Major capital projects have expected costs of greater than $20m. Financially, these projects are standalone from the base expenditure we approve at the outset of the regulatory period, with separate incentive arrangements. Transpower is not able to use funds from its base allowance, or an approved major capital project to fund over expenditure of another major capital project.

The Capital Expenditure Input Methodology sets out the requirements Transpower follows when preparing major capital proposals and the criteria that we use to review and approve a major capital proposal.

Read more about input methodologies.

Bombay-Otahuhu Regional Major capital proposal

The transmission network supplying Bombay and Wiri substations is ageing and requires refurbishment. This network includes the transmission lines between Bombay and Otahuhu substations and Bombay and Meremere substations.

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Waikato and Upper North Island voltage management

The closure of Southdown and Otahuhu Power stations in Auckland and the proposed closure of the Rankine units at Huntly Power Station in Waikato are expected to cause voltage management issues in the Auckland and Waikato regions as peak electricity demand increases.

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North Island grid upgrade

On 6 August 2015 we made a decision on Transpower's application to amend the major capex allowance for the North Island grid upgrade project.

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Bunnythorpe-Haywards A and B lines conductor replacement project

On 9 May 2014 we approved Transpower's proposal to upgrade the Bunnythorpe Haywards lines A and B.

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Upper North Island dynamic reactive support project

On 11 November 2013 we approved Transpower's proposal to expand the geographical area within which it can test its demand response initiatives.

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Bombay 110 kV bus security project

On 1 November 2013 we approved Transpower's proposal to amend the outputs of the Bombay 110 kV bus security project.

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Otahuhu Substation diversity project

On 12 April 2013 we approved Transpower's proposal to increase the major capex allowance for the Otahuhu Substation Diversity project.

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Upper South Island grid upgrade – stage 1

On 11 February 2013 we approved Transpower's proposal to upgrade the Upper South Island grid to increase the transmission capacity of the 220 kV circuits connected to Islington Substation.

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