Power supply risk made real

An equipment failure at a Transpower substation sent two Auckland power stations offline yesterday - a shutdown that could have been avoided had a new line of 400kV power pylons been built through the Waikato.

Transpower, the state-owned enterprise that owns and runs the national power grid, said a "disconnector" failed at its substation yesterday morning, which took out one of its lines connecting Otahuhu with Whakamaru, near Taupo.

Generation at the Glenbrook co-gen plant and at Southdown shut down as a result of the voltage disruption.

Transpower is planning a new 400kV line of pylons connecting Auckland with the rest of the national grid, strengthening the links between the growing load in the north of the North Island and generation further south.

It wants to build the pylons by 2010, saying that security of supply is slowly falling for Auckland and north, with the impact of events like yesterday's failure becoming more severe.

Public meetings on the plan last year became heated affairs, with local residents burning effigies and threatening to blow up pylons. Transpower chief executive Ralph Craven was also the target of death threats.

The Electricity Commission is looking at the 400kV plan to see if it is really the best option for the network. A Transpower spokesman said a new link would have allowed power to travel more easily along existing lines.