How Much Power Does a Solar Carport Generate Per Bay?
About 1.5 kWp fits over a standard parking bay, and a shallow-pitched canopy in the UK returns roughly 730 to 950 kWh for every kWp installed. That puts a single bay between 1,100 and 1,420 kWh a year — and the city you are in moves it by a third.
Start with capacity per bay, not panel count
At commercial scale a car park sizes at approximately 1.5 kWp per parking bay once you allow for column lines, drive aisles and accessible bays. A 60-bay staff car park is therefore about 90 kWp, 120 bays about 180 kWp, and 200 bays about 300 kWp. Panel wattage changes how many modules make up that figure; it does not change the roof area you have to work with.
Then use the canopy's own pitch
This is where most estimates go wrong. A canopy is pitched shallow, around 10°, to keep clearance and wind loading sensible. Modelled on PVGIS v5.3 (SARAH3 2005–2023, 14% losses, free-standing, south-facing), a 10° canopy returns about 946 kWh/kWp a year in Cardiff, 920 in London, 875 in Birmingham, 807 in Manchester, 805 in Edinburgh, 791 in Aberdeen and 772 in Glasgow. That is 9.5–11.5% below the same array at 35°. A stated yield of 1,000–1,100 kWh/kWp for a UK car park overstates generation everywhere, and by about a third in the Highlands.
Per bay, in round numbers
Multiply through: at 1.5 kWp per bay, a bay generates about 1,420 kWh a year in Cardiff, 1,380 in London, 1,310 in Birmingham, 1,210 in Manchester and 1,160 in Glasgow. For a 200-bay scheme that is roughly 284,000 kWh in Cardiff against 242,000 kWh in Manchester — same steel, same panels, 17% difference in output.
Self-consumption decides what it is worth
Generation is not saving. Units used on site displace the full import tariff; exported units earn an export rate that is typically a fraction of it. A car park attached to a building with steady daytime demand — a supermarket, a hospital, a factory on day shift — captures most of the output. A school car park runs into the six-week summer break falling across the highest-yielding months, so model it on a term-time profile rather than an annual average.
And December decides battery sizing
At 10°, December returns about 21.6 kWh/kWp in London, 10.5 in Glasgow and 7.4 in Inverness. Winter generation cannot refill a battery, so any storage sized on an annual average will disappoint between November and February; size it against the tariff instead. The full cost and payback picture, including the tax treatment, is on our solar carport cost page.
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