2 May 2021 under-frequency event

The system operator recommended that the causer of the 2 May 2021 under‑frequency event (UFE) was Genesis Energy Limited as the generator that owns Huntly Unit 5. Our draft determination agrees with the system operator’s recommendation.

We did not receive any submissions on the draft determination for the 2 May 2021 UFE.

Our final determination, under clause 8.61 of the Code, is that Genesis was the causer of the under-frequency event on 2 May 2021 at 07:36 am.

Our reasons for this final determination are:

• a UFE occurred on 2 May 2021 at 07:36am when the frequency fell to 49.15 Hz in the North Island and 49.18 Hz in the South Island,
• the interruption/reduction of electricity occurred at the grid injection point for Huntly Unit 5, which belongs to Genesis,
• no other asset was identified as having caused or potentially caused the UFE, and
• the system operator and Genesis agree that Genesis was the causer of the UFE.

In accordance with clause 8.65 of the Code, the clearing manager will rebate the event charge to relevant participants. The charge advised in the system operator's report to the Electricity Authority is $263,750.