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
Hydro inflows remained strong this week with storage continuing to sit well above the average for this time of year at 139%. Solar generation reached a new record of 15 GWh with Kōwhai Park coming online.
In this week's insight we look at the influence Battery Energy Storage Systems are having in the reserve market.
Security of Supply and Capacity
Energy
National hydro storage remained steady at 139% of the historic mean. South Island storage decreased slightly from 150% to 148% and North Island storage remained at 81%.
Capacity
Residuals last week were healthy. The lowest residual of 866 MW occurred on Monday 14 September during the evening peak.
The N-1-G margins in the NZGB forecast continue to increase with healthy levels through to mid November. 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 decreased slightly last week to 779 GWh compared to 806 GWh the week prior. The highest demand peak occurred at 6:30 pm on Wednesday 16 August at 5,963 MW.
Weekly Prices
The average wholesale electricity spot price increased at Ōtāhuhu to $48/MWh from $39/MWh in the previous week. Prices peaked at $220/MWh at 7:00 am on Monday 14 September with price separation between the North and South Islands, coinciding with low North Island wind generation.
Periods of both intra-island and inter-island price separation occurred throughout the week. The South Island price separation between Invercargill and Benmore was a result of the planned Aviemore-Benmore-1 outage.
Generation Mix
There was little movement in the generation mix last week from the week prior. Hydro generation last week decreased slightly to 61% of the generation mix from 62% the week prior, slightly above its yearly average of 60%. Wind generation increased from 10% to 11% last week. Geothermal generation sat around its annual average of 24%. Solar generation was shy of 2% and thermal was just above 1% of the mix.
HVDC
HVDC flows last week was entirely northward. In total 116 GWh was transferred north.
Consultations and Engagement
Ancillary Services Procurement Plan
We are proposing updates to the Ancillary Services Procurement Plan (ASPP) to implement the new Emergency Reserve ancillary service. We're inviting feedback on this plan through to 25 September. You can read more here.