UK guide — May 2026

How to apply for a commercial solar grant in the UK — step by step.

The major direct grants of recent years (IETF, PSDS, UKSPF) have closed to new applications. The active 2026 routes — REPF, Local Growth Fund, Salix loans, Scottish IETF, GBE Community Fund — each have distinct application processes. This is the working guide.

Step 1 — Identify the right route for your project

The first and most important decision in any commercial solar grant application is choosing the right scheme. Wrong-scheme applications waste 8-12 weeks of effort and assessor goodwill. The active 2026 routes by sector and geography:

UK manufacturers (English/Welsh) — IETF closed. Use Full Expensing alone or with a competitive PPA. No grant application needed.
UK manufacturers (Scottish) — Apply for Scottish IETF (SIETF) via Scottish Government / Scottish Enterprise.
Public sector bodies (NHS, councils, schools, FE) — PSDS closed. Apply for Salix interest-free loans via Salix Finance portal. LCSF for HDP funding.
Rural enterprises (farms, food processors, country hotels) — Apply for REPF via your local council\'s economic development team.
Businesses in 11 Mayoral Authority areas — Apply for Local Growth Fund via the relevant Mayoral Authority investment plan.
Community-led organisations (charities, faith buildings, social clubs) — Apply for GBE Community Fund via Great British Energy.
Welsh manufacturers — Apply for Welsh Industrial Decarbonisation funding via Welsh Government.
Northern Irish businesses — Apply for Invest NI Capital Grants (case-by-case).
Tax allowances (Full Expensing, AIA, 0% VAT) — No application; claimed automatically.

Step 2 — Pull half-hourly meter data and run the energy audit

Every UK commercial solar grant application requires energy data. The standard expectation is 2-4 years of half-hourly meter data, broken down by load type. This is what funders use to validate that the project sizing is sensible and that solar will actually displace material electricity.

Not sure which grants apply to your business? Use the grant eligibility checker to find out in 60 seconds. Half-hourly data is typically obtained from your electricity supplier (Octopus, EDF, British Gas, etc.) on request. Larger commercial sites have it as standard with their MIC (Maximum Import Capacity) contracts. We pull this data as the first step of any client engagement and run an energy audit identifying load patterns, daytime vs overnight demand, weekend operation, seasonal variation. The audit informs system sizing and the funder narrative.

Step 3 — Build the MCS-compliant system design

Funders want to see a properly engineered design — not a back-of-envelope sizing. The standard documentation:

System sizing rationale tied to half-hourly demand profile
Module and inverter selection (Tier 1 modules, commercial-grade inverters)
PVsyst yield assessment for the specific site latitude, orientation and shading
Mounting structure specification
Single-line electrical diagram showing AC connection
G99 DNO application status
Structural assessment (engineer\'s report on roof load capacity)

Step 4 — Build the financial model

Funders score on net economics, not gross. The financial model must show:

Headline capex broken down by line (panels, inverters, mounting, DNO, install, design, contingency)
Annual generation (kWh/year, year by year for 25 years with degradation)
Self-consumption rate from half-hourly modelling
Annual savings (electricity displacement + SEG export)
Tax effects (Full Expensing/AIA on net of grant)
Three energy price scenarios (base, upside, downside)
NPV at funder-specified discount rate (HM Treasury Green Book 3.5% real for public sector)
IRR and payback period
Sensitivity analysis

Step 5 — Write the funder-specific narrative

This is the highest-leverage part of the application. Each scheme rewards different scoring criteria:

REPF

Productivity outcomes — jobs created or supported, contract revenue enabled, GVA contribution, rural enterprise diversification. Decarbonisation is a secondary factor. We have written REPF narratives that anchored on contract grain-drying enabling 2 seasonal jobs as the primary scoring driver.

Local Growth Fund

Local economic outcomes aligned to the relevant Mayoral Authority\'s investment plan themes. Cluster fit — for sites in named clusters (Aire Valley logistics in WYCA, Atom Valley in GMCA, AMRC in SYMCA), narrative alignment with cluster strategy strengthens scoring. Authority-specific net zero milestones if the authority has a target ahead of 2050.

Salix BAU loans

Loan repayment from energy savings — the financial model must show savings cover repayments with margin. Savings calculation methodology aligned to Salix preferred metrics. Project timeline tied to public sector procurement frameworks.

