Consultation on a draft determination of causer for under-frequency event

We are seeking your feedback on the draft determination of causer for an under-frequency event (UFE) on 24 January 2023.

The normal frequency band in New Zealand is between 49.8 and 50.2Hz. An under-frequency event occurs when the frequency falls below 49.25 Hz because of a loss of injection of more than 60 megawatts into the grid.

The Electricity Authority’s draft determination under clause 8.61 of the Electricity Industry Participation Code 2010 is that Genesis Energy Limited (Genesis), as a generator, was the causer of the 24 January 2023 UFE. The reasons for the draft determination are:

• the interruption/reduction of energy injected into the grid occurred at Unit 5 of the Huntly power station, which belongs to Genesis
• no other asset was identified as having caused or potentially caused the UFE
• in the system operator’s view, Genesis is the causer of the UFE
• in reply to the system operator’s letter, Genesis accepted that it was the causer.

The Authority is required to consult with every generator, grid owner and other participant substantially affected by the UFE on its draft determination.

We look forward to receiving your responses to this consultation by 5pm on Tuesday 3 October 2023.

Have your say - read the draft determination of causer.

We will carefully consider all submissions received before making a final determination on the UFE.

We also invite comment on the system operator’s calculation of the megawatts of power lost during the event, which the system operator uses for calculating the UFE charge.