We take power for granted.
Power as in the electricity (and gas) that heats our homes, refrigerates and cooks our food, pumps our water from private bores and water tanks, charges our phones and tablets, and keeps our computers ‘plugged in’ to the outside world. Power that at the community level keeps our water infrastructure flowing, our production lines humming, our surgical suites operating, and our Eftpos machines ka-chinking!

Until all of a sudden … there’s no power. As when the region suffered its major power loss in early August, for example, and Napier residents were asked to not take baths or flush toilets “unless absolutely necessary” because of potential wastewater pumping issues. That was a minor inconvenience compared to rural residents who in the worst cases went without power for weeks.

Reflecting on the recent outage, Hawke’s Bay energy providers are being asked to reassess the resilience of their networks and be more open with customers,subpreparing them better for potential risks.

In fact, our national and local gas and electricity distribution networks are quite vulnerable, given the region’s propensity for natural disasters and sitting at the furthest end of single source supply lines for energy mainly produced outside the area where most outages occur.

The Transpower national grid and the First Gas pipeline both feed regional suppliers from three locations and supply could be interrupted by weather or geological disturbances at dozens of distribution points.

Seismic activity poses the greatest threat to uninterrupted supply along with flooding, landslips, severe wind, ashfall and bridge failure, particularly if such structures support gas networks.

Reflecting on the recent outage, Hawke’s Bay energy providers are being asked to reassess the resilience of their networks and be more open with customers, preparing them better for potential risks.

Roger Fairclough, advisor to the government’s National Infrastructure Unit (NIU) and chair of the New Zealand Lifelines Council (NZLC), says everyone from infrastructure providers to their residential, commercial and industrial customers need to be more aware of what to do before things go wrong.

He says regional Lifelines groups – providers of essential services such as water, power, gas, transport and telecommunications – should be undertaking risk-assessments and having more transparent customer conversations.

“You cannot guarantee 100% supply… they need to encourage customers to address resilience as there’s a mismatch in expectations.”

Vulnerability inventory
The HB Engineering Lifelines group began a comprehensive assessment of energy supply vulnerabilities nearly 20 years ago, and despite massive changes in technology and readiness, its 15-year-old report, Facing the Risks, is still the only hard-copy risk reference.

Facing the Risks feeds into a 2015 report to inform the Hawke’s Bay Regional Council’s Energy Futures inventory of needs and risks intended to inform a regional energy strategy.

While core data has been migrated to map-based geographical information systems (GIS) on natural hazard threats, work on adding lifeline networks and their interdependencies remains incomplete.

The HB Lifelines group faded from sight until plans for its resurrection were announced concurrent with the government’s NIU publishing its report urging regions to get a better handle on infrastructure resilience.

The HB Lifelines group faded from sight until plans for its resurrection were announced concurrent with the government’s NIU publishing its report urging regions to get a better handle on infrastructure resilience.

According to the NIU, Lifelines groups are essential to the success of its aspirational plan of a nation with resilient, coordinated infrastructure “contributing to a strong economy and high living standards” by 2045.

Hawke’s Bay Civil Defence Emergency Management Group (CDEMG) controller Ian Macdonald says the Lifelines groups arise from the Civil Defence Act requiring suppliers of power, gas, telecommunications, roading and ports to have contingency plans for reducing risk.

He concedes HB Lifelines started off “with a hiss and a roar” then died away. “Maybe they thought they’d done the work or there was a lack of drive,” but now they’re back. “It not only makes good sense but it’s good for business.”

They need to “work together to get themselves back up and running as soon as possible after an emergency,” says Macdonald.

Lifelines recharged
The man tasked to drive things forward is new chairman Oliver Postings, senior planner with the New Zealand Transport Authority (NZTA), who stuck his hand up to “drive things forward” from September 2015.

His priority is to build understanding by mapping the ‘network’ of vital infrastructure and service providers, their interdependencies, preparedness for emergencies and what can be done to improve things “so we can all respond a lot quicker”.

