TPM current consultations

On this page you will find current consultation packages as well as information on closed consultations where a final decision is pending. See a summary of past consultations below.

Closed consultation: Proposed starting BBI customer allocations for NZGP Phase One CNI and HVDC Reactive Support projects

Our consultation on the proposed benefit-based investment (BBI) starting customer allocations for two (out of three) components of the Net Zero Grid Pathways (NZGP) phase one project has now closed. Submissions were due by 5pm Wednesday, 06 September 2023. We did not receive any submissions and so there will not be a cross-submission period.

The NZGP team submitted a major capex project (MCP) proposal to the Commerce Commission (Commission) in December 2022 and sought further views on a preferred option after discussions with the Commission. Our proposed starting customer allocations for these two investments are not affected by the change, so we aligned consultation periods. You can read the NZGP updated preferred option consultation documents and submissions received here.


Consultation package


Additional modelling information released after consultation period

On 23 May 2024, we published additional modelling information  to supplement the information already provided in the TPM consultation for the proposed BBI customer allocations for the NZGP Phase One Central North Island (CNI) and HVDC Reactive Support projects.

Additional information includes:
•Further generation expansion scenario detail
•The transmission constraints used to derive the generation expansion scenarios
•Further explanation on the transmission constraints used for the starting BBI customer allocations SDDP dispatch simulations

Click here to download an overview of the additional modelling.

Click here to download the additional modelling.


NOTE: We consulted on our proposal to treat the components of the MCP as separate BBIs and the proposed starting BBI customer allocations (calculated using the pricing-quantity method under the TPM) for two of the three components of the MCP - specifically the Central North Island (CNI), and the High Voltage Direct Current (HVDC) Reactive Support components. We did not consult on one component of the MCP proposal, which relates to work in and around Wairakei. We plan to calculate and consult on allocations for this component once the Commerce Commission makes its decision on Transpower's Capex IM (the decision will determine whether we use the simple or standard method to calculate proposed starting customer allocations, both of which are outlined in our BBC Assumptions Book).


Consultation process

We commenced this consultation on Thursday 27 April 2023. Submissions were due by 5pm Wednesday, 06 September 2023. No submissions were received. Following the Commission’s decision whether to approve the MCP proposal, we will finalise calculations of the starting customer allocations for the CNI and HVDC Reactive Support BBIs.   


We welcome your feedback on our consultation approach 

The new TPM came into effect on 1 April 2023. This is the first time we have consulted on proposed starting customer allocations when the investment decision by the Commission is unknown. Should the Commission's process result in changes to the MCP, we may need to consult again. 

Consulting on proposed starting customer allocations now ensures customers have information about any allocation they would receive for the proposed NZGP investments prior to the Commission's consultation process. Starting customer allocations are used to calculate an investment's benefit-based charges.

We welcome any feedback you may have on our consultation timing and approach. You can email us at [email protected]


Past consultationsDecision
Consultation on the starting BBI customer allocations for WUNIVM1b OTA STATCOM29 Sept 23
Consultation on HVDC Pole 2 refurbishment benefit-based investment28 Jun 23
Consultation on WUNIVM1a benefit-based investment28 Jun 23
Consultation on proposed updates to assumptions book (v1.1)16 Mar 23
Consultation on draft prudent discount and reassignment manuals01 Feb 23
Consultation on connection asset replacement costs15 Sept 22
Consultation on reclassification of Buller region assets15 Sept 22
Consultation on CUWLP benefit-based investment15 Sept 22
Consultation on draft assumptions book (v1.0)15 Sept 22
Consultation on baseline data (not published on TPM decisions page)N/A