Transpower warns of low electricity generation tonight after less wind power available

Large parts of two Wellington suburbs - and more than 900 customers - have been left without power following an unplanned outage.

According to Wellington Electricity, 933 customers in Miramar and Seatoun have been affected.

The outages, of which the cause is still to be determined, were first reported around 9.30pm and it was estimated to last until 12.45am.

It was not immediately clear if the outages were linked to earlier warnings that electricity supply could be disrupted.

Earlier today Transpower asked for more power to be generated to avoid disruption to Kiwis' electricity supply.

The transmission company issued a notice to the electricity industry advising that there was a low level of residual generation - less than 200 MW - expected for the evening peak.

"The low residual generation was due to the expected electricity demand being higher than predicted, and less wind generation available than offered," Transpower chief executive Alison Andrew said.

"We have already seen additional generation being offered into the market as a result of the [notice]."

Andrew added that at this stage Transpower did not anticipate any disruption to consumers' electricity supply.

This afternoon, Transpower issued a notice to the electricity industry advising that there was a low level of residual generation. Photo / File

Last week, Transpower issued a nationwide warning notice - revealing there was a risk of insufficient power generation and reserve to meet the country's demand.

On Thursday the state-owned enterprise issued the warning as the first big winter chill hit the country, with Kiwis pumping their heaters.

At the time Andrew said the grid emergency was due to losing generation from three sources - including a Contact Energy power station, Genesis' power station in Huntly and a wind drop from 90 to 30 megawatts.