....if I might fill in the dots. NZ Steel to close. NZ Refining to drastically downsize into a fuel depot and turn off the refining plant. => no growth in NI power demand.
Tiwai to close => big fall in SI power demand.
So Meridian will have a lot of spare power generating capacity down south and no obvious market to sell that power into, even if the south to north transmission lines are upgraded. Manapouri looks to be 1/3 of Meridians total generation capacity.
=> a lot of spilling to occur at Manapouri.
Manapouri looks to be producing around 1/3 of Meridian's energy.
https://en.wikipedia.org/wiki/Meridian_Energy
But it wouldn't account for 1/3 of Meridians profits because of low energy prices to the smelter. So maybe Meridian profits will drop to 5/6 (say) of what they were pre the triple shut down?
SNOOPY