From the time the three big state-owned power generators were partly privatised in 2013, the possible closure of the Tiwai Point aluminium smelter was highlighted as a risk.

The biggest, Meridian, which supplies Tiwai, said closure of the Rio Tinto-controlled New Zealand Aluminium Smelters (NZAS) may result in a reduction in wholesale electricity prices and in electricity prices generally, and therefore a reduction in Meridian's revenue.

"In some circumstances, the impact on Meridian is likely to be severe," Meridian said then.

Gavin Evans: Smelter review a wake-up call on energy policy
Premium - Tiwai Point smelter says


Manapouri power

Big changes ahead

Demand destruction

Dark science

Phased withdrawal

All messed up