On 31 October 2005, Transpower applied to the Electricity Commission for approval of interim grid expenditure (IGE) for a number of investments designed to improve the transmission grid. On 16 December 2005, Transpower applied for approval of IGE for two additional investments.

The Commission could approve such expenditure before it makes final decisions on the Grid Upgrade Plan (GUP), if the expenditure met certain requirements as set out in rule 16 of section III of part F of the Electricity Governance Rules 2003.

In its 31 October 2005 application, Transpower grouped the investment proposals (Grid Development Proposals or GDPs) into seven initiatives at a total cost of $96.4 million. For the purposes of technical analysis, the Commission treated those investments as nine individual projects. The 16 December 2005 application was for two projects at a total cost of $33.5 million.

The Commission completed a review of both GDP Applications and made indicative decisions for the IGE in each GDP project at its 29/30 November 2005 and 20/21 December 2005 Board meetings.

Having previously signalled its intention to engage with stakeholders as much as possible within the confines of the transitional provisions contained within rule 16, the Commission published a paper, setting out its indicative decisions, for consultation, pursuant to rule 16.4.2 of section III of part F, on 22 December 2005.

On 7 February 2006 Transpower provided further information in respect to the configuration of the proposed substation at Huntly East:

Configuration of proposed substation

The Commission considered the submissions received during the recent consultation and made some final decisions about the GDP applications. Details of the Commission's decisions can be found in the letter to Transpower.

The Commission published a document summarising submisisons received and setting out the reason for its decision:

The Commission approved grid expenditure on a number of projects proposed by Transpower under the Transitional Provisions in rule 16 of section III of part F of the Electricity Governance Rules 2003. Approved expenditure to date is summarised in the following table: