Specialist solar panels for schools in Merton
25.7 percent of what a Merton school roof makes arrives in July and August, which is when the buildings are shut. A survey here starts with the covering and the structure, then the incoming supply, then what the timetable actually draws.
902 kWh per kWp a year at this latitude, so a 360 kWp array, the size applied for at the nearest school scheme on record, models at about 324,700 kWh. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.
Book a roof survey in Merton- 1 teaching block
- 2 hall and kitchen
- 3 sports hall
- 4 1960s block, no array
- first phase
- later phase
Illustrative layout for an estate of this size. The array is drawn at about 345 kWp, roughly 53 percent of the 650 kWp these three roofs would hold, because a school sizes to the load it can use in term time rather than to the roof it has: generation it cannot use is exported at a much lower rate than it pays to import. The hatched block carries no array because its structure has not been assessed, which on a school of that era is the usual starting point rather than an exception. Your own figures, and which of your blocks can take an array, come from the roof survey.
Solar PV for academy trusts across Greater London
A one kilowatt-peak array on a shallow pitched roof in Merton models at 902 kWh a year, from modelled irradiation of 1,159 kWh per square metre in the plane of the array (EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss). Merton models 2 percent above our mean. That is a real advantage, though a smaller one than the difference between an array matched to the timetable and one matched to the roof.
Scaled up, a 360 kWp array, sized to what the nearest school scheme on record applied for, 18 miles away at Sevenoaks, models at about 324,700 kWh a year before shading, and needs roughly 1,069 square metres of clear roof. We take the size from the nearest real application rather than a round number, so the example is anchored to something a planning officer has already seen.
Spread across the year that is about 83,400 kWh landing in July and August and roughly 16,900 kWh across December and January. UK Power Networks sets what may go back onto the network here, so the July figure is the one worth putting in front of a governing body first.
Merton ranks 39 of 50 towns we cover in Greater London on modelled yield, against a national mean of 886 kWh per kWp. The county runs from 847 to 987, a spread of 140 kWh per kWp. On a 500 kWp array that is about 70,000 kWh a year between the strongest and weakest town in the county.
The planning position for Merton schools
No school or college solar scheme appears in Merton and the area around it in the Renewable Energy Planning Database. That is a reporting threshold rather than a verdict. The database records generating stations from one megawatt upward reliably and smaller ones patchily, and almost every school array is a fraction of that, so a roof full of panels on a Merton secondary could be generating today without ever reaching it.
The closest recorded one is about 18 miles away at Sevenoaks: The Sennocke Centre, High Street, a 360 kWp roof mounted array applied for by Sevenoaks School, which holds consent and is awaiting construction. We were not involved in it. We cite it because it is a public record of what has cleared planning in this part of Kent. Source: Renewable Energy Planning Database, Q1 2026.
Why demand in Merton falls as the roof peaks
The generating year and the school year are out of step in Merton. July and August carry 25.7 percent of the modelled output (EU PVGIS v5.2), and the site is closed for most of those nine weeks. July is the single strongest month here at 14 percent of the annual total, and it falls almost entirely inside the holiday.
At the other end of the year the mismatch flips. Only 5.2 percent of output falls in December and January, the two months when a Merton school is fully occupied and its heating and lighting are at their heaviest. The roof makes 5.7 times as much in July as it does in December, and August alone outproduces December by about 4.8 to one. 74 percent of the year arrives between April and September, and the point of that figure is not that the summer half goes unused, because April, May and June are full teaching months that draw hard. It is that the concentration peaks in the few weeks at the end of it when the building is shut.
Put the two calendars together and roughly 49 percent of a school's generation nationally lands on a session day, against about 71 percent for a business open every weekday. That gap is the whole difference between appraising a school roof and appraising any other commercial one, and it barely moves from town to town.
And the week has the same hole in it. Two days in seven the site is closed altogether, at no cost to the generation, which is part of why the session day share sits where it does. Weekend lettings are the one lever a Merton school has over that, and they are worth counting properly.
