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 slightly below the seasonal average at 94% of mean for this time of year. Demand last week was significantly lower than the week prior with a change from colder than average to warmer than average weather.
This week’s insight discusses our current consultation on how equally-priced generation offers at the same location are selected for dispatch.
Security of Supply and Capacity
Energy
New Zealand hydro storage remains slightly below average for this time of year, dropping from 95% of the seasonal average to 94% over the past week. Both hydro inflows and the hydro generation share were above average last week. South Island hydro storage dropped from 90% to 88% while North Island storage increased from 134% to 140%.
Capacity
Capacity margins were relatively healthy last week with residual at all peaks exceeding 500 MW. Compared to the prior week, milder weather meant that peaks were able to be met with more residual despite lower thermal unit commitment (no Rankine units running).
The N-1-G margins in the NZGB forecast are healthy through to late September. 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 dropped significantly to 843 GWh last week from 886 GWh the week prior, with weather changing from colder than average for the time of year to warmer than average. The highest demand peak was 6,381 MW at 6:30pm on Thursday 31 July, which was 634 MW lower than the previous week's highest peak.
Weekly Prices
The average wholesale electricity spot price at Ōtāhuhu last week decreased to $126/MWh from $169/MWh the week prior. Wholesale prices peaked at $287/MWh at Ōtāhuhu at 6:00pm on Tuesday 29 July during the evening peak.
Generation Mix
Hydro generation contributed 62% of the generation mix last week, the same share as the previous week. Wind generation increased from 4% to 8% of the mix. Thermal generation decreased from 12% to 6% with lower demand and higher wind generation. The geothermal share increased from 20% to 22% with some units coming back from outages.
HVDC
HVDC flow last week was predominantly northward with overnight periods of southward flow coinciding with periods of lower North Island demand. In total, 36 GWh was sent north and 8 GWh was sent south.
Evolving market resource co-ordination: Tie-breaker provisions consultation
On 24 July, Transpower in its role as System Operator published a consultation asking for feedback on how tie-breaker situations should be resolved for multiple competing generator offers in the wholesale electricity market. See consultation pack here. Submissions are due by 5pm Thursday 14 August, with one week for cross-submissions closing Thursday 21 August.