Electricity Asset Management Plan 2019-2029
152
Vector Limited://
DESCRIPTION
DISCUSSION OF OPTION
ESTIMATED COST (NPV IF APPLICABLE)
STATUS
Forecast security shortfall arising from residential growth at Riverhead
Option 1: Install load management. The installation of hot water load control at Riverhead will defer a major upgrade of the Riverhead substation 2027/28 Option 2: Upgrade the Riverhead substation transformers. By 2028 the deferral benefits arising from the installation of load control will have been exhausted, requiring the provision of additional capacity at Riverhead substation. Two new transformers are proposed at this time Option 3: Earlier installation of two larger capacity transformers at Riverhead. The NPV calculation based on the two projects proposed in Options 1 and 2 is $3.26M compared to Option 3 which delivers an NPV of $3.01M Option 4: 11kV feeder upgrade – Kumeu: This feeder will expand the capacity available to provide for the forecast growth in the Kumeu/Huapai area Option 1: Establish a new zone substation at Redhills. Greenfields residential growth to the west of Westgate if forecast to exceed the capacity available from Westgate substation. A new 2 x 20MVA substation is proposed at Redhills Option 2: Expand Westgate substation to supply Redhills. Westgate substation supplies Westgate commercial centre and east towards Hobsonville. This substation is forecast to be at capacity by the end of the next decade. The area to the west towards Redhills Rd is expected to contribute a further 15.4MVA of residential load. This is in addition to the forecast load on Westgate and beyond the capacity of Westgate substation to supply Option 3: Non-network solutions. No practical solutions will offset the need for a new zone substation Future-proofing ducts to Westgate zone substation: Westgate substation will be a key subtransmission distribution site providing connections to Hobsonville and Hobsonville Point. Future subtransmission connections to this substation will include the future Redhills and Whenuapai substations. NZTA are upgrading SH16 and the installation of ducts in conjunction with this project is important to support future subtransmission requirements Option 1: Establish a new zone substation at Hobsonville Point: This project is already underway and is expected to be commissioned in 2019. The budget allows for completion of this project Option 2: Future-proofing duct SH18: To enable the capacity from Hobsonville Point substation (Option 1) to be distributed, ducts will be installed SH18 as part of NZTA motorway upgrade Option 3: Future-proofing duct - Greenhithe Bridge: As for Option 2, this project extends the ducts across the Greenhithe Bridge to enable the connection of the Hobsonville Point network to that of Greenhithe substation Option 1: Install new transformers with increased capacity. The substation load exceeds the N-1 capacity of the existing transformers by 8MVA and relies on 11kV load transfer for network security. Backup capacity is limited, advancing the need for early replacement of the existing transformers
$1.45M Selected
$0.5M Selected
Rejected
$0.4M Selected
Forecast security shortfall arising from residential growth at Redhills
$6.35M Selected
Rejected
Rejected
Forecast security shortfall arising from residential growth at Westgate
$1.4M
Selected
Forecast security shortfall arising from growth at Hobsonville
$1.4M Selected
$1.0M Selected
$1.9M Selected
Forecast security shortfall arising from growth at Te Atatu
$3.4M
Selected
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