Specialist solar panels for schools in Hemel Hempstead
UK Power Networks runs the network around Hemel Hempstead, and on a school site their answer on export shapes the design as much as the roof pitch does. We look at the roof, the switchboard and the timetable in that order, then set the array size against what the site draws in term time.
25.6% of the modelled year lands in July and August, on a roof that returns 895 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 Hemel Hempstead- 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.
School rooftop solar across Hertfordshire
A one kilowatt-peak array on a shallow pitched roof in Hemel Hempstead models at 895 kWh a year, from modelled irradiation of 1,146 kWh per square metre in the plane of the array (EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss). That is within a few percent of our mean. Latitude is not the variable here. When the building is occupied is.
Scaled up, a 170 kWp array, sized to what the nearest school scheme on record applied for, 6 miles away at St Albans, models at about 152,200 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 39,000 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.
Hemel Hempstead ranks 9 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.
What the planning record shows around Hemel Hempstead
Search the Renewable Energy Planning Database for the HP2 postcode district 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 nearest education scheme on the record is 6 miles from Hemel Hempstead, at St Albans: 200 kWp at Samuel Ryder Academy, applicant Scholars Education Trust, which was withdrawn before determination. That is someone else's application, not ours, and it is here because it shows what Hertfordshire planning has already accepted at an education site. Source: Renewable Energy Planning Database, Q1 2026.
The summer holiday problem for a Hemel Hempstead school
25.6 percent of the annual output modelled for Hemel Hempstead arrives in the two months a school uses least (EU PVGIS v5.2). Term ends in the third week of July and the buildings stay largely empty until September. July is the single strongest month here at 13.9 percent of the annual total, and it falls almost entirely inside the holiday.
The inverse holds at the other end. December and January together return only 5.1 percent of the year, and those are the months with the heating, the lighting and the full timetable all running at once. The roof makes 6 times as much in July 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.
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.
The same mismatch repeats every day. Peak generation lands between eleven and three, the timetable ends shortly after, and by four the site is down to caretaking and cleaning. An annual consumption figure cannot show that, which is why we ask for the half hourly data instead.
None of that makes a Hemel Hempstead 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 | 25 | 16 | 9 |
| Feb | 15 | 39 | 21 | 18 |
| Mar | 21 | 73 | 49 | 24 |
| Apr | 12 | 104 | 42 | 62 |
| May | 17 | 119 | 65 | 54 |
| Jun | 21 | 123 | 86 | 37 |
| Jul | 11 | 125 | 44 | 81 |
| 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 | 897 | 437 | 460 |
Grid connection through UK Power Networks
Connections around Hemel Hempstead 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.
Across Hertfordshire the planning database records 119 solar schemes totalling 844 MW, of which 12 are operational (REPD Q1 2026).
How many schools Dacorum has
Dacorum has 68 open state-funded schools and colleges on the DfE register teaching 24,550 pupils between them. Source: DfE Get Information About Schools.
The split is 56 primary, 9 secondary and 3 special, at an average of 361 pupils a site. 6.2 primaries per secondary is a mix weighted towards small sites. The roof area, and therefore most of the generation, sits with the 9 secondaries.
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.
Start with the Hemel Hempstead roof
The first survey answers three questions at once: what the roofs carry, what they generate against your own timetable, and how a Hemel Hempstead school pays for it. Send the postcode, an approximate roof area per block and half hourly meter data if the school can get it from its supplier.
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.
Questions governors ask us about Hemel Hempstead schools
- What would a 170 kWp array produce at a Hemel Hempstead school?
- Yes, and the figure matters more than the sunshine. 895 kWh per kWp a year puts a 170 kWp array at around 152,200 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 Hemel Hempstead?
- 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 Hemel Hempstead?
- 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 Dacorum?
- 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 Dacorum. We confirm it either way.
- How many schools are there around Hemel Hempstead?
- Dacorum has 68 open state-funded schools and colleges on the DfE register, with 24,550 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.