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 increased to 96% of the historic mean last week as large inflows hit the South Island. Demand has also eased with warmer spring weather.
In this week’s insight we look at the effect of the recently contracted grid scale battery energy storage system on reserve prices.
Security of Supply and Capacity
Energy
Inflows across the motu last week resulted in national hydro storage levels, increasing to 96% of the historic mean from 83% the week prior. South Island hydro storage increased from 78% to 93% of historic mean and North Island storage increased from 110% to 114%.
Capacity
Capacity margins were healthy last week with residual at all peaks exceeding 1,000 MW. The lowest residual occurred on the morning of 21 August, at 1,007 MW.
The N-1-G margins in the NZGB forecast are healthy 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 last week decreased from 822 GWh the week prior to 787 GWh, as temperatures warmed across the motu. Total demand is now sitting near levels of previous years. The highest demand peak occurred at 7:30am on Monday 15 September, at 5,901 MW which was 507 MW less than the previous week's highest peak.
Weekly Prices
The average wholesale electricity spot price at Ōtāhuhu last week decreased to $103/MWh from $174/MWh the week prior in line with higher than average wind generation and increased hydro storage. Wholesale prices peaked at $224/MWh at Benmore at 5:00am on Monday 15 September.
Fast instantaneous reserve prices spiked at 9:30am on Thursday 18 September in both islands.
Generation Mix
Renewable generation contributed 91% of the generation mix last week. Hydro generation increased to sit close to its average contribution, at 55% of the generation mix. Wind generation increased its share of the mix from 11% to 14% of the mix, above its average contribution of 9%. Thermal generation decreased from 10% to 8% reflecting lowered demand. The geothermal share remained close to its average level at 21% of the mix.
HVDC
HVDC flow last week was predominantly northward with only three overnight periods of southward flow early in the week. These periods coincided with periods of high wind generation and lower North Island demand. In total, 44 GWh were Transferred north and 6 GWh were transferred south.
CACTIS Consultation Open
Consultation to seek feedback on the proposed Connected Asset Commissioning, Testing and Information Standard (CACTIS) opened on 1 September. The closing date for submissions is 29 September. More information on this consultation can be found here.