PSDS Application Timing: Why Early NHS Trusts Win Funding

The Public Sector Decarbonisation Scheme has funded more NHS estate decarbonisation than every other mechanism combined, and it has one characteristic that estates teams consistently underestimate: it rewards preparation far more than it rewards merit. Two Trusts with identical schemes do not have identical chances — the one whose application lands early, with auditable evidence attached, wins.

How the funding actually flows

PSDS is run by Salix Finance on behalf of DESNZ. All NHS Trusts, foundation trusts, and NHS-owned facilities are eligible, with awards typically running from £500,000 to £10m+ per application and eligible measures funded at up to 100% of capital cost. Phase 4 carries a dedicated NHS allocation.

Application windows open, fill, and close. Because the scheme is heavily oversubscribed, applications are effectively assessed against the available envelope as they arrive in assessable form. A strong scheme submitted late competes for whatever remains; a strong scheme submitted on day one competes for everything. That asymmetry is the entire argument of this article.

What “ready to submit” really means

A PSDS application is not a form — it is an evidence pack. The energy savings calculation must be auditable, which in practice means:

• SBEM modelling of the building energy baseline, not estimates from annual bills
• PVSyst yield modelling for the solar contribution, file available for verification
• Twelve months of half-hourly consumption data covering both winter heating and summer cooling peaks
• A delivery programme demonstrating the grant can be spent within the scheme window, ideally with the procurement route already named

Assembling that pack from a standing start takes two to four months. Trusts that begin when the window opens have already lost the timing race — the work has to be done before the window opens, which means commissioning feasibility work in the preceding spring or summer.

The combined-scheme advantage

PSDS exists primarily to decarbonise heat. Solar-only applications can succeed, but applications pairing heat pump electrification with rooftop PV score better, because the PV supplies the new electrical load the heat pumps create. Combined schemes typically sit in the £2–10m range per Trust site and are routinely 80–100% grant funded.

The planning implication: even if your Trust only wants solar this year, model it alongside the heat decarbonisation programme in your Green Plan. An application that shows PV as phase one of a coherent heat-and-power pathway reads very differently from a stand-alone panel purchase — and scores accordingly.

A timing calendar that works

Based on the application-to-grant cycle of four to six months and the evidence assembly period before it, a realistic Trust calendar looks like this:

1. Months 1–2: Desk feasibility. Half-hourly data and roof drawings to a specialist; system sizing, costs, and savings modelled. Green Plan alignment checked.
2. Months 2–4: Evidence pack. SBEM and PVSyst modelling completed, delivery programme drafted, procurement route confirmed with the Trust’s procurement team.
3. Months 4–5: Governance. Trust Board (and ICB where required) sight of the scheme before submission — boards resent discovering applications after the fact, and PSDS terms require the Trust to stand behind the delivery commitment.
4. Window opens: Submit in week one. Not month two.
5. Months 6–12: Award, mobilisation, procurement execution.

The cost of missing a window

A Trust that misses a PSDS window does not just wait for the next one — it loses a year of savings, a year of carbon reduction against a fixed 2032 interim target, and frequently the internal momentum that got the scheme onto the capital agenda. The fallback options are real but inferior: the interest-free Salix Decarbonisation Loan suits projects in the £100k–£1m range, and Trust operational capital can carry smaller schemes. Both keep a programme alive; neither matches a grant at up to 100% of capex.

The practical conclusion is unglamorous: hospital solar is won in the preparation months, not the application window. If your Trust’s Green Plan includes solar — and almost all now do — the cheapest decision available is to have the feasibility and evidence pack ready before the next Phase 4 window opens. Our PSDS funding guide covers the scheme mechanics in full, and a desk feasibility is the first artefact in the pack.