Commercial solar surveys in the South West

Key facts for commercial solar in the South West

Network operators and connection capacity

National Grid Electricity Distribution (NGED, formerly Western Power Distribution) runs the network across Cornwall, Devon, Somerset, Bristol and Gloucestershire. Scottish and Southern Electricity Networks serves large parts of Wiltshire and Dorset through its Southern Electric licence area. The boundary does not follow county lines, so confirm your operator with the Energy Networks Association postcode tool.

The South West was one of the first parts of Britain where the network struggled to accept new generation, after a wave of solar farms in the 2010s. Some areas still have limited capacity for export, and a G99 application can come back with a restricted export figure or a reinforcement cost. That does not stop commercial rooftop solar, which is mostly used on site, but it changes the design:

• size the array to your daytime demand so little needs exporting;
• use an export limitation scheme under G100 to connect a larger array with capped export;
• add a battery to store midday surplus for later use.

Read our G99 and DNO applications guide before committing to a design that relies on export income.

Yield: the strongest in mainland Britain

In our PVGIS model (version 5.2, SARAH2 data, 14% system losses), a south-facing 1 kWp array at the optimum tilt near Truro in Cornwall gives about 1,060 kWh a year, and an east-west layout at 10 degrees about 890 kWh. Bristol gives about 1,020 kWh for the south-facing case. Coastal and western sites generally do best. As elsewhere, real roofs come in lower than the optimum, but South West sites tend to sit at the top of the national range.

Planning and clean air zones

Planning follows the national rules for England, including the December 2023 widening of permitted development for non-domestic rooftop solar. The region has a large share of protected land, including Dartmoor and Exmoor National Parks, National Landscapes such as the Cotswolds, the Mendip Hills, the Cornwall National Landscape and Dorset, and the City of Bath World Heritage Site. Ground-mounted arrays and carports in these areas need more care. See our planning permission guide.

Two charging clean air zones apply:

• Bristol is a Class D zone, so it charges non-compliant buses, coaches, taxis, HGVs, vans, minibuses and private cars.
• Bath is a Class C zone, charging non-compliant buses, coaches, taxis, HGVs, vans and minibuses, but not private cars.

Businesses running vans into either city have a direct reason to electrify, and daytime depot charging can absorb solar output that the local network might not accept as export. See EV charging for business.

The South West's commercial buildings

• Dairy and livestock farming. Somerset, Devon and Cornwall are dairy heartlands. Milking parlours, milk cooling and water heating create a twice-daily demand, and large agricultural sheds provide roof space. See our farms page.
• Food and drink. Cheese making, cider production and meat and dairy processing are spread across the region, often in rural units with refrigeration loads.
• Aerospace and engineering. The Filton area north of Bristol has a long aerospace history, and engineering firms are spread along the M5 and M4.
• Distribution. Avonmouth and Severnside, near the M4 and M5 junction, hold some of the largest warehouses in the region. Swindon, on the M4, is another logistics centre.
• Tourism and hospitality. Hotels, holiday parks and attractions in Cornwall and Devon have summer peaks that match solar generation well. See our hospitality page.

Support and finance

South West businesses use the national schemes for England: capital allowances, the business rates exemption for eligible onsite generation and storage plant to 31 March 2035, and the Smart Export Guarantee for exported power. See grants and support in England and confirm tax treatment with your accountant.

Cities with their own page

• Bristol: the Clean Air Zone, Avonmouth and the city's commercial estate.

How the free survey works in the South West

Send the short form and we will call to understand your site and demand. If it looks suitable, we arrange a free survey, in person or virtual, with one MCS certified installer matched to the site. In the South West the installer should check published network capacity and, where export looks limited, design around self-consumption, export limitation or storage from the start. Your details go to that installer only, with no obligation to proceed.