has anyone heard of these power outages happening across the globe

Sabotaging power grids is a legitimate concern. I don't know about the UK, but it's a point of contention within the US and between the US and Canada.

There was a Chinese hacker group that ransom wared the uk and many other countries several years ago,doctors couldn't pull up their patients,corporations not being able to do business,like delivering groceries tostores also power outages in Ukraine:

Scare videos like this one are created to make money. Don't bother paying attention to it.