Solar procurement under the Procurement Act 2023: a guide for public-sector buyers

Are you a procurement lead, estates manager or finance officer at a council, school, university or NHS trust? Buying solar is more than an engineering decision. It’s a regulated procurement. Get the process wrong, and it can cost you as much as getting the technical spec wrong.

Since 24 February 2025, a new statute has governed that process: the Procurement Act 2023. It replaced the Public Contracts Regulations 2015 (PCR 2015) as the legal framework contracting authorities must follow. This guide explains what actually changed. It also covers the two realistic routes to market for a solar project. And it sets out the value-for-money and audit obligations that come with each.

What the Procurement Act 2023 changed

The Act had a bumpy road to commencement. It was originally due to go live on 28 October 2024. However, the government pushed it back four months to redraft the National Procurement Policy Statement that sits alongside it.

The Act finally came into force on 24 February 2025, with transitional “saving provisions” attached. Any procurement already started under the old PCR 2015 rules finishes under those rules, rather than switching regime mid-tender. Anything you start today falls under the Act, not the old regulations.

For a public body buying solar, the practical changes that matter most are:

• Two procedures instead of many. PCR 2015 offered a menu of competitive procedures: open, restricted, competitive with negotiation, and competitive dialogue. The Act collapses this to just two — the Open Procedure (a single-stage competition, no negotiation) and the Competitive Flexible Procedure. The Competitive Flexible Procedure gives you far more freedom to design your own process. You can build in a shortlisting stage, dialogue with bidders, or a technical-clarification round. Just set out the design upfront and follow it consistently, whatever you choose.
• A single digital front door. All regulated notices now go through the Central Digital Platform. That includes pipeline notices, tender notices, contract award notices, contract change notices and more. It’s the enhanced Find a Tender Service that went live alongside the Act. Suppliers register once and reuse their core details across bids. Contracting authorities can’t award a contract to a supplier who isn’t registered.
• A shorter, better-defined standstill period. Before you can sign a contract, unsuccessful bidders must receive an assessment summary — their debrief. You must also publish the contract award notice. You can then only sign the contract after an 8-working-day standstill period has run. That gives bidders a window to challenge the decision before it becomes binding.
• Mandatory KPIs on larger contracts. For any public contract worth more than £5 million, the contracting authority must set at least three KPIs. It must publish them. Then it must report supplier performance against those KPIs. That reporting runs at least once every 12 months, for the life of the contract. This transparency requirement didn’t exist under PCR 2015.

Two realistic routes to market

Most public bodies procuring solar choose between running their own compliant tender or buying through an existing framework agreement. Neither is automatically “better.” The right choice depends on project size, in-house procurement capacity, and how quickly you need to move.

	Run your own tender	Buy via a framework (e.g. RM6314)
Route	Open Procedure or Competitive Flexible Procedure, run and published by your own organisation	Direct award or mini-competition under an existing multi-supplier framework
Speed	Slower — full notice, tender, evaluation and standstill cycle	Faster — competition already run once by the framework owner
Control over spec	Full control; you write the technical specification from scratch	Constrained to the lots and supplier pool the framework already defines
Compliance burden	You own every notice, debrief and standstill obligation	Framework provider has already run OJEU/FTS-compliant procurement; your call-off still needs its own audit trail
Best fit	Large, complex or unusual sites; portfolio-wide standardisation; where you want bespoke evaluation criteria	Single-site or straightforward projects; smaller teams without deep procurement resource

Route one: running a compliant tender yourself

Below a set financial threshold, a contract sits outside the Act’s full “covered procurement” rules and carries lighter obligations. However, the thresholds aren’t fixed. The government revises them every two years. That keeps pace with currency movements and the UK’s commitments under the WTO Government Procurement Agreement.

As of the most recent update (effective 1 January 2026), the goods-and-services threshold is £135,018 for central government departments. For the wider public sector — councils, NHS bodies, schools and universities among them — it’s £207,720. The works threshold is £5,193,000.

A single-site rooftop solar installation is very unlikely to clear the works threshold. That said, a multi-site portfolio procurement can clear it more easily than people expect. So can a design-and-build works contract that bundles structural reinforcement with the installation.

