Photo: Florence Charvin

[As published in May/June BayBuzz magazine.]

With power supply to the region cut off and our local electricity network in tatters, a simple cuppa was a pleasure denied to thousands of people in Hawke’s Bay in the aftermath of Cyclone Gabrielle. 

This is the story of how the two main players in getting power to the people – Transpower and Unison – worked together to get the lights back on during February and March.

As well as, of course, exploring the all-important questions about were they adequately prepared and what comes next? BayBuzz caught up with Unison’s Jason Larkin, General Manager Commercial, and Quentin Varcoe, General Manager People and Culture, to learn more about the challenges facing the company and how it responded to the many challenges brought about by the cyclone.

Unison’s cyclone response involved more than 250 people in a massive operation that saw all of the company’s 13 Hawke’s Bay crews on the ground as well as 12 crews from out of region lines companies that swung in behind.

Jason Larkin says that the whole of Unison can be proud. “It has been a team effort. From those in the field working very long hours in those first days and weeks, there was an unending amount of work.”

It wasn’t just high winds and rain that inflicted damage, but also floodwaters that wreaked havoc on the local network and at Transpower’s Redclyffe substation, where connection to the national grid was lost. And with it, power to most of Napier and substantial parts of Hastings District.

Larkin says Unison and Transpower worked together really well, with the preparation for restoring power detailed through the regional 110Kv contingency plan, developed by the two companies after the 2016 snowstorm. This details how (in the event of loss of the main 220 Kv transmission connection) power would be fed from the South through Woodville and Waipawa to Fernhill.

Cyclone Gabrielle Napier New Zealand Sunday 19 February 2023 Photo by John Cowpland alphapix

“The fact that we had done this work with Transpower, all the switching plans were in place, all the protections had been engineered and programmed … it was a multi-year project. It was the difference between having parts of Hastings on within hours or a number of days, had that work not been done. This is testament to the kind of efforts that have been going on to ensure there is resilience between both Transpower and ourselves … in the event of a major loss of supply to the region,” says Larkin.

Speaking of the relationship with Transpower, Quentin Varcoe talks about the initiative that Transpower and Unison showed – working together – to work around the issues affecting Redclyffe. “When we really needed them they shone. Their creativity to get power back on to Napier was something that most people won’t understand,” says Varcoe.

Each year Unison invests between $55 million and $65 million in capital expenditure, with another $10 million to $12 million on maintenance. Larkin wouldn’t be specific on how much Cyclone Gabrielle has cost the company, saying it was well into the millions (but not tens of millions, yet).

“We have three substations flooded … they’re going to have to be re-located and rebuilt from scratch. The Commerce Commission has given us more time to update our asset management plan.”

Diana Kirton, Chair of Hawke’s Bay Power Consumers’ Trust – the entity that owns Unison on behalf of the people of the region – says Unison’s response was phenomenal on all levels.

“I feel that power consumers can be enormously proud of the company that they are all shareholders in.

“Every action has been in the best interest of power consumers … to the point where they are now individually knocking on doors,” says Kirton.

Unison says that it identifies risks in relation to its network. Larkin says when it comes to capital expenditure one of the factors Unison considers is delivering the best outcomes for the most customers. That means that urban projects are prioritised.

“The three substations … those vulnerabilities were known from a criticality point of view. They’re not at the top of the list. And the reason for that is they are rural with a smaller number of customers. They were planned to be addressed in the future, more from an asset condition and performance point of view. And when they reach end of life or replacement they would have been replaced with a resilient modern equivalent.”

Unison describes its new look substations – such as in Windsor, Hastings – as resilient and sustainable. Built 1.5 metres off the ground, with a cable basement that can have water in, or through it and not have any impact on the substation. It’s built to the IL4 building standard, meaning it has to be operational after a major event like an earthquake.

Turning to the connections to the national grid, Transpower’s General Manager of Grid Development, John Clarke, says that Hawke’s Bay is reasonably well served in terms of grid power supply compared to other parts of New Zealand.

Our main grid connection goes from Redclyffe back out past Pan Pac at Whirinaki all the way to Wairakei, and a local network runs down towards Palmerston North, and north to the Waikaremoana hydro scheme.

