The ISO has published a consultation paper outlining the proposed methodology that will be followed when undertaking ESS studies in the NWIS to inform procurement of SRESS for 2026-27.
The paper details the methodology ISO proposes to conduct power system studies necessary to determine the required headroom for credible system conditions and configurations in the procurement period. The paper also discusses different approaches to determining the largest credible contingencies considered in ESS studies under different network configurations.
The paper does not include study results or details of ISO’s approach to ESS procurement.
Stakeholders are invited to submit their feedback by 5pm on Tuesday 21 July 2026.
Submissions on the stakeholder consultation questions will be considered and published on the ISO’s website. ISO will publish stakeholder responses and its finalised ESS studies methodology.
| Event | Date | Status |
|---|---|---|
| Publish consultation paper and invitation for submissions | 7 July 2026 | Complete |
| Public submission period | 7 July – 21 July 2026 | In progress |
| Publish responses to stakeholder submissions and final ESS studies methodology | 4 August 2026 | Not started |
| Pre-negotiate ESS contracts | August – September 2026 | Not started |
| Seek proposals for ESS | September – October 2026 | Not started |
| Consultation on Draft Decision for ESS | October 2026 – November 2026 | Not started |
| Final Decision on ESS | November 2026 | Not started |
Submissions
Stakeholders are invited to submit their feedback by 5pm on Tuesday 21 July 2026.
All submissions received are taken into account in decision-making.
Submissions must be received by the deadline. Please provide submissions electronically via our online form.
Documents related to this proposal