Fears Queenstown at risk of Auckland-style blackout

Monday, 16 September 2019

The Frankton substation that supplies Queenstown is operating near capacity and nearing the end of its design life.

Tourist hotspot Queenstown may be at risk of a lengthy blackout unless power supplies are urgently upgraded.

Transmission lines and the Frankton substation are operating near capacity and are vulnerable to major weather events, natural disasters and population growth.

National grid company Transpower's South Island transmission network, showing the 110,000-volt lines running from Cromwell to Frankton.

Some fear a major power outage similar to one that lasted five weeks in Auckland in 1998.

Queenstown Lakes Mayor Jim Boult said he had been aware of the issue for sometime, and responses from lines company Aurora Energy and national grid owner Transpower had been unsatisfactory.

Aurora believes there is enough capacity for the next three to five years, while national grid owner Transpower says only 'a few customers' might need to be switched off if there is a fault during peak times in the next year or two.

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Boult said: 'They just haven't appreciated the growth of the district and what that means for their infrastructure. 'They're aware of it but I think they need to pick their game up.'

The issue was a concern to the Otago Lifelines group, a group charged with preparing and overseeing the region's infrastructure in the event of an emergency, which Boult chaired.

According to Queenstown Lakes District Council statistics Queenstown has a resident population of about 27,000 and hosts more than 44,000 visitors a day in peak seasons. Further, the council predicts it will need another 17,000 houses to meet population growth over the next 30 years.

Civil engineer Justin Ralston raised the issue at a chamber of commerce lunch with Urban Development and Transport Minister Phil Twyford on Friday

The transmission line supply from Cromwell to Queenstown exceeded Electricity Authority grid supply safety rules at peak demand, he said.

The vulnerability meant any failure could cause blackouts as well as the loss of sewerage and water supplies in Queenstown.

The transformers and substation at Frankton were also operating at capacity and nearing the end of their design life.

According to a 2018 Transpower Transmission Planning Report report they were due to be replaced last year.

Queenstown Lakes District Council chief executive Mike Theelen said the council was 'entirely aware' of the issue and was working with Transpower and Aurora to fast track an upgrade.

'A suggestion recently that the best way to solve it is to put battery packs into the district is completely untenable to us.'

Ralston said the main line and back-up line feeding Queenstown were attached to the same pylons, meaning both could be affected simultaneously

Theelen said the council had back-up facilities to manage power outages for critical water and wastewater facilities.

'Transpower and Aurora are very much aware of these issues and the need to ensure they deliver both adequate capacity and resiliency across the entire district,' he said.

Aurora Energy is owned by the Dunedin City Council and manages the electricity network assets for the region. The company has been under fire in recent years for its under-investment in infrastructure leading to rotting and dangerous power poles.

Aurora asset management and planning manager Glenn Coates said the company believed there was sufficient capacity to Queenstown for the next three to five years, but was looking at ways to achieve greater capacity out of the existing lines over the next five years.

'We remain committed to implementing the short term tactical upgrades to guarantee supply to the Queenstown community.'

Transpower stakeholder engagement manager Geoff Wishart said the Queenstown supply was 'actually quite robust'.

'Our infrastructure is neither coming to the end of its life nor operating at above capacity at peak times, and nor is Queenstown facing blackouts.'

However, there were concerns that if there was a fault or trip in the next year or two, the company might not be able to supply all of Queenstown demand.

Some customers might have controlled power cuts if a fault happened at peak time.

Transpower was talking to Aurora and lines company PowerNet about incremental investments to meet that risk.

Several small investments should provide the region another 10 years cover, 'but after that a new and much larger investment will be needed to continue providing this level of security'.

Ralston said it appeared the growth figures Transpower were relying on were out of line with reality.

The 2018 Transmission Planning Report includes allowances for a 1 megawatt (MW) or 2MW increase in Queenstown's peak demand each year until 2033.

Each new hotel required about 0.5MW and there are at least four under construction in the resort and several others preparing to build.

NZ Ski chief executive Paul Anderson said any blackouts would be worrying, although there were emergency generators at the Remarkables and Coronet Peak.

'We would be very concerned if there was a power-supply weakness there.

'Power is critical for us - not just for our business, for our community as well.

'We have got limited generating capacity at both the Remarkables and Coronet Peak. But we can't run full operations off generators, and snowmaking would be severely curtailed.'

Skyline Enterprises chief executive Geoff McDonald had not heard about the issue but would 'start to ask questions'.

'Up on the hill we have back-up generators in place for any emergency.'

That was important to keep the gondolas going in the occasional event of any storm-triggered power cut, he said.

PowerNet did not respond to a request for comment.