“It was actually a real blessing for the region during the floods. While the main grid connection was lost, because everything goes through Redclyffe – which was a vulnerability – the Genesis hydro scheme and Fernhill substation both remained running and in service, and that’s why people in Hastings had minimal interruption.”

Redclyffe, on the banks of the Tūtaekurī River was built in 1927. It was upgraded in the 1970s, when engineers assessed the stopbanks as being sufficient to prevent flooding at the substation in a major event. A new switch room was built in 2010 for $8 million. Surprisingly, flood risk hasn’t always been high on Transpower’s risk radar; a review of historical company documents outlining risks to Hawke’s Bay transmission supply mention snow and wind, but not flood.

Redclyffe days after flooding

Of the damage at Redclyffe, Clarke says it exceeded what had been modelled in the one-in-500-year event scenario, and had any planned resilience work been implemented, it would not have withstood the extent of the flooding experienced.

The 1927 substation was only lightly flooded, the switch room was not affected, and the 1970s substation part of the site, which is the main grid connection, as opposed to the local connections elsewhere, were the worst impacted part of the site, along with the control room.

“Our big challenge is to rebuild the control room.”

Clarke says that resilience is a conversation. With climate change beginning to have an impact, Transpower did a lot of scoping studies in 2020, looking at 170 substations. Redclyffe scored really highly on both risk of flooding and criticality. As a result Transpower planned to put a $109 million proposal to the Commerce Commission for its 2025-2030 funding period to do three sites.

In the weeks after Gabrielle, Transpower announced that 12 substations nationwide “vulnerable to extreme flooding” would receive additional resilience work. Three of the 12 are in Hawke’s Bay; Redclyffe, Whirinaki, and Whakatu.

Transpower is doing the investigation and costing so that it can upgrade its funding request, and Clarke says it “will be looking for more than $109 million, particularly around addressing flooding risk”.

Clarke is at pains to point out that flooding is one risk, among a range of risks including seismic, volcanic, rain, and snow.

As for Redclyffe, Transpower will make a “directional decision about the way we’re going in the next three months”, says Clarke.

“Is it viable to look for somewhere else, given the various constraints, or do we just get on with it and roll up our sleeves and build something, even though we’re on a floodplain? We think we can make resilience against a similar event in the future.”

The rough cost of the options for Redclyffe range from $30 million to $60 million, with some of the costs covered by insurance.

Clarke reassures: “We’re committed to sorting things out, getting a resilient supply. Whether it’s a rebuilt or partly rebuilt Redclyffe, or relocated, it is a priority for us.”

What was learnt? And the rebuild

Larkin, Unison’s lead on the cyclone response says there is very little Unison would do differently in terms of overall decision making. “I think we made the right calls … and the results speak to that.” Referring to the teamwork between Unison and Transpower and the initiatives taken to bypass Redclyffe and connect to other parts of the electricity network in the Bay, Larkin says: “If we had just fixed the problem, and repaired what was damaged, a large part of Napier would still be off.”

Clarke says that Transpower will develop a bigger resilience programme.

“Do we need more temporary or mobile equipment like a temporary control room that we can deploy?

“We’ll be having a good think about that. But mobile substations and temporary control rooms at grid scale are not trivial things. Maybe we should’ve had some of those things on hand … to help us recover faster. Especially where you have a lot of sites that may have met standards at the time, but don’t meet current standards,” Clarke says.

Consumer Trust Chair Kirton says that the cyclone has highlighted a number of things for Unison that are going to be cause for reflection when it develops its next business plan.

“Things around the configuration of the network and substations, and working with Transpower with an eye to the future, in light of past events.”

The Trust will be keeping an eye on Transpower’s remedial work with respect to its vulnerable Hawke’s Bay substations.

“Now we know how vulnerable areas can be. We will be speaking up for the consumers to make sure that it is a priority,” she says.

Transpower and Unison are working together on the rebuild, just as they did on the response. Unison recently said it was working alongside Transpower to ensure supply into the region meets demand ahead of winter, with a firm plan in place to undertake the work required to build additional resilience and security in transmission supply, ahead of peak demand during the cooler months.

