New rules for power security

Powerline companies will be able to remove vegetation on private property if it obstructs local lines, when amendments to the Electricity (Hazards from Trees) Regulations come into effect later this year.

Energy Minister Simeon Brown says the change will ensure greater security of electricity supply, particularly during severe weather events.

“Trees or parts of trees falling on powerlines is one of our most common causes of electricity outages, particularly in high winds,” Brown says.

“During Cyclone Gabrielle, out-of-zone tree outages interrupted electricity supply to 68,000 households. These interruptions and outages underscored how important it is to proactively manage risks to local electricity infrastructure.

“Many of the outages experienced during the cyclone could have been prevented if these proposed regulations were in place.”

Amendments to the regulations will target trees directly surrounding existing Growth Limit Zones (GLZ) by creating a ‘clear to the sky’ zone to prevent vegetation hanging over lines. GLZs vary according to the voltage of the powerlines, but generally range from 0.5 metres to 2.5 metres.

The regulations will also create a ‘notice zone’ of one metre around the GLZ. If vegetation enters this zone, the line owners will be able to alert tree owners about the risk of the encroaching vegetation.

“Repairing damages lines is a costly and time-consuming exercise,” Brown says. “By introducing the ‘clear to the sky’ zone and increasing the notification zone by one metre, we will both protect lines from damage, and reduce costs to lines companies.”

Consultation will also start shortly on further possible changes to reduce the risk to powerlines from ‘at risk’ trees outside the GLZ falling onto lines.

The amendments to the hazards from trees regulations are expected to be gazetted in September.