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 / More Information
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Current Storage Positions
Overview
New Zealand hydro storage increased to 141% of the historic mean last week and now sits above the 90th percentile.
This week’s insight looks at severe weather events over the past week and the impacts on system operations.
Security of Supply and Capacity
Energy
Inflows to catchments continued last week resulting in national hydro storage increasing to 141% of the historic mean from 121% the week prior. South Island hydro storage increased from 118% to 142% of historic mean while North Island storage decreased from 143% to 134%.
Capacity
Capacity residual margins were relatively healthy for most of last week despite extreme weather. The lowest residual of 799 MW occurred during the morning peak on Thursday 23 October during stormy weather across the motu. Although Thursday morning's residual margin was relatively healthy, there was a significant loss of supply (LoS) in the upper South Island due to transmission outages resulting from the weather. More information on this can be found in this week's insight.
We continue to monitor capacity closely during the spring shoulder season despite decreasing demand. Outages, reduced thermal unit commitment, and the possibility of cold snaps or large swings in wind generation mean that capacity can be tight despite much lower peaks than in winter.
The N-1-G margins in the NZGB forecast are healthy through to mid December. Within seven days we monitor these more closely through the market schedules.. The latest NZGB report is available on the NZGB website.
Electricity Market Commentary
Weekly Demand
Total demand last week decreased from 762 GWh the week prior to 743 GWh and is similar to that observed at this time of year over the past three years. The highest demand peak at 5,449 MW occurred at 8:00 am on Monday 20 October, which was more than 200 MW lower than the previous week's demand peak.
Weekly Prices
The average wholesale electricity spot price at Ōtāhuhu last week decreased to $10/MWh from $26/MWh the week prior in line with increasing hydro storage and higher than average wind generation. Energy prices remained below $10/MWh for almost the entire week, with the exception of Thursday 23 October, where energy and reserve prices spiked due to the weather induced disruptions on the system.
Wholesale prices peaked at $842/MWh at Ōtāhuhu at 9:30am on Thursday 23 October following the tripping of Pole 2 in the extreme weather event.
Generation Mix
Last week had the highest average renewable contribution since 2014 at 98.2% of the generation mix. Wind generation slightly increased its share of the mix from 13% to 14% of the mix, while remaining above its average contribution of 9%. Hydro generation was above average and remained at 62% of the mix. Thermal generation remained low at just 1% of the mix reflecting high hydro and wind generation and thermal outages including Huntly unit 5. The geothermal share increased to 22% of the mix, close to its annual average level of 23%.
HVDC
HVDC flow last week was predominantly northward with the exception of some brief periods of overnight low southward flow. These periods coincided with periods of high wind generation and lower North Island demand. In total, 48 GWh was transferred north and just 1 GWh was transferred south.
SOSFIP Consultation Open
Consultation on a draft amendment to the System Operator Forecasting and Information Policy (SOSFIP) is now open. The closing date for submissions is 5pm on Tuesday 4 November 2025, with cross-submissions due by 5pm on Tuesday 11 November 2025.