Where are all the solar panels in Britain? Are they in the south? The sunny east? The countryside, the city?
The UK's office "Ofgem" publishes open data about the solar PV installations that they know about. In the latest "feed-in tariff" (FiT) data, there are about 800,000 of them. The "installed capacity" adds up to about 4.9 gigawatts, about half of which comes from big industrial field-scale installations and half from domestic rooftop solar.
It would be handy to know where the solar panels are - for example, if you're searching for solar panels to map...
For privacy purposes, Ofgem don't publish exact locations, nor unique IDs, in their big spreadsheet. So the data aren't perfect for mapping, but they do give us the postcode district for 90% of these 800 thousand. So, using that postcode info, I've taken their data and simply plotted them on a choropleth. Let's take a look!
Before you look, please note that I'm plotting the raw numbers per postcode district, and NOT normalising the data to account for the size of the district. This partly explains why the plots look "dark" in the regions (such as London) which are chopped up into lots of small districts. Smaller districts should have fewer things in... but on the other hand, smaller districts are supposed to equate to higher density of households, so maybe the postcode district is a good unit of analysis after all.
Here are the plots - three plots showing, respectively, the raw number of installations per district, the total installed capacity in each district, and finally to get an idea of household density I also plot the number of households there are in each district according to census data:
And here's a CSV spreadsheet of the summary FiT numbers I used to plot these. Sorry for not showing (Northern) Ireland, it's not in the data I found.
(The CSV and the images are all derived from Ofgem's FiT data which are published under the Open Government Licence.)
Note that there are A LOT of caveats about this data. About 10% of the solar installations (80 thousand!) whose postcode district was listed as "unknown". Also some postcodes are allegedly not quite right (e.g. some of them are the postcode of the person who registered, not the location of the thing itself). Some of the installations they've listed might have been discontinued, and we don't really have much way of knowing. Oh, and... the postcode area data I'm using seems to have some omissions, hence the occasional white gap in Britain. But notwithstanding all that, this gives us some indication of the distribution.
One thing that pops out to me is that these three plots don't seem very correlated. I'd have expected them all to be highly correlated. For some reason it looks like a relatively high number of small-capacity installations across Yorkshire down into Essex. There's plenty of regional variation and clustering, which may be due to geographical/weather differences, or perhaps to local initiatives.