New Zealand mainly uses renewable energy sources and most of the New Zealand’s Electricity is generated from the hydro-electric stations and the rest of it is generated from both geothermal, wind power and thermal. Electricity demand has grown by an average of 2.1 per cent per year since 1974 and 0.6 per cent from 2005 to 2011. New Zealand has been called as one of the least energy efficient countries in comparison to the economic output against electricity consumption, despite being slightly above global average in the list of countries by energy intensity. The National Grid which is owned and operated by Trans power New Zealand is the high voltage transmission network of lines and ...view middle of the document...
This document explains Trans power’s application of the grid investment test and forms part if the NAaN GUP Investment Proposal. In order, to approve the proposed investment by the Electricity Commission it must meet all the requirements of the grid investment test (GIT) and the GIT requires that a proposed investment of the grid reliability standards has a lower expected net market cost or a higher expected net market benefit than and “Alternatives Projects” as defined under the rules, in a robust manner with respect to sensitivity analyses.
In this research report, I came up with Two Suggestions which could be an alternative to overhead transmission lines.
Suggestion One with three Options to be approved:
The first option which could be approved is the Cross Harbour Cable which includes:
The installation of a 220kV cable from Penrose to Albany, via tunnels, ducts and the Auckland Harbour Bridge and through new GXPs with 220kV Trans power buses adjacent to the existing Vector substations at the Hobson Street and Wairau Road.
Installing a second cable circuit from Pakuranga to Penrose in 2026 and a cable from Penrose to Roskill in 2028.
The second option that could be approved is the High Temperature Conductor which comprises of the following:
Replacing the conductors on 110kV lines parallel to the Otahuhu – Henderson 220kV double circuit with high temperature conductors, between 2021 and 2040
The third option which could be approved is the Roskill Reinforcement which basically includes the following:
Installing of a 220kV cable circuit from Pakuranga to Penrose substation
Installing a 220kV cable between Penrose and Mt Roskill substations.
Installing a second cable circuit from Pakuranga to Penrose in 2026
In 2026, installing a 220kV cable from Penrose to Albany, via Auckland Harbor Bridge and tunnel.
The rating of these cables are shown in the table below:
FROM - TO RATING
Pakuranga to Penrose 900 MVA
Penrose to Hobson Street 1000 MVA
Hobson Street to Wairau Road 800 MVA
Wairau Road to Albany 800 MVA
This 220 kV circuit from Pakuranga to Penrose will basically increase the capacity to the Penrose 220kV bus by simply adding the third 220kV circuit which will assist the 220kV existing double circuit line from Otahuhu to Penrose and it will also increase the diversity for transmission from south to the Auckland Regions and on the other hand the 220kV circuit from Penrose to Albany should increase the capacity to the Northland regions and provide security and capacity to Vector’s Hobson Street and Wairau road substations.
The following table shows a breakdown of costs associated with these three options:
Option 1 – Cross Harbor Cable Option 2 – High Temperature Conductor Option 3 - Roskill Reinforcement
Vector Costs 4,508 91,885 91,885
Lines 58,647 85,947 58,647
Investigation 3,154 2,503 2,423
Cables 116,263 0 64,274
Project Management 17,932 9,833 11,352
Substations 77,415 43,666 44,105