The OSM UK community is great, but it's hard to guarantee we can do the detective work to spot all 800,000 solar PV installations. There's a "long tail" of solar panels tucked away down side-streets. It's very much a needle in a haystack, and we would benefit from as many hints as possible.
(We're already working with (a) machine learning and (b) official data sources. They're good sources of hints too, but not the full picture.)
We could ask the general public for help with this. Almost everyone must pass a solar panel during their daily commute, their weekend stroll, or suchlike. But we can't expect the general public to use map editing tools, or in fact anything that requires technical commitment or expertise. Also nothing that requires login or user registration.
Can we make a tool that makes it so simple, that many thousands of people can send in just one or two sightings each?
We don't have the resources to make a fancy phone app. (And would people use it if we did?)
Option one: "drop a pin in a map" approach. Provide a simple webpage which lets people, with no login required, put a pin at a location where they think there's a solar panel. This is fairly easy to code (and could use the OSM Notes API, e.g. with a specific pre-agreed template for the Note text). However it's not ideal for people out-and-about with a smartphone, since it's all about the top-down birds-eye view.
Option two: people can take a photo of a solar panel they see, and post it to a service they already use. (Smartphones often record GPS location along with photos.) Posting to Twitter (with a particular hashtag) would be easy to set up and to scrape. However not everyone uses Twitter. Loads of people use WhatsApp. Can they report their solar spottings directly through a WhatsApp number? It would need someone to set up a number, fine - and then the coding required is to create a system that can slurp whatever photos were sent in, do a bit of sanity-checking and maybe some basic "bot" interactivity, and output a dataset of suggested-geolocations for panels. (These suggested-geolocations would not go into OSM directly, they're not appropriate for that. We can simply provide them as a dataset for mappers to refer to.)
Thanks to Max+Esther at 10:10 for suggesting the second idea. I approached them because 10:10 has previously been involved in something a little bit similar (a mobile app for spotting rooves that would be good places for new panels). They've clearly got the right idea for the kind of simple everyday interaction that's needed.