It comes as Transpower warns households that unless they save electricity they could face possible power cuts on Friday.
“It's disappointing that this has happened so early in the winter, but it's a good wake-up call for the industry,” said Deborah Hart, president of the Consumer Advocacy Council.
“We have a long-term challenge in New Zealand to manage peak winter demand as our population grows and the country electrifies. The council believes that fundamental change is needed in the wholesale market – there must be sufficient renewable energy available all year round. “
The early warning was welcome as it gave the industry time to respond, she said.
“It is wise to do this within 24 hours, without there being a shortage of supply. It gives the industry time to react and avoid the worst possible outcome: power needs to be turned off to consumers.
“Consumers can also do their part to relieve pressure on the system, but ultimately it is the industry that must take the lead in these times of pressure.”
If no progress is made, consumers would pay a high price, she said.
“The solutions lie in the hands of industry, government and regulators. If we don't make progress, there will be more warnings like today and a heavy price will be paid by consumers small and large.”
Chantelle Bramley, managing director of Transpower, said the entire industry came together to avoid power outages.
“This time of year can be challenging. Generators need to make the necessary planned outages to perform maintenance on their power plants before winter. They need to perform maintenance on these plants.”
The weather was unusually cold, she said.
“We will work with line companies to, as a last resort, disconnect power to locations for a short period.”
When asked if she could guarantee this wouldn't happen during the colder months, Bramley said no.
“No energy system can absolutely guarantee supply, but as we have seen today, if the industry comes together we can ensure there is enough in the system.”
Cold start
MetService meteorologist Ngaire Wotherspoon said the current cold snap was “not going anywhere, and tonight is likely to be the coldest of them all”.
“However, there will be plenty of clear skies before the end of the week. Showers are forecast for southern and eastern areas on Friday as a weak front moves north, but we expect widespread dry weather for the weekend.
“There is relief from these cold conditions on the horizon as southerly winds diminish this weekend, but residual cold air is expected to persist into next week.
“These cold nights will continue for a while, but warmer and wetter weather should return later in the week.”
The weekend was expected to be cold but dry with light winds for much of the country.