Lower than anywhere else in the UK. Worth knowing before you spend, and worth knowing that where you put it still matters more than the latitude.
| Mounting | North Scotland | South and Central |
|---|---|---|
| Garden frame, 30 degrees south | 623 kWh | 656 kWh |
| Ideal pitched roof, 35 degrees south | 628 kWh | 661 kWh |
| Vertical south-facing wall | 470 kWh | 491 kWh |
| Vertical east or west wall | 321 kWh | 337 kWh |
Per year, for an 800 W device, unshaded, at Inverness and Glasgow, from PVGIS.
A well-placed panel in Inverness beats a badly placed one in Glasgow, and it is not close.
A garden frame in the north returns 623 kWh. An east-facing wall in the central belt returns 337 kWh. The southern site has better light and still loses, by a wide margin, because orientation does more work than latitude.
Which is where the Scottish metre allowance becomes useful rather than merely interesting. More room to project means more room to angle the panel properly, and angling it properly is most of the difference between those two numbers.
They are a ceiling. Unshaded, correctly angled, at one city standing in for a large and varied area. A panel behind a tree or on a north-facing gable will not come near them.
We can run these for your actual coordinates rather than for Inverness or Glasgow.
Most of what is written about plug-in solar in the UK describes English rules. Send us a postcode and we will tell you which of the two Scottish operators covers it, what the device would make there, and which permitted development class applies to what you have in mind.