Consultation opens on proposals to refine the TPM

Today, the Electricity Authority Te Mana Hiko (Authority) opened consultation on proposed amendments to the Transmission Pricing Methodology (TPM) to improve its efficiency and workability.

While the TPM framework remains sound, the Authority and Transpower have identified aspects that are not working as intended since it was introduced in 2023. As with any major regulatory change, we review how it works in practice and make targeted improvements where needed. The TPM is now sufficiently embedded to assess what is working well and where refinements would improve outcomes.

Our consultation paper sets out seven amendments that are relatively quick to implement and would:

• better align transmission charges with benefits
• reduce volatility and uncertainty in charges
• lower administrative and compliance costs.

The proposals include improvements to the calculation of charges for battery storage, and for anticipatory connection assets, and simplifications to how charges are adjusted when new customers join. Together, these proposed changes aim to improve how the TPM operates in keeping with its core design.

Three proposals were identified by the Authority and four were requested by Transpower through Workstream 1 of its TPM Operational Review. They reflect industry feedback and implementation experience and focus on practical improvements with long-term benefits for consumers.

We welcome your feedback. Submissions are due for six of the seven proposals by 24 July 2026, with submissions on the proposal on anticipatory capacity for connection assets due on 7 August 2026.

We expect to decide on six of the seven proposals in November 2026, allowing Transpower to incorporate any changes into its 2027/28 prices. We plan to decide on the proposal for anticipatory capacity in early 2027, as we expect more substantive submissions and will need more time for analysis.

This work forms part of our wider network pricing reform programme, alongside work on distribution and distributed generation pricing, so the overall framework sends coherent and durable network use and investment signals across the system.

View consultation