UK food retail chain · 22 MWp solar across 320 sites
22 MWp combined across 320 sites (avg 65 kWp per site) commercial solar PV installation with combined grant + tax relief stack delivering 2.4 years post-tax post-tax payback on £18,000,000 gross capex.
Anonymised composite case study
Names, dates and exact financial figures have been changed to preserve client confidentiality. Project structure, funding combinations, technical configuration, and order-of-magnitude figures are real and based on completed work. Full editorial disclosure on the about page.
Project snapshot
| Sector | Convenience and forecourt retail · multi-site |
| Location | England, Scotland, Wales |
| System size | 22 MWp combined across 320 sites (avg 65 kWp per site) |
| Battery storage | None on solar; site-level UPS maintained for EPOS resilience |
| Gross project capex | £18,000,000 |
| Grant value | £0 (capex programme) |
| Year-1 tax relief | £4.5m (Full Expensing across the group) |
| Net effective cost | £13.5m |
| Annual savings/revenue | £6.2m/year (£19,400/site average) |
| Post-tax payback | 2.4 years post-tax |
| CO2 saving | 26,500 tCO2e/year (Scope 2 reduction) |
| Year commissioned | 2024 |
Context
The retail chain operates ~1,200 convenience and forecourt sites across the UK — including standalone convenience stores, fuel-station-attached convenience, and standalone forecourts. Annual group revenue £4.2bn, ~28,000 staff. The 2024-2026 solar rollout targeted 320 sites with rooftop area exceeding 400 m² and refrigeration load sufficient for ≥50% solar self-consumption.
In 2023, the group's Board approved a £25m investment in sustainability infrastructure, with solar PV as the largest single component. The investment was driven by: (a) Operator's own 2030 net zero pathway, (b) major brand customer pressure for verifiable Scope 2 reduction, (c) electricity cost volatility creating margin pressure across the convenience estate, (d) PE-backed group with stringent capital efficiency expectations.
The challenge
Multi-site complexity at scale:
1. **Per-site selection.** Of ~1,200 stores, only ~600 had adequate rooftop and structural capacity. Of those, ~400 had sufficient refrigeration load for strong self-consumption. Final shortlist 320 sites.
2. **DNO connection variability.** Sites across 6 main UK DNO regions. Some required network reinforcement (£15,000-£40,000 per site); others minimal upgrade.
3. **Roof condition variability.** 18 sites had ACS roofing requiring replacement before solar (£25,000-£60,000 per site). Built into programme cost.
4. **Programme delivery scale.** 320 sites in 24 months meant 2-3 sites per week installation rate — substantial logistics for installer panel.
5. **EPOS resilience.** Each site has critical EPOS / refrigeration UPS systems. Solar inverter integration must not affect resilience.
Funding approach
The group ran a competitive tender for installer framework agreements with 3 major UK commercial solar installers. Framework agreements specified:
- Unit pricing: £0.78/Wp average across the framework - Standardised mounting and inverter specifications - 10-year workmanship warranty + 25-year panel warranty - Specific HSE protocols for EPOS-critical site work - Standardised DNO application process - Standardised commissioning, monitoring and reporting
Funding stack:
- **Internal cash:** £8.4m (47% from retained earnings + RCF) - **Asset finance:** £6.6m (37% via Lombard, Aldermore, Praetura — competitive tendered) - **Revolving credit facility:** £3m (16% bridging finance during construction)
Total capex: £18m. Full Expensing tax saving: £4.5m. Effective net programme cost: £13.5m.
Outcome & performance
The 24-month programme completed in Q1 2025 — 4 months ahead of target. Performance metrics:
- **Combined solar generation:** 20.9 GWh/year across all 320 sites - **Combined self-consumption:** 67% (refrigeration drives strong daytime use) - **Annual electricity import reduction:** £5.4m/year - **SEG export revenue:** £600,000/year combined - **REGO sales revenue:** £190,000/year combined - **Combined annual savings/revenue:** £6.2m/year - **CO2 saving:** 26,500 tCO2e/year (Scope 2 reduction) - **Per-site average saving:** £19,400/year
Customer audit programmes passed Q2 2025-Q1 2026 with no findings. The chain's two largest brand customers (representing 32% of revenue) extended supply contracts at improved terms based on verifiable Scope 2 disclosure. The group has now approved a follow-on £12m programme to install solar at an additional 250 sites in 2026-2028.
Lessons learned
- Multi-site rollouts at scale achieve materially better unit pricing — £0.78/Wp on this 320-site framework vs ~£0.95/Wp typical for single-site convenience retail.
- Per-site selection (roof condition, structural capacity, electrical service, refrigeration load) is more important than scale. 320 well-selected sites outperform 600 marginal sites.
- Customer audit timelines drive procurement urgency. Most retailers face supplier code updates with 12-month implementation windows — solar must deliver within that horizon.
- ACS roof replacement is the single biggest hidden cost on multi-site retail solar. Identify ACS roofs pre-application and decide whether to include or exclude.
- Asset finance + Full Expensing combination preserves working capital while capturing full year-one tax relief — best fit for capital-efficient PE-backed retailers.
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