Solar PPA in the UK: How It Works for Businesses
A solar power purchase agreement (PPA) is a long-term contract to buy electricity from a solar system that someone else pays for, owns and, in most cases, maintains. You pay for the power it produces, not for the panels. For a UK business that wants cheaper, greener electricity without a large capital outlay, it is one of the main routes to solar. It is not automatically the cheapest one, and the contract details matter more than the headline rate.
This guide covers how UK solar PPAs are structured, how they are priced, where they go wrong and how they fit with workplace and fleet EV charging.
TL;DR
A solar PPA is a long-term deal to buy solar electricity at an agreed price. Corporate PPAs typically run for 10 to 15 years.
The two structures to know are private wire (a direct connection to your site) and sleeved (power delivered through the grid by a licensed supplier).
A PPA is not guaranteed to beat market rates. A fixed price can end up above the market if wholesale prices fall.
Settle REGO ownership, volume rules and price adjustments in writing before you sign.
If you charge EVs on site, solar and smart load management work well together, because daytime generation matches daytime charging.
Table of Contents
What a solar PPA is, and what it is not
In a PPA, a generator sells electricity and a buyer agrees to purchase it. GOV.UK describes a PPA as a long-term electricity purchase agreement between a generator and a buyer. The same source estimates that corporate PPAs make up roughly 2.5% to 5% of the GB power trading market, with wind and solar the main technologies.
For a business, there are two broad ways this looks in practice:
On-site solar under a PPA. A funder installs panels on your roof, car park canopy or land. You buy the power used on site at an agreed rate per kWh. The funder owns the equipment and handles upkeep.
Off-site solar under a PPA. A solar farm elsewhere generates the power, and the contract delivers its output to you through the grid.
A PPA is not a green tariff. Business Energy Deals explains the difference: in a corporate PPA the power comes from a named wind or solar project at an agreed price, whereas a green tariff is a supply product from a utility.
It is also not a lease or a loan. You are buying a commodity, electricity, and the contract says how much, at what price, for how long and what happens when things change.
Private wire and sleeved PPAs
The structure decides which sites a PPA suits. Browne Jacobson sets out the two main physical structures:
Private wire | Sleeved | |
How power reaches you | Direct physical connection between generator and site | Exported to the grid, then delivered by a licensed supplier |
Typical generator | On your roof or land, or very close by | Anywhere, including large solar farms |
Main limit | Proximity | Added complexity and supplier involvement |
Best for | Sites with space and a steady daytime load | Larger buyers wanting off-site generation |
The same source notes that private wire is limited by distance, while sleeved PPAs allow off-site generation and are increasingly used for large-scale procurement.
For a depot, distribution centre or business park with its own roof and car park, the on-site route is usually the first to examine. If you are weighing how a nearby generator could supply a depot by direct connection, this practical checklist for planning outdoor power supply (in German) is a useful reminder of how much site-level detail a technician needs to settle before work starts.
With a sleeved deal, remember that you still need a standard supply contract. GOV.UK’s discussion of PPAs points out that buyers often underestimate the work of balancing volumes, because the PPA covers only part of your total demand.
How solar PPAs are priced
There is no standard price list. Pricing is negotiated between buyer and seller. Business Energy Deals lists the common structures:
Fixed price: a flat rate for the whole term.
Indexed price: linked to a benchmark such as the N2EX Day-Ahead Baseload Price or EPEX SPOT UK, often with a floor and a cap.
Inflation-linked adjustments: the same source notes a market shift from RPI to CPI for long-term adjustments.
Pay-as-produced or fixed volume
Most solar PPAs are pay-as-produced. You take whatever the panels generate, and you carry the variability. According to GOV.UK, this is the industry standard because it transfers generation risk to the buyer, while baseload or fixed-volume products carry high premiums to compensate the generator for managing solar’s ups and downs.
In practice, that means the sun produces most in the middle of the day, in summer. Your PPA delivers the most value if you are using power then. A site with a high daytime load, such as a warehouse, school or office, is a stronger fit than one that is quiet until evening.
Worked example: why timing matters
Take an illustrative site (these figures are made up to show the logic, not a quote). Your system generates 400,000 kWh a year, and your site uses 300,000 kWh of it directly. The remaining 100,000 kWh is exported. Your PPA rate applies to what you consume. What happens to the export, and whether you are paid for it, depends on the contract and your export arrangement. Ask for this to be modelled before signing, using your half-hourly meter data, not annual totals.
Is a PPA cheaper than buying the system?
Not necessarily, and honest advisers say so. Lawyers at Foot Anstey note that PPAs offer long-term price shielding but are not guaranteed to be cheaper: in a falling wholesale market, a fixed-price PPA could cost more than standard market rates. You are weighing that risk against budget certainty and sustainability claims.
There are three broad ways to get solar on your site:
Route | Upfront cost | Who owns the system | Who carries maintenance | Best when |
Buy outright | Highest | You | You | You have capital and want the full saving |
PPA | None, in most on-site deals | The funder | The funder, usually | You want savings without capital |
Finance or lease | Low or none | You, after the term | Varies | You want ownership with spread payments |
If your cost of capital is low and your roof is in good condition, ownership often has the stronger long-term return. If capital is committed elsewhere, or you do not want to run a generation asset, a PPA keeps the balance sheet lighter. Ask each provider for a comparison against buying outright over the same period, not only against your current tariff.
Risks to check before you sign
PPAs are long contracts. Most problems come from vague wording, not from solar itself.
