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What would plug-in solar save you?
Twelve UK cities, four orientations, three ways of mounting it. Real irradiance data, not a rule of thumb.
What would it produce where you live?
How this is worked out
Output comes from PVGIS v5.3, European Commission Joint Research Centre, retrieved 2026-08-11, at14% system losses (PVGIS default). The table holds annual output per kilowatt peak for each city, orientation and tilt; your kit size scales it. Tilts between the measured 30°, 60° and 90° are interpolated.
Savings count only the electricity you use while the panel is generating. Exported units earn nothing without an export arrangement, and a plug-in kit cannot store them. The default rate of26.11p is the Ofgem cap for 1 July to 30 September 2026; replace it with the one on your bill. The daily standing charge is not reduced by generating, so it is excluded.
Payback is simply price divided by annual saving. It ignores inflation, rate changes and panel degradation. Treat it as an order of magnitude.
The number most calculators leave out
Change the mounting from a railing to a tilted frame and watch the figure move. In our modelling that single choice is worth about a quarter of the output in every city we checked, which is a bigger difference than moving from Cardiff to Glasgow.
It also matters that savings count only the electricity you use while the panel is generating. A kit that produces plenty while nobody is home saves very little, which is why the question about your day is on the form.
The underlying figures and the method behind them are set out inour guide to what plug-in solar produces in the UK. Before you buy anything, checkwhat the law allows and remember you musttell your network operator.
Irradiance data: PVGIS v5.3, European Commission Joint Research Centre, retrieved 2026-08-11.