Why the right grant stack matters
UK office solar grant stacks compound. A well-structured proposal applies tax relief (AIA or FE) on year-one capex to reduce post-tax cost by 25%, layers capital grant funding (PSDS for public sector, IETF for industrial-context offices) where eligible, captures revenue stream from SEG exports, and may use government-guaranteed debt (UKIB, RLS) to spread cash flow.
The difference between a clinically-structured grant stack and a "we'll just claim AIA and the rest is too much hassle" approach is typically 15-35% of effective capex on public-sector and industrial-context office projects. We map every applicable route in the free feasibility study and draft applications on qualifying schemes (PSDS, IETF, WCS, UKIB).
The eight routes — by category
Tax relief (every UK office)
Tax relief
Annual Investment Allowance (AIA)
100% first-year deduction up to £1m
All UK businesses (Ltd, LLP, sole traders)
Read more →Tax relief
Full Expensing (FE)
50% first-year deduction (special-rate pool — covers solar PV)
Limited companies only
Read more →Capital grants (sector-specific)
Grant
Salix PSDS Phase 4
Up to 100% capex grant
Central government, NHS, local authority, FE/HE, schools
Read more →Grant
Workplace Charging Scheme (OZEV)
£350/socket × 40 sockets max = £14,000
Any UK business with off-street parking
Read more →Grant
Industrial Energy Transformation Fund (IETF)
Up to 30% capex grant (max £6m)
Industrial sites in England (incl. R&D HQs)
Read more →Revenue streams
Debt finance (cash-flow tools)
Debt finance
UK Infrastructure Bank (UKIB)
£5m-£100m debt finance, below-market rates
Larger commercial projects (£5m+)
Read more →Debt finance
Recovery Loan Scheme (RLS)
Up to £2m, 70% government-guaranteed
UK SMEs (turnover <£45m)
Read more →How the stack works in practice
Three worked examples of grant stacking on typical UK office projects:
Example 1: Private-sector multi-let landlord, £300k capex
- AIA on full £300k → £75k year-one corporation tax relief
- Effective net capex: £225k
- SEG revenue (~20% export): £4-7k/year
- Workplace EV chargers (12 × 22kW): £4,200 WCS grant on £45k EV capex
- Total relief / contribution: £79k+ (26% of solar capex)
Example 2: NHS Trust administrative HQ, £600k capex
- Salix PSDS Phase 4: up to 100% capex grant — £600k
- SEG revenue: £6-8k/year
- Workplace EV chargers: £4,200 WCS grant
- Net capex impact on Trust budget: £0 (PSDS-funded). Pure delivery cost.
Example 3: Office-in-industrial-park R&D HQ, £1.2m capex
- IETF Phase 3 grant: up to 30% capex = £360k
- AIA on remaining £840k → £210k corporation tax relief
- UKIB debt finance (optional): below-market rate, 25-yr term on £500k
- SEG revenue: £15-20k/year
- Total grants / relief / capex offset: £570k+ (48% of capex)
Application timelines
Grant application timelines vary materially. Plan into the overall project programme:
- AIA, FE, SEG: No application — claimed via Corporation Tax return / DNO registration. Zero timeline impact.
- WCS: Voucher application 5-10 working days; voucher valid 4 months. Trivial.
- Salix PSDS Phase 4: Annual application window typically January-March. Funding awards by June. Project must complete within 12-18 months of award. Plan 6+ months for application drafting.
- IETF Phase 3: 2-3 application windows per year. 4-6 month assessment. Project must complete within 24 months of award.
- UKIB: Initial pitch + advisory engagement 4-8 weeks; credit application + committee approval 8-16 weeks total.
- RLS: Standard commercial lender timeline 2-6 weeks dependent on lender appetite.
What we provide
For every office solar proposal we map the optimal grant stack to the customer's specific project. On qualifying schemes (PSDS, IETF, WCS, UKIB), we draft applications as part of the install package — typically saving 40-100 hours of in-house effort and significantly improving application strength.
Drop your details into the quote form and we'll model the eligible grant routes alongside the technical proposal. No charge, no obligation.