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

The model gives 985 kWh a year for every kWp installed at this latitude, so a 590 kWp array comes out at roughly 581,200 kWh a year before shading. It needs about 1,752 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 Dorchester school waste its generation in August?

25.6 percent of the modelled annual output for Dorchester 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 Dorchester accept the export?

Scottish and Southern Electricity Networks is the distribution network operator for Dorset. 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 Dorchester?

Usually permitted development covers a roof array on a school, with prior approval from Dorset 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.

Has a school near DT1 already done this?

2 school schemes are on record in this postcode district, including a 190 kWp array at Damers First School that holds consent and is awaiting construction. We were not involved in it. It is a public planning record, and it matters less as proof that solar works than as evidence of what this authority and this network operator have already accepted. Source: Renewable Energy Planning Database, Q1 2026.

How many schools are there around Dorchester?

Dorset has 155 open state-funded schools and colleges on the DfE register, with 44,528 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.

Specialist solar panels for schools in Dorchester

2 school solar schemes sit on the public planning record around Dorchester, Damers First School among them, and each one is a governing body that has already put this through an application. 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.

581,200 kWh a year, modelled for a 590 kWp array on roughly 1,752 sqm of clear roof. That is the median size schools around Dorchester have applied for. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.

Book a roof survey in Dorchester

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

Drawing Illustrative estate, not a Dorchester school

Blocks 4, 3 with array

Array about 345 kWp

Yield about 340,000 kWh/yr

Frontage about 90 m / Rev A / DT1

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.

Dorchester / Dorset

A school on the edge of a South West market town, solar arrays on its roofs and rolling farmland beyond — School buildings of the kind we survey across South West. Not a named school and not our work.

Schools near Dorchester already on the planning record

The Renewable Energy Planning Database records 2 school and college solar schemes in the DT1 postcode district. A 190 kWp roof mounted array at Damers First School holds consent and is awaiting construction. The applicant on record is Solar Options for Schools Limited. Thomas Hardye School applied for 590 kWp of roof mounted array, and that application holds consent and is awaiting construction. The applicant on record is Solar Options for Schools Limited.

We had nothing to do with any of them. They are public planning records, and they are on this page because the useful question for a governing body is not whether school solar works in the abstract but whether it has been consented nearby. Source: Renewable Energy Planning Database, Q1 2026.

The site plan at the top of this page is a generic estate drawn to show scale and sequencing. It is not Damers First School, and it is not any other building in Dorchester. We hold no drawings, roof data or consumption data for the schools named above.

The median array applied for here is 390 kWp, with the largest at 590 kWp. At 390 kWp you are covering roughly 1,158 square metres of roof once walkways, edge zones and rooflight setbacks come out, which on most sites means a sports hall plus one teaching block rather than the whole estate.

Site on record	Applicant on record	Size	Mounting	Status
Damers First School	Solar Options for Schools Limited	190 kWp	Roof	Awaiting Construction
Thomas Hardye School	Solar Options for Schools Limited	590 kWp	Roof	Awaiting Construction

School rooftop solar across Dorset

A one kilowatt-peak array on a shallow pitched roof in Dorchester models at 985 kWh a year, from modelled irradiation of 1,258 kWh per square metre in the plane of the array (EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss). At 11 percent above our mean, Dorchester is at the strong end of the range, and a roof here earns more for every square metre than the same roof would further north.

Scaled up, a 590 kWp array, sized to the median array applied for at schools around Dorchester itself, models at about 581,200 kWh a year before shading, and needs roughly 1,752 square metres of clear roof. That size is not one we chose. It is what schools in this district have actually applied for.

Spread across the year that is about 148,800 kWh landing in July and August and roughly 29,600 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.

FIG. 1 Dorchester against the rest of Dorset

Weymouth1006
Dorchester985
Christchurch981
Bournemouth971
Bridport971
Poole965
Wimborne964
Sherborne924

Dorchester ranks 2 of 8 towns we cover in Dorset on modelled yield, against a national mean of 886 kWh per kWp. The county runs from 924 to 1006, a spread of 82 kWh per kWp. On a 500 kWp array that is about 41,000 kWh a year between the strongest and weakest town in the county.

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 summer holiday problem for a Dorchester school

25.6 percent of the annual output modelled for Dorchester 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 5.9 times as much in July as it does in December, and August alone outproduces December by about 5 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.

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.

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 Dorchester school has over that, and they are worth counting properly.

None of that makes a Dorchester 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 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 Dorchester roof against the English 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 Dorchester, 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	27	17	10
Feb	15	43	23	20
Mar	21	80	54	26
Apr	12	115	46	69
May	17	133	73	60
Jun	21	135	95	41
Jul	11	136	48	88
Aug	0	115	0	115
Sep	20	88	59	29
Oct	17	53	29	24
Nov	21	33	23	10
Dec	15	23	11	12
Year	190	981	478	503

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 Dorchester 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 English school year of 190 days. Your own trust or authority may differ by a few days either way. Source: EU PVGIS v5.2, session days from a typical school calendar

Grid connection through Scottish and Southern Electricity Networks

Scottish and Southern Electricity 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 Dorset the planning database records 149 solar schemes totalling 1078 MW, of which 47 are operational (REPD Q1 2026).

How many schools Dorset has

Dorset has 155 open state-funded schools and colleges on the DfE register teaching 44,528 pupils between them. Source: DfE Get Information About Schools.

The split is 119 primary, 29 secondary, 6 special and 1 further education, at an average of 287 pupils a site. 4.1 primaries per secondary is a mix weighted towards small sites. The roof area, and therefore most of the generation, sits with the 29 secondaries and the 1 further education site.

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.

Aerial view of a school site with teaching blocks of several different ages, a sports hall and a playing field, solar arrays on two of the flat roofs — A school site with blocks of several ages, which is the usual starting point for a trust estate survey.

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Start with the Dorchester roof

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.

Questions governors ask us about Dorchester schools

Is there enough sun around Dorchester for this to be worth doing?: The model gives 985 kWh a year for every kWp installed at this latitude, so a 590 kWp array comes out at roughly 581,200 kWh a year before shading. It needs about 1,752 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 Dorchester school waste its generation in August?: 25.6 percent of the modelled annual output for Dorchester 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 Dorchester accept the export?: Scottish and Southern Electricity Networks is the distribution network operator for Dorset. 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 Dorchester?: Usually permitted development covers a roof array on a school, with prior approval from Dorset 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.
Has a school near DT1 already done this?: 2 school schemes are on record in this postcode district, including a 190 kWp array at Damers First School that holds consent and is awaiting construction. We were not involved in it. It is a public planning record, and it matters less as proof that solar works than as evidence of what this authority and this network operator have already accepted. Source: Renewable Energy Planning Database, Q1 2026.
How many schools are there around Dorchester?: Dorset has 155 open state-funded schools and colleges on the DfE register, with 44,528 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.

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