What would a 210 kWp array produce in St Austell?

Yes. At 936 kWh per kWp a year, a 210 kWp array on a St Austell roof models at around 197,000 kWh. What changes the answer is how much of that the building uses during opening hours rather than exports. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.

Is planning permission needed for panels on a St Austell office or shop?

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 Cornwall 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.

Will rooftop solar improve the EPC rating of a let building in St Austell?

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.

Does the grid around St Austell have capacity for export?

National Grid Electricity Distribution is the distribution network operator for Cornwall. Arrays above 3.68 kW per phase connect under G99, and the application sets the export limit. It is part of the design work we arrange.

Commercial building solar panels in St Austell

Most commercial roofs around St Austell already carry plant, a parapet and an access hatch, and the space between them is where the array goes. The survey starts with the membrane and the deck: how many years the covering has left, what the roof can carry in ballast, and where plant and its shade rule panels out.

936 kWh per kWp a year at this latitude, so a 210 kWp array models at about 197,000 kWh. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.

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Drawing St Austell commercial roof

Roof 60 x 32 m, 1,920 m²

Array 210 kWp, east-west

Yield 197,000 kWh/yr

Scale 1:400 / Rev A / PL25

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.

24,360: people in the St Austell built-up area (ONS Census 2021)
2,980: office properties on the rating list in Cornwall (VOA, March 2025)
5,750: retail properties, 160 of them large-format (VOA, March 2025)
0: named commercial rooftop schemes 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 Cornwall

Yield on a St Austell commercial roof

Modelled irradiation here is 1,193 kWh per square metre a year on a low-tilt array, which works out at 936 kWh for every kWp installed (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.

How many commercial buildings Cornwall has

On the Valuation Office Agency's count, Cornwall holds 5,750 retail and 2,980 office properties on the rating list. By office stock the district sits in the top tenth 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.

160 of those retail properties are superstores, large food stores, large shops or retail warehouses, together about 418,000 square metres. Single storey boxes of that size are where most commercial rooftop solar actually gets built, because the roof is big, flat or shallow, and uninterrupted.

The same list carries 1,890 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.

The built-up area holds about 24,360 people, so the stock here runs to high street premises, a supermarket or two and the odd hotel (ONS Census 2021 built-up areas).

Surveys run across PL postcodes, PL25 outward.

FIG. 1 What a St Austell roof makes, month by month

Jun produces 5.9 times what Dec does on the same roof. A 210 kWp array here models at about 197,000 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	25	5,250
Feb	42	8,820
Mar	76	15,960
Apr	110	23,100
May	127	26,670
Jun	130	27,300
Jul	127	26,670
Aug	111	23,310
Sep	86	18,060
Oct	53	11,130
Nov	30	6,300
Dec	22	4,620

Source: EU PVGIS v5.2

FIG. 2 St Austell against the rest of Cornwall

Penzance979
Falmouth943
Newquay940
Truro940
St Austell936
Bodmin929
Bude929
Camborne921

St Austell ranks 5 of 8 towns we cover in Cornwall on modelled yield, against a national mean of 886 kWh per kWp. The county runs from 921 to 979, a spread of 58 kWh per kWp. On a 210 kWp commercial roof that is about 12,180 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

All solar on record near PL25

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
Menear Road - Solar & Battery storage	Anesco Limited	17.51 MW	Ground	Awaiting Construction
Par Market, Par Moor Road - Solar Array	Par Market	0.5 MW	Ground	Application Withdrawn

Grid connection through National Grid Electricity Distribution

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

Across Cornwall the planning database records 174 solar schemes totalling 1116 MW, of which 88 are operational (REPD Q1 2026).

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 St Austell

What would a 210 kWp array produce in St Austell?: Yes. At 936 kWh per kWp a year, a 210 kWp array on a St Austell roof models at around 197,000 kWh. What changes the answer is how much of that the building uses during opening hours rather than exports. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.
Is planning permission needed for panels on a St Austell office or shop?: 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 Cornwall 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.
Will rooftop solar improve the EPC rating of a let building in St Austell?: 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.
Does the grid around St Austell have capacity for export?: National Grid Electricity Distribution is the distribution network operator for Cornwall. Arrays above 3.68 kW per phase connect under G99, and the application sets the export limit. It is part of the design work we arrange.

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