TPM proposal to the Electricity Authority


In mid-2020 the Electricity Authority (Authority) published new transmission pricing methodology (TPM) Guidelines and tasked Transpower with developing a proposed new TPM. We delivered a proposed new TPM to the Authority on 30 June 2021, in accordance with the Guidelines and the Electricity Industry Participation Code 2010. The Authority made some changes to our proposal and consulted on it. On 2 December 2021, we submitted our response to the Authority's consultation paper. You can read it on our Regulatory Submissions page. The Authority made further changes after reviewing submissions.

On 12 April 2022 the Authority announced its decision to adopt the new TPM. The Authority's decision paper and the new TPM are available on the Authority's website.

In December 2022 we notified customers of their 2023/24 prices and updated our Grid Pricing web page with the relevant information. 

Thank you to our customers and interested stakeholders who contributed to the development of the proposed new TPM that we submitted to the Authority. Your feedback and insights were invaluable as we worked to create a workable TPM.


Useful links



Indicative pricing updates

To help customers understand and prepare for pricing changes under the new Transmission Pricing Methodology (TPM), we published several indicative pricing updates after submitting our initial proposal to the Authority (which is below).

The purpose of publishing indicative pricing was to provide an example of what transmission charges could be if the TPM was applied to the 2022/23 pricing year. We also projected out to the 2034/35 pricing year to illustrate how indicative prices may evolve over time. We used a model we developed and updated during the TPM development phase (which comprised a number of process steps, databases and Excel spreadsheets). They were not formal calculations or notifications of transmission charges. We recommended anyone making decisions based on the indicative prices should consult the new TPM, any relevant information they have access to, and seek independent expert advice.


Indicative pricing updates:


Additional support materials:


Our 30 June 2021 TPM proposal to the Electricity Authority


Part one refer back proposal - non-Benefit Based Charge (BBC) aspects

We received a letter from the Authority (28 July), where it referred non-BBC aspects of the TPM proposal back to us for further consideration. On 25 August we resubmitted on these:


Part two refer back proposal - Benefit Based Charge (BBC) aspects

We then received a letter from the Authority (18 August), where it referred BBC aspects of the TPM proposal back to us for further consideration. On 15 September we resubmitted on these: