Summary
Security of Supply
National hydro storage has seen an uptick this week and has returned to sitting within the 10th to 90th percentile of the historic range. This results from the biggest inflow event over South Island catchments since 13 February, coupled with reduced demand due to two consecutive long weekends and unseasonably warm weather. Despite this, inflows continue to be lower than generally seen at this time of year, in line with prevailing La Niña conditions.
National hydro storage is now sitting at 85% of average for the time of year; 66% of full. Both North Island and South Island hydro storage have increased, with the North Island now sitting at 113% of average and the South Island at 83% of average. Lake Manapouri and Lake Te Anau have now returned to comfortably within their main operating ranges.
A partial loss of supply event took place in Queenstown on 21 April at around 7am. This tripping was caused by lightning, which took out half of the Frankton bus.
Weekly Demand
National demand was 719 GWh this week, remaining relatively steady with the week prior (both weeks included a public holiday date). A four day period of reduced demand between 15 and 18 April, over the Easter long weekend, can clearly be seen for each of Auckland, Wellington and Christchurch on page 4 of this report. We expect to see another week of reduced demand resulting from ANZAC day.
This week national demand peaked at 5,478 MW on Tuesday 19 April at 6:00 pm.
Generation Mix
Total generation was 749 GWh this week. In reflection of current hydrology, hydro generation comprised just 50% of the total generation mix (an increase of 4 percentage points on the previous week), while thermal comprised 18.3% of the mix (a decrease of 4 percentage points on the previous week).
Wind generation contributed 7.3% of the generation mix this week, peaking at 752 MW on Friday 22 April at 3pm.
Weekly Prices
Prices continue to hover near $200/MWh, rising by just 2% on the previous week to $189/MWh.
Prices peaked at $278/MWh on Tuesday evening at 5.30pm. This coincided with a period of low wind generation during the evening peak.
HVDC
This week transfer was generally northward during the day and southward overnight, with the exception of Easter Monday (18 April) which saw very little northward transfer - likely as a result of reduced demand leading to a lesser need for energy export from South Island lakes.
Energy Risk Curves (ERCs)
Our ERCs have been updated for April. We note there is an increase in risk of 100-200 GWh between April and August. This is largely due to a planned outage of TCC between 17 July and 21 August.
Fun Fact
NIWA has indicated that New Zealand's sunniest four locations for 2022 (as at the end of March 2022), are Taranaki (867 hrs), Wellington (828 hrs), Manawatū-Whanganui (823 hrs), and West Coast (810 hrs).
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