The System Security Forecast (SSF) is produced every two years and revised every six months if required.
Revisions to the SSF are required if changes to the power system materially affect the SSF. The 
SSF Guidelines [ pdf 666.68 KB ] document determines the purpose and principles of the SSF.
Our website has a dedicated page outlining thermal generation decommissioning analysis, including power system operation and security of supply. See Impact of thermal generator decommissioning.
The 2020 version of the System Security Forecast has incorporated the upper North Island (UNI) and upper South Island (USI) report sections within the respective North Island and South Island Backbone reports.
2020
The 2020 System Security Forecast based on new information known by the System Operator.
SSF Change Summary [ pdf 468.34 KB ]
Note: The Voltage Stability Transfer Limits calculated and presented in Table 4-4 to Table 4-7 were calculated incorrectly and have been removed. These limits will be updated in the next System Security Forecast minor update due December 2021.
| Part A | Date |
|---|---|
| Executive Summary [ pdf 386.27 KB ] |
Dec 2020 |
| Part B | Date |
|---|---|
| Grid Configuration and Operations [ pdf 753.9 KB ] |
Aug 2021 |
| Part C | Date |
|---|---|
| Study Approach and Assumptions [ pdf 331.04 KB ] |
Dec 2020 |
| Part D | Date |
|---|---|
| Security Analysis North Island Grid Backbone and UNI Limits [ pdf 1.22 MB ] |
Oct 2021 |
| Security Analysis South Island Grid Backbone and USI Limits [ pdf 1.13 MB ] |
Aug 2021 |
| Security Analysis GZ01 Northland [ pdf 567.03 KB ] |
Aug 2021 |
| Security Analysis GZ02 Auckland [ pdf 839.79 KB ] |
Aug 2021 |
| Security Analysis GZ03 Hamilton [ pdf 763.58 KB ] |
Aug 2021 |
| Security Analysis GZ04 Edgecumbe [ pdf 748.14 KB ] |
Aug 2021 |
| Security Analysis GZ05 Hawkes Bay [ pdf 578.23 KB ] |
Aug 2021 |
| Security Analysis GZ06 Taranaki [ pdf 708.1 KB ] |
Dec 2020 |
| Security Analysis GZ07 Bunnythorpe [ pdf 780.76 KB ] |
Dec 2020 |
| Security Analysis GZ08 Wellington [ pdf 878.72 KB ] |
Aug 2021 |
| Security Analysis GZ09 Nelson Marlborough [ pdf 574.16 KB ] |
Dec 2020 |
| Security Analysis GZ 10 and 11 Christchurch and Canterbury [ pdf 593.29 KB ] |
Dec 2020 |
| Security Analysis GZ12 West Coast [ pdf 571.64 KB ] |
Dec 2020 |
| Security Analysis GZ13 Otago [ pdf 640.35 KB ] |
Aug 2021 |
| Security Analysis GZ14 Southland [ pdf 570.58 KB ] |
Aug 2021 |
| Part E | Date |
|---|---|
| Frequency Principal Performance Obligations [ pdf 369.7 KB ] |
Dec 2020 |
| Part F | Date |
|---|---|
| Dry Year Operational Issues [ pdf 365.72 KB ] |
Aug 2021 |
| Part G | Date |
|---|---|
| Resources (Maps, Site Codes, SLDs etc) [ pdf 1.04 MB ] |
Dec 2020 |
