Multi-academy trust · 22 primary school solar PV rollout
615 kWp combined (avg 28 kWp per school) commercial solar PV installation with combined grant + tax relief stack delivering N/A (fully grant-funded) post-tax payback on £3,600,000 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 | Primary education · multi-academy trust |
| Location | North East England (Durham, Tyne & Wear, Northumberland) |
| System size | 615 kWp combined (avg 28 kWp per school) |
| Battery storage | None |
| Gross project capex | £3,600,000 |
| Grant value | £3.6m (PSDS Phase 3b — 100%) |
| Year-1 tax relief | N/A (charitable trust) |
| Net effective cost | £0 |
| Annual savings/revenue | £128,000/year combined |
| Post-tax payback | N/A (fully grant-funded) |
| CO2 saving | 113 tCO2e/year |
| Year commissioned | 2025 |
Context
The trust operates 22 primary schools across Durham, Tyne & Wear and Northumberland. Average school: 350 pupils, 1,500 m² floor area, 110,000 kWh/year electricity. Combined estate electrical consumption: 2.4 GWh/year. The trust had previously installed LED lighting and BMS upgrades across the estate via the Salix Energy Efficiency Loan Scheme between 2019-2022.
In 2023, the trust's net zero strategy committee (formed in response to the DfE Sustainability & Climate Change Strategy) identified solar PV and heat pump retrofit as the next priorities. The strategy committee chair was a non-executive trustee with energy industry experience — a critical factor in the success of the PSDS application that followed.
The challenge
PSDS competition is intense. Phase 3a (October 2021) closed within 72 hours; Phase 3b (March 2023) closed within 48 hours. The trust had to be application-ready before the window opened.
Specific constraints:
- **Roof condition.** Many schools had Asbestos Cement Sheet (ACS) roofing dating from the 1960s-70s. Of the 22 schools, 8 needed full roof refurbishment before solar — adding £840,000 to total programme capex. - **Heat pump dependencies.** PSDS strongly prefers integrated heat pump + insulation + solar packages. The trust had to design heat pump systems for buildings with 1960s-era radiator circuits — requiring fabric upgrade work (insulation, double-glazing, draught-proofing) as well. - **Procurement timing.** PCR 2015 procurement requirements meant 8-12 weeks of contractor tendering — the trust had to award contracts within 4 months of PSDS grant offer to meet delivery milestones. - **Operational disruption.** All construction had to happen in school holidays — summer break primarily, with smaller works in Easter and February half-term.
Funding approach
The trust engaged a specialist estate consultant in summer 2022 to develop RIBA Stage 3 design for all 22 schools — a £180,000 fee committed at risk before the PSDS window opened. This included:
- Per-school energy audit and roof structural assessment - Heat pump sizing and refrigerant selection - Roof refurbishment specification for ACS sites - Solar PV layout (typical 28 kWp per school) - Carbon savings methodology aligned to current DESNZ carbon factor - Five-case business case to HM Treasury standard
The trust's PSDS Phase 3b application went in within 90 minutes of the window opening. The application was approved at £3.6m — covering the full eligible project capex including roof refurbishment.
Funding stack:
1. **PSDS Phase 3b grant.** £3.6m (100% of qualifying capex). 2. **Salix Recycling Fund.** £180,000 at 0% interest over 8 years for the BMS upgrades not eligible under PSDS. 3. **No SEG income initially** — schools sized for high self-consumption to maximise carbon impact.
Delivery in two waves: 11 schools in summer 2024, 11 schools in summer 2025.
Outcome & performance
The programme completed on time in August 2025. Estate-wide performance year one:
- Combined annual generation: 585,000 kWh - Combined self-consumption: 47% (school holidays drag the figure down) - Combined export: 310,000 kWh — but trust opted for high self-consumption sizing rather than export optimisation - Annual saved import: £128,000 across 22 schools - Annual CO2 saving: 113 tCO2e (vs 96 modelled — colder weather increased heat pump electrical demand which solar offset) - **No payback maths required — fully grant-funded.** The trust effectively gained £128k/year of free budget.
The trust now reports against its net-zero-by-2035 pledge with credible Scope 2 evidence. The 2025 annual report cited the solar programme as the largest single contributor to the trust's carbon reduction.
Lessons learned
- PSDS application preparation must start 12-18 months before the funding window opens. The £180k consultant fee committed at risk was the deciding factor in winning the grant.
- Asbestos cement roof refurbishment is the single biggest hidden cost in school estate solar — budget £30-60k per school.
- Heat pumps + solar + fabric upgrades is the winning PSDS package. Solar-only applications struggle.
- School holiday delivery is logistically constrained — even with strong contractors, you can deliver maybe 12-15 schools per summer holiday.
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