Residents have had numerous unplanned outages in the past six weeks. Yesterday Aurora Energy general manager operations and network performance Matt Settle said there had been a similar number of unplanned outages compared with the same time last year, but more people had been affected this year.
Despite repeated attempts, Aurora Energy chief executive Richard Fletcher has not responded to requests for an interview.
Retired electrical engineer Steve Tilleyshort, who was a network designer and planner in Central Otago for 20 years, said Aurora Energy’s weak network had been well documented, but the recent spate of long outages meant it also had a protection problem.
All lines had mechanical protection known as reclosers that "tripped" and cut out power if an animal or tree touched the line. These should reset automatically when whatever caused it moved away.
If the fault remained, such as when an insulator was broken, the line stayed out of service.
The control room would be notified and linesmen would be called out to find the fault, Mr Tilleyshort said.
In some places there were multiple reclosers, which should contain outages to the area of the fault.
However, if the protection was not set up properly the fault could run back down the line and trip out the entire system, which he suspected happened in Central Otago last month.
"I think it’s poor maintenance. I think [their maintenance is] wanting."
What he found more disturbing was Aurora had hiked up prices to stop this sort of problem, yet Central Otago still had significantly more outages than Dunedin.
Mr Tilleyshort went to hearings when the Commerce Commission allowed Aurora to seek millions from its customers for upgrading work on the network.
One of the conditions of that agreement was to be more open and transparent with the public, he said.
"Now they come into town and they have their slide show and glossy pictures and graphs and goodness knows what else, but that’s not the communication I think people want.
"I think people want to know if they have an outage, why did it happen and what are they doing about it?" Mr Tilleyshort said.
Aurora had told small businesses they should have a generator on hand if they were affected by outages.
Cafe owners, depending on how much cooking was done on their premises, would probably have to store diesel to run the generator, which led to a whole host of issues around storage, Mr Tilleyshort said.
Commerce Commission general manager of infrastructure regulation Andy Burgess said the commission was aware unplanned outages had increased in the year to March 31 last year, in both number and the length of time customers had been without electricity supply.
The report shows Aurora’s primary cause of outages in that year was defective equipment, with adverse weather events such as high winds across Central Otago and Dunedin also playing a role.
All electricity supply companies have to comply with minimum quality standards. Their performance is measured from April 1 to March 31 each year. The companies are required to report to the commission explaining any outages and their causes. The next compliance statement is due in August.
If Aurora is found to have breached quality standards, the commission’s enforcement powers range from writing warning letters, to seeking court penalties.
In early 2020 Aurora Energy was ordered by the High Court at Wellington to pay a penalty of almost $5million for excessive power outages in the 2016-19 years.
In 2020 the commission said it came close to taking the Dunedin City Council-owned company back to court but instead issued a warning.
In March 2021, Aurora Energy agreed to a customised price-quality path with the Commerce Commission to recover $563 million from its customers for much-needed upgrade work.
That included a 14.8% increase in average customer charges.
