Specialist solar panels for schools in Tonbridge
A kilowatt-peak on a Tonbridge school roof models at 927 kWh a year, above the mean across the towns we cover, and the roofs it applies to are mostly carrying nothing. The survey records sheet type, remaining life, purlin spacing and the state of the incoming supply, and the model runs off your own meter data rather than an average.
927 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 333,700 kWh. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.
Book a roof survey in Tonbridge- 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 Kent
A one kilowatt-peak array on a shallow pitched roof in Tonbridge models at 927 kWh a year, from modelled irradiation of 1,189 kWh per square metre in the plane of the array (EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss). That is around 5 percent above the mean across the towns we cover, which is about as strong as a UK school roof gets.
Scaled up, a 360 kWp array, sized to what the nearest school scheme on record applied for, 7 miles away at Sevenoaks, models at about 333,700 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 85,800 kWh landing in July and August and roughly 17,400 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.
Tonbridge ranks 8 of 12 towns we cover in Kent on modelled yield, against a national mean of 886 kWh per kWp. The county runs from 915 to 990, a spread of 75 kWh per kWp. On a 500 kWp array that is about 37,500 kWh a year between the strongest and weakest town in the county.
The planning position for Tonbridge schools
The TN9 postcode district has no education solar entry in the Renewable Energy Planning Database. Almost no school array is large enough to be captured there reliably, so the absence tells you about the reporting threshold and very little about what is already on the roofs around Tonbridge.
The closest recorded one is about 7 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 Tonbridge falls as the roof peaks
The generating year and the school year are out of step in Tonbridge. 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 Tonbridge 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 4.7 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.
Nationally this comes out at about 49 percent of annual generation falling on a session day. A business open every weekday sees roughly 71 percent. The 22 point gap is what a school appraisal has to absorb, and it is much the same in Tonbridge as anywhere else.
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 Tonbridge school has over that, and they are worth counting properly.
The conclusion is not that a Tonbridge school should do nothing. It is that the array should be sized to the load that survives the holidays, which is usually the server room, the catering refrigeration, the ventilation and the hot water, plus whatever the site lets out over the summer. Anything above that line needs storage or an export agreement with UK Power Networks to earn its keep.
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 | 39 | 21 | 18 |
| Mar | 21 | 74 | 50 | 24 |
| Apr | 12 | 107 | 43 | 64 |
| May | 17 | 123 | 67 | 56 |
| Jun | 21 | 129 | 90 | 39 |
| Jul | 11 | 130 | 46 | 84 |
| Aug | 0 | 109 | 0 | 109 |
| Sep | 20 | 85 | 57 | 28 |
| Oct | 17 | 53 | 29 | 24 |
| Nov | 21 | 32 | 22 | 10 |
| Dec | 15 | 23 | 11 | 12 |
| Year | 190 | 929 | 452 | 477 |
The school estate in Tonbridge and Malling
Tonbridge and Malling has 58 open state-funded schools and colleges on the DfE register teaching 23,485 pupils between them. Source: DfE Get Information About Schools.
The split is 45 primary, 11 secondary and 2 special, at an average of 405 pupils a site. At 4.1 primaries to every secondary, most of the buildings here are small. That is not a reason to skip them, but it does mean the usable area on a primary is a hall roof and a teaching block rather than an estate.
For a trust with more than one site in Tonbridge and Malling, the first survey is worth running across the whole estate. It tells you which roofs are near the end of their covering life, which have the switchboard headroom, and therefore which one should carry the first array.
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.
Across Kent the planning database records 237 solar schemes totalling 2072 MW, of which 45 are operational (REPD Q1 2026).
Send us the school postcode
A survey in Tonbridge starts with three things from you. Give us the postcode, the approximate roof area and, if you can get it from your supplier, twelve months of half hourly readings. What comes back is a usable area figure per block, output modelled against your own load rather than an average, and the ways a Tonbridge school can pay for it.
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 Tonbridge trusts ask before a survey
- Is there enough sun around Tonbridge for this to be worth doing?
- The model gives 927 kWh a year for every kWp installed at this latitude, so a 360 kWp array comes out at roughly 333,700 kWh a year before shading. It needs about 1,069 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 Tonbridge school waste its generation in August?
- 25.7 percent of the modelled annual output for Tonbridge 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 UK Power Networks. We model all three against your half hourly data before an array is sized.
- Will the network around Tonbridge accept the export?
- UK Power Networks is the distribution network operator for Kent. 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 Tonbridge?
- Usually permitted development covers a roof array on a school, with prior approval from Tonbridge and Malling 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 Tonbridge?
- Tonbridge and Malling has 58 open state-funded schools and colleges on the DfE register, with 23,485 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.