Analysis of regional wind speed data and what it means for on-site wind generation economics.
Why capacity factor matters
Capacity factor is the ratio of actual energy output to the theoretical maximum output over a given period. A wind turbine with a 30% capacity factor generates 30% of the energy it would produce if it ran at full rated power every hour of the year. This single metric determines whether an on-site wind installation makes economic sense. Below approximately 20% capacity factor, the economics of small-scale on-site wind become challenging. Above 25%, wind becomes a compelling component of a blended energy system.
Regional variation across the UK
Wind resource varies significantly across the UK. Coastal regions of Scotland, Wales, and the north-west of England consistently show the highest average wind speeds, with capacity factors for well-sited small turbines typically ranging from 25 to 35%. The Midlands and south-east generally show lower average wind speeds, with capacity factors of 15 to 22%. However, localised topography can create significant variations within regions: an elevated or exposed site in the south-east may outperform a sheltered site in Scotland.
Site-specific assessment is essential
Regional averages provide a useful starting point, but they are not sufficient for investment decisions. Local obstacles, terrain, building interference, and micro-climate effects can all significantly affect the wind resource at a specific site. Saber conducts detailed wind assessments using a combination of regional data, satellite wind mapping, and where appropriate, on-site anemometry to build an accurate picture of the wind resource before making any recommendation.
Wind as part of a blended system
The strongest case for on-site wind is often not wind alone, but wind as part of a blended system alongside solar PV. The two technologies have complementary generation profiles: solar produces more in summer and during the day, whilst wind typically produces more in winter and at night. A blended solar-and-wind system delivers a more consistent generation profile across the year, reducing grid dependency in all seasons. For sites with suitable wind exposure, adding wind to a solar installation can increase total self-consumption by 15 to 25 percentage points.
Planning and permitting considerations
Unlike rooftop solar, which typically falls under permitted development, on-site wind turbines generally require planning permission. Height restrictions, noise considerations, visual impact assessments, and proximity to residential properties all factor into the planning process. Saber carries the planning application as part of the service, working through specialist planning partners with experience across multiple local planning authorities to maximise the likelihood of approval.
