Is there enough sun in Dorchester for a commercial roof array?

Modelled at 985 kWh per kWp a year for a low-tilt array at this latitude, a 210 kWp system comes out at roughly 207,000 kWh a year before shading. It needs about 1,390 m² of flat roof once the edge strip, plant and walkways are kept clear. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.

Do we need planning permission for solar on a commercial building in Dorset?

Usually not a full application. In England, panels on the roof of a non-domestic building are permitted development under Class J of Part 14 of the General Permitted Development Order, with no capacity cap since December 2023. Above 50 kW, which covers most commercial arrays, you must first apply to Dorset for a determination on prior approval of the design and appearance, in particular glare on neighbouring land. On a flat roof panels may stand no more than 1 metre above the roof and must sit at least 1 metre from its edge, and listed buildings and scheduled monuments are excluded. See our planning permission guide for the detail.

Does solar help a Dorchester landlord meet MEES?

It can. A non-domestic EPC is an asset rating, and on-site generation counts in the calculation, so an array usually lifts the score. Let property in England and Wales must be EPC E or better today. The government's interim response of 18 June 2026 proposes EPC B, where cost effective, from 2031 for let buildings over 1,000 m², and drops the EPC C step once planned for 2027. How far solar moves a particular building depends on its fabric and services, which is why the EPC assessor models it before anything is fitted.

Which network operator handles the connection in Dorchester?

Capacity varies street by street and only Scottish and Southern Electricity Networks can answer it for your connection. We ask early, because an export-limited offer changes the design rather than ending the scheme, and most commercial buildings use most of what they generate anyway.

Commercial building solar panels in Dorchester

Commercial roofs in Dorchester tend to be flat, membrane covered and cluttered with plant, which shapes the layout more than the size does. What decides a scheme is the roof covering, the parapet height and the plant layout, which is why the survey happens on the roof rather than from a satellite image.

985 kWh per kWp a year at this latitude, so a 210 kWp array models at about 207,000 kWh. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.

Book a roof survey in Dorchester

Drawing Dorchester commercial roof

Roof 60 x 32 m, 1,920 m²

Array 210 kWp, east-west

Yield 207,000 kWh/yr

Scale 1:400 / Rev A / DT1

Illustrative layout for a flat commercial roof of this size, with plant, shade and access kept clear. Your own figures come from the roof survey.

21,360: people in the Dorchester built-up area (ONS Census 2021)
2,000: office properties on the rating list in Dorset (VOA, March 2025)
3,170: retail properties, 80 of them large-format (VOA, March 2025)
1: named commercial rooftop scheme on the planning record nearby (REPD, Q1 2026)

The commercial edge of a South West market town, with rooftop solar on several buildings — Commercial stock of the kind we survey across South West. Generated illustration, not a named site.

Commercial rooftop solar across Dorset

Yield on a Dorchester commercial roof

Modelled irradiation here is 1,258 kWh per square metre a year on a low-tilt array, which works out at 985 kWh for every kWp installed (EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss). That is around 11 percent above the mean across the towns we cover.

How many commercial buildings Dorset has

On the Valuation Office Agency's count, Dorset holds 3,170 retail and 2,000 office properties on the rating list. By office stock the district sits in the top quarter of the 318 districts in England and Wales; by retail stock it sits in the top tenth of the 318 districts in England and Wales.

The big roofs are in the 80 large-format retail units, superstores and retail warehouses in the district, about 159,000 square metres of floorspace under largely single storey roofs.

The same list carries 850 hotel, leisure and assembly properties in the district. Leisure centres and hotels run seven days a week, which puts weekend generation to use that an office would export.

Source: Valuation Office Agency, Non-domestic rating: business floorspace, 31 March 2025 (published December 2025), counts and floorspace by special category code and local authority district, England and Wales.

Commercial rooftop solar already planned near Dorchester

The Renewable Energy Planning Database records one roof-mounted scheme on public sector buildings in this postcode district. These are other organisations' projects, listed from the public record, not ours.

