https://gridwatch.co.uk
https://www.gridwatch.templar.co.uk
Both show live power sources for UK, take your pick.
IE Questions: What Keeps Our Electric Grid Humming? | Inside Energy
Explains what happens when there is a sudden change in the Supply or Demand
https://www.bmreports.com/bmrs/?q=remit
Web page showing power station status changes as posted as a screenshot in post #16 (yes I know post number are not maintained but in this case I think it will do).
Happy pylons
(Link wouldn't work without Quote stuff. I stopped fiddling when it burst into life. Oh no I didn't and it's dead now! Back to life I hope.)