He says Facing the Risks would be too expensive to revise, but it remains a key reference. Many of its recommendations have been acted on, including seismic strengthening of the West Shore bridge which has a gas line running underneath it.

The common threads remain. We rely on a single conduit for gas and electricity and Hawke’s Bay is one of the most earthquake prone regions in New Zealand, with 22 known active faults and folds producing high level shaking over large parts of the territory.

The main Transpower supply link for all the East Coast comes from the Wairakei geothermal power station across the rugged terrain of the Napier-Taupo Rd. Its massive towers are highly exposed, and although built to “structural seismic design codes” that’s no help in a landslide or if the ground distorts beneath them.

The Redclyffe substation (behind Taradale) is the major switching subpreparing station connecting Transpower’s 220kV (220,000 volt) supply with Hawke’s Bay and the region’s 110kV system supplying points south and via the Waikaremoana power stations at Tuai northward to Wairoa and Gisborne.

A fault at Redclyffe at 9.45am on 18 December 2012 resulted in Hawke’s Bay and Gisborne being without power for two and a quarter hours.

Unison commercial manager, Jason Larkin.

Circuit breakers broke
Most of Transpower’s national grid feeders and their numerous support structures have twin circuits. It’s a rare event when both fail, unless you get a “simultaneous lightning strike” like the one in April 2014, or a once-in -54-years snow event like August 5-6 which caused double failures.

With the 220kV lines under heavy snow loading, when wind caused the snow on one of the conductors to release, it acted like a rubber band, flicking up and hitting the line above it causing the first circuit to trip.

Around 3.30am on August 6 the second circuit also tripped due to snow and the system isolated itself to prevent further damage.

Efforts were made to re-energise both circuits, then as snow built up, the first circuit tripped again; fearing the second could fail, a decision was made to ramp up generation and “island” the region.

That meant isolating the East Coast into its own island grid linking the emergency diesel-based supply at Whirinaki to the Waikaremoana generators. The next step was to bring on the old Waipawa to Bunnythorpe 110kV link, but before that could happen the second Transpower 220kV circuit tripped.

Unison commercial manager Jason Larkin says an imbalance of load meant there was “too much generation” for the local network to handle and Transpower’s attempted “islanding” failed when the second outage occurred around 10am.

Most of Transpower’s national grid feeders and their numerous support structures have twin circuits. It’s a rare event when both fail, unless you get a “simultaneous lightning strike” like the one in April 2014, or a oncein- 54-years snow event like August 5-6…

The snowstorm destroyed over 200 power poles in Unison’s high country distribution network. While both Transpower outages were restored within four hours, it was almost a month before some remote Taupo Plains customers were restored, with them having to rely on back-up diesel generation brought in to supply power.

A decade and a half ago, Facing the Risks had identified the 220kV lines from Wairakei as a major vulnerability of supply. Unless lines from the south could provide sufficient supply and Waikaremoana was operating at full capacity, severe loading restrictions would need to be imposed.

Holding the line
However, the report didn’t factor in Whirinaki generation, which was being sold off by the Government at the time. Under Contact Energy it still acts as an emergency back-up, but such contingencies are unstable and limited.

The report also warned the twin-circuit branch line north from the national grid was a major vulnerability. “Any loss or disruption of that 220kV link, even momentarily, would affect the whole of Hawke’s Bay-East Coast region “until system stability is restored.”

In September 2000 Hawke’s Bay and Gisborne lost power for up to four hours in two early morning outages after storm, snow and ice damage. This and the August 2016 outages could have had more serious economic consequences in peak hours.

At the end of September Unison called a meeting with Transpower to hear what improvements were planned and what could be done to improve resilience.

“They’re considering physical things such as spacers to prevent line clashing, and we wanted to understand more formally their changes in operating practices, so islanding supply [would] ensures success so we don’t drop the region,” says Unison’s Jason Larkin.

