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 remains at 137% of the historic mean, well above the 90th percentile and approaching the maximum capacity of 4,400 GWh.
This week’s insight looks at the effect of space weather on the grid on 12 and 13 October.
Security of Supply and Capacity
Energy
National hydro storage remains at 137% of the historic mean. North Island hydro storage increased from 131% to 133% of the historic mean while South Island hydro storage remains at 138%.
Capacity
Residuals were high last week (all above 700 MW) with relatively low demand peaks, one Huntly Rankine unit running, and most weekday demand peaks having significant wind generation and some solar generation.
The possibility of low capacity residuals remains at this time of year with increased outages and low thermal unit commitment. However, generally low and flat demand and the low probability of cold snaps makes low residuals unlikely. At this time of year, higher temperatures result in higher electricity demand for some weekday peaks due to cooling load.
The N-1-G margins in the NZGB forecast are healthy through to the start of January. 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 to 737 GWh from 752 GWh the week prior, and is in line with demand levels usually seen at this time of year. The highest demand peak at 5,366 MW occurred at 5:30 pm on Monday 10 October.
Weekly Prices
Average wholesale spot prices decreased last week, with very low prices over the weekend. The average wholesale electricity spot price at Ōtāhuhu last week was $72/MWh, down from $107/MWh the week prior. Wholesale prices peaked at $200/MWh at Ōtāhuhu at midday on Monday 10 November.
With significant northward power flow on the grid and some planned outages on the North Island 220 kV transmission network, some price separation occurred between Haywards and Ōtāhuhu from Monday 10 November to Friday 14 November. Inter-island price separation occurred on Tuesday 11 November and Friday 14 November, with the HVDC reaching its maximum northward transfer limit during these periods. Due to sufficient reserve availability, the full capacity of the HVDC was able to be economically dispatched.
Generation Mix
Wind generation remained at 10% of the generation mix, just above its average contribution of 9%. Hydro generation was above average at 68%, just below its 69% share the week prior. Thermal generation remained at 2% of the mix. The geothermal share remained below average at 17% of the mix due to planned outages.
HVDC
HVDC flow last week was entirely northward with high hydro generation and decreased geothermal generation. The peak HVDC transfer was 898 MW at 8:00am on Friday 14 November. In total, 83 GWh was transferred north.
Consultations
Cross-submissions on our draft amendment to the System Operator Forecasting and Information Policy (SOSFIP) have now closed. Two cross-submissions were received and have been posted on the consultation page.
Consultation on the Security of Supply Assessment (SOSA) reference case assumptions and sensitivities is open. Submissions are due by Monday 24 November. We have also opened our survey of planned generation investment for the SOSA. If this applies to you then you should have received an email. If you have not, please contact [email protected].
We have published our response to submissions on tie-breaker provisions in the Scheduling, Pricing and Dispatch model.