here you go:

https://focustaiwan.tw/society/202203030007

tl;dr it was a result of a malfunction in one of the plants that caused a cascading issue.

You can see the impact of reduced usage (in comparison to the day prior) here:

https://i.imgur.com/8gbziHJ.jpg

Here is a video from the repair crew inspecting the unit:

https://i.imgur.com/aI1tmuf.mp4