Auckland's history of power cuts

ELECTRIC: Pylons carry power to Auckland along the Southern Motorway.
ELECTRIC: Pylons carry power to Auckland along the Southern Motorway.

It's not an everyday Third World city-type occurrence but Aucklanders are getting used to major power outages.

These outages are often followed by political promises that it will not happen again and assurances that ageing infrastructure will be fixed.

The big one was in 1998, which kicked off a five-week long power outage across the central city.

On January 20 that year a 40-year-old gas-insulated 110 kV cable in Quay Street failed.

The cable was well passed its use-by date and the failure was blamed on hot and dry conditions.

There were three other cables but the crisis slowly evolved when a second cable failed on February 9 and then the last two a week later.

The entire city was left with a single 22 kV cable.

Most of downtown Auckland closed for days until an army of generators kicked in.

Queen St was noisy and smelly but many of the businesses simply moved out - to South Auckland or other cities.

At one point a large ship was tied up to the Auckland city grid and pumped power into the city.

An ugly emergency overhead line was rapidly run into the city and slowly the power was restored.

Mercury Energy and Vector were able to replace the cables and reinforce the supply into Auckland.

More than 2000 new cables brought power into the city through a large tunnel running under the city.

But Auckland discovered it still had shaky power.

On June 12, 2006, a corroded shackle at Transpower's Otahuhu substation broke in high winds, sending an earth wire onto live cables and wiping out power to around 700,000 people at various times.

The shackle broke at 8.30am and Aucklanders did not begin to regain power until the end of the day.

The six-hour long blackout affected 230,000 households and businesses and caused disruption to rail and traffic services, radio transmission, phone services and caused partial hospital closures.

Since then there had been major spending on the Otahuhu substation and attempts have been made to lessen its importance to the Auckland grid.

Surprisingly, a side-effect of the outages was Aucklanders quickly got used to driving without the help of the city's thousands of traffic lights.

It was discovered most people were pretty well-mannered and traffic flowed relatively smoothly through both incidents.

In October 2009, electricity was cut to about 280,000 people in Northland and parts of Auckland. New Zealand's only oil refinery at Marsden Point also had to be temporarily shut down.

A forklift carrying a container hit the only operating 220kV transmission line between Otahuhu and Henderson, cutting power to Northland and northern Auckland.

The other circuit was undergoing maintenance at the time.

Aucklanders were hit again in 2011 when a fault occurred just outside the Huntly Power Station between generators and the connection to the national power grid.

The fault caused about 94,000 customers in various parts of the North Island to lose power for several hours.