Counterparty risk
Energy UK says uptake in UK industry remains low, with counterparty risk and price sensitivity among the reasons, and suggests de-risking the contract and aligning it with your wider procurement strategy. Ask who the funder is, how it is financed and what happens to your contract if it is sold on.
Volume and price mechanics
Legal practitioners at Sprintlaw warn that most disputes arise from poorly defined volume and pricing mechanics. Avoid vague “reasonable efforts” wording, and make sure every price adjustment rests on clear, objective data so you can calculate an invoice exactly.
REGOs and green claims
Many buyers assume a renewable claim comes with the PPA. It may not. Foot Anstey flags that some generators keep the Renewable Energy Guarantees of Origin (REGOs) and sell them separately. State in the contract whether REGOs are included in the price or must be bought on top, particularly if you report on sustainability. For background on the scheme that sits alongside, Ofgem’s Renewables Obligation guidance explains how supplier obligations work.
Roof, term and exit
A 10 to 15 year term outlasts many leases and roof coverings. Before you commit, check:
Your lease length, and landlord consent if you do not own the building.
The age and condition of the roof. Reroofing mid-term is expensive and may need panels removed.
What happens if you sell, relocate or close the site.
Buy-out terms: can you purchase the system early, and at what formula?
Who insures the equipment and who is liable for damage.
A step-by-step route to a solar PPA
Gather your data. Twelve months of half-hourly meter readings, your current tariff, and your plans for new loads such as EV chargers or heat pumps.
Survey the site. Roof area and condition, shading, structure, the electrical connection and available grid capacity.
Decide the structure. On-site, private wire or sleeved, and pay-as-produced or another volume model.
Request comparable proposals. Ask for the same inputs: price per kWh, escalation, term, REGO treatment, export treatment and buy-out terms.
Test the downside. Run a scenario where wholesale prices fall and one where your usage changes.
Have the contract reviewed. Use an energy lawyer for anything with a long term and indexation.
Plan the connection. Check grid connection requirements with your distribution network operator early, as timing can slow projects.
Public bodies have another option: the Government Commercial Agency’s RM6289 agreement gives central government and the wider public sector access to renewable electricity through long-term contracts with suppliers.
Why solar and EV charging belong in the same plan
Most businesses add EV chargers and solar at the same time, or one soon after the other. The two interact in useful ways.
Workplace charging happens in the working day, which is when solar generates. Fleet vehicles that return to a depot in the afternoon may charge into the evening, when solar output is falling, so storage and scheduling matter. Smart charging software with load management can shift charging toward the hours when your own generation is highest, and cap total demand so you avoid costly grid upgrades.
Adding chargers also changes your load profile. That affects how big a solar system should be, and how much of its output you can use on site. Put the EV plan in front of your PPA provider before the system is sized, not after.
Our view on solar PPAs and EV charging
We design, supply, install and manage commercial EV charging, and many of the sites we assess also ask about solar PV, battery storage and heat pumps. Here is how we see it.
Start with the load, not the product. A PPA suits sites that use a lot of power in daylight. If your chargers will mostly run at night, the case for on-site solar changes and batteries come into play. We would rather model that early than discover it after signing.
Plan charging and generation as one system. Charger numbers, power ratings, load management and the grid connection all affect how much solar you can use. Sizing them together avoids oversized connections and unused generation.
Read the contract as closely as the quote. A low rate with unclear REGO treatment, volume terms or exit costs is not a low rate. Ask for every adjustment mechanism in plain numbers.
Match the funding to the project. Some sites suit ownership, others do better with funded or shared-investment models. On the charging side we offer fully funded installation, full ownership packages, joint investment options and charging as a service, so the structure can follow your finances rather than the other way round.
— Swift Charging
Where Swift Charging fits
We are not a PPA broker, and we will not pretend that a solar contract is the right answer for every site. What we do is help you get the EV side of the plan right, and assess complementary renewables alongside it.
If you are planning chargers and considering solar, our Energy Solutions for Businesses page explains how we look at solar PV, storage and heat pumps next to charging. For sites that need chargers for staff and visitors, see our workplace EV charging service. For depots, see fleet EV charging. If you want a first view of what is feasible on your site, start with our Commercial EV Feasibility Review. We can also help you look at available UK EV charging grants where you are eligible.
For wider context on costs, our guide to fleet charging costs and 2026 grants is a useful companion, and our procurement guide helps if you are buying through a tender.
FAQ
How long is a typical UK solar PPA?
Corporate PPAs typically last 10 to 15 years, though individual contracts vary. Check the term against your lease, your roof’s remaining life and your plans for the site.
Does a solar PPA cost nothing upfront?
On-site PPAs are usually structured so the funder pays for the installation, and you pay for the electricity you use. That is not the same as free: you are committing to buy power over many years, so compare the total cost with buying outright and with your current tariff.
Is a PPA always cheaper than my current electricity supply?
No. A fixed-price PPA can end up above market rates if wholesale prices fall, as Foot Anstey points out. The benefit is price certainty over a long period, so judge it on that as well as on the starting rate.
Do I automatically get renewable energy certificates with a PPA?
Not automatically. Some generators keep the REGOs and sell them separately, so ask for the position in writing before you make any green claims.
Can I combine a solar PPA with EV chargers?
Yes, and it often makes sense. Share your planned charger numbers and charging patterns with the solar provider before the system is sized, and use load management so charging makes the most of your own generation.
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