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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MO Latest Update.pdf
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Current Storage Positions
Security of Supply and Capacity
Energy
Lower than average inflows and increased demand drew the lakes down last week. National hydro storage dropped from 99% to 93% of the historic mean for this time of year. South Island storage decreased to 94% of average, while North Island storage fell from 103% to 79% of average.
Capacity
There were a few tight capacity margins last week due to the first decent cold snap of the year. A Low Residual Customer Advice Notice (CAN) was sent out for the morning of Wednesday 8 May, as well as a CAN which was then escalated to a Warning Notice (WRN) for the morning peak of Friday 10 May. Thanks to response from industry, we got through Friday morning with just over 200 MW of residual.
Looking at NZGB, there are some days throughout May with low N-1-G margins (less than 200 MW), and a negative margin of -10 MW on 23 May. We recommend that participants consider rescheduling outages to avoid these days and avoid scheduling any further outages that may reduce generation margins. The latest NZGB report is available on the NZGB website.
Electricity Market Commentary
Weekly Demand
Total demand increased by 62 GWh to 844 GWh last week, in line with colder temperatures. Demand peaked at 6437 MW on the morning of Thursday 9 May, up ~450 MW on the week prior. Note that Friday morning would likely have had an even higher load peak if not for demand reduction in response to the WRN.
Weekly Prices
The average wholesale energy price at Otahuhu last week rose to $374/MWh from $246/MWh the week prior; the price rarely dropped below $200/MWh. On four occasions the wholesale energy price spiked to greater than $2000/MWh, coinciding with high peak demand due to the cold snap and consequently low residual margins. Wholesale prices peaked at $4934/MWh at Otahuhu on Wednesday morning. Demand response and additional low priced generation on Friday morning contributed to lower spot prices.
Generation Mix
The renewable percentage of the generation mix dropped a single point to 81% last week. Geothermal generation was steady but due to higher demand it dropped as a percentage of the generation mix by 2.5%. This was made up for in roughly equal parts by hydro, wind and thermal generation.
HVDC
HVDC flows were predominately northward for the last week with a few overnight periods of southward flow. In total 61 GWh were sent north and 4 GWh were sent south.
Draft Security of Supply Assessment 2024 consultation
Transpower, as the system operator, is responsible for publishing the medium-term Security of Supply Assessment (SOSA) annually. This analysis provides a 10-year assessment (2024 to 2033) of the balance between supply and demand in the New Zealand electricity system. The draft 2024 SOSA is now live on the website here for consultation. Please submit any feedback submissions by 4 June 2024.