Metered, not modelled
Southampton vs Bath
Southampton and Bath roofs made much the same last year.
796 against 793 kWh per kWp at the median, from 145 and 59 real systems.
Where the two actually overlap
Both areas, grouped by what each system made. The medians differ, but the shapes sit largely on top of one another — a good Bath roof beats a poor Southampton one comfortably. Location moves the odds; it does not decide the outcome.
Southampton: the middle half of 145 systems made 698–864 kWh per kWp. Bath: the middle half of 59 systems made 673–872 kWh per kWp.
Both figures are what real systems metered last year, so the gap mixes sunlight with system age, roof direction and shading. It is the difference in what people actually got, not a difference in sunshine alone.
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Output figures from openclimatefix/uk_pv (Hugging Face, CC-BY-4.0), collected by Sheffield Solar. How we measure.
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