I had spotted this in the Octopus source code, but not seen it deployed until now. Now, I'm not charging any battery, so not sure what its trying to say? But the recommendation is to unplug at the moment, so looks like its being driven by real data emissions wise.
Which is no surprise given that the sun isn't shining and the wind isn't blowing. It's clearly very positive that coal has almost dropped out of the mix. I understand that the average contribution of coal over the past year has been something around 3%. Nobody is saying that fossil fuels are out of the picture yet but the very idea of renewables having the potential to be where they are today would never have been given accepted just a few years ago. Let's just be pleased that the media is actually taking notice in a positive way at last.
Honestly, that is SUCH a cool feature! Octopus are to the Energy market what Orange used to be in telecoms in the 90s: geeky, cool, innovative and responsive. Let’s hope they don’t go down the same route.
Hah! that popped up for me too yesterday evening. I also had a hunt around in the page source and fount the api the javascript was calling. The battery it refers to is your laptop battery, it's using this to get charging level and state Battery Status API and it uses this to get grid carbon intensity https://api.carbonintensity.org.uk/intensity I knocked up a quick working demo as I wanted to get it working on another site https://myteslalive.com/batt.php