Clearing the threshold changes the procedure and notice obligations that apply. So always check the current figures on GOV.UK’s threshold guidance before scoping a tender — they move.

Above threshold, the sequence looks like this:

1. Pipeline and planned procurement notices (where applicable) signal the opportunity to the market early.
2. Tender notice, published via the Central Digital Platform, with the specification and evaluation criteria.
3. Evaluation, scored against the weighted criteria in the tender documents — price, technical quality, warranty terms, delivery programme and more.
4. Assessment summaries issued to all bidders, debriefing them on their own score and, in outline, the winning bid’s.
5. Contract award notice published, starting the 8-working-day standstill period.
6. Contract signature, once standstill has run and nobody has lodged a challenge.

Our procurement and tender support service covers this whole sequence for solar specifically. It writes an output-based specification bidders can price against consistently. It also manages the tender and bidder queries, and runs a structured, weighted evaluation. As a result, the process stays defensible if it’s ever challenged or audited.

Route two: buying through the Crown Commercial Service’s RM6314 framework

For many public bodies, the faster and lower-risk route is an existing framework. Someone else has already run the competition among suppliers once, compliantly. The relevant framework for solar is the Crown Commercial Service’s Demand Management & Renewables Agreement (RM6314).

The Crown Commercial Service awarded it in May 2023. It was one of two replacements for the previous Heat Network and Electricity Generation Assets (HELGA) arrangement. The framework spans several lots.

It gives public bodies access to suppliers for solar PV design, feasibility, installation and maintenance. That’s alongside heat pumps, battery storage and wider decarbonisation services. Solar PV projects under the framework run up to roughly £1 million in scope.

Calling off a framework doesn’t remove your compliance obligations entirely. You still need to run whatever call-off or mini-competition process the framework’s rules require. You also still need an auditable record of why you selected that supplier.

That said, the underlying market competition, supplier vetting and core terms are already in place. This is usually significantly faster than an open-market tender for a single, relatively standard site.

Value for money and audit — what you actually have to evidence

Public bodies don’t just have to buy compliantly. They also have to show, after the fact, that the process delivered value for money. Three things matter most in practice:

• A documented evaluation trail. Weighted scoring against stated criteria, kept on file, turns “we chose the cheapest-looking bid” into a defensible decision. That matters if an unsuccessful bidder challenges the outcome, or if internal audit or the National Audit Office queries it.
• A realistic cost benchmark to test bids against. UK commercial rooftop solar typically installs for somewhere in the region of £700–£1,200 per kWp before VAT. Larger systems benefit from economies of scale. Our commercial solar cost guides break this down by system size. If a bid sits well outside that range, in either direction, ask why before award, not after.
• KPI reporting where it applies. Any solar contract that clears the £5 million works threshold now carries a statutory obligation. It must set, publish and annually report against at least three KPIs. Build that reporting cost and process into the contract management plan from day one. Don’t leave it as an afterthought once the system is already generating.

None of this is unique to solar. However, solar procurements have a specific failure mode worth naming. Installer quotes vary so much in what they actually include — panel count, inverter brand, warranty length, yield assumptions.

If a public body doesn’t write a tight, output-based specification, it ends up comparing bids that aren’t really comparable. That’s exactly the kind of process weakness an audit will find.

Where this fits

Whichever route you take — an open-market tender or a framework call-off — one thing protects you from challenge and audit criticism. You need a specification precise enough that bids are genuinely comparable. You also need an evaluation record that shows why the winning bid represented value for money.

That’s the gap our procurement and tender support service closes for public-sector solar buyers specifically. We hold no supplier relationships or product lines. So we build the specification and evaluation purely in your interest. The audit trail is already in the right shape if anyone asks.

Sources: Procurement Act 2023 (legislation.gov.uk) · GOV.UK — Central Digital Platform / Find a Tender guidance · Cabinet Office PPN 023 — 2026 threshold amounts · Crown Commercial Service — RM6314 Demand Management & Renewables Agreement