Transpower’s Clarke says the work it’s currently doing with Unison “takes us back to where we were, pre-cyclone”. The first task is to unwind the emergency fixes put in place to compensate for Redclyffe, before proceeding to additional resilience work that Transpower is seeking funding for.

Regarding the future and the right way to supply the region from the national grid, Larkin says that Unison and Transpower are evaluating the options, and that once a decision is made “we’ll certainly be involving the community and stakeholders in that decision, because ultimately there are costs that go along with it.”

It would seem to BayBuzz that keeping local stakeholders well informed of just how our electricity infrastructure providers plan to build back smarter over the long term is a critical transparency and engagement requirement for both organisations, essential to protecting community goodwill stemming from the cyclone response.

Supporting infrastructure – bigger, safer, stronger, smarter?

No discussion on the rebuild of electricity infrastructure would be complete without touching on the stop banks.

We all know that Gabrielle’s devastation was fatal to lives, ways of life, and livelihoods. The big unknown is just how big was it? Hawke’s Bay Regional Council (HBRC) says that it will take a year to do that calculation. Right now its focus is on rebuilding flood protection infrastructure back to pre-Gabrielle levels, which in all but the recently upgraded Taradale stop bank is a 1 in 100 level of protection.

Pre-cyclone HBRC committed to increase the level of protection across all stop banks to 1 in 500, which will come with a hefty price tag and a long timeframe; the short distance of the Taradale upgrade cost $4 million (co-funded by Government and HBRC) and took two years.

In the meantime the question of whether Gabrielle was bigger than a 1 in 500 event remains unanswered for the foreseeable future. As does the even more critical question of whether a 1 in 500 level of flood protection will be adequate going into a climate change future that NIWA says promises increasingly severe rainfall events?

What can Hawke’s Bay do about building back better, stronger, safer and smarter?

Cam Wylie, geotechnical engineer and CEO of RDCL, says Hawke’s Bay is a dynamic physical environment characterised by floods, drought, earthquakes and even volcanoes.

“The challenges to resilience are many. It is a long term game. Gabrielle is the regional development opportunity to frame the response and commit to the resilience.”

“If we do not build back better, in whatever form that may be, we should accept that large events will disrupt our, or our children’s, or our children’s children’s lives. With all the tragedy, loss, and cost that comes with these things. Without question that will happen,” he warns.

With that in mind, BayBuzz encourages Hawke’s Bay people to get more involved.

We can have a say, albeit indirectly, on the running of Unison by voting for the Hawke’s Bay Power Consumers Trust board. We should pay more attention to oversight of this lifeline utility, and how it performs for the community. But sadly few of us care enough to get involved. At the last election nearly 70% of those eligible to vote chose not to participate in these important elections.

Surely that’s where the real power lies in getting power to the people. 

Unison’s Cyclone Gabrielle response 

• Over 60,00 hours, including extra contractors that came in to help.  

• 25 crews: > 13 Hawke’s Bay crews > 3 Taranaki LinePower crews > 2 Hamilton WEL Networks crews > 3 Whakatane Horizon Networks crews (includes 1 Vegetation crew) > 3 Rotorua Unison crews plus management & office support > 1 Taupō Unison crew

230 power poles replaced

80 kms of power lines replaced

18 generators supplying power to around 2580 properties.

• 25 community meetings attended

• At 8am on 5 April there are <100 residential connections still without power, that are yet to be inspected and livened

• A further 301 properties are unable to be safely reconnected due to flood/ cyclone damage

• Has a plan for every customer affected 

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4 Comments

  1. Excellent article, Unison did an outstanding job and went above and beyond for the people of HB, good job all round.

  2. Hi,
    You have sought the information for your article from the people responsible for the work and (as you might have guessed) they have given you a rather biased (sanitised) version of the facts. There’s a lot more to this story than you will get by asking Unison and Transpower to tell you how well they did.

  3. Having worked for 45 years in the power supply industry I certain agre that Unison and Transpower did their best AFTER the event to get the power back on.
    But there are some unanswered questions about the lack of resilience in the design of both of their networks which has not been addressed at all.

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