Scheme	Applicant	Type	Capacity	Status
Dorchesters Corn Exchange	Dorchester Town Council	civic	n/a	Under Construction

The built-up area holds about 21,360 people, so the stock here runs to high street premises, a supermarket or two and the odd hotel (ONS Census 2021 built-up areas).

We arrange surveys across the DT postcode area, starting from DT1.

FIG. 1 What a Dorchester roof makes, month by month

Jul produces 5.9 times what Dec does on the same roof. A 210 kWp array here models at about 207,000 kWh across the year, but it arrives unevenly, which is why we size against your summer daytime load and then look at whether storage is worth adding for the shoulder months.

Monthly figures as a table

Month	kWh per kWp	210 kWp array
Jan	27	5,670
Feb	43	9,030
Mar	80	16,800
Apr	115	24,150
May	133	27,930
Jun	135	28,350
Jul	136	28,560
Aug	115	24,150
Sep	88	18,480
Oct	53	11,130
Nov	33	6,930
Dec	23	4,830

Source: EU PVGIS v5.2

FIG. 2 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 210 kWp commercial roof that is about 17,220 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: location is not the lever, consumption is. Source: EU PVGIS v5.2, modelled per town

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).

All solar on record near DT1

Every scheme in this postcode district in the government's Renewable Energy Planning Database, Q1 2026, ground and roof mounted, commercial or not. None of them is ours. Together they are a fair guide to how the local network has been treating export applications.

Scheme	Operator	Capacity	Mounting	Status
Dorchesters Corn Exchange - Solar Panels & Biomass Boiler	Dorchester Town Council	n/a	Roof	Under Construction
High East - Solar Panels	21st Century Homes	0.26 MW	Roof	Awaiting Construction
Prince Of Wales Road - Solar Photovoltaic Equipment	Solar South West Limited	0.2 MW	Roof	Awaiting Construction
Damers First School - Solar Panels	Solar Options for Schools Limited	0.19 MW	Roof	Awaiting Construction
Thomas Hardye School - Solar Panels	Solar Options for Schools Limited	0.59 MW	Roof	Awaiting Construction

Book the survey

Send us the postcode

Tell us where the building is, roughly how big the roof is, and whether you own it or lease it. We come back with what it can carry, what it would generate against your consumption, and the three ways to pay for it.

Lenzie Consulting Ltd arranges the survey and passes your details to our MCS-certified installation partner so they can quote.

Your name Company Email Phone Site postcode Building type Your interest in the building Roof area Annual electricity spend What are you looking at?

Anything we should know about the roof?

We pass your details to our MCS-certified installation partner so they can quote. Read the privacy notice.

Questions about solar in Dorchester

Is there enough sun in Dorchester for a commercial roof array?: Modelled at 985 kWh per kWp a year for a low-tilt array at this latitude, a 210 kWp system comes out at roughly 207,000 kWh a year before shading. It needs about 1,390 m² of flat roof once the edge strip, plant and walkways are kept clear. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.
Do we need planning permission for solar on a commercial building in Dorset?: Usually not a full application. In England, panels on the roof of a non-domestic building are permitted development under Class J of Part 14 of the General Permitted Development Order, with no capacity cap since December 2023. Above 50 kW, which covers most commercial arrays, you must first apply to Dorset for a determination on prior approval of the design and appearance, in particular glare on neighbouring land. On a flat roof panels may stand no more than 1 metre above the roof and must sit at least 1 metre from its edge, and listed buildings and scheduled monuments are excluded. See our planning permission guide for the detail.
Does solar help a Dorchester landlord meet MEES?: It can. A non-domestic EPC is an asset rating, and on-site generation counts in the calculation, so an array usually lifts the score. Let property in England and Wales must be EPC E or better today. The government's interim response of 18 June 2026 proposes EPC B, where cost effective, from 2031 for let buildings over 1,000 m², and drops the EPC C step once planned for 2027. How far solar moves a particular building depends on its fabric and services, which is why the EPC assessor models it before anything is fitted.
Which network operator handles the connection in Dorchester?: Capacity varies street by street and only Scottish and Southern Electricity Networks can answer it for your connection. We ask early, because an export-limited offer changes the design rather than ending the scheme, and most commercial buildings use most of what they generate anyway.

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