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| Risk date | DateOfPublication | Risk curves | Series | Value (GWh) |
|---|---|---|---|---|
| 30/01/2015 | 30/01/2015 | ERC revisions | ERC revised | Confirmed outages update - improved modelling of Waikaremoana - Tekapo conversion factor fix |
| 27/02/2015 | 27/02/2015 | ERC revisions | ERC revised | Confirmed outages update - new demand forecast - changes to TCC operation (reduction in capacity factor) |
| 31/03/2015 | 31/03/2015 | ERC revisions | ERC revised | Confirmed outages update - revised water values - removed Southdown generator from 1/1/2016 - new version of Emarket |
| 29/04/2015 | 29/04/2015 | ERC revisions | ERC revised | Confirmed outages update - first version of 2016 HRC data |
| 26/05/2015 | 26/05/2015 | ERC revisions | ERC revised | Confirmed outages update |
| 26/06/2015 | 26/06/2015 | ERC revisions | ERC revised | Implemented minimum flow constraint out of Lake Tekapo - adjusted some generation maximum capacity to align model with assumptions - corrected Kaimai generation profile - removed Teviot generator from model - updated generation and transmission outages |
| 29/07/2015 | 29/07/2015 | ERC revisions | ERC revised | Minor adjustments made to the demand forecast - removal of a Manapouri generation/storage function - updated the maximum storage level of Manapouri + Te Anau - adjusted the merit order of generation - updated generation and transmission outages |
| 18/08/2015 | 18/08/2015 | ERC revisions | ERC revised | Removal of Otahuhu Combined Cycle from Oct 2015 - removal of capacity factor limitations on the Taranaki Combined Cycle generator from Oct 2015 - updated generation and transmission outages |
| 23/09/2015 | 23/09/2015 | ERC revisions | ERC revised | Addition of security constraints - change to the grid configuration in the LSI in 2016 - updated generation and transmission outages. |
| 29/10/2015 | 29/10/2015 | ERC revisions | ERC revised | Updated generation and transmission outages |
| 27/11/2015 | 27/11/2015 | ERC revisions | ERC revised | Updated generation and transmission outages (including a restriction on the HVDC caused by BPE_PRM_HAY_2 outage) |
| 17/12/2015 | 17/12/2015 | ERC revisions | ERC revised | Updated generation and transmission outages (including a restriction on the HVDC caused by BPE_PRM_HAY outages) |
| 28/01/2016 | 28/01/2016 | ERC revisions | ERC revised | Updated demand forecast to correctly accommodate Cobb and Mill Creek embedded generators and updated generation and transmission outages |
| 26/02/2016 | 26/02/2016 | ERC revisions | ERC revised | Updated generation and transmission outages and updated hydrology dataset using the Electricity Authority?s Hydrological Modelling Dataset |
| 24/03/2016 | 24/03/2016 | ERC revisions | ERC revised | Updated generation and transmission outages |
| 28/04/2016 | 28/04/2016 | ERC revisions | ERC revised | Updated generation and transmission outages |
| 30/05/2016 | 30/05/2016 | ERC revisions | ERC revised | Updated demand forecast - added 2015 hydro information - corrected minor inconsistency in hydro data - included Te Ahi O Maui generation and updated generation and transmission outages |
| 28/06/2016 | 28/06/2016 | ERC revisions | ERC revised | Updated generation and transmission outages |
| 26/07/2016 | 26/07/2016 | ERC revisions | ERC revised | Updated generation and transmission outages |
| 23/08/2016 | 23/08/2016 | ERC revisions | ERC revised | Updated generation and transmission outages |
| 27/09/2016 | 27/09/2016 | ERC revisions | ERC revised | Updated generation and transmission outages |
| 27/10/2016 | 27/10/2016 | ERC revisions | ERC revised | Updated generation and transmission outages |
| 25/11/2016 | 25/11/2016 | ERC revisions | ERC revised | Updated generation and transmission outages |
| 20/12/2016 | 20/12/2016 | ERC revisions | ERC revised | Updated generation and transmission outages |
| 30/01/2017 | 30/01/2017 | ERC revisions | ERC revised | Updated generation and transmission outages |
| 28/02/2017 | 28/02/2017 | ERC revisions | ERC revised | Updated generation and transmission outages |
| 23/03/2017 | 23/03/2017 | ERC revisions | ERC revised | Updated generation outages |
| 21/04/2017 | 21/04/2017 | ERC revisions | ERC revised | Updated generation outages for next two months |
| 30/05/2017 | 30/05/2017 | ERC revisions | ERC revised | Updated generation outages for next two months |
| 30/06/2017 | 30/06/2017 | ERC revisions | ERC revised | Updated demand and generation outages |
| 26/07/2017 | 26/07/2017 | ERC revisions | ERC revised | Updated generation outages and commissioning date of Te Ahi O Maui - Included Junction Road - Whirinaki generation increased by 15GWh per annum |
| 11/09/2017 | 11/09/2017 | ERC revisions | ERC revised | Updated generation outages (including Tarankai Combined Cycle Nov/Dec outage). Revised water values. Whirinaki generation limit increased to 30GWh. |
| 27/09/2017 | 27/09/2017 | ERC revisions | ERC revised | Updated generation outages for the next two months, including Huntly Unit 5 and Tarankai Combined Cycle. |
| 30/10/2017 | 30/10/2017 | ERC revisions | ERC revised | Updated generation outages for the next two months, new minimum flows for Waitaki, Emarket model update. |
| 30/11/2017 | 30/11/2017 | ERC revisions | ERC revised | Updated generation outages for the next two months. |
| 22/12/2017 | 22/12/2017 | ERC revisions | ERC revised | Updated generation outages for the next two months, new demand forecast, temporary de-rating of Ohaaki generation. |
