Commercial building solar panels in Bethesda
Whether solar pays on a Bethesda commercial building depends less on the panels than on who owns the roof and who pays the bill. 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.
704 kWh per kWp a year at this latitude, so a 210 kWp array models at about 148,000 kWh. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.
Book a roof survey in BethesdaIllustrative layout for a flat commercial roof of this size, with plant, shade and access kept clear. Your own figures come from the roof survey.
- 790
- office properties on the rating list in Gwynedd (VOA, March 2025)
- 1,610
- retail properties, 40 of them large-format (VOA, March 2025)
- 0
- named commercial rooftop schemes on the planning record nearby (REPD, Q1 2026)
Solar PV for commercial property across Gwynedd
What a flat roof in Bethesda generates
Modelled irradiation here is 902 kWh per square metre a year on a low-tilt array, which works out at 704 kWh for every kWp installed (EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss). That is about 21 percent below the mean across the towns we cover, so the case here rests more on daytime consumption than on raw generation.
Commercial stock in Gwynedd
Gwynedd has 790 office premises and 1,610 shops and other retail premises on the non-domestic rating list, according to the Valuation Office Agency. By office stock the district sits below the median of the 318 districts in England and Wales; by retail stock it sits above the median of the 318 districts in England and Wales.
40 of those retail properties are superstores, large food stores, large shops or retail warehouses, together about 74,000 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 500 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.
Bethesda ranks 6 of 6 towns we cover in Gwynedd on modelled yield, against a national mean of 886 kWh per kWp. The county runs from 704 to 887, a spread of 183 kWh per kWp. On a 210 kWp commercial roof that is about 38,430 kWh a year between the strongest and weakest town in the county.
Grid connection through SP Energy Networks
SP Energy 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 Gwynedd the planning database records 19 solar schemes totalling 221 MW, of which 6 are operational (REPD Q1 2026).
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.
Questions about solar in Bethesda
- How much would solar on a commercial building in Bethesda generate?
- The model gives 704 kWh for every kWp installed here, so 210 kWp is about 148,000 kWh a year before shading losses. Allow roughly 1,390 m² of roof for it. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.
- Is planning permission needed for panels on a Bethesda 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 Gwynedd 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 Bethesda?
- 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 Bethesda have capacity for export?
- SP Energy Networks is the distribution network operator for Gwynedd. 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.