Manawa Energy Limited (formerly Trustpower Limited) applied for judicial review (JR) of the Authority’s 2020 TPM guidelines decision in July 2020. Other parties actively involved in the JR were Fonterra and Nova (on the applicant's side), Meridian (in defence of the decision), and Transpower (a neutral intervener). The High Court hearing of the JR application ran from 18-27 October 2021.

The High Court released its judgment on 21 June 2022. The Court decided that the application for judicial review is dismissed. The judge found that:

  • The Authority did not err in its interpretation of its statutory objective or role.
  • There is no evidence the Authority's decision was biased or pre-determined.
  • The Authority's use of cost-benefit analysis was not unlawful.
  • The Authority's decision on the residual charge was not unlawful.

 The High Court’s judgement can be found on the Courts of New Zealand’s website.