Electricity Authority Review of 9 August 2021 event under the Electricity Industry Act 2010
On 9 August 2021, approximately 34,000 customers across New Zealand experienced an electricity cut without warning. In response, the Electricity Authority (the Authority) used its statutory powers under section 16(1)(g) of the Electricity Industry Act 2010 (Act) to launch a two-phase review into the outages.
The Phase 1 review (published in September 2021) focused on the system operator’s demand allocation tool and communication processes and protocols.
The Phase 2 review (published in April 2022) was wider in scope and provided a final summary of the various investigations, observations and recommendations which have been conducted by the Authority, Transpower and the Ministry of Business, Innovation and Employment (MBIE).
In addition to the two-phase review, the Authority has considered alleged breaches of the Code on 9 August 2021 by three participants and an Undesirable Trading Situation claim
Progress since 9 August 2021
Phase 2: Final report - Complete April 2022
The Authority’s phase two review focused on lessons that can be learnt from the event for the Authority, lines companies, the system operator, generators, retailers, and direct connect consumers.
The Phase 2 review:
(a) confirms the earlier findings of the Authority’s Phase 1 review, and the Ministerial Investigation, that Transpower’s coordination and communication failures meant consumers were disconnected unnecessarily
(b) takes into account recommendations made in the various reports and investigations looking into the 9 August events conducted by the Authority, system operator (Transpower), and the Ministerial Investigation
(c) makes new observations and recommendations intended to create enduring, and widespread, system improvements to the management of future events.
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9 August 2021 Demand management event Phase 2 Report
9-August-2021-demand-management-event-Phase-2-Report.pdf (PDF, 1.2 MB)
Last updated: 27 April 2022
9 August 2021 event timeline

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Quarterly ministerial reports
The Minister requested quarterly progress updates on the response to recommendations made in the Ministry of Business, Innovation and Employment’s final report on the investigation into electricity supply interruptions of 9 August 2021 (the Ministerial investigation).
The first report was provided in March 2022. The second report was provided in June 2022.
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Report to Minister March 2022 9 Aug 2021 progress
Report-to-Minister-March-2022-9-Aug-2021-progress.pdf (PDF, 543 KB)
Last updated: 31 May 2022
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Report to Minister June 2022 9 Aug 2021 progress
June-Report-to-Minister-March-2022-9-Aug-2021-progress.pdf (PDF, 598 KB)
Last updated: 15 July 2022
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Report to Minister September 2022 9 Aug 2021 progress
Report-to-Minister-September-2022-9-Aug-2021-progress.pdf (PDF, 586 KB)
Last updated: 26 October 2022
Phase 1: Immediate Assurance Review - Complete September 2021
The Authority actively manages the performance of the system operator, Transpower.
During Phase 1, the Authority worked closely with Transpower and interviewed a range of industry participants, including direct connect consumers, distributors, retailers and generators to gather the facts and understand the response to the events on 9 August.
Phase 1 of the review found issues in the system operator’s tools and processes. The key areas of concern were communication processes and a miscalculation of demand allocation using the Load shed and restore (LSR) decision support tool.
The Authority published a report of its findings and recommendations for Transpower on September 10, 2021.
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Terms of reference - Electricity Authority Review of 9 August 2021 event
Last updated: 13 August 2021
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Immediate assurance review of the 9 August 2021 demand management event
Immediate-assurance-review-of-the-9-August-2021-demand-management-event.pdf (PDF, 587 KB)
Last updated: 10 September 2021
Transpower's progress on the Phase 1 recommendations
The system operator has made significant improvements to its communication processes and associated protocols since 9 August, 2021.
The Authority is working closely with the system operator to close out the Phase 1 recommendations. A number of these have been addressed and we have processes in place for progressing or resolving the remaining recommendations.
The Authority and Transpower also have joint project plans and governance arrangements to progress the recommendations informed by MBIE’s investigation.
The Authority is confident the adoption of the Phase 1 recommendations will ensure the system operator’s decision support tools and communications processes are better placed to manage future demand management events and to minimise impact on consumers.
