South West England

The region holds 39% of England's dairy cattle, according to Defra's June 2024 survey. A parlour, a milk tank and a cubicle shed draw power every day, and that steady load is a good match for a roof array. For a dairy unit the sensible size is the one the herd's daily demand can use, not the largest system the roof could hold.

Sunshine is good, yet not unique. PVGIS models about 1,066 kWh a year from each kilowatt-peak in Truro and 1,052 in Exeter. The East of England matches that, with 1,083 in Ipswich. So the South West case rests on its farms and its prices, not on a special solar resource.

The grid is the limit to plan around. NGED's South West report of May 2024 says a high volume of new connections, mainly batteries and solar, has caused constraints where the distribution network meets the national grid. It names limits on transformer capacity, on 275 kV and 400 kV circuits and on 132 kV fault levels. NGED is discussing new grid supply points at Axminster, Indian Queens, Alverdiscott, Abham and Iron Acton. A farm roof array is small beside those projects, but it uses the same network. Ask NGED early and check its capacity map.

Fields in the region are smaller and more irregular than in the east. That favours roofs first, and for land, smaller screened arrays or grazed designs over single large blocks. Whatever the layout, a scheme above 100 MW in England goes to the Secretary of State, and smaller ones to the local planning authority.