| 31/01/2018 | 31/01/2018 | ERC revisions | ERC revised | Updated generation outages for the next two months |
| 28/02/2018 | 28/02/2018 | ERC revisions | ERC revised | Updated to include latest demand forecast data, adjustments to generator capacity assumptions and generation profiles, updated frequency keeping and instantaneous reserves assumptions, and major generator outages and de-ratings. |
| 22/03/2018 | 22/03/2018 | ERC revisions | ERC revised | Updated generation outages for the next two months |
| 27/04/2018 | 27/04/2018 | ERC revisions | ERC revised | Updated generation outages for the next two months |
| 04/05/2018 | 04/05/2018 | ERC revisions | ERC revised | Updated demand forecast data to include increased Tiwai load, and updated generation outages for the next two months. |
| 13/06/2018 | 13/06/2018 | ERC revisions | ERC revised | Updated generation outages for the next two months. |
| 20/07/2018 | 20/07/2018 | ERC revisions | ERC revised | Updated generation outages for the next two months, extended Ohaaki de-rating until 31 Dec 2018, adjusted Junction Road and Te Ahi O Maui commissioning dates |
| 29/08/2018 | 29/08/2018 | ERC revisions | ERC revised | Updated generation outages for the next two months, and excluded Tekapo contingent storage from 1 October to 31 March. |
| 25/09/2018 | 25/09/2018 | ERC revisions | ERC revised | Updated generation outages for the next two months and Te Ahi O Maui commissioning date |
| 12/10/2018 | 12/10/2018 | ERC revisions | ERC revised | Updated generation outages for the next two months |
| 06/11/2018 | 06/11/2018 | ERC revisions | ERC revised | Updated generation outages for the next eight months that cannot be deferred in an emergency situation. |
| 15/11/2018 | 15/11/2018 | ERC revisions | ERC revised | Updated generation outages for the next eight months that cannot be deferred in an emergency situation and updated HVDC outages |
| 11/12/2018 | 11/12/2018 | ERC revisions | ERC revised | Updated generation outages for the next eight months that cannot be deferred in an emergency situation and updated generator capacities. |
| 31/01/2019 | 31/01/2019 | ERC revisions | ERC revised | Updated generation outages for the next two months |
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This report publishes the historical electricity risk curves (ERCs) against controlled storage as presented by the system operator undertaking their security of supply forecasting function. Changes or discontinuities with the approach over time are indicated with a vertical grey line.
The system operator is responsible for publishing the electricity risk curves (ERCs) as part of its security of supply forecasting function. The set of ERC’s established in 1 Aug 2019 are available under the show parameter and include, risk status boundaries, percentage risk curves (these have been established the longest), contingent storage release boundaries, and official conservation campaign triggers. These various curves are produced for New Zealand and the South Island. Please see https://www.transpower.co.nz/system-operator/security-supply-and-ercs for current ERCs and further information. The system operator inherited the responsibility for forecasting security of supply from the Electricity Commission, the Electricity Authority’s predecessor, in November 2010.
The Authority monitors the market response to shortage. This report tracks the history of the risk of shortage in the New Zealand electricity system, as reported by the system operator.
Hydro data (storage and/or inflows) is sourced from NZX hydro (data provided by NIWA) and is not available for download. Please see https://energy.nzx.com for more information. In this report controlled storage in the North Island includes Lake Taupo, and in the South Island, Lakes Tekapo, Pukaki, Hawea, and Te Anau and Manapouri.
The framework for monitoring security of supply has evolved through time, particularly with regard to the treatment of contingent storage and the volume of available contingent storage. These changes are marked with vertical grey lines. The current set of curves have included available contingent storage from 1 August 2019. On 27 Feb 2020, following Meridian’s announcement that it could fully utilise the consented contingent storage in Lake Pukaki, storage increased by a further 367 GWh. To accurately represent the new regime and changes to available contingent storage, step changes in storage, mean storage, and maximum storage were added. The mean storage represented in the report is no longer the mean of the historical data presented in this report, but an adjusted mean to reflect the change from this point forward (i.e. without changing what was presented in the past). Prior to the 1 Aug 2019 contingent storage was excluded from the framework. A change was made on 29 August 2018 to bring the treatment of Tekapo contingent storage into line with the excluded treatment of other contingent storage as detailed in the SoSFIP. This change removed 220 GWh of Tekapo contingent storage from controlled storage over summer (denoted as 1 October – 31 March).
The set of electricity risk curves are updated periodically including when there is a material change to the inputs. These updates are marked with a black triangle in the figure and have occurred for the following reasons:
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