Price of power in a stormy city may have just gone up
many parts of the city where old lines have been replaced. Vector spends $10 million-$12 million a year replacing old overhead lines, especially in at-risk areas. That includes places where cars keep hitting the poles.
Of the 45 per cent of power lines still above ground, 60 per cent is in the north and northwest, much of it in small town and rural areas.
Undergrounding is not easy. The work has to be co-ordinated with Chorus, so broadband cabling goes in at the same time. Street lighting needs to be redesigned and footpaths often need to be re-laid.
The lines have to be at least a metre down, often more, and in areas of volcanic rock that means a difficult dig. Regulations state they can’t dig under the drip lines of trees, which limits where the lines can be laid.
Is undergrounding the whole urban area even possible?
“It’s possible,” says Mackenzie, “but it’s very challenging. The costs are extremely challenging.”
He says undergrounding costs from four to 10 times as much as running the cables above ground. Vector’s rough estimate is that to put all remaining cables underground, just within the urban limits, never mind about the west coast, Riverhead and all the other exposed rural areas, would cost about $3 billion.
“That’s equal to the entire value of our current asset,” says Mackenzie.
A question for Auckland, right there. What does this cost-averse city want to pay for a secure power supply?
Still, Mackenzie says network resilience is high on the agenda and there are things they’re doing already. In Kawakawa and Wellsford, for example, Vector is building two micro-grids, where the power will come from solar batteries backed by diesel generators. Self sufficiency, with added environmental benefits.
It’s an approach that already works in some other isolated parts of the country, and in some Pacific Island territories when disaster strikes. Many of the other more isolated parts of the city could use it too.
To limit the threat of rising sea levels, new substations are sited higher above sea level.
“Smart poles” can address the issue of trees on suburban streets. With these, the lines are bundled and strung higher so they’re less likely to be in your vision line and more likely to be out of the way of wayward branches. Beyond that, there’s some tough talking to do with the Auckland Council, the Government and the Electricity Authority about how best to manage those trees.
Another problem? Auckland’s growth. “We’ve budgeted to spend about $2 billion over the next seven or eight years,” says Mackenzie. “That’s just to accommodate new growth.”
He says they can fund the work, but it does put a brake on what else they can do.
Is that a problem for the existing network? Does all this add up to infrastructure that’s overworked, too old and unfit for purpose?
“I don’t know why you would think that,” says Mackenzie. He says the average age of the lines is 20 years, and they should last 40. “You could say the network is in its midlife.”
Older lines, he says, “are identified and in replacement programmes”.
Health and Safety regulations mean they no longer work in a “live line environment”, which requires more planned outages when maintenance is required.
And then there is the traffic. Vector vehicles are not allowed to use rooftop flashing lights, so they can’t get through the congestion quickly when they need to. Mackenzie tells a story of a truck stuck in traffic for 90 minutes, trying to get to Freemans Bay. The job itself, when they finally arrived, took just five minutes.
Auckland infrastructure: Turns out the problems all join up.