Blackout fears for Dunedin dismissed

The man who blew the whistle on dodgy power poles maintenance in Otago now says Dunedin’s power supply is at risk.

Former Delta Energy worker Richard Healey alleges ageing cables supplying electricity to the city are failing, but Aurora Energy says his claims are incorrect.

Aurora chairman Steve Thompson in a statement said: ‘‘These allegations are without merit, and clearly exaggerated for effect to provoke unnecessary alarm.

‘‘The public can take confidence in the status of Aurora Energy’s subtransmission network in Dunedin.’’

The whistleblower’s previous actions prompted an independent review and sparked the company, later split into Delta and Aurora, to review its infrastructure and fast-track a pole replacement programme.

Healey’s latest concerns come as the Commerce Commission releases an open letter to the electricity sector, which includes a reference to a ‘‘quality standard breach’’ by Aurora.

Healey, who worked on the cables for 40 years, claimed main cables failed at three substations in recent weeks, though Thompson rejected this.

Healey said main cable outages put extra pressure on backup cables.

‘‘The problem is the frequency of the faults is so high and the duration of the repairs is so long that the chance of getting two to go out simultaneously is going up exponentially.’’

In the worst-case scenario, Dunedin could face blackouts similar to Auckland in 1998 when several older gas-insulated cables failed, Healey said.

Power was out for five weeks and tens of thousand of people were forced from the CBD.

Thompson said the company’s board preferred ‘‘the advice of our knowledgeable engineers and qualified and experienced industry experts over the opinion of a single individual’’.

All of the Dunedin zone substations were in service and none of the cables that supplied them had failed, he said.

‘‘Like all asset owners, on occasion we take individual cables out of service when we need to carry out repairs or routine maintenance.’’

Aurora planned to replace the older gas-insulated underground cables in the city as part of a wider programme of network renewal.

‘‘Aurora Energy is progressively upgrading its older, gasinsulated subtransmission cables in Dunedin to modern cables with solid insulation.’’