He insists there was no shortfall in performance – “it was an extreme event” – but Unison still needed reassurance that Transpower would ensure better matching of generation to load during ‘islanding’ which is difficult to manage at the best of times.

Natural gas pipeline atop. Lifelines chairman, Oliver Postings.

Maintaining stable supply across the Hawke’s Bay grid also presents challenges. Transpower has points of supply into Waipawa-Waipukurau through Centralines (Unison) with 7,500 customers and Wairoa serviced by Eastland Network with 5,200 customers.

Sub-zones upgraded
Unison’s main Hawke’s Bay network, servicing 60,000 customers who use around 850Gw per year, covers the area between Te Aute in the south, the Kaweka Ranges in the west and Putorino (north of Napier).

Its primary 33kV (33,000 volt) grid spurs spread out from Redclyffe, Whakatu and Fernhill with exit points to 23 zone substations supplying homes and businesses.

The common threads remain. We rely on a single conduit for gas and electricity and Hawke’s Bay is one of the most earthquake prone regions in New Zealand, with 22 known active faults and folds producing high level shaking over large parts of the territory.

Facing the Risks identified switchyards in sub-stations as being vulnerable to seismic activity, particularly those on higher support structures with extensive buswork and overhead line connectors.

It flagged nine switch stations across Hawke’s Bay as being at risk, including the cable from Faraday St to Bluff Hill in Napier and the Faraday 33kV switchyard on “reclaimed liquefaction land” which placed the entire Napier CBD at risk.

Larkin says Unison has attended to most concerns including replacing cable, geotech stabilising, civil engineering and risk management work. Flaxmere was upgraded recently with remaining rural sub-stations now being targeted.

He says the average age of network assets is around 20 years, although some are up to 50 years old. “By industry standards we now have a relatively young network. We’ve put a lot of effort in over the past 10 years with more modern approaches to assessing, controlling, managing and maintaining our assets so we have a good picture for risk management.”

Larkin says Unison’s network is geared for redundancy. “You have diversity like a spider web so any outage impacts a limited number of customers with a degree of intermeshing allowing us to isolate a problem then backfeed around that from another supply.”

Power base back-up
Meanwhile, the Unison Alternate Operations Centre near the Te Mata Road sub-station in Havelock North is now geared to take over from its Omahu Road headquarters in emergencies.

Following the Christchurch earthquake, Unison decided more substantial backup than the unit in a shipping container parked next to the Hastings City Council buildings was needed to manage significant events for longer periods.

CDEMG controller Ian Macdonald says big lessons came out of Christchurch that have been heeded and built into the asset management plans of many organisations.

The goal is getting redundancy in systems and making existing systems more resilient, and to that end CDEMG is rolling out a refreshed community resilience plan which could take up to five years. Still, he adds: “We’re dreaming if we think we’re going to have 24/7 uninterrupted power living in New Zealand.”

He says the new challenge is getting the message across to small to medium business. “They’re the ones that folded in Christchurch and that’s where most jobs were lost; the quicker they get back up and running the better.” They need to have a back-up of customer records stored off site, make arrangements with staff, and decide whether a generator is vital to business.

And vulnerable areas like Clive and the Cape Coast need to take resilience more seriously. “They need to depend on their own community if roads are cut off through flooding and there’s no guarantee police or fire can get to you.”

Keeping Napier dry
The Napier CBD for example is at risk, as are the Napier pumping stations. “Napier is only kept dry because of those pumping stations.”

The challenge is to think outside the square. For example, there are two big generators “so the lights don’t go out half way through a cricket game at McLean Park”, that can be uplifted and moved to the pumping stations.

Hawke’s Bay Hospital has its own generator and gas. While Napier and Hastings councils have generator capacity, “that’s being reviewed and its likely there’ll be more generator purchases,” says Macdonald.

National Lifeline’s Council chairman, Roger Fairclough says a regional strategy is needed so infrastructure providers and businesses can plan how they’ll survive through prolonged energy loss.

