Category: Process

How Long Does a Solar PPA Take to Set Up?

A realistic UK timeline for a commercial solar PPA: 6-12 months from first enquiry to switch-on, broken into stages, plus the steps that cause most delays.

A typical UK commercial solar power purchase agreement takes 6 to 12 months from first enquiry to switch-on. Around half of that is procurement and contracting; the rest is grid approval and construction. Simple rooftop sites with spare grid capacity sit at the faster end, while large ground-mount or grid-constrained sites push towards 12 months or beyond.

Why a PPA takes longer than a cash-bought system

When you buy a solar system outright, the timeline is mostly survey, order and install. A PPA adds a financing and legal layer on top: a third party funds, owns and maintains the system on your roof or land, and you sign a long-term contract to buy the electricity it generates. That contract — usually 10 to 25 years — has to be negotiated, the funder has to credit-check your business, and the legal terms around the lease of your roof space have to be agreed. Those extra steps are what stretch the calendar.

The upside is that the funder is carrying the capital cost and the performance risk, so the longer lead time buys you a system with no upfront outlay. If you want the full picture of who does what, our guide to how a solar PPA works walks through the roles of the off-taker, funder and EPC contractor before you commit any time to the process.

The full timeline, stage by stage

Below is an indicative breakdown. Stages overlap in practice — your survey can run while heads of terms are being drafted, for example — so the totals are not simply additive. Treat the ranges as guidance, not guarantees.

Stage	Indicative duration	Who leads it
1. Enquiry & indicative tariff	1-3 weeks	You + adviser/provider
2. Site survey & technical assessment	2-4 weeks	EPC / installer
3. Heads of terms	2-4 weeks	Funder + you
4. Contract negotiation & legals	6-12 weeks	Solicitors both sides
5. DNO / G99 grid application	4-12 weeks	EPC + your DNO
6. Procurement & build	2-8 weeks	EPC
7. Commissioning & energisation	1-3 weeks	EPC + DNO

Stage 1 — Enquiry and indicative tariff (1-3 weeks)

You share basic site details: location, roof area or available land, annual electricity consumption (kWh) and a recent bill. From this a provider models a rough system size and quotes an indicative PPA rate per kWh. This is a desktop estimate, not a binding offer — but it tells you quickly whether a PPA is likely to beat your current grid tariff. Getting good numbers in early avoids wasting weeks chasing a deal that was never going to stack up. Our page on 2026 solar PPA rates explains what drives the per-kWh figure you will be quoted.

Stage 2 — Site survey and technical assessment (2-4 weeks)

A surveyor visits to confirm roof condition, structural loading, shading, available roof or ground area, and the position of your incoming supply. For rooftop PPAs the roof's remaining lifespan matters: funders want a structure that will outlast the contract, so an ageing roof can trigger a re-roof condition or kill the deal. Booking the survey promptly is one of the easiest ways to keep the schedule moving.

Stage 3 — Heads of terms (2-4 weeks)

Heads of terms (HoTs) set out the commercial shape of the deal before the lawyers engage: contract length, the starting tariff, any annual escalator, the system size and the broad responsibilities of each party. Agreeing HoTs is where you decide whether the deal is worth pursuing — and resolving the big commercial points here, rather than mid-contract, saves weeks later.

Stage 4 — Contract negotiation and legals (6-12 weeks)

This is usually the longest single stage and the one most within your control to speed up or slow down. Solicitors on both sides work through the PPA itself plus the roof or land lease, the off-taker covenant (the funder assessing your business's creditworthiness), break clauses, end-of-term options and step-in rights. Instructing a solicitor who has done renewable energy PPAs before — rather than your usual conveyancer — typically shaves weeks off this stage because they already know the standard positions.

Stage 5 — DNO / G99 grid application (4-12 weeks)

Any commercial-scale system has to be approved for connection by your Distribution Network Operator (DNO) under Engineering Recommendation G99. The EPC submits the application; the DNO assesses whether the local network can accept the generation. On a site with spare capacity this is quick. On a constrained part of the grid the DNO may require reinforcement works, impose an export limit, or quote a connection cost — any of which can add months and reshape the economics. This stage runs in parallel with the legals, which is why it rarely sits on the critical path alone, but it is the single biggest source of unpredictable delay.

Stage 6 — Procurement and build (2-8 weeks)

Once contracts are signed and grid approval is in hand, the EPC orders panels, inverters and mounting, and mobilises to site. A standard commercial rooftop install is often a one-to-two-week job; larger or phased sites take longer. Equipment lead times are the main variable here, so an EPC that pre-orders against a firm pipeline tends to be faster.

Stage 7 — Commissioning and energisation (1-3 weeks)

The system is tested, metering is fitted and the DNO formally energises the connection. Generation metering and any monitoring are commissioned so that billing under the PPA can begin. From the moment of energisation you start buying solar electricity at your agreed tariff, and the long-term contract is live.

What causes most of the delays

Across UK commercial PPAs, the same handful of issues account for most of the slippage against an optimistic schedule:

• Grid constraints. A congested DNO area can turn a four-week connection into a multi-month process, or require costly reinforcement.
• Roof condition. An old or under-engineered roof forces remedial works or a re-roof before a funder will commit.
• Inexperienced legal advisers. Solicitors new to PPAs renegotiate settled market positions and add weeks to contract.
• Slow internal sign-off. Board, landlord or group-treasury approvals that were not lined up early stall the deal at the worst moment.
• Landlord consent. If you lease your premises, your own landlord must usually agree to the rooftop lease and any step-in rights.
• Incomplete consumption data. Missing half-hourly data means the funder cannot size the system or price the tariff with confidence.

How to keep your PPA on schedule

You cannot control the DNO queue, but you can remove almost every other bottleneck before it bites. A few practical moves:

1. Pull together 12 months of half-hourly consumption data and a recent bill before you enquire.
2. Confirm roof age and structural capacity early — commission a survey rather than waiting for the funder to ask.
3. Instruct a solicitor with renewable PPA experience from the outset.
4. Get internal and landlord approvals lined up in principle before contracts land on a desk.
5. Work with an experienced provider who can run survey, legals and the grid application in parallel rather than in sequence.

The quality of your provider has an outsized effect on the timeline, because a good one sequences the stages to overlap and pre-empts the common blockers. Our guide to choosing UK solar PPA providers sets out what to look for, and if you are still weighing the model itself, our page comparing PPA vs buying shows where each option wins on speed and on cost.

So how long, realistically?

For a straightforward commercial rooftop with available grid capacity, a well-run PPA can complete in 6 to 8 months. Build in 9 to 12 months if your site is larger, your roof needs work, you sit in a constrained grid area, or internal approvals are likely to be slow. The fastest route to a firm answer for your specific site is an indicative tariff and a high-level grid check — both of which take days, not months.

Want a realistic timeline and a tariff for your own building? Request a no-obligation PPA quote and we will model your site, flag any likely grid or roof issues early, and match you with providers who can move at the pace you need.