Market Operations Weekly Report

Our Market Operations Weekly Report contains the latest information about the electricity market, including security of supply, wholesale price trends and system capacity.

It is published every Tuesday. Click here to receive the report via email every week. 

If you have any comments or questions please contact the Market Operations Team at [email protected].

Latest Report

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Previous Reports

Current Storage Positions

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Security of Supply and Capacity

Energy

National hydro storage now sits at 92% of the historic mean, down from 95% a week ago. South Island storage is at 87% of the historic mean, down from 90%, and North Island storage dropped from 150% to 147% of the historic mean. 

Capacity

Capacity margins were healthy last week with higher thermal unit commitment coinciding with the HVDC outages. The lowest residual point of 818 MW occurred on Tuesday morning.

Forecast N-1-G margins are high until late April, with some lower margins forecast in May. The lowest N-1-G margin during the forecast period is 208 MW on 10 May. The latest NZGB report is available on the NZGB website.  

Electricity Market Commentary

Weekly Demand

Total demand was 747 GWh, up slightly from 743 GWh the week prior. This is higher than what was observed at this time of year over the past three years. Demand peaked at 5,360 MW on the morning of Thursday 26 February.

Weekly Prices

The average wholesale price at Otahuhu last week was $211/MWh, up from $176/MWh the week prior. The increased average wholesale price last week was in line with thermal contribution to the generation mix rising as hydro generation dropped.

The Otahuhu price peaked at $340/MWh on Tuesday 26 February at 7:30am during a morning peak with low wind generation.

There were periods of high reserve prices and inter-island price separation during the two HVDC outages - a planned pole 2 outage that ran from February until 12:30 pm on Wednesday 14 March, and a planned pole 3 outage that ran from 4:30 am to 6 pm on Sunday 17 March.

There was one trading period of price separation between Invercargill and Benmore at 2 am on Wednesday 13 March. This is discussed in our weekly insight below.

Generation Mix

The renewable percentage of the generation mix dropped to 82%, the lowest since September. Wind generation decreased slightly from 12% of the mix to 11%. Hydro generation decreased from 53% of the generation mix to 51%, likely affected by the HVDC outages. This is the lowest hydro contribution since April of 2022, when hydro storage dropped below the 10th percentile of historic storage for that time of year. Thermal generation increased to 16% of the mix from 13%. 

HVDC

HVDC flows were more southward than northward over the past week, in line with low South Island hydro generation, high North Island thermal generation and above average North Island wind generation. HVDC flows before 12:30 pm on Wednesday 14 March were limited by a planned pole 2 outage, and flows between 4:30 am and 6 pm on Sunday 17 March were limited by a planned pole 3 outage. The recent series of HVDC outages has now concluded.

SOROP cross submissions close tomorrow (20 March)

Transpower is seeking views from the electricity industry on proposed changes to the System Operator Rolling Outage Plan (SOROP). The period for cross submissions closes tomorrow 20 March. Please see our website for further details.