Scottish IETF

Carbon savings per pound of grant (tCO2e/£100k) — this is the single number SIETF assessors anchor on. Bundled measures (PV + heat + process electrification) score higher than standalone PV. Deep Decarbonisation route requires specific narrative on pathway alignment.

Step 6 — Submit and manage clarifications

Submission is via the funder\'s portal (each scheme has its own). After submission, expect 4-12 weeks of funder review. Most funders raise clarification questions during review — typically focused on energy data interpretation, monitoring methodology, and supplier quotation quality. Most clarifications resolve within 48 hours of being raised. Award decisions come as a batch at window close.

Step 7 — Award, contract and milestone delivery

On award, the funder issues a grant funding agreement covering deliverables, milestones, monitoring requirements and clawback conditions. Project delivery typically runs 12-16 weeks for sub-1MW commercial rooftop projects. Grant funding draws down against actual milestones, with monitoring & verification (M&V) continuing for 18-36 months post-commissioning.

What we do for clients

The free funding review takes 4 minutes. We come back within one working day with a written shortlist of routes you would credibly use, the documentation needed for each, and the realistic timeline. Engagement fees only kick in if you ask us to write the application — initial scoping is always free.

Free funding review

See which grants your business qualifies for — free 20-minute funding review.

Tell us your sector, roof size and energy spend. We come back within one working day with a shortlist of grants and the realistic capex you can expect to recover.

Start Funding Review Call 020 4525 6101

No obligation. We don't charge for grant scoping.

Application FAQs

How do I apply for a UK commercial solar grant in 2026?

The application process depends on which grant route applies to your business. The active 2026 routes and their application processes: REPF — apply via your local council's economic development team. Local Growth Fund — apply via the relevant Mayoral Authority's investment plan portal. Salix BAU loans — apply via the Salix Finance portal. Scottish IETF — apply via the Scottish Government's SIETF portal during open windows. GBE Community Fund — apply via Great British Energy directly. Tax allowances (Full Expensing, AIA, 0% VAT) and SEG — no application required.

What documents do I need for a commercial solar grant application?

For competitive grants (REPF, Local Growth Fund, Salix BAU loans, Scottish IETF), the standard document set includes: (1) Energy audit referencing 2-4 years of half-hourly meter data, (2) MCS-compliant PV system design with PVsyst yield model, (3) Three supplier quotes for the work, (4) Financial model showing capex, opex, payback, IRR and NPV, (5) Carbon savings narrative (tCO2e per pound of grant — the metric assessors anchor on), (6) Business case anchoring on the funder's scoring criteria (productivity for REPF, local economic outcomes for Local Growth Fund), (7) Decarbonisation roadmap or Heat Decarbonisation Plan where applicable.

How long does a commercial solar grant application take?

For competitive grants, allow 6-10 weeks of preparation effort and 8-12 weeks of funder review. Total kickoff to grant decision: 16-22 weeks. Tax allowances and SEG sign-up are immediate — no application timeline. We can compress preparation to 4-6 weeks for clients with clean half-hourly meter data and an existing decarbonisation strategy document.

What's the success rate for UK commercial solar grant applications?

Our 24-month success rate across REPF, Salix and Scottish IETF applications is 92%. The wider UK market success rate for unsupported applications (no specialist consultancy) is roughly 35-50% depending on scheme. The difference comes from three things: (1) only applying for routes the project genuinely fits, (2) anchoring the application narrative on the funder's actual scoring criteria, (3) ensuring all documentation is complete and consistent before submission.

Do I need a consultant to apply for a UK commercial solar grant?

No, but it materially improves outcomes for £150k+ projects. Specifically: assessors score on funder-specific criteria that aren't obvious from public guidance; the technical documentation (energy audit, PVsyst yield modelling, financial model) takes specialist effort to produce correctly; and the application timeline competition for Local Growth Fund or Scottish IETF means well-prepared submissions land in pole position. We work on a fixed-fee or success-fee basis — no charge for initial scoping.

What happens if my commercial solar grant application is rejected?

For most schemes, you can resubmit in the next window with a strengthened application. Funders typically provide feedback identifying scoring weaknesses. About 40% of our resubmitted applications succeed on second attempt. The most common rejection reasons: (1) energy data thin or inconsistent, (2) decarbonisation narrative under-developed, (3) financial model assumptions over-optimistic on energy prices, (4) wrong scheme route chosen for the project type.