Editorial: Message in city's blackout

Tell us it isn't so. Fully eight years after a single cable failure cut power to the Auckland central business district for four weeks, the city suffered another power failure yesterday - attributed to a single wire in a South Auckland substation. An earth-wire at the Otahuhu substation snapped under high overnight winds, cutting 1000 megawatts to the isthmus, about half the normal load on a winter morning.

The power cut lasted between four and eight hours depending on where you were, rather than the four weeks of 1998, but yesterday's blackout affected a much larger area of the city and threatened to cause chaos when 300 traffic lights were out for the morning peak hours. In the event people coped as they do, the traffic running surprisingly smoothly on only the right-hand rule.

People in business coped too, firing up generators that many had probably acquired after the 1998 power failure if not before.

But shops and small business were less fortunate and many simply had to close their doors for the morning. Those that serve the substantial lunchtime trade effectively lost their entire day, a fifth of their weekly turnover. And Auckland was not alone. About 50 similar power cuts occurred in other parts of the country after the storms of the previous night.

But the scale of Auckland's blackout makes it unusually worrying. Localised power cuts can happen anywhere but in this case a single wire failure deprived half the country's most populous region of power. No region should be as vulnerable as this. It is staggering that the national grid is so delicate in some places. The Otahuhu substation is the main supplier of Auckland's electricity and no back-up circuitry evidently exists.

Eight years ago, when one of four cables to the CBD failed, triggering a collapse of three other cables, blame was heaped on the local lines company Vector, as it is now called. This time the culprit is the national lines company, Transpower. It has claimed to be running the national grid on the operating principle that no single failure of a major component, such as a transmission line or a power station, will disrupt supply. But evidently there is no automatic bypass for the main metropolitan substation.

Yesterday's power loss could be a blessing in disguise for Transpower if it confirms the urgency of new investment in the national grid, though it might now be wondered whether the doubling of the capacity of the lines into Auckland, whether by giant pylons or other means, is of higher priority than ensuring the city's substations can cope. The regulators who have been challenging Transpower's charges and second guessing its investment decisions should be wiser for yesterday's lesson.

The Commerce Commission has restricted Transpower's price increases to just below the inflation rates while the company has been warning that the investment required by the ageing transmission system requires prices to rise at least 10 per cent a year. Meanwhile, the Electricity Commission, set up by the present Government to ensure investment in reserve generation for periods of low rainfall, has taken a lively interest in the transmission system too. Some suspect it harbours an ambition to be the central planner of the power supply rather than a regulator of last resort.

Transmission lines are a natural monopoly that need careful regulation if the company operating them is not to gouge excessive revenue from consumers. But New Zealand's competitive electricity generating system and consumer servicing companies have every incentive to keep a public watch on Transpower's charges, and they do. They also know the network needs urgent upgrading at many bottlenecks. Now nobody can doubt it. No city of any size should have its power supply hanging by a single thread.