Hydro and thermal generation remain at healthy levels (117% of average), and the risk of shortage this winter remains low. Storage traditionally declines through Winter as demand is high and inflows are low as precipitation typically fall as snow.
As mentioned last week, Transpower and the Electricity Authority are jointly hosting an industry briefing on the new Security of Supply Forecasting and Information Policy and related Code changes. The briefing is an opportunity for stakeholders to hear from the project teams and better understand the new security of supply policy framework.
Details of the briefing are as follows:
Time: 10am–12pm Date: Thursday, 4 July 2019 Location: Transpower, 22 Boulcott St, Wellington, 6011 and by video conference
Please RSVP to system.operator@transpower.co.nz if you would like to attend or for Skype details.
We updated the Hydro Risk Curves (HRCs) for this month. One of the key changes was to identify and remove a step in our process that overwrites calculated New Zealand HRC values with South Island HRCs if the South Island HRCs values were higher. We believe this step in our process is unnecessary as there is no need to account for elevated risk in the South Island in the New Zealand HRCs. The step would have meant that a national Official Conservation Campaign (OCC) would be triggered if storage fell to the South Island 10% HRC.
While new outages included in the HRC model caused an increase to the HRCs from June to August 2019, the removal of the above process step meant there was a net decrease to New Zealand HRCs from July to November in 2019 and 2020.
Current Situation
Aggregate New Zealand storage decreased over the last week and is at 76% of total storage, this is above the historical average (117% of average) for this time of the year.
Weekly hydro generation over the last 12 months has ranged between 54% and 66% of total generation. Last week hydro generation contributed 63% of total generation.
Hydro Storage Update
Controlled storage remains above average on the New Zealand and South Island hydro risk curves.
Inflows into Lake Taupo over the last week were lower than the historical average for the time of the year and there was a decrease in North Island storage.
South Island inflows were also lower than the historical average over the last week and storage levels have also decreased.
The spot price, based on available final and interim prices, has averaged $107 per MWh over the last two weeks, this is higher than prices experienced this time last year.
We periodically update the base HRC data curves and the Simulated Storage Trajectory Curves. The updated files for these are available on the Hydro Risk Curve page.
Data
Last Updated
Hydro Risk Curve Data File and Input Assumptions
25 June 2019
Simulated Storage Trajectories and Assumptions
21 May 2019
Next Report
The next scheduled weekly Security of Supply Report is due Tuesday 2 July 2019.
