What would a 320 kWp array produce at a Pontcanna school?

Yes, and the figure matters more than the sunshine. 936 kWh per kWp a year puts a 320 kWp array at around 299,500 kWh, on roughly 950 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 Pontcanna?

Less is wasted than governors expect, but the figure is worth seeing: 25.4 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 National Grid Electricity Distribution.

Who do we apply to for export near Pontcanna?

Only National Grid Electricity Distribution 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.

Specialist solar panels for schools in Pontcanna

A school roof in Pontcanna makes 6.3 times as much in June as it does in December, and the school year runs against that curve rather than with it. 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.

299,500 kWh a year, modelled for a 320 kWp array on roughly 950 sqm of clear roof. That is 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 Pontcanna

1 teaching block
2 hall and kitchen
3 sports hall
4 1960s block, no array
first phase
later phase

Drawing Illustrative estate, not a Pontcanna school

Blocks 4, 3 with array

Array about 345 kWp

Yield about 323,000 kWh/yr

Frontage about 90 m / Rev A / Cardiff

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.

Pontcanna / Cardiff

A two storey 1970s school block with a shallow pitched roof covered in solar panels, empty playground in front and a playing field beyond — School buildings of the kind we survey across Cardiff. Not a named school and not our work.

Solar PV for academy trusts across Cardiff

A one kilowatt-peak array on a shallow pitched roof in Pontcanna models at 936 kWh a year, from modelled irradiation of 1,193 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 6 percent above the mean across the towns we cover, which is about as strong as a UK school roof gets.

Scaled up, a 320 kWp array, sized to what the nearest school scheme on record applied for, 15 miles away at Weston-super-Mare, models at about 299,500 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 76,100 kWh landing in July and August and roughly 14,400 kWh across December and January. National Grid Electricity Distribution 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.

FIG. 1 Pontcanna against the rest of Cardiff

Canton936
Pontcanna936
Cathays908
Splott908

Pontcanna ranks 2 of 4 towns we cover in Cardiff on modelled yield, against a national mean of 886 kWh per kWp. The county runs from 908 to 936, a spread of 28 kWh per kWp. Within Cardiff that difference is small enough to ignore: where the building sits is not what decides this scheme, your consumption pattern is.

Bars are zero based, so length is proportional to the figure. Where a county is flat, that is the finding: latitude is not the lever, the timetable is. Source: EU PVGIS v5.2, modelled per town

The planning position for Pontcanna schools

There is no school entry for Pontcanna and the area around it 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 Pontcanna.

The closest recorded one is about 15 miles away at Weston-super-Mare: Weston College, a 300 kWp roof mounted array applied for by Weston College, 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 Somerset. Source: Renewable Energy Planning Database, Q1 2026.

Why demand in Pontcanna falls as the roof peaks

The generating year and the school year are out of step in Pontcanna. July and August carry 25.4 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 14.1 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 4.8 percent of output falls in December and January, the two months when a Pontcanna school is fully occupied and its heating and lighting are at their heaviest. The roof makes 6.3 times as much in June as it does in December, and August alone outproduces December by about 5.1 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.

Summed over the year, about 49 percent of what a school roof makes arrives while the school is open. For a business trading every weekday the equivalent is roughly 71 percent. Nothing about Pontcanna changes that ratio much, but plenty about your own site changes what to do with it.

The weekly pattern repeats the annual one. Saturdays and Sundays generate as well as any other day and consume almost nothing, so before storage or export is even discussed it is worth knowing what the site does at a weekend, which only half hourly data will tell you.

A Pontcanna governing body should read that as a sizing constraint, not a reason to stop. The base load that runs through the holidays, servers, comms, refrigeration, ventilation and hot water, is the floor the array should be built up from, and everything above it has to be justified by storage, export or summer occupancy.

We set out the whole argument about term dates and the generation curve on the home page, and what it does to a payback figure under costs.

FIG. 2 A Pontcanna roof against the Welsh school year

generated while the school is open
generated at a weekend or in the holidays

The same figures as a table

Monthly output for a 1 kWp array in Pontcanna, split by whether the day is a school session day. Across the year 49 percent of generation lands while the school is open.
Month	Session days	Output, kWh per kWp	School open	School closed
Jan	20	24	15	9
Feb	15	41	22	19
Mar	21	76	51	25
Apr	12	110	44	66
May	17	130	71	59
Jun	21	132	92	40
Jul	11	130	46	84
Aug	0	108	0	108
Sep	20	85	57	28
Oct	17	50	27	23
Nov	21	30	21	9
Dec	15	21	10	11
Year	190	937	456	481

Per kWp installed, month by month, separating generation while the school is open from generation at a weekend or in the holidays. 74 percent of the Pontcanna year sits between April and September, most of which is term time; it is the tail of that period, the last week of July and all of August, that the school is not there for. The daily split is a flat apportionment of each month, not a metered one. Session days follow a typical school year in England and Wales, 190 days on broadly the same dates. Your own authority or trust may differ by a few days. Source: EU PVGIS v5.2, session days from a typical school calendar

Grid connection through National Grid Electricity Distribution

National Grid Electricity Distribution operates the distribution network across Cardiff, 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.

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Send us the school postcode

We survey school and college roofs throughout Cardiff. We need the postcode, a rough roof area and your half hourly meter data if the trust has it. From that we model what the roof carries, what it generates against the timetable, and which of the funding routes actually suits a school of your size.

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 Pontcanna trusts ask before a survey

What would a 320 kWp array produce at a Pontcanna school?: Yes, and the figure matters more than the sunshine. 936 kWh per kWp a year puts a 320 kWp array at around 299,500 kWh, on roughly 950 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 Pontcanna?: Less is wasted than governors expect, but the figure is worth seeing: 25.4 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 National Grid Electricity Distribution.
Who do we apply to for export near Pontcanna?: Only National Grid Electricity Distribution 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.