIA	Owns the system	Best for
Cash purchase	Full cost	Yes	You, from day one	Profitable firms with capital to deploy
Asset finance	None to low	Yes	You, at term end	Firms wanting ownership without tying up cash
PPA	None	No, funder does	Funder, until any buyout	Organisations that cannot or will not fund capex

Which route wins depends on your tax position, your appetite to own an asset, and how long you expect to hold the building. We model cash, finance and PPA on every quote with the IRR for each, so the decision is made on numbers rather than a pitch. The FAQs cover the common questions on tenure, selling the building and settling finance early.

PV only or PV plus battery

Funding decisions also interact with system design. Adding battery storage changes the amount of grid electricity you displace, which changes both the saving and the payback. For a building with meaningful evening, weekend or overnight demand, storage typically lifts self-consumption from the 55% to 75% range up to 80% to 95%, and adds roughly 25% to 40% to annual savings. It also lengthens the payback, because the battery is additional capital that does not attract export income.

Option	Self-consumption	Effect on saving	Effect on payback	When it makes sense
PV only	55% to 75%	Baseline	Shortest, 5 to 8 years	Strong daytime load, little evening demand
PV plus battery	80% to 95%	Up to 25% to 40% higher	Longer, extra capital	Evening, weekend or overnight demand, or resilience

The battery earns its keep in hospitality, retail with refrigeration, and any site with load outside daylight hours. We design every system to be battery-ready even where storage is not installed on day one, so you can add it later without reworking the array.

How much does the support actually save

Put the pieces together and the numbers become concrete. Take a 250 kW warehouse system with a headline cost of around £190,000 to £240,000. A profitable company reclaims the VAT, then deducts the full capital under AIA, cutting the effective net cost to roughly three-quarters of the headline figure. On top of that, the surplus it exports earns SEG income for 20 years, and the bill saving is a permanent hedge that grows every time grid prices rise.

The support does not make solar free. What it does is turn a strong capital project into a very strong one, pulling a typical commercial payback down toward the 5-year end of the 5 to 8 year range for high self-consumption sites. That is the honest position, and it is more than good enough without exaggeration.

Getting the funding stack right for your building

The correct mix of grants, relief and finance is specific to your tax position, your building type and your consumption shape. A loss-making company gains nothing from AIA but might still stack a PPA with a regional grant. An energy-intensive factory should chase the IETF window. A school routes everything through Salix and PSDS. There is no single answer, which is exactly why generic comparison sites are unhelpful here.

If you want a model built from your actual half-hourly meter data, with cash, finance and PPA compared and every applicable grant flagged, request a free quote. We will tell you honestly which routes apply to your organisation and which do not.