Power outages: Hawke's Bay loses power for second time in a week

Transpower has had to cut power to Hawke's Bay residents for the second time in a week. Photo / Bevan Conley

Some Hawke's Bay residents have had their power cut off by Transpower for the second time in a week after another power surge.

In a post on its Facebook page this morning, Transpower apologised to its consumers in Hawke's Bay, saying it had an "issue with local generation".

It then had to ask providers Unison Networks and Eastland Network to reduce electricity use in the area.

However, when contacted by the Herald, a Transpower spokesman said it didn't appear as though residents were plunged into darkness like last week.

He believed the networks had likely sorted the issue by reducing, or shutting off, hot water.

"We are working hard to get you reconnected as soon as possible."

Transpower was alerted to an issue at the Genesis-run Tuai power station, Lake Waikaremoana, at 7.20pm when it lost full generation.

A Genesis spokesman said it could take "several days" to work out why there was a loss of power at its site.

"This morning we lost supply of local power services to the Waikaremoana scheme which meant the scheme was tripped at approx. 7:14am and returned at 7:44am.

"The Hawke's Bay area has transmission constraints which means for a lot of the time they rely on some generation from our scheme being available. This has been the case for many years."

The spokesman said they weren't aware of any blackouts to customers, however that was down to the lines distributor in the region who may have opted to reduce hot water charging.

"As is usual with these events we are investigating today's loss of supply to local power services. This will take several days."

Transpower general manager of operations Dr Stephen Jay said it asked lines companies Unison and Eastland networks, which take electricity from Tuai, to shed 26 megawatts of load in order to maintain system stability following the sudden drop in generation.

The power was fully reconnected by about 8.15am, at which Transpower told the lines companies they could begin to restore load, he said.

"We understand from both lines companies that they did not need to disconnect consumers but were able to manage the situation through hot water control and drawing on electricity from other areas."

However, it did see spot price for electricity soar to more than $230,000. It usually sits between $150 and $300.

The shut off comes just a week after about 30,000 homes around the North Island, from Wellington to Whangārei, lost power due to a record high of users due to cold weather.

Transpower had warned electricity providers in the 36 hours leading up to the blackout, however it was later revealed by Energy Minister Megan Woods it had overestimated the amount needed to be shed.

Investigations are still ongoing into that event, including from the Electricity Authority.