Transmission pricing methodology

TPM technical amendments: regulatory asset base indexation and simple method benefit-based charge cap

Upcoming Open Closed Decision
View submissions Submissions closed 29 August 2025
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Consultation

Thanks to everyone who provided feedback on two proposed technical amendments to the transmission pricing methodology.

We proposed:

  • Aligning the transmission pricing methodology with recent Commerce Commission changes to index Transpower’s regulatory asset base. This would ensure the approach to valuation and depreciation of assets in the TPM is consistent with the Commission’s approach.
  • Clarifying the simple method benefit-based charges cap formula so it always uses the same customer allocations that applied at the start of the relevant (five-year) simple method period. This would ensure the result of the cap calculation is the same regardless of when the adjustment occurs within the five-year period.

These proposed changes would help ensure the transmission pricing methodology continues to function as intended.

A well-functioning transmission pricing methodology supports timely, well-placed investment and use of the grid, and the electrification of the economy for the benefit of all New Zealanders.

Consultation paper

TPM technical amendments: Implementing regulatory asset base indexation and clarifying the simple method benefit-based charge cap - Consultation paper

TPM technical amendments: Implementing regulatory asset base indexation and clarifying the simple method benefit-based charge cap - Consultation paper

Submissions