Generating Units offline for a transmission system limitation are eligible for a full Tier 2 exemption. These outages are not due to poor planning by the generation operator. Relevant text from Schedule 53:
Schedule 53 ->II. Tier 1 and Tier 2 Planned Outage Exemption Requirements -> D. Limitation Provided by Transmission Provider or Transmission Operator.
The Transmission Provider will grant the equivalent of a Tier 2 Planned Outage exemption if a Schedule 53A Resource is provided an operating limitation, such as thermal, voltage, or stability limits referenced in the BPM - 008 Outage Operations, provided by the Transmission Provider or the Transmission Operator to preserve the reliability of the Transmission