Creating a stocktake of interdependencies and weakness and how these can be addressed is a conversation that’s long overdue, he says. Under legislation, Fairclough notes, there’s a requirement for suppliers to continue delivering to their customers, and in some cases that might mean offering remote area solar or generator power.

Circular dependencies
So what do businesses need? Water, telecommunications to transact cash, a diesel generator to keep some things working… petrol stations might not be operating without electricity so “circular dependencies start kicking in”, says Fairclough.

Electricity sector service people need petrol to do their job so it’s important some service stations still operate, and isolated, remote and coastal communities need to carefully consider how they’ll cope, says Fairclough.

Meanwhile the HB Lifelines committee is back on track, mapping the resilience of essential services providers including roading networks, specifically where their infrastructure intersects with the provision of electricity, gas, sewage piping, water and telecommunications.

“Our members are focused on understanding how prepared they are and if they’re not then doing something to address that,” says chairman Oliver Postings.

Lifelines data will be provided to Civil Defence at the emergency hub beside Hastings District Council buildings to help prioritise infrastructure at risk, including power transformers and sub-stations and what needs fixing after an event.

Unison’s Jason Larkin concedes the ideal goal of regional self-sufficiency is not how New Zealand’s electricity system is topologically configured. “We have to get power from where it’s produced to where it’s used in a secure way…the generation resources aren’t here.”

He reassures that the regional network is in good condition with enough capacity to cope in emergencies; in fact we’re probably better off than Auckland which uses a lot of power but generates very little.

“The grid has security and capacity and there are contingencies” and Transpower are looking at further improvements, he says.

Confidence of supply is a basic business principle and, for a region looking to grow its economy, getting the message of resilience across is paramount.

In fact all employers and managers are required to engage in risk assessment, continuity plans and ensuring worker safety under the Health and Safety in the Workplace Act.

Essentially then, as well as the Lifelines and NIU wake-up calls, local authorities and infrastructure providers are already under a legal and public good imperative to meet household, commercial and industrial needs and collaborate on back-up plans to ensure there’s power to the people.

Gas vulnerabilities
The loss of gas supply to Hawke’s Bay in 2004, when an NZTA bridge was swept away in the Manawatu, was a classic case of how interdependency can impact essential lifelines networks, says Lifelines Group chairman Roger Fairclough.

After the Saddle Rd Bridge near Ashhurst was lost, a 30 metre section of gas pipeline was left hanging in the air, cutting gas supplies to Hawke’s Bay by 90% just ahead of Art Deco weekend in mid-February 2004.

It took two weeks to restore services. Heinz Wattie was one of the hardest hit, with dozens of extra 45kg gas bottles rushed in from other regions to keep the wheels of industry ticking over.

“They should have known about that vulnerability and reticulated to major customers at least,” says Fairclough.

The gas pipeline servicing most of Hawke’s Bay is at the end of a system which originates in Taranaki and along with the distribution pipes remains vulnerable to damage.

First Gas (replacing Vector from October 2016) provides 80 kilometres of high pressure lines to the region, redistributed from gates in Takapau and Hastings by Powerco and a couple of others. In 2014 Powerco had 4,438 residential and small business customers, 284 commercial and 20 industrial clients providing 1,606 petajoules (PJs) of gas annually.

A long intermediate pressure (IP) line has supplied Napier from the Hastings gas gate for 30 years. Powerco began replacing the majority of the seismically vulnerable cast iron and asbestos pipes with polyethylene from 2013.

Several local energy retailers distribute from Powerco’s Karamu Road gate, which is the transfer point for the 36 kilometre pipeline to Whirinaki and to industrial and commercial customers in both cities and points between.

Nova Energy also has its own gas pipeline covering parts of Hastings, Napier, Havelock North and Waipukurau.


Unison is pleased to sponsor robust examination of energy issues in Hawke’s Bay. This reporting is prepared by BayBuzz. Any editorial views expressed are those of the BayBuzz team.

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