Summary
Security of Supply
National hydro storage decreased by 1% to 89% of the historical average for the time of year. This remains within the historical 10th to 90th percentile range. High hydro generation in the first half of the week contributed to the decline in NI hydro storage despite average inflows. North Island hydro storage decreased by 18% to 147% of the historical average. South Island storage increased by 1% to 84% of the historical average for the time of year.
Weekly Demand
Continued cold weather helped sustain high demand at 849 GWh. Demand peaked at 6,764 MW on Wednesday 29 June at 5:30pm, as the evening peak coincided with cold temperatures and low wind generation. Demand peaks were relatively high in the first half of the week, and were tempered on Friday alongside increasing temperatures.
Generation Mix
Renewable contribution to the generation mix continued to decrease, dropping the percentage of renewable generation down to 82%. This is now lower than the renewable generation percentage at this time of year in 2019, but still higher than the previous two years. It included hydro generation, which decreased from 61% to 58% of the generation mix, and wind generation, which comprised 6% of the total generation mix.
Thermal generation peaked mid week in response to high demand and low wind generation, similar to the week prior. Wind generation was low during Tuesday and Wednesday, then picked back up for the rest of the week.
Weekly Prices
Average prices decreased from the week prior. At Haywards, prices decreased by 7.5% from $182/MWh to $168/MWh. Prices generally stayed at around $200, with a few periods of $10/MWh-$20/MWh underpinned by high wind generation and low demand. Prices were high during peak demand periods on Tuesday and Wednesday where there was low wind generation.
Prices peaked at $726/MWh on Wednesday 29 June at 5:30 pm, where low wind generation and cold temperatures coincided with the evening peak.
HVDC
Transfer across the HVDC link over the past week again reflected typical winter conditions, with high northward flow during the day and some periods of southward flow at night as a result of low demand. There continued to be some northward flow overnight due to low wind generation mid week.
Security of Supply Assessment (SOSA)
The 2022 Security of Supply Assessment was published on Thursday 30 June to the Transpower website.
Outages and Loss of Supply
No outages or loss of supply events to note.
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