Oakhurst Academy Trust: Salix PSDS 6-School Solar

The trust

Oakhurst is a six-school MAT covering 4,800 pupils across Bolton, Bury and Wigan. The estate ranges from a 1968 system-built secondary in Westhoughton to a 2014 PFI-built academy in Atherton. The trust’s sustainability committee had been pushing for solar for three years; the bursary team had been blocking it, citing capex pressure on the GAG (general annual grant).

The brief

The trust wanted PV on every school but had no capital budget. The previous installer they spoke to had pitched a Salix interest-free loan — but the bursar didn’t want debt, even interest-free, on the trust’s balance sheet. They came to us asking whether 100% grant funding was realistically available.

What we did

The PSDS Phase 3b window was open for 11 weeks. PSDS scoring rewards integrated retrofit, not solar alone. We assessed each of the six schools for a heat pump retrofit potential and ranked them by ease — three were straightforward gas boiler replacements with hydronic retrofits possible, two needed fabric upgrades alongside, and one (the 2014 PFI school) was already low-carbon and excluded from the bid.

The Heat Decarbonisation Plan was the single hardest piece of work. We commissioned full Stage 4 surveys on the five qualifying schools, modelled DHW and space-heat profiles in IES VE, and built a scoring narrative around 6.8 tCO2e/£100k of grant — comfortably above the PSDS threshold.

The application

The bid covered:

• 1,200 kWp of rooftop PV across five schools (220–280kWp per site)
• 5 air-source heat pump systems (60–280 kW thermal each) replacing gas boilers
• Fabric upgrades on two pre-1980 buildings (cavity wall + secondary glazing)
• Building Management System upgrades on three schools
• 18 months of monitoring & verification

Total bid: £3.86m. Carbon score: 7.4 tCO2e/£100k (well above threshold). Award decision came back in 14 weeks at 100% of the asked amount.

The numbers

• Grant secured: £3.86m
• Trust capex contribution: £0
• Annual electricity savings (post-PV): £198,000
• Annual gas savings (post-heat-pump): £146,000 (with electricity uplift, net £67,000)
• Annual carbon savings: 412 tCO2e
• Payback to trust: instant — the trust never funded the asset

What was hard

DNO sequencing across five schools was complicated. ENWL needed simultaneous G99 applications on geographically clustered substations. We staged the applications over 10 days to avoid overloading any single primary substation review.

The procurement route was constrained — PSDS requires public-sector frameworks. We ran the install procurement through ESPO’s MSTAR3 framework, which limited the installer pool but kept procurement cleanly compliant.

What happened next

All five schools were commissioned in waves between July and December 2024 to land within the PSDS milestone schedule. M&V monitoring is now in month 6 of an 18-month obligation period; data is feeding back into Salix as required.

The trust has since used the project as a teaching resource — Oakhurst’s KS3 geography programme now includes a “live carbon dashboard” on each school’s intranet showing PV generation in real time, drawn from the SolarEdge API. The bursary team has confirmed the trust will apply for Phase 4 to cover the remaining PFI school once contractual constraints allow.

Why it worked

The trust came in early enough to do the HDP properly. Most failed PSDS bids we audit are submitted with a hastily-prepared HDP that doesn’t justify the carbon scoring. Oakhurst gave us 11 weeks; the HDP took 7 of them. That up-front investment is what bought the 100% award.