None of that makes a Merton scheme a bad one. It changes what the scheme should be: sized against the base load that runs whether or not the school is open, which on most sites is servers, comms, catering refrigeration, ventilation and hot water, with lettings, holiday clubs and summer works added on top. Where that base load is thin, the choices are storage, an export arrangement through UK Power Networks, or a smaller array that consumes nearly everything it makes.
We set out the complete version of the term time arithmetic on the home page, and what it does to a payback figure under costs.
- generated while the school is open
- generated at a weekend or in the holidays
The same figures as a table
| Month | Session days | Output, kWh per kWp | School open | School closed |
|---|---|---|---|---|
| Jan | 20 | 25 | 16 | 9 |
| Feb | 15 | 38 | 20 | 18 |
| Mar | 21 | 72 | 49 | 23 |
| Apr | 12 | 105 | 42 | 63 |
| May | 17 | 120 | 66 | 54 |
| Jun | 21 | 124 | 87 | 37 |
| Jul | 11 | 126 | 45 | 81 |
| Aug | 0 | 106 | 0 | 106 |
| Sep | 20 | 83 | 55 | 28 |
| Oct | 17 | 52 | 29 | 23 |
| Nov | 21 | 30 | 21 | 9 |
| Dec | 15 | 22 | 11 | 11 |
| Year | 190 | 903 | 441 | 462 |
Grid connection through UK Power Networks
Connections around Merton are handled by UK Power Networks, which sets the export limit for the site. Above 3.68 kW per phase the connection runs under G99, so the export limit is agreed in advance rather than assumed. Where the local network is constrained, an export-limited connection usually still makes the scheme work, because a school uses most of what the roof makes during the working day.
The school estate in Merton
Merton has 56 open state-funded schools and colleges on the DfE register teaching 27,206 pupils between them. Source: DfE Get Information About Schools.
The split is 43 primary, 9 secondary, 3 special and 1 further education, at an average of 486 pupils a site. Read 4.8 primaries per secondary as a sequencing hint rather than a statistic. A primary is a single survey visit and a modest array; a secondary is several roofs of different ages on one site, and that is where both the area and the complications are.
A trust holding more than one of these sites should look at them together. Grouping the surveys turns the grid question, the funding question and the procurement route into one exercise rather than four, and it usually changes which roof goes first.
Send us the school postcode
Lenzie Consulting Ltd arranges roof surveys for schools across Greater London. Send the school postcode and a rough idea of the roof area, and the last twelve months of half hourly meter data if the school holds it. We come back with what the roofs can carry, what they would generate against your own consumption, and the funding routes open to a school.
Lenzie Consulting Ltd arranges the survey and passes your details to an MCS-certified installation partner so they can quote. We do not carry out the installation ourselves.
What Merton trusts ask before a survey
- What would a 360 kWp array produce at a Merton school?
- Yes, and the figure matters more than the sunshine. 902 kWh per kWp a year puts a 360 kWp array at around 324,700 kWh, on roughly 1,069 square metres of roof. The value of that depends on your term time load. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.
- What happens to the electricity during the summer holidays in Merton?
- Less is wasted than governors expect, but the figure is worth seeing: 25.7 percent of the year is modelled to arrive in July and August here (EU PVGIS v5.2), against a site running on holiday base load. Lettings, holiday clubs and summer works take some of it, storage takes more, and the rest is an export question for UK Power Networks.
- Who do we apply to for export near Merton?
- Only UK Power Networks can answer it for your connection. What we can say is that a capped export limit rarely breaks a school scheme, because the array that suits a school is sized to the term time load rather than to the roof.
- How many schools are there around Merton?
- Merton has 56 open state-funded schools and colleges on the DfE register, with 27,206 pupils on roll. Source: DfE Get Information About Schools. We survey across the whole of that area, and where a trust holds several sites we look at them in one pass.