Specialist solar panels for schools in Wandsworth
25.6 percent of what a Wandsworth 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.
25.6% of the modelled year lands in July and August, on a roof that returns 908 kWh per kWp a year. The worked example below runs at 490 kWp, the size applied for at the nearest school scheme on record. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.
Book a roof survey in Wandsworth- 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 Wandsworth models at 908 kWh a year, from modelled irradiation of 1,166 kWh per square metre in the plane of the array (EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss). Wandsworth 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 490 kWp array, sized to what the nearest school scheme on record applied for, 19 miles away at Windsor, models at about 444,900 kWh a year before shading, and needs roughly 1,455 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 113,900 kWh landing in July and August and roughly 23,600 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.
Wandsworth ranks 15 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 Wandsworth schools
Search the Renewable Energy Planning Database for Wandsworth and the area around it and nothing comes back under education. That is worth stating plainly and then setting aside: the register is built around generating stations, a school array is a fraction of the size it captures reliably, and plenty of school roofs never appear in any national record at all.
The closest recorded one is about 19 miles away at Windsor: St Johns Beaumont School, Priest Hill, a 260 kWp roof mounted array applied for by St Johns Beaumont School, which was refused. We were not involved in it. We cite it because it is a public record of what has cleared planning in this part of Berkshire. Source: Renewable Energy Planning Database, Q1 2026.
Why demand in Wandsworth falls as the roof peaks
The generating year and the school year are out of step in Wandsworth. July and August carry 25.6 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 13.9 percent of the annual total, and it falls almost entirely inside the holiday.
At the other end of the year the mismatch flips. Only 5.3 percent of output falls in December and January, the two months when a Wandsworth 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. 73 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.
Then there is the afternoon. From roughly three o'clock the building empties while the roof is still working, so a system sized on annual consumption will over-generate in exactly the hours nobody is there. We size on half hourly data for that reason.
None of that makes a Wandsworth 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 full treatment of the school year against the generation curve 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 | 26 | 17 | 9 |
| Feb | 15 | 38 | 20 | 18 |
| Mar | 21 | 73 | 49 | 24 |
| 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 | 84 | 56 | 28 |
| Oct | 17 | 53 | 29 | 24 |
| Nov | 21 | 31 | 22 | 9 |
| Dec | 15 | 22 | 11 | 11 |
| Year | 190 | 908 | 444 | 464 |
Grid connection through UK Power Networks
UK Power Networks is the network operator here, and their answer on export capacity shapes the design. Any commercial array above 3.68 kW per phase connects under G99 rather than G98, and the application fixes what you are allowed to push back onto the network. If the local network is tight, limiting export rarely breaks the case here: most of the generation is consumed on site while the building is working.
The school estate in Wandsworth
Wandsworth has 79 open state-funded schools and colleges on the DfE register teaching 30,676 pupils between them. Source: DfE Get Information About Schools.
The split is 61 primary, 11 secondary, 6 special and 1 further education, at an average of 388 pupils a site. 5.5 primaries per secondary is a mix weighted towards small sites. The roof area, and therefore most of the generation, sits with the 11 secondaries and the 1 further education site.
Across an estate of that size the roofs will not be in the same condition, and that is the point of surveying them together: the block with the best orientation is often not the block whose covering has twenty years left in it.
Send us the school postcode
Roof condition decides the order of works on most school estates, so that is where we start. Send us the postcode and a rough roof area, with twelve months of half hourly readings if you have them, and we come back with usable area, modelled output against your own load, and the funding routes.
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 Wandsworth trusts ask before a survey
- What would a 490 kWp array produce at a Wandsworth school?
- Yes, and the figure matters more than the sunshine. 908 kWh per kWp a year puts a 490 kWp array at around 444,900 kWh, on roughly 1,455 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 Wandsworth?
- Less is wasted than governors expect, but the figure is worth seeing: 25.6 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 Wandsworth?
- 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 Wandsworth?
- Wandsworth has 79 open state-funded schools and colleges on the DfE register, with 30,676 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.