Taiwanese people don’t know how lucky they are having the government still subsidizing electricity, public transport, etc. In the UK it’s about US$0.30/kWh. In Elbonia it’s US$0.20-25, depending on region (minimum wage, for context, is $6/day). US$0.10 (which is about what I’m paying) is just laughably cheap.
While I disagree with the idea of subsidizing energy - because it encourages waste - it’s not the proximate cause of rolling blackouts. Subsidy of public goods has some distinct upsides, but it needs to be done with a bit of common sense. The problem is that once you start doing it, people come to expect it and get ornery if you try to wind it back.
It varies, but if you want a simple answer, “poor design, increasing demand, changing energy policy, and lack of maintenance”. For an example of “changing energy policy”, in the UK the government has essentially made it illegal, or at least extremely difficult, to use anything except electricity for space heating. That requires the National Grid to be entirely reconfigured, in a very wasteful manner, to cope with the new demands that will be placed upon it. The engineering estimates suggest the grid capacity will have to be tripled or quadrupled.
Give it ten years or so.
‘Elbonia’ is a specific place in my posts, but it’s also a placeholder for other countries with similar problems/policies.