Mystery vibration delays completion of new power station

4.00pm

An expert has been flown to Hawke's Bay to help find a mystery vibration that is delaying completion of the $150 million Whirinaki power station.

Contact Energy site manager Neil Jeneway said a 100-hour reliability trial had been delayed until the source of the intermittent vibration could be found and eliminated.

The vibration is being shown on the power station's computer control system but has defied efforts to find its source.

Mr Jeneway said the problem occurred only when the unit started up and engineers believed it was a cable problem.

"We believe it might be caused by cables running too close together," he said.

There had been no sign of the vibration in four start-up runs while temporary cables were used.

However, the plant could not be commissioned while the temporary cables were in use, he said.

A vibration expert from Pratt and Whitney, the manufacturers of the jet-engines powering the plant, had been brought to Whirinaki to find the cause of the problem.

"It's a real mystery," Mr Jeneway said.

A third attempt at the 100-hour reliability trial would not be made until the fault was found and the problem rectified.

The first reliability trial was stopped when an automatic voltage regulator tripped, and the second test was abandoned after the vibration probe tripped out the number three unit, he said.

Since the power station began commission trials earlier this month, it had used nearly 4 million litres of low-sulphur diesel, worth $2.6 million at pump prices. The diesel for the station had been purchased by tender in a bulk-supply contract, for a price the Government refused to reveal, saying it was commercially sensitive.

The 155 megawatt station is being designed as an emergency plant to provide cover in exceptionally dry years when South Island hydro lakes are low.

It will be one of the most expensive in the country to run and will produce electricity at a cost of about 15c a unit.

It will be used to remove some of the price spikes that last winter saw the spot price of electricity on the wholesale market at times rise to almost $1 a unit.

- HAWKE'S BAY TODAY