Specialist solar panels for schools in Trowbridge

School rooftop solar across Wiltshire

A one kilowatt-peak array on a shallow pitched roof in Trowbridge models at 909 kWh a year, from modelled irradiation of 1,162 kWh per square metre in the plane of the array (EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss). Trowbridge models 3 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 320 kWp array, sized to what the nearest school scheme on record applied for, 10 miles away at Chippenham, models at about 290,900 kWh a year before shading, and needs roughly 950 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 74,200 kWh landing in July and August and roughly 14,800 kWh across December and January. Scottish and Southern Electricity 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.

What the planning record shows around Trowbridge

There is no school entry for the BA14 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 Trowbridge.

The nearest education scheme on the record is 10 miles from Trowbridge, at Chippenham: 320 kWp at Wiltshire College, Lackham, applicant Wessex Energy Solutions, which holds consent and is awaiting construction. That is someone else's application, not ours, and it is here because it shows what Wiltshire planning has already accepted at an education site. Source: Renewable Energy Planning Database, Q1 2026.

The summer holiday problem for a Trowbridge school

25.5 percent of the annual output modelled for Trowbridge 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 13.8 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 daily curve does the same thing in miniature. Load drops sharply after about three o'clock, generation does not, so the last three hours of a summer afternoon are pushing into an empty building unless something absorbs them. Half hourly meter data is the only way to see how much.

None of that makes a Trowbridge 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 Scottish and Southern Electricity 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.

Grid connection through Scottish and Southern Electricity Networks

Connections around Trowbridge are handled by Scottish and Southern Electricity 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 Wiltshire the planning database records 159 solar schemes totalling 1585 MW, of which 56 are operational (REPD Q1 2026).

How many schools Wiltshire has

Wiltshire has 237 open state-funded schools and colleges on the DfE register teaching 68,445 pupils between them. Source: DfE Get Information About Schools.

The split is 201 primary, 28 secondary, 6 special and 2 further education, at an average of 289 pupils a site. A ratio of 7.2 to one tells you where the roof area is. It is not with the 201 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.

Questions governors ask us about Trowbridge schools

Is there enough sun around Trowbridge for this to be worth doing?

The model gives 909 kWh a year for every kWp installed at this latitude, so a 320 kWp array comes out at roughly 290,900 kWh a year before shading. It needs about 950 square metres of clear roof once walkways and rooflight setbacks are allowed for. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.

Does a Trowbridge school waste its generation in August?

25.5 percent of the modelled annual output for Trowbridge falls in July and August, when the buildings are closed for most of six weeks (EU PVGIS v5.2). It does not go to waste, but it only has three places to go: the base load that runs regardless, such as servers, catering refrigeration and ventilation; storage; or export under an agreement with Scottish and Southern Electricity Networks. We model all three against your half hourly data before an array is sized.

Will the network around Trowbridge accept the export?

Scottish and Southern Electricity Networks is the distribution network operator for Wiltshire. Anything above 3.68 kW per phase connects under G99, and the application fixes the export limit. On a school site the incoming supply is often the binding constraint rather than the roof, so we ask that question before anyone sizes an array.

Is planning permission needed for panels on a school in Trowbridge?

Usually permitted development covers a roof array on a school, with prior approval from Wiltshire needed above a capacity threshold. A ground mounted array in the grounds is a different question and much more likely to need a full application. We check both before design sign-off.

How many schools are there around Trowbridge?

Wiltshire has 237 open state-funded schools and colleges on the DfE register, with 68,445 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.

Nearby

• School roofs in Swindon
• School roofs in Salisbury
• School roofs in Chippenham
• School roofs in Devizes
• School roofs in Melksham
• School roofs in Warminster

All Wiltshire locations