2026 Update: PSDS & IETF closed. AIA gives 100% year-one relief on solar. 2026 active stack still delivers 40–60% effective subsidy. See 2026 grants →

UK data centre solar — May 2026

Solar funding for UK data centres: AIA, PPAs and the post-IETF stack.

UK data centres are exceptional self-consumption sites — 24/7 IT-load demand, large rooftops or adjacent land for ground-mount PV. With customer-driven decarbonisation pressure and PPA economics that scale, data centres now drive 15-20% of UK commercial solar capacity additions.

Why data centres are now central to UK commercial solar

UK data centre demand has tripled since 2018 driven by cloud growth and AI capacity expansion. Hyperscale operators (AWS, Microsoft, Google), colocation providers (Equinix, Digital Realty, Iron Mountain) and UK-specialist operators (Pulsant, Kao Data, Virtus, Next Generation Data) collectively run a UK estate that consumes more than 12 TWh/year of electricity in 2026 — approximately 3.5% of UK total electricity demand.

Customer and regulatory pressure to demonstrate renewable supply is intense. Most major data centre operators have made 100%-renewable supply commitments under the Climate Pledge or equivalent. Solar PV — both on-site and via sleeved off-site PPAs — is now central to delivering those commitments.

The 2026 funding stack for UK data centres

What's still active by region:

  • Scotland — SIETF closed in March 2025 (it covered up to 30% of capex, 50% deep decarbonisation, in past calls). Scottish data centres benefit from cooler ambient temperatures (lower cooling load), driving recent expansion in central Scotland. SIETF closed in March 2025.
  • England — English IETF closed for new applications after Spring 2024. Active stack: AIA + SEG + PPA. PPA is the dominant route at data centre scale because of operator covenant strength and project size.
  • Wales — Welsh Industrial Decarbonisation programmes are active. Next Generation Data at Newport (the largest UK data centre by floor area) has been a notable beneficiary.
  • Northern Ireland — Invest NI Capital Grants are case-by-case for major data centre developments.

On-site PV vs sleeved off-site PPA

Two distinct routes that most major UK data centre operators are using together:

On-site rooftop and ground-mount PV

Direct generation behind the data centre's electrical supply. Typical scale 500kWp-5MWp depending on roof area and adjacent land. Self-consumption rates exceptional (60-95%) because of 24/7 IT-load. Funded under AIA or PPA.

Sleeved off-site PPA

For the larger volumes that on-site can't deliver, sleeved PPAs allocate output from a remote ground-mount solar farm to the data centre's electricity supply contractually. Tariffs are weaker than on-site (10-13p/kWh against on-site PPAs at 6-9p) but the volumes can scale much higher. Most hyperscale operators now run combined on-site + sleeved structures targeting 70-100% renewable supply.

Battery storage and grid services

Data centres are increasingly significant participants in UK grid services markets (Balancing Mechanism, Demand Flexibility Service, Dynamic Frequency Response). UPS batteries can provide grid services revenue alongside their primary backup function. Adding solar PV creates a behind-the-meter system that combines self-consumption, peak shifting and grid services. Aggregators like Flexitricity, GridBeyond, Limejump are active across the UK data centre market.

Related

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Data centre solar FAQs

Are UK data centres eligible for solar grants?
Scottish data centres were eligible under SIETF (none open that we found; the last call closed in March 2025). English data centres were IETF-eligible for efficiency and decarbonisation projects, but the IETF never funded solar PV and closed in July 2025 with no successor; data-centre solar now runs on the AIA then the 50% special-rate FYA, plus PPAs. Welsh data centres access Welsh Industrial Decarbonisation programmes. Northern Irish data centres access Invest NI Capital Grants. Across all regions, the dominant funding mechanism for UK data centre solar in 2026 is Power Purchase Agreement structures because of project scale (typically 1-10MWp) and operator covenant strength.
What size solar PV does a typical UK data centre need?
Data centre electricity demand is exceptional — a 10MW IT-load data centre uses 90+ GWh/year (with cooling). On-site solar PV typically targets 5-15% of annual demand because of roof area constraints. Typical UK data centre solar projects are 500kWp-5MWp on rooftop, plus ground-mount where adjacent land is available. Several major hyperscale data centres are now combining on-site PV with sleeved off-site PPAs for substantially larger renewable supply percentages.
Do data centres have specific decarbonisation pressure?
Yes — significantly more than most UK commercial sectors. Data centres are under regulatory and customer pressure to demonstrate renewable supply. Climate Pledge signatories (Microsoft, Amazon Web Services, Google) have made public 100%-renewable commitments by specific dates. Major UK data centre operators include Equinix, Digital Realty, Iron Mountain, Virtus Data Centres, Kao Data, Pulsant. Most are several years into multi-MWp PPA + on-site PV rollouts.
Where are UK data centres concentrated?
London and Slough form the largest UK data centre cluster (the "Slough corridor"). Other concentrations include Manchester (Reynolds House, Salford Quays), Cardiff (Next Generation Data, the largest UK data centre), Edinburgh (Pulsant), and increasingly the M62 corridor. Scottish data centres benefit from cooler ambient temperatures (lower cooling load); SIETF, which closed to new applications in March 2025, is no longer a route.
Can data centres use battery storage with solar?
Yes, and battery storage is increasingly standard in UK data centre solar. Two driving factors: (1) data centres already have substantial UPS battery infrastructure, so adding behind-the-meter solar batteries is a smaller incremental step, (2) data centre demand is genuinely 24/7 — battery storage shifts solar generation into overnight self-consumption, lifting self-consumption from typical 60-75% to 85-95%. Battery analysis.

Funding by asset class

The allowance depends on the asset, and most pages on this topic get it the wrong way round. Solar PV is special-rate expenditure (HMRC Capital Allowances Manual CA22335), so the 100% year-one route is the Annual Investment Allowance — Full Expensing is a main-rate measure and does not reach it. Battery storage, EV charging and heat pumps are Heat pumps for space or water heating are special-rate: AIA, then the 50% FYA. Standalone batteries are probably main-rate (full expensing for companies), but HMRC has no specific guidance; confirm with your adviser.

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What you get
  • 1. A short written funding note naming every scheme your site qualifies for in 2026 — and the ones it does not.
  • 2. Indicative system size and a capex band for your roof.
  • 3. Year-one tax treatment per asset in £ — solar is special-rate expenditure, so the route is the Annual Investment Allowance; heat pumps for building heating are also special-rate integral features, and standalone battery storage is probably main-rate plant (HMRC has no specific guidance, so confirm with your adviser). Most pages get this the wrong way round.
  • 4. Projected SEG export revenue at current rates.
  • 5. Any red-flag eligibility or DNO issues we can see up front.

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