Specialist solar panels for schools in Watford
25.5 percent of what a Watford 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.
25.5% of the modelled year lands in July and August, on a roof that returns 898 kWh per kWp a year. The worked example below runs at 170 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 Watford- 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 Hertfordshire
A one kilowatt-peak array on a shallow pitched roof in Watford models at 898 kWh a year, from modelled irradiation of 1,153 kWh per square metre in the plane of the array (EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss). That puts Watford in the middle of the national range, close enough to our mean of 886 kWh per kWp that the interesting question moves straight to consumption.
Scaled up, a 170 kWp array, sized to what the nearest school scheme on record applied for, 8 miles away at St Albans, models at about 152,700 kWh a year before shading, and needs roughly 505 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 38,900 kWh landing in July and August and roughly 7,800 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.
Watford ranks 7 of 10 towns we cover in Hertfordshire on modelled yield, against a national mean of 886 kWh per kWp. The county runs from 895 to 911, a spread of 16 kWh per kWp. Within Hertfordshire that difference is small enough to ignore: where the building sits is not what decides this scheme, your consumption pattern is.
The planning position for Watford schools
There is no school entry for the WD18 postcode district in the Renewable Energy Planning Database. The register is dependable for anything from a megawatt upward and incomplete below it, and a school array is usually nearer a fifth of a megawatt, so this says more about the threshold than about Watford.
The closest recorded one is about 8 miles away at St Albans: Samuel Ryder Academy, a 200 kWp roof mounted array applied for by Scholars Education Trust, which was withdrawn before determination. We were not involved in it. We cite it because it is a public record of what has cleared planning in this part of Hertfordshire. Source: Renewable Energy Planning Database, Q1 2026.
Why demand in Watford falls as the roof peaks
The generating year and the school year are out of step in Watford. July and August carry 25.5 percent of the modelled output (EU PVGIS v5.2), and the site is closed for most of those nine weeks. June is the strongest single month here at 13.8 percent of the annual total, which is still term time, and that works slightly in your favour against towns whose curve peaks in July.
At the other end of the year the mismatch flips. Only 5.1 percent of output falls in December and January, the two months when a Watford school is fully occupied and its heating and lighting are at their heaviest. The roof makes 5.9 times as much in June as it does in December, and August alone outproduces December by about 5 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.
Across the country the arithmetic settles at roughly 49 percent of output on a session day, against about 71 percent for a weekday business. That figure hardly varies by location, which is why the local numbers that matter here are the yield, the roofs and what has already cleared planning nearby.
Daily shape compounds it. A school's load climbs from breakfast club, holds through the teaching day and falls away from about three in the afternoon, while generation is still strong until six in high summer. That is why we size against half hourly meter data rather than against annual consumption: the annual figure hides both problems.
That argues for a particular shape of scheme rather than against one. Size to the load that does not stop at the end of term, count in lettings, holiday clubs and summer works honestly rather than optimistically, and then decide whether storage or an export arrangement with UK Power Networks pays for the surplus that is left.
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 | 25 | 16 | 9 |
| Feb | 15 | 39 | 21 | 18 |
| Mar | 21 | 73 | 49 | 24 |
| Apr | 12 | 104 | 42 | 62 |
| May | 17 | 120 | 66 | 54 |
| Jun | 21 | 124 | 87 | 37 |
| Jul | 11 | 124 | 44 | 80 |
| Aug | 0 | 105 | 0 | 105 |
| Sep | 20 | 82 | 55 | 27 |
| Oct | 17 | 51 | 28 | 23 |
| Nov | 21 | 30 | 21 | 9 |
| Dec | 15 | 21 | 10 | 11 |
| Year | 190 | 898 | 439 | 459 |
Grid connection through UK Power Networks
UK Power Networks operates the distribution network across Hertfordshire, so the export application goes to them. Anything larger than 3.68 kW per phase falls under G99, which means an application before commissioning rather than a notification afterwards. A constrained network is not the end of a scheme. Capping export costs little when the building already absorbs most of what the roof produces.
Across Hertfordshire the planning database records 119 solar schemes totalling 844 MW, of which 12 are operational (REPD Q1 2026).
The school estate in Watford
Watford has 38 open state-funded schools and colleges on the DfE register teaching 15,202 pupils between them. Source: DfE Get Information About Schools.
The split is 32 primary, 4 secondary, 1 special and 1 further education, at an average of 400 pupils a site. A ratio of 8 to one tells you where the roof area is. It is not with the 32 primaries, which mostly offer a hall and a teaching block each, but with the larger sites that were built with a sports hall and a dining block attached.
Where a multi-academy trust holds several of those sites, surveying the estate in one pass beats taking a roof at a time. The design work, the connection applications and the procurement paperwork are the same job repeated, and a trust that runs them together gets a better answer on all three.
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 Watford trusts ask before a survey
- What would a 170 kWp array produce at a Watford school?
- Yes, and the figure matters more than the sunshine. 898 kWh per kWp a year puts a 170 kWp array at around 152,700 kWh, on roughly 505 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 Watford?
- Less is wasted than governors expect, but the figure is worth seeing: 25.5 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 Watford?
- 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.
- Do we need planning permission in Watford?
- Often not, because panels on the roof of a school building usually sit within permitted development for non-domestic buildings. The exceptions are listed buildings, conservation areas and arrays that project too far above the roof plane, and larger schemes still need prior approval from Watford. We confirm it either way.
- How many schools are there around Watford?
- Watford has 38 open state-funded schools and colleges on the DfE register, with 15,202 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.