The research took these scenarios and modelled how they might change Auckland's sea level, the frequency and severity of wind and storms, change rain patterns and temperature extremes.
The report, from EY, titled The Physical Risks from Climate Change — Report of Findings for Vector Limited (November 2017)*, looked at how the network would be impacted around Auckland either directly, with king tides and storm surges, combined with rising sea levels, causing a critical substation to be inundated during flooding; or indirectly — more frequent, strong winds bringing down more trees on to power lines.
The report found climate change would cause increased risks to Auckland's electricity network, mainly from weather related causes, and we should prepare now. That big April storm, when nearly a third of Auckland had no power at one stage, was a classic example. Hurricane-force winds, in part due to climate change, blew thousands of trees and branches on to lines all over Auckland.
We have a vegetation management programme to manage the risk trees pose. But given the scale of destruction from the April storm, it's clear there's room for more understanding of the role lines companies, landowners and government must play in managing that risk.
What Vector can do about trees is governed by 15-year-old regulations which also set out what private landowners should do. With extreme weather events expected to increase, it's time to decide who needs to do what, and the choices and trade-offs required to achieve different levels of resilience, especially given electricity's increasing criticality in a low-carbon world.
The report provided recommendations to mitigate the increased risks from climate change. Many are well under way.
Our approach involves maintenance and strengthening programmes covering 8000km of overhead lines and 10,000km of underground lines, managing trees near lines, and increasing the share of distributed generation, storage, and demand management across the network to improve the ability to absorb storm events.
Technology is dramatically changing the way electricity is provided. If a storm hits and a tree knocks out a line on your street your power might not have to go off if there's an alternative source nearby. This could be a domestic solar and battery system, a community microgrid, or even an electric vehicle whose battery could power your home.
The research Vector commissioned was a drop in the bucket of what's needed to get New Zealand prepared for the worst impacts of climate change. Vector is also looking past the physical effects of climate change and towards what economic adaptation might be needed in the transition to zero carbon by 2050.
* EY Disclaimer: The report has been prepared for Vector. EY disclaims all liability in relation to any other party who seeks to rely upon the report or any of its contents.
Kate Beddoe is Vector's chief risk officer.
