Transpower Welcomes Draft Decision

Embargoed 12pm

Media release
27 May 2009
Transpower Welcomes Draft Decision

Transpower welcomes the draft decision released by the Board of Inquiry today. The decision approves Transpower’s proposal to construct a new transmission line between Whakamaru and South Auckland, known as the North Island Grid Upgrade Project.

Transpower CEO, Dr Patrick Strange says the project is of vital importance to New Zealand’s economy. “The North Island Grid Upgrade Project provides essential security of supply into the upper North Island,” he said.

There are six transmission lines running north to Auckland. Most of these were built in the 1950s and 60s. In the intervening 40 years, the population of the upper North Island has more than doubled and electricity use has more than trebled.

“The upper North Island has experienced several issues with electricity supply in recent years, illustrating the need for the increased capacity that this project will provide, long into the future,” said Patrick Strange.

“We will work hard to establish effective partnerships with communities and respectful and fair relationships with affected landowners.”

“The local benefits of this project include the creation of additional jobs and investment in the wider Waikato region, but we also recognise the major impact the project has on individual landowners and communities.

Transpower will spend the 20-day review period considering the decision and conditions set by the Board of Inquiry.

“We will take time to consider any conditions before making any comment on the decision itself,” said Patrick Strange.

The final decision is expected later in the year.

North Island Grid Upgrade Proposal

The North Island Grid Upgrade Project is designed to provide a more secure supply of electricity to the upper north island. The project is separated into three components: overhead transmission line, substations and cables. The 190km, 400 kv capable overhead transmission line runs from a new substation at Whakamaru (north of Taupo) to a new switching station in South Auckland. Two underground cables will run from this switching station – one to a new substation at Pakuranga and at a later date, the second to Otahuhu.
The line will be built so that it is capable of running at 400 kV, but will initially run at 220 kV.

The project involves:

* Building an overhead transmission line from Whakamaru to near the South Auckland urban boundary, which will be 400 kV capable but will operate initially at 220 kV.
* A transition station at Brownhill Rd near the South Auckland urban boundary, where the overhead line will connect to underground cables.
* An underground cable section from the transition station to Pakuranga substation, which will be 220 kV capable, reducing dependencies on Otahuhu.
* A second underground cable section to Otahuhu substation to be added at a future date (around 2030, as demand increases).
* Voltage to be raised on the overhead line from 220 kV to 400 kV at future date (around 2030).
* Using triplex conductor (a bundle of three wires) to maximise the capacity of the overhead line, pushing the need for another new line well into the future.
* The EC approved budget is $683 million (in 2006 dollars), which is $824 million in 2011 dollars.

The line is consistent with other major Transpower projects, including the HVDC upgrade (Pole 3), which will increase capacity to bring inexpensive South Island generation to the North Island; the Wairakei Ring upgrade, which will reinforce transmission capacity to Whakamaru, where the NIGU starts; and the NAaN project, which starts at Pakuranga and runs through Auckland to Albany in the north.

History

Transpower has been investigating the need for a major upgrade of the transmission network in the upper North Island since 2003.

In 2004, Transpower began to consult publicly on a route for a new 400 kV transmission line between Otahuhu and Whakamaru. That process culminated in a final route and centre-line being confirmed in January 2006.

As well as the process to select a route, Transpower also engaged with the Electricity Commission who must approve such a project in order for Transpower to recover its project costs. Following an initial draft ‘no’ to Transpower’s original proposal in April 2006, Transpower submitted an amended proposal in October 2006, which the Electricity Commission approved in July 2007.

In August 2007, the Government ‘called in’ the project, meaning the Resource Management consent process would be heard by a Board of Inquiry.

After hearing submitters between March and October 2008, and considering that evidence, the Board of Inquiry has now released its draft decision. The final decision will be issued in the coming months.

Project Key Facts

Project

Total estimated cost /$824 million

Proposed Line – Overhead Route

Length of overhead route/185 km

Number of properties affected by the new line/314

Number of towers required/426

Average tower height/59 metres*

Maximum tower height/70 metres

Minimum tower height:
- Double circuit tower/46.3 metres*
- Single circuit tower/25 metres*

Average span length (distance between each tower)/437 metres

Maximum span length/837 metres

Minimum span length/54 metres

Design capacity of new line/2700 MVA per circuit

Proposed Line – Underground Cable Route to Pakuranga/
Length of underground cable route(s)/9.5 km

Arapuni-Pakuranga 110 kV Line

Length of line to be removed/147 km

Number of towers to be removed/460

Average height of towers/25 metres

Capacity of old line/114 MVA

* Subject to minor change

ENDS

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