TPM Operational Review

This review is about enhancing transparency and future-proofing transmission prices for the future as Aotearoa New Zealand becomes increasingly electrified.

Purpose of the review

The TPM determines how Transpower recovers the annual cost of running the national electricity grid from our transmission customers.

We want to make sure the TPM continues to meet its intended objectives and that customers can easily understand and manage their transmission charges.

Since the Authority introduced the new TPM in 2023, we’ve listened to feedback from customers and investors about how it could work better, particularly around reducing uncertainty, volatility and complexity.

The operational review aims to improve the operation of the TPM, addressing potential issues identified by stakeholders and Transpower since the implementation of the TPM.

Key Objectives

• Refine adjustment mechanisms to reduce volatility and customer disruption.
• Reconsider the delineation between the simple and standard methods for calculating Benefit-Based Charges (BBCs).
• Improve BBC calculations and inputs to reduce complexity and reliance on judgement, enabling stakeholders to replicate and forecast charges with confidence.
• Ensure First Mover Disadvantage and Prudent Discount provisions remain fit for purpose in an evolving electrification landscape.

These changes aim to support stable, efficient pricing and help New Zealand transition to a low-emissions economy.

Consultations

TPM Operational Review Workstream One 

We are now seeking feedback on the first workstream of potential changes we are considering as part of the TPM Operational Review. 

The primary focus of workstream 1 of the Operational Review is on ‘quick wins’ that we consider can be achieved in relation to adjustment events and housekeeping. The latter includes a general clean-up of TPM legal text to remove redundant and outdated clauses and make other minor drafting improvements. 

We are also seeking views on whether and how certain issues with connection charges and first mover disadvantage (FMD) should be addressed through further workstreams of the Operational Review.

Consultation package  
Please find a list of the consultation documents below

• Consultation paper on TPM Operational Review Workstream 1
• Appendix A - TPM guidelines
• Appendix B - cost-benefit analysis for adjustment event proposal
• Appendix C - proposed TPM drafting for housekeeping changes
• Appendix D - questions from the consultation on TPM Operational Review
• Appendix E - proposed TPM drafting for housekeeping changes with track changes

Industry Working Group (IWG) documents

The following papers include materials produced by Transpower for the Industry Working Group (IWG) and final advice from the IWG. They reflect our evolving thinking on the issues and should not be taken as Transpower’s final or formal views on the issues presented.

• Meeting one - agenda and briefing paper
• Meeting one - feedback to Transpower
• Meeting two - briefing paper
• Meeting two - feedback to Transpower
• Meeting three - briefing paper
• Meeting three - feedback to Transpower
• Adjustment event workflows

Consultation process  

The consultation period will run for three weeks, commencing Tuesday 3 March 2026. Submissions are due by 5pm on Friday 20 March 2026.  

There will be no cross-submission period due to the technical nature of the proposals for adjustment events, prudent discounts, FMD and housekeeping that we may progress as part of workstream 1, as well as the timing constraints for the changes to be implemented for the next pricing year (1 April 2027 – 31 March 2028).  

For workstream 1 changes to take effect by then, we need to deliver any change proposal/s to the Electricity Authority for consideration in early April 2026.  

How to submit 

Please send all submissions to [email protected].  

We will acknowledge receipt of each submission and all submissions will be published on this page.

If your submission contains confidential material, please ensure this is clearly identified and provide a version of your submission that can be published. Please note that all information provided to Transpower is subject to potential disclosure under the Official Information Act 1982. 

Online presentations

We are holding two online presentations to detail our proposed changes and give you an opportunity to ask us questions. The dates of these presentations are:

• Monday 9 March 2pm – Presentation and a short Q&A
• Monday 16 March 2pm – Final Q&A session

To register your interest for one or both of the presentations, please email [email protected]. We will respond to your email with the meeting invite.

Presentation recordings

Presentation one - Workstream one briefing and Q&A 

A recording of our first online presentation and its slide pack are available below.

Presentation one slide pack

Presentation two - intra-regional allocator (IRA) proposal and Q&A 

Operational Review's four workstreams

High level timeline to April 2026  

TPM Operational Review Working Group

We are pleased to announce the members selected for the TPM Operational Review Working Group:

• Alan Eyes – Blue Scope Steel
• Anna (Yuanjun) Wei – Fonterra
• Bas Van Esch – Vector
• Ben Gibson – Egen
• Dan Roos – Buller Network
• Darren Gilchrist – OJI Fibre Solution
• David Rohan – Contact Energy
• Dayle Parris – Orion Energy
• Mary Ann Mitchell – Independent Electricity Generator Association
• Nikki Stigley – Electra
• Paul Burnaby – Pacific Power
• Peter Apperley – Lodestone

This group will provide expert input into our review of the TPM, helping to refine the methodology and reduce complexity, uncertainty and volatility while supporting efficient transmission pricing.

We will hold our first meeting in February. 

Click here to read the TPM Operational Review Working Group Terms of Reference.

What we’ve done so far

Earlier in 2025, we worked with Concept Consulting to complete a two-stage Post-Implementation Review (PIR) of the TPM.

The PIR gave us valuable insights into how well the TPM is meeting its intended objectives, what’s working and where improvements could be made.

The review included:

• Stage 1: An online survey of stakeholders, including electricity distribution businesses, grid-connected customers, and electricity generators.
• Stage 2: Workshops to explore the key themes and ideas raised in the survey.

You can read the full PIR report here.

More information

For more information about the operational review, please contact us at [email protected]. 

You can find more information about the TPM here on our website.

The TPM itself is available on the Authority’s website.