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 continues to drop sharply and is now below the 10th percentile for this time of year, at 77% of the seasonal mean. South Island storage is lower at 74% of the seasonal mean, also below the 10th percentile.
In this week’s insight we look at the differences in daily generation profile between different solar farms.
Security of Supply and Capacity
Energy
New Zealand hydro storage remains below average for this time of year, dropping sharply from 83% of the historic mean to 77% over the past week following inflows that were lower than average in both islands. South Island hydro storage decreased from 78% to 74% of historic mean and North Island storage decreased from 116% to 103%.
Our August monthly Energy Security Outlook will be published this week and will provide more information on energy risks for 2026.
Capacity
Capacity margins were healthy last week with residual at all peaks but one exceeding 800 MW. The lowest residual occurred on the morning of 21 August, at 791 MW.
The N-1-G margins in the NZGB forecast are healthy through to mid October.'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 increased slightly from 876 GWh the week prior to 881 GWh, which is higher than we have previously seen at this time of year. The highest demand peak occurred at 6:00pm on Tuesday 19 August, at 6,944 MW which was 101 MW higher than the previous week's highest peak.
Weekly Prices
The average wholesale electricity spot price at Ōtāhuhu last week increased to $218/MWh from $196/MWh the week prior in line with lower than average wind generation and declining hydro storage. Wholesale prices peaked at $363/MWh at Invercargill at 9:00pm on Friday 22 August.
The Ruakākā battery has added significant reserve capacity to the market which has helped keep reserve prices low in recent weeks.
Generation Mix
Hydro generation contributed 57% of the generation mix last week, lower than the previous week but still slightly above average for the past 52 weeks. Wind generation increased from 4% to 6% of the mix, below its average contribution of 9%. Thermal generation increased slightly from 12% to 13% with higher demand and lower hydro generation. The geothermal share remained close to its average level at 22% of the mix.
HVDC
HVDC flow last week was mostly northward with overnight periods of southward flow coinciding with periods of lower North Island demand. In total, 28 GWh was sent north and 13 GWh was sent south.
Evolving market resource co-ordination: Tie-breaker provisions consultation
Our consultation on how tie-breaker situations should be resolved for multiple competing generator offers in the wholesale electricity market closed on 21 August. The seven submissions and two cross-submissions received can be seen here. A summary of submissions and decisions reached will be published soon.