Engineers fly in to fix Sparky

By FIONA ROTHERHAM

Siemens engineers from Brazil are being flown in this weekend to work on Contact Energy's Otahuhu B power station following a mechanical failure in a transformer.

It is not known at this stage how much damage was caused to the transformer or how long the combined cycle power station would be out of service.

"All I can say at this stage is that two engineers will be arriving over the weekend to have a look at it from the manufacturing plant where the transformer was made in Brazil," said Siemens New Zealand managing director John Britton.

The Otahuhu B station, known as Sparky, normally supplies around 9 per cent of the country's electricity demand.

The extended outage of Otahuhu B has contributed to transmission line constraints which have pushed Upper North Island spot wholesale power prices into the hundreds of dollars during peak demand periods.

The main beneficiary has been state-owned enterprise Genesis, owner of the gas and coal-fired Huntly station.

Transpower said it had no concerns about security of supply providing Huntly stayed in the picture.

"Once Otahuhu comes back, Huntly may decide to not offer as much of its electricity because it won't be getting the same prices," said Transpower grid operating services manager John Clarke.

The gas-fired Otahuhu B had only just been brought back to full capacity this week after being shut down at the beginning of May, initially for a one-month routine overhaul.

Contact corporate affairs manager David Hunt said the delay followed Siemens bringing forward additional maintenance work covered by warranty.

The plant was gradually cranked up to a capacity generation of 360 megawatts on Tuesday and then suffered the failure the next night.

Contact expected the cost of the repairs and lost generation to come under the original construction warranty but Siemens wouldn't confirm this.

The plant was commissioned last December after a 13-month delay, believed to have been caused by problems with a steam recovery unit, a type of boiler, at the heart of the station.

The original turnkey construction contract with the German-based technology group meant Contact didn't pay for the facility until it was in full working order.

Contact has never confirmed how much compensation it was paid or the final bill for the plant. Industry speculation suggested Siemens hit the $70 million cap agreed for liquidated damages, meaning the final cost to Contact was nearly 25 per cent lower than the contract price of between $300 million and $350 million.