Cyclone Gabrielle: A year on, are we more resilient?
Power firms and telcos front up on what they have done to ‘build back better’ and what’s still to do. Tom Pullar-Strecker reports.
If a storm identical to Cyclone Gabrielle were to strike the country on the first anniversary of that disaster on Wednesday, it might cause a little less disruption.
About 240,000 homes, or 11% of households, lost power during the peak of Cyclone Gabrielle on Valentine’s Day last year, according to Electricity Networks Aotearoa.
Electricity companies and telcos are reporting worthy progress improving the resilience of their networks since then, with more improvements in the pipeline.
Flooding, and damage to power lines and fibre-optic cables caused by trees and forestry slash piling into bridges, were responsible for many of the electricity and communications outages last year.
New Zealand Transport Agency Waka Kotahi can’t say whether the cyclone flushed out most of the loose trees and slash that caused so much damage or whether – like a penny-pusher game at the fair – a whole new bunch of “coins” have built up, ready to drop if given a further nudge.
Linda Stewart, its director of regional relationships for the central North Island, explains it doesn’t have oversight of “broader assessments of forestry debris and loose trees”.
But she says it has recognised the importance of clearing such debris as quickly as possible.
“An example of this was in November last year when wood debris was cleared from under State Highway 35’s Gladstone Road bridge following a storm,” she says.
“We continue to have a good working relationship with the forestry industry, and acknowledge the industry’s focus on mitigating risks in the event of future adverse weather.”
The problems caused by flood-borne debris appear to have been a wake-up call for telcos, including broadband network company Chorus, which have since built more resilience into their networks.
Telecommunications Forum chief executive Paul Brislen says hundreds of kilometres of fibre have been installed to replace damaged lines and provide extra back-up.
Some telcos have built “self-healing” capabilities into their networks, he says.
If that sounds reminiscent of the discussion in the movie Brazil about an air-conditioning unit supposedly fixing itself, the reality is a little less futuristic.
“The fibre is connected in loops so if the eastern side is down, all traffic routes via the west. It’s at the speed of light so the customers don’t notice at all,” Brislen says.
“Previously this would be done manually but now the automation is at a level where it kicks in straight away.”
The telco industry was at pains to point out last year that most cellphone sites that were knocked offline by Cyclone Gabrielle – 660 across the country – were cut off because of a loss of power, rather than damage to their own infrastructure.
The only way to address that was to truck-in portable generators and diesel to the road-damaged regions.
One NZ, Spark and 2degrees have all “refreshed and expanded” their fleets of generators and now have additional units ready for use around the country, Brislen says.
“Batteries are all on a schedule to be replaced and upgraded, and members are also introducing better automated power management that enables them to turn off features during times of excess need so core services will last longer.”
Some telcos have invested in “mobile exchanges on wheels”, cutely nicknamed Meows, that have satellite connectivity, to restore some service as quickly as possible after a disaster, he says.
In a possible game-changer for emergency communications, at least, all are planning to launch new services that should let ordinary smartphones send and receive text messages via satellite if customers are outside areas of normal coverage, including because of an outage caused by a natural disaster.
While One NZ has claimed an edge in this space because of its relationship with satellite-network giant Starlink, all three mobile operators have a track record of helping each other out and sharing their network capabilities in emergencies.
The biggest single cause of power cuts during Cyclone Gabrielle was the flooding of Transpower’s Redclyffe substation in Hawke’s Bay.
Redclyffe was one of 12 “critical” substations across the country that the national grid operator had previously identified in a 2020 report as being at risk of flooding.
The challenge is that moving a major substation is a huge undertaking and Transpower needs approval from the Commerce Commission to make major capital investments, given it is a monopoly that passes its costs on to customers.
Before the cyclone, Transpower had been preparing to ask the commission for permission to spend money making “two or three” of the substations more resilient to flooding between 2025 and 2030.
But Cyclone Gabrielle has caused it to attempt to pick up the pace.
Transpower grid delivery manager Mark Ryall says that as an “interim measure” it has rebuilt its control room at Redcylffe and elevated it by two metres, so that is higher than the flood waters reached last year.
It is now finalising a broader plan for the Hawke’s Bay, alongside local lines company Unison, that will take into account the result of new modelling of flood risks and projected power demand, he says.
“We would expect to have an update for the Hawke’s Bay community in a few months.
“Ahead of that, we are aiming to meet
with key stakeholders including mana whenua, councils, other infrastructure agencies and local landowners.”
Work has also been going on at the other 11 at-risk substations, as well as another four that weren’t on that list.
“For some sites, improvements are already under way. For others we are undertaking further investigation, and for others we are working constructively with councils to develop longer term regional plans,” Ryall says.
“This includes projects at Kaiapoi and Stoke that will provide greater resilience against flooding.”
Transpower has scheduled a workshop at the end of the month to discuss options for its Edgecumbe substation “following ongoing engagement over the criticality of this site to the region”.
The work is not cheap. A proposal Transpower submitted to the Commerce Commission in November asks for permission to spend $200 million on measures to improve resilience between 2025 and 2030, Ryall says.
“This is a mixture of hardening the grid and investing in readiness with portable equipment and spares.”
Transpower chief executive Alison Andrew told Parliament’s transport and infrastructure select committee on Thursday she would be very interested to see how the commission handled that request.
“At the end of the day, it comes down to how New Zealanders are going to pay for it.
“The interesting learning we had in Hawke’s Bay is it not just ‘power being available’, but it’s water being available, fuel being available, road access and telecommunications – we all want to come together as critical services and how do we make sure that resilience is appropriate across all of those central services?”
Unison network manager Gaganpreet Chadha says Transpower’s emergency repairs have made the Redclyffe substation more resilient.
Three smaller substations owned by Unison itself were also damaged by floods last year and have been built back better during “temporary repairs” in part by elevating equipment, he says.
“Permanent reconstruction of Unison’s flood-affected sites is in planning and will also be carried out using modern, modular and elevated design standards to ensure greater resilience.”
Chadha says regulatory reforms would help reduce the risk of localised power outages caused by the likes of falling trees.
Of the 240,000 homes that lost power because of Cyclone Gabrielle, about 67,000 were cut off because of falling vegetation, according to Electricity Networks Aotearoa.
It suggested in a submission to the Government in May that lines companies could take on more responsibility for trimming trees in people’s gardens to ensure they didn’t encroach on power lines.
That would be in return for foresters and commercial landowners taking full responsibility for vegetation on their own land.
Chadha says the electricity industry would like to see progress on updating the tree regulations, but appears under no illusions that will be easy.
“We understand this is a complex process involving property rights as well as commercial interests,” he says.