The IESO is proposing changes to Market Manual 7.2: Near-Term Assessments and Reports. The proposed change would add a new condition in section 1.3.4: IESO Control Actions (Nuclear Manoeuvres Forecasted or Occurring) to allow the IESO to curtail wheel-through transactions if a nuclear shutdown is scheduled in future hours concurrent with wheel-through transactions.
Curtailing wheel-through transactions to prevent a nuclear shutdown may be the appropriate market response during this circumstance given:
• The IESO’s scheduling tool does not account for all of the implications of a nuclear shutdown for future hours – including the fact that a nuclear unit can take up to 72 hours to re-start after a shutdown; and
• The fact that the next set of economic resources after the nuclear shutdown are likely to have limited flexibility to be dispatched in this timeframe.
As a result of the feedback received during the webinar, as well as through the stakeholder comment process for the IMDC, the IESO has revised the IMDC. The revised IMDC clarifies and emphasizes the rationale that the IESO will curtail linked wheel-through transactions for reliability. The IESO has also developed a Q&A document to address stakeholder feedback.