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Letter - Transpower response to Authority Phase One Review
Letter-Transpower-Response-to-EA-Phase-One-Review-24-September-2021.pdf (PDF, 192 KB)
Last updated: 28 September 2021
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Attachment - Transpower response to Authority Phase One Review
Letter-Attachment-Transpower-Response-to-EA-Phase-One-Review-24-September-2021.pdf (PDF, 424 KB)
Last updated: 28 September 2021
Other reviews and investigations relating to the events of 9 August
The Authority received an Undesirable Trading Situation (UTS)(external link) claim from four industry participants: Haast Energy Trading Ltd, Electric Kiwi Ltd (Electric Kiwi), Flick Energy Ltd (Flick Electric) and Switch Utilities Ltd (Vocus NZ).
The claim alleged the UTS was individually and jointly caused by Contact Energy and Genesis Energy for not offering additional generation on the night of 9 August 2021.
The Authority investigated and has published its preliminary decision that a UTS did not occur in relation to the trading periods 37 to 42 on 9 August 2021. The Authority released a supplementary consultation paper seeking further feedback on the issue of scarcity pricing on 19 April.
- Preliminary decision on claim of an undesirable trading situation on 9 August 2021 - Supplementary consultation paper
- The Authority’s UTS preliminary decision paper – 9 August 2021(external link)
- Electricity Authority UTS claims and decisions – 9 August 2021(external link)
- UTS – Submissions on preliminary decision paper(external link)
The Authority has considered alleged breaches of the Code on 9 August 2021 by three participants:
- Contact Energy Ltd: The Authority closed a case concerning an alleged breach of the Code on 9 August 2021 by Contact Energy Limited.
Contact Energy Limited was alleged to have breached clause 13.5A(2)(a) by withholding generation capacity during trading periods 37 – 42 on 9 August 2021. In December 2021, the Authority declined to take further action on the alleged breach, on the basis that the evidence did not establish a breach of clause 13.5A. More information is available here.(external link)
- Genesis Energy Ltd: The Authority has discontinued an investigation into a trading conduct breach alleged of Genesis Energy Limited for not offering generation from Huntly Unit 4 on 9 August 2021. The investigation found no breach, concluding Genesis’ behaviour to not offer HLY4 for the evening of 9 August was within the realm of behaviours consistent with that of a rational generator which does not hold significant market power. Read more on the Authority’s decision(external link).
- Transpower as the System Operator: On 12 April 2022, the Authority decided, under regulation 23(3)(b) of the Electricity Industry (Enforcement) Regulations 2010, to lay a formal complaint with the Rulings Panel against Transpower New Zealand Limited as the system operator. The complaint related to alleged breaches by the system operator in relation to its management of the grid emergency on 9 August 2021. Ten potential breaches of the Code were investigated, and the Authority has decided to lay a formal complaint with the Rulings Panel in relation to four alleged breaches. Read more here(external link).
For more details on these current investigations, visit the Code and Compliance section of our website.
The Minister of Energy and Resources directed MBIE to investigate the power disconnections of 9 August 2021. MBIE provides policy advice to the government on energy issues and investigated the causes and factors contributing to the power interruptions.
Many of the recommendations in MBIE’s report relate to the Authority – either in its role in determining the regulatory settings or in its role overseeing Transpower. The Authority is working closely with Transpower in ensuring the recommendations are actioned.
The Authority met with MBIE on 15 February 2022 to clarify recommendations in the report, particularly those with a policy focus and provided a progress update to the Minister for Energy and Resources in late March 2022.
The terms of reference and final report for this review are published on MBIE’s website:
MBIE’s investigation into electricity supply interruptions of 9 August 2021(external link)
Market Development Advisory Group - 100% Renewable power supply
The Authority already has work underway that will respond in part to some of the more complex, industry wide recommendations of MBIE’s report. This includes work by the Authority’s Market Development Advisory Group (MDAG) investigating how the wholesale electricity market would operate under a 100 percent renewable electricity supply.
The MDAG 100% Renewable power supply issues paper and progress is detailed further on our website:MDAG 100% Renewable power supply - discussion paper and consultation(external link)
Transpower as the system operator conducted an investigation to further their understanding of the event and the industry’s response on the night of 9 August.
As system operator, Transpower has a programme of work underway to address recommendations from each of the reports on the 9 August events.
The Transpower-commissioned reviews are published on their website.