Why the summer holidays decide the business case
A school is shut for the six weeks that produce a fifth of the year’s solar generation, closed every weekend, and empty by four o’clock. No other building type has a load profile this badly matched to a solar array, and almost no guide on the subject mentions it.
School solar is having a moment. Great British Energy has put panels on 245 schools and colleges with another 250 in the pipeline, and the Department for Education reported in July 2026 that secondary schools are saving £58,600 a year and primaries £21,000. Those are real figures from real installations. They are also averages that conceal a design question most bursars are never asked, and getting it wrong costs years of payback.
- Roughly half a school’s solar generation lands when nobody is there. The summer holiday alone accounts for about 20% of annual output, term-time weekends another 20%, and the rest of the closures around 10%.
- The right array size depends on who pays for it. Grant-funded, fill the roof. Funded from school capital or a loan, a smaller array matched to baseload returns more per pound and pays back faster.
- You cannot apply for the Great British Energy programme. The Department for Education selects schools and contacts them directly, targeting areas of deprivation. Guides describing an application process are wrong.
- The headline savings include LED lighting. The £58,600 and £21,000 figures cover solar and a lighting upgrade together. Attributing all of it to the panels overstates the solar business case.
- Costs run £900 to £1,200 per kW below 100 kW, falling to £700 to £850 per kW above 500 kW. A primary school array typically costs £35,000 to £90,000, a secondary £90,000 to £270,000.
Why schools are different
Most commercial solar guidance assumes a building occupied five days a week, fifty weeks a year, from eight in the morning until six at night. On that profile, a large array self-consumes most of what it makes and the arithmetic is straightforward.
A school breaks every one of those assumptions. It is open around 190 days a year rather than 250. It closes at three or four in the afternoon rather than six. And its longest closure runs through July and August, the two months that between them produce roughly a quarter of the year’s solar output.
The good news is that schools also have several structural advantages: large unshaded roofs, daytime rather than evening demand, access to funding no commercial building can touch, and a real educational use for the monitoring data. The design job is to lean on those advantages while working around the calendar.
- Self-consumption
- The share of generation used on site rather than exported. The single most important number in a school solar business case.
- Baseload
- The electricity a school draws even when closed: servers, fridges, security, ventilation, heating pumps and standby loads. Typically 15 to 30% of term-time daytime demand.
- Half-hourly data
- Consumption recorded every thirty minutes by the meter. Any credible school proposal should be modelled from twelve months of it.
- PSDS
- The Public Sector Decarbonisation Scheme, administered by Salix Finance, providing capital grants for public buildings.
- Salix Decarbonisation Loan
- An interest-free loan repaid from the energy savings the project generates, so the school’s net cash position stays neutral or positive.
- PPA
- Power purchase agreement. A third party owns the panels on your roof and sells you the electricity at an agreed rate for 20 to 25 years.
- DNO application
- Network operator approval, required before installation for arrays above the G98 threshold. Can take months and may return an export limit.
- Export limitation
- A cap on how much the array may send to the grid, sometimes imposed as a condition of connection. It changes the business case materially.
The holiday problem, quantified
UK solar generation is heavily concentrated in the summer. Roughly 13% of annual output arrives in July and 11% in August. The standard six-week summer holiday spans most of that window.
Work through a typical English school calendar against a typical generation profile and the picture is stark.
Only about 42% of the array’s output arrives while the building is occupied and drawing full load. The rest meets baseload if there is any, and otherwise exports.
This is not an argument against school solar. Exported electricity still earns money, and a school with summer lettings, holiday clubs, a swimming pool or a leisure centre attached has a very different profile. It is an argument for modelling the calendar properly rather than assuming a standard commercial load shape.
How big should the array be?
The instinctive answer is to fill the roof. Whether that is right depends entirely on who is paying, and this is the part of the decision most proposals skip.
Schools typically buy electricity on contract at 22p to 28p per kWh and export it for 4p to 8p. A self-consumed unit is therefore worth around four times an exported one. As the array grows, self-consumption falls, and each additional kilowatt returns less than the last.
| Array | Generation | Self-used | Annual value | Cost | Payback |
|---|---|---|---|---|---|
| 30 kW | 28,500 kWh | 80% | £6,042 | £34,500 | 5.7 yrs |
| 50 kW | 47,500 kWh | 50% | £7,363 | £52,500 | 7.1 yrs |
| 100 kW | 95,000 kWh | 35% | £12,018 | £100,000 | 8.3 yrs |
| 200 kW | 190,000 kWh | 20% | £18,620 | £180,000 | 9.7 yrs |
Read the two right-hand columns together. The 200 kW array saves three times as much money in absolute terms as the 30 kW one, and takes nearly twice as long to pay for itself. Both statements are true, and which matters depends on the funding route.
If the capital is granted, fill the roof. The school pays nothing, so payback is irrelevant and every exported kilowatt-hour is free income.
If the school or trust is paying, from reserves or a loan repaid out of savings, size to the summer baseload plus term-time daytime demand. A smaller array returns more per pound and repays faster.
If it is a PPA, the developer’s interest is a large array and yours is a well-matched one. Expect to negotiate on this point.
The practical method is the same in all three cases: pull twelve months of half-hourly meter data and model the array against it. Any proposal that sizes from roof area alone, without asking for that data, should be treated as a sales document rather than a design.
What it costs in 2026
Commercial solar is priced per kilowatt installed, and unit cost falls as systems get bigger.
| System size | Cost per kW | Total installed | Typical for |
|---|---|---|---|
| Below 100 kW | £900-£1,200 | £35,000-£90,000 | Primary schools |
| 100 to 500 kW | £750-£950 | £90,000-£270,000 | Secondaries, sixth forms |
| Above 500 kW | £700-£850 | £350,000+ | Large campuses |
| Multi-academy trust programme | £700-£900 | £250,000-£1.5m+ | Several sites at once |
| Battery storage, 50-100 kWh | £450-£650/kWh | £22,500-£65,000 | Rarely justified |
| Roof survey and structural report | – | £1,500-£4,000 | All projects |
Two costs are routinely missing from early proposals. Older school roofs frequently need remedial work or replacement before panels go on, and putting a 25-year array on a roof with eight years left in it is an expensive mistake. And flat roofs, which most post-war schools have, need ballast the structure may not carry, so the structural report is not optional.
All of this carries 0% VAT until 31 March 2027, after which the rate reverts to 5%. On a £270,000 secondary school installation that window is worth around £13,500. For any project already in planning, the timing is worth a conversation with the finance lead.
What it actually saves
In July 2026 the Department for Education published figures from schools already running government-funded solar. Secondary schools were saving £58,600 a year and primaries £21,000.
Those numbers are substantially higher than the £3,000 to £7,000 range that circulates in older guidance, and they deserve a caveat that the press coverage generally omitted: they describe schools that received solar panels and an LED lighting upgrade. Lighting is often the larger share of the saving in a building with old fluorescent fittings, and it is far cheaper per pound saved.
LED lighting typically pays back in two to four years against six to ten for solar, and needs no roof survey, no network application and no structural report. If a school is choosing where to start rather than being handed a funded package, lighting is almost always the first move and solar the second.
For a solar-only business case, the modelling above is the better guide: roughly £6,000 to £12,000 a year for a primary array and £18,000 to £45,000 for a secondary, depending heavily on size and self-consumption.
Funding routes compared
Schools have access to more funding routes than any other building type in Britain. Scores are out of five and are our editorial judgement, weighted for cost to the school, control of the asset, and how realistic access actually is.
Salix interest-free loan, right-sized array
Available to schools that are not selected for a grant programme, repaid out of the savings the project generates, with the school owning the asset outright.
The best deal available and the one you cannot pursue. The school pays nothing, owns the panels, and typically receives an LED lighting upgrade alongside. The catch is entirely in access: the Department for Education selects sites, prioritising areas of deprivation in the North East, West Midlands and North West, with at least ten schools per English region.
Best for: Selected state schools and colleges in England. Nobody else can use it
Capital grants administered by Salix, with Phase 4 running to 2028. The important shift is that recent phases emphasise whole-building decarbonisation rather than isolated measures, so solar on its own is unlikely to succeed. Package it with heat decarbonisation, insulation and lighting. Rounds are heavily oversubscribed and close fast, so preparation matters more than speed on the day.
Best for: State-maintained schools and eligible academies with a broader decarbonisation plan ready
Interest-free lending repaid from the energy savings the project delivers. On a right-sized array the annual saving usually exceeds the annual repayment from year one, so the school’s cash position never goes negative and it owns the asset outright at the end. The most broadly useful route for schools that are not handed a grant.
Best for: Any state school with a project that pays back inside the loan term
Straightforward, fast, and the best long-run return if reserves are available. A six-year payback on a right-sized array is a stronger use of surplus than most alternatives open to a governing body. The question is opportunity cost: capital spent on panels is capital not spent on the estate, and school roofs frequently need attention first.
Best for: Independent schools and well-capitalised trusts with sound roofs
A non-profit society raises money from local investors, funds the array, and sells the school electricity below grid rates, often transferring ownership after a set period. It brings the community into the project and can cover up to 100% of costs. It is slower than the alternatives and depends on finding a society willing to take your site.
Best for: Schools with active parent and community networks, and time to build the arrangement
A developer installs and maintains the array at no cost and sells you the electricity for 20 to 25 years at a discount to grid rates. It removes the capital barrier entirely, which for some schools is decisive. It also puts a commercial asset on your roof for a quarter of a century, with consequences discussed below that governing bodies should understand before signing.
Best for: Schools with no access to grant or loan funding and no capital of their own
The Great British Energy programme
This is the largest solar funding programme ever offered to UK schools, and the most widely misunderstood.
It began in April 2025 as part of a £200 million commitment covering around 200 schools and 200 NHS sites. By March 2026, 100 school installations were operational. By July 2026, 245 schools and colleges had government-funded panels, with a further 100 announced backed by up to £40 million, and around 250 in total expected to be running by summer 2026. Estimated lifetime savings across the programme are around £220 million.
There is no application form. The Department for Education identifies and contacts schools directly, targeting areas of deprivation. Several commercial sites present the programme as something you can apply for, sometimes attached to a lead capture form. If your school has not been contacted, this route is not currently available to you and your time is better spent on Salix.
A second model launched in July 2026. A further 150 schools and colleges across Yorkshire and Humber, the East Midlands and the South East will pilot a private sector arrangement, with a commercial partner installing and maintaining the systems. That is closer to a PPA than a grant in structure, and schools in those regions should read the terms carefully rather than assuming it mirrors the original programme.
£200 million committed across roughly 200 schools and 200 NHS sites, with £80 million earmarked for education.
Agreements in place for a share of up to £100 million, with the first installations operational and cutting bills.
Sites clustered in the North East, West Midlands and North West, with at least ten schools in every English region.
DfE reports secondaries saving £58,600 and primaries £21,000 a year, and launches a private sector delivery pilot in three regions.
Energy-saving materials revert to 5% VAT, adding around £13,500 to a £270,000 secondary school project.
£1.17 billion allocated through to this point, with £300 million for the 2026/27 financial year.
PPAs and the ownership question
A power purchase agreement solves the capital problem elegantly and creates an estate management problem that rarely appears in the sales material.
Under a PPA, a third party owns equipment attached to your building for 20 to 25 years, with a legal right of access to maintain it. Governing bodies should establish the answers to five questions before signing.
- What happens if the roof needs replacing? Who pays to remove and refit the array, and does the term extend?
- What if the school expands or a building is demolished? Capital projects on the estate become considerably harder to plan around an encumbrance.
- What if the school closes, merges or changes trust? The agreement usually transfers, which affects any future amalgamation.
- What does the electricity actually cost by year twenty? Ask for the full indexation schedule, not the year-one discount.
- What are the buyout terms? There should be a stated price at fixed points, not a valuation to be agreed later.
None of this makes PPAs a bad choice. For a school with no capital, no loan capacity and no grant, a PPA delivers savings that would otherwise never materialise. It simply belongs in a different category from ownership, and should be assessed by the estates lead as well as the finance lead.
Practical considerations
Roof condition first
Panels last 25 to 30 years. If the roof has fewer than fifteen years left, the sequencing is wrong. Get a condition survey before a solar survey, and if the roof is due for replacement, do both together and save the scaffolding twice over.
Network connection
Anything above the smallest arrays needs a G99 application to the distribution network operator, which can take several weeks to several months. Approval sometimes arrives with an export limit attached, which reduces the value of a large array considerably. Submit early and ask what the business case looks like if a limit is imposed.
Half-term installation windows
Working on an occupied school site brings safeguarding requirements, enhanced DBS checks for contractors, restricted working hours and scaffolding that has to be secured against pupils. Most schools install during the summer holiday, which means the delivery pipeline is heavily seasonal and booking early matters.
Getting educational value out of it
A live monitoring display in reception costs a few hundred pounds and turns the array into a teaching resource. Generation data supports maths, geography and science at every key stage, and it is the one benefit that no other capital project on the estate offers. Specify the monitoring at design stage rather than adding it later.
Export arrangements
Commercial export rates vary far more than domestic ones, and a school exporting half its generation should treat the export contract as seriously as the installation contract. Rates of 4p to 8p per kWh are common; better deals exist for sites with predictable output.
Independent schools and academy trusts operating commercially may be able to claim capital allowances on the investment, which state-maintained schools cannot. This is a question for the trust’s accountant early in the process, because it changes the comparison between owning and a PPA.
Pros and cons
- Access to grants and 0% loans no commercial building can get
- Large, unshaded, unused roof area on most sites
- Demand is daytime, matching generation hours
- Savings go straight back into teaching budgets
- Live data is a working curriculum resource
- 0% VAT until 31 March 2027
- Closed for a fifth of annual generation in summer
- Closed every weekend and empty by four o’clock
- Flat roofs often need structural work before ballast
- Many school roofs need replacing first
- Grant routes are selective or heavily oversubscribed
- PPAs encumber the estate for 20 to 25 years
Pull twelve months of half-hourly meter data before anyone quotes.
Get a roof condition survey before a solar survey.
Do the LED lighting first if you are choosing where to start.
Size the array to the funding route, not to the roof area.
Wait for the Great British Energy programme. You cannot apply for it.
Accept a proposal that models a standard commercial load profile.
Sign a PPA without the estates lead reading the access and buyout terms.
Assume the £58,600 headline figure comes from solar alone.
Frequently asked questions
How much do solar panels cost for a school?
A primary school array of 30 to 80 kW typically costs £35,000 to £90,000, and a secondary school array of 100 to 300 kW costs £90,000 to £270,000. Unit costs run £900 to £1,200 per kW below 100 kW, falling to £750 to £950 between 100 and 500 kW and £700 to £850 above that. All zero-rated for VAT until 31 March 2027.
How much can a school save with solar panels?
The Department for Education reported in July 2026 that secondary schools were saving £58,600 a year and primaries £21,000, though those figures cover solar panels and an LED lighting upgrade together. For solar alone, expect roughly £6,000 to £12,000 a year for a primary array and £18,000 to £45,000 for a secondary, depending on size and self-consumption.
Can my school apply for Great British Energy solar panels?
No. There is no application process. The Department for Education selects schools and contacts them directly, prioritising areas of deprivation in the North East, West Midlands and North West, with at least ten schools per English region. If your school has not been approached, the Salix Decarbonisation Loan is the route that is actually open to you.
Do solar panels work for schools given the summer holidays?
Yes, but the array should be sized for it. Around 20% of annual generation falls during the summer break, another 20% on term-time weekends and 10% across other closures, so only about 42% arrives while the school is occupied. Surplus still earns export income, but at roughly a quarter of the value of electricity used on site.
What size solar system does a school need?
It depends on who is paying. If the capital is granted, fill the roof, because every exported unit is free income. If the school is funding it from reserves or a loan, a smaller array matched to baseload and term-time demand pays back faster: on a typical primary profile, a 30 kW array pays back in about 5.7 years against 9.7 for a 200 kW one.
What is the payback period for school solar panels?
Typically six to ten years for a school-funded array, with well-matched smaller systems at the shorter end. With a Salix interest-free loan repaid from savings, the school’s net cash position is usually neutral or positive from year one, so payback in the conventional sense stops being the relevant measure.
Should a school choose a PPA or own the panels?
Own them if any route to capital exists, because ownership captures the full saving and leaves the estate unencumbered. A PPA removes the capital barrier entirely, which for some schools is the difference between doing it and not, but it places a third party’s asset on your roof for 20 to 25 years with access rights. Establish the buyout terms and what happens if the roof needs replacing before signing.
Should we do solar or LED lighting first?
Lighting, in almost every case. LED upgrades typically pay back in two to four years against six to ten for solar, need no roof survey, no structural report and no network application, and they reduce the demand the solar array then has to meet. Doing lighting first also means the solar can be sized against a lower, more accurate load.
Reflects Department for Education figures published on 16 July 2026, the Great British Energy Solar Partnership position as at that date, and Public Sector Decarbonisation Scheme Phase 4 allocations.
Size it to the calendar, not to the roof
School solar works, and the funding available to schools is better than anything offered to any other kind of building in Britain. The Great British Energy programme has put panels on 245 sites at no cost to them, and the interest-free Salix route is open to every state school that can build a case.
What most proposals get wrong is the shape of the year. A school is shut for the six weeks that produce a fifth of the annual output, closed every weekend, and empty by four. An array designed on a standard commercial load profile will export far more than the model assumed, at roughly a quarter of the value.
Pull twelve months of half-hourly data, do the LED lighting first, survey the roof before the array, and size the system to the funding route. If it is granted, fill the roof. If the school is paying, the smaller array almost always wins.
METHODOLOGY: Generation modelled at approximately 950 kWh per kWp per year for a well-oriented UK school roof. Self-consumption estimated against a standard English school calendar of roughly 190 opening days, applied to a typical UK monthly generation profile. Electricity valued at 25p per kWh on a commercial contract and exported at 6p. Cost per kilowatt ranges compiled from UK commercial solar installers, 2026. Savings figures for funded schools are as published by the Department for Education in July 2026 and cover solar and LED lighting measures together.
DISCLAIMER: Scores are our editorial judgement. Every school site differs in roof condition, structure, load profile, network capacity and funding eligibility; commission a survey and model against your own meter data before committing. Funding programme terms, eligibility and VAT treatment change; verify the current position with Salix Finance, the Department for Education and your local authority or trust. We do not provide financial advice.
