Brian Rudman: Get real, Transpower, this is the 21st century

When it comes to skins, they don't come any thicker than that of electricity transmission company Transpower.

Still black-eyed and bloody-nosed from its recent encounter with the pylon-hating cockies and lifestyle-blockers of the Waikato, Transpower has now come north of the Bombay Hills and is proposing to sling new high-voltage cables from Otahuhu to Penrose, possibly via Mangere and Onehunga.

To be fair, new overhead cables only feature in three of Transpower's five options for beefing up the link between the Otahuhu and Penrose substations.

But that they feature at all as a 21st-century solution for transmitting bulk power across heavily urbanised South Auckland is breath-taking.

The only mention of pylons in the context of urban Auckland we should be hearing is of Transpower's timetable for their removal. That they are an ugly excrescence on the city landscape should be reason enough. But there are also health concerns - much debated - which surely cannot be ignored, when large numbers of people have to work and live and travel around and under them.

The upgrade between Otahuhu and Penrose is a necessary part of a major upgrade of the national grid through Auckland to Northland. Without it, the people of Whangarei and places north could be showering in cold water and reading by candles by 2013.

Thanks to good planning in the late 1990s, Transpower has an agreement with local lines company Vector to run two new 220kV cables through Vector's underground tunnel from Penrose to downtown Auckland.

From there the cables will be slung under the harbour bridge, then run in special ducts running under the North Shore busway to Albany. Resource consents have been obtained and installation of cables along the busway is expected to begin by 2009.

That's the good news. But it raises the question that if it's possible and economic to run the enlarged grid north from Penrose underground, and unacceptable to sling it above ground, over the top of the wealthy part of Auckland, then why are the people in the poorer parts, south of Penrose, forced to accept an inferior solution.

The most intrusive and unacceptable of the options is to convert the existing 110kV overhead line from Otahuhu via Mangere and Onehunga to Penrose to higher-voltage 220kV. This would require new pylons and a new substation in Onehunga. No price has been developed for this option.

Another overhead option is to take a detour via the Pakuranga substation, and combining cables buried in roads with new overhead lines. Cost: between $80 million and $130 million.

The remaining overhead option - unpriced - is to string a 220kV cable above the main trunk rail line, linked by underground cables to the two substations.

For between $100 million and $130 million, the two stations could be linked with cables buried along existing roads. Alternatively, for around $180 million, a deep, purpose-built tunnel, similar to the Vector tunnel, could be constructed.

As the future-proofed, easy-maintenance option, the last makes the most sense. And don't take the word of an ignoramus like myself. I borrow it from a paper on New Zealand energy infrastructure, delivered a couple of years ago by Murray Jackson, chief executive of Genesis Energy.

Talking of the significant investment that was going to be needed to ensure security of supply for Auckland and places north, he concluded: "An underground tunnel from the Bombay Hills to Penrose is an investment that will satisfy Auckland's environmental and residential development requirements over the next 50 years. Such a scheme may initially appear too expensive, but the alternative does not work."

Of course, Transpower might just be raising the bogey of pylons to soften us up for whatever its second-best option might be. But if it is genuinely considering them as a possibility, has it forgotten how tortuous the consultation and legal processes can be? Even the objection of one landowner in Onehunga has delayed its plans to increase the capacity of the existing 220kV line north from Otahuhu to Henderson for more than a year. Auckland City has granted temporary authority to increase the power in emergency situations, but a full, notified resource consent hearing looms.

With the farmers revolting south of the Bombays and Onehunga and Hillsborough quietly simmering, how many legal fronts is Transpower planning to open before it accepts there's a better, 21st-century solution through Auckland? A tunnel.