Northland power outage: What we know so far

Power has been restored to tens of thousands of properties in Northland - but there is no hot water.

Many homes and businesses in Northland have been without power after a Transpower tower fell near Glorit about 11am on Thursday.

Northpower said in a statement just before 8pm that 65,000 of the properties it supplied had been affected.

Electricity had been restored to all but 5000, which were businesses and industrial customers. By 11pm, those had also been restored.

It said there could be rolling blackouts on Friday because power supply was limited, so it had turned off hot water to stretch the supply further.

It was urging people to conserve power until 10pm, and between 6am-9am on Friday.

Meanwhile, the other lines company, Top Energy, had 30,000 properties that were initially affected, but that had been reduced to around 7000 by Thursday evening.

At midnight, the company's outage map was showing only 177 properties were still without power.

The crisis arose after Northpower lost a major high voltage line into the substation at Maungatapere, a major feed from the grid, which caused much of the region to lose its supply.

Transpower said earlier 70 percent of consumers should have power back on by Thursday evening.

Executive general manager grid delivery Mark Ryall told Checkpoint its alternative supply was now up and running.

Northpower and Top Energy would be allocating the electricity to the majority of consumers.

"We do ask consumers if they don't need to put on dryers and things tonight, if they're lucky enough to have their power on, keep lights off in rooms you're not using so if everyone conserves a bit that will help a few more people get power. But it will be a balance to get through."

Outages might last until at least Friday night

Northpower chief executive Andrew McLeod said earlier on Thursday evening power might be out at least until the end of Friday for some consumers but potentially a day or two longer than that. It was awaiting Transpower's confirmation.

It was likely that on Thursday and Friday Northpower would rotate power availability so that customers were on for at least some period of the day, he said.

Northpower had about a third of the power it needed until the Transpower system was restored, he said.

There were two lines into the district and Transpower had turned one of them back on but it was relatively small compared to the one that was down.

"We have about 100 megawatts of load all over our network and we can supply about 30.

"What we're doing at the moment is configuring the network to get the critical load, so things like hospitals, we're making sure the refinery's on, we're making sure sewage pumps and things can run and just depending where those critical loads are, you [as a resident] might be lucky enough to be on as well."

Transpower was coordinating with all the power distributors in the region in a combined effort to get as much energy as possible, he said.

"They've got construction crews on site, they've got equipment on site, they're working at pace to really address this tower, that's a big structure down and to get it sorted in a day, or even three days, is pretty impressive."

Once Transpower had informed Northpower when power would be back on line, Northpower would publish clear information on its website about the plan for which areas get power when, he said.

Given that some would not have access to power to look at their computers, McLeod said the company would also be publicising it via radio and hoped that those with power could spread the word to their neighbours who may be without.

McLeod said the national grid was very well maintained and this was an extremely unusual situation and the first time he had heard of a power pylon falling in this way.

What caused the tower to fall?

Transpower's Mark Ryall said it was still too early to say.

There would be a full investigation, but the priority was restoring power to the region.

Ryall said he did not know why the tower fell over, but it should not have done so in the conditions.

A maintenance crew had been working on it and he was thankful no one had been injured.

As far as he was aware there was no corrosion problem with the tower.

"We've 12,000 towers around the country and we maintain them in very good condition and tower failure is exceptionally rare."

What to do if you're affected

Civil Defence advises:

• Check Transpower's website and Facebook page plus retailers' websites and local lines companies for up-to-date outage information.
• Turn off your power if you are told to do so. Unplug small appliances as these may be affected by power surges.
• Don't use candles for lighting as these can cause fires
• Don't use outdoor/patio heaters or barbecues indoors as these can cause carbon monoxide poisoning
• Use battery operated radios and use your cellphone sparingly to conserve its power
• Check in on your neighbours and make sure they're okay