Transpower is looking at ways of boosting generation and making Northland's power network more resilient, following a region-wide power cut caused by the 20 June pylon collapse. Photo: Transpower
Beefed-up transmission lines allowing more energy to be produced in the Far North, and a grid-scale battery to keep the lights on if the national grid fails again, are among options being explored after a pylon collapse earlier this year.
National grid operator Transpower and its contractor Omexom last week announced a $1 million fund for projects benefiting Northland's economy.
It was part of a package of measures agreed with Northland leaders after June's region-wide power cut cost businesses an estimated $60m, according to economics consultancy Infometrics.
Other measures include developing plans for improving the reliability of Northland's power network, and for unlocking the region's renewable energy potential.
Transpower acting chief executive John Clarke said the Far North could become a significant producer of solar and wind power - the challenge was getting that power to Auckland, where it was most in demand.
Far North lines company Top Energy already had a geothermal power station at Ngāwhā, near Kaikohe, and Lodestone Energy had built New Zealand's biggest solar farm near Kaitāia.
But the development of more renewable power in the Far North was limited by the capacity of the existing transmission lines between the Kaikohe substation and Marsden Point, south of Whangārei.
The lines from Marsden Point to Auckland had plenty of unused capacity, because Marsden Point used to have two large oil-fired power stations.
Under the current system, the cost of upgrading the lines from Kaikohe to Marsden Point would be borne by Northland power users - even if the aim was to supply Auckland.
Clarke said the review would consider other ways that upgrade could be funded.
Options included splitting the cost between generators, or seeking other sources of funding.
"It's an opportunity to supply Auckland more effectively than power being dragged all the way up from the south, but we don't want the cost of those upgrades to fall on the local consumers," he said.
Clarke said the Northland Corporate Group - which brings together Whangārei's biggest businesses - had put up some suggestions for how it could be funded.
A power line upgrade was also one of the ideas put to Regional Development Minister Shane Jones when he visited the Far North last month seeking uses for the government's $1.2 billion Regional Infrastructure Fund.
Clarke said the resilience review would look at how existing infrastructure could be "hardened" so it was less likely to fail in storms, or when one of the two main lines supplying Northland was down for maintenance - as was the case when the pylon toppled in June.
A grid-scale battery, like this one being built by Meridian at Marsden Point, is one option being considered for the Far North, though the cost would be high. Photo: Supplied / Meridian
The review would also look at whether the Far North's power network could be altered to operate in "island mode" when not connected to the national grid.
Ngāwhā's geothermal power station cannot currently supply power when the grid was down, because - unlike something like hydro power stations, where flow can be increased or decreased to match changing demand - its output was at a constant level.
One possibility being examined was building a grid-scale battery in the Far North to smooth out supply and demand, but that would be expensive, Clarke said.
After the 20 June pylon collapse, Ngāwhā was able to supply domestic users across Northland once Transpower had restored the backup line connecting Northland to the national grid.
"Part of the regional resilience study is looking at, are there ways to allow Ngāwhā and future development of solar to operate on their own? That's not easy, but we have people looking at the technological challenges," Clarke said.
"The other thing is making sure it's less likely you would lose both connections to the grid, and if there are any ways of increasing the capacity of the backup line. There might be simple things we can do, because we're mindful this will cost money."
Clarke said the plan was due to be completed by the end of the year.
Northland MP Grant McCallum said sorting out Northland's power resilience, and providing a reliable supply of renewable electricity, would encourage businesses to invest and create jobs in the region.
Meridian Energy is currently building a grid-scale, 100-megawatt battery at Marsden Point, south of Whangārei.