Vector seeks pledge on Auckland power

By CHRIS DANIELS energy writer

Power network company Vector has asked the state-owned operator of the national power grid, Transpower, to confirm that the electricity supply to Auckland and Wellington is secure.

The question comes after big power users in Christchurch and the top of the South Island were told this week that transmission problems could mean rolling blackouts on particularly cold evenings.

Simon Mackenzie, group general manager of networks for Vector, said it had asked Transpower to "review and confirm" that it had no concerns or problems with its supply to these areas.

Transpower had yet to respond to this request, but "in regards to the security of supply for our distribution network, we have no concerns at all regarding our networks in Auckland and Wellington", he said.

Transpower spokesman Chris Roberts said the two main areas of concern for the future were the Auckland region and the top of the South Island.

A new line from Whakamaru, in the southern Waikato, connecting to South Auckland, was planned to be built by 2010.

He said this would be the biggest single transmission project undertaken during the the past 40 years.

Once finished, this line could cope with the next 20 or 30 years of predicted growth.

Constraints on supplying Auckland with electricity were different from those seen in the South Island, which tended to happen in winter.

In Auckland, constraints were more likely in summer, especially with the increasing demand from air-conditioning.

When temperatures really soar, the Huntly power station, New Zealand's biggest thermal generator, is restricted in the water it can take from the Waikato river.

Christchurch and the top of the South Island import electricity on ageing wires from the Waitaki River. Auckland gets power from the Otahuhu, Southdown and Huntly stations, which means it is not as dependent on ageing supply infrastructure as Christchurch is.