[josaka]

I suspect it's, in part, because humidity is low. The fab needs to tightly control humidity and temperature. Pulling water from air is energy intensive. Facilities team in the fab I used to work in said their most energy intensive days where the most humid days.

[bigtimesink]

Humidity in Taiwan can be very high.

[mort96]

And I'm betting that combatting that humidity is a significant cost for TSMC.