> Down here in NZ the govt subsidizes an aluminium smelter which uses 13% of the national electricity just to provide 3,000 jobs

I'm not in favour of giving the smelter owners a sweet deal but I believe there is some nuance which is lost in your comment.

When you say subsidize I assume you're talking about the price the smelter pays for electricty (I'm not aware of any direct subsidy).

Until about 2022 the transmission lines out of Manapouri heading north could only handle a part of what Manapouri could produce, other lines headed towards Tiwai Point to feed the smelter with the balance of Manapouri's output. This meant that negotiating electricity prices with the smelter owners was tricky because it was perfectly clear that there was nowhere else to take the electricity. In the past five years more capacity has been added to allow electricity from Manapouri to reach the National Grid and so, I presume, this significantly dilutes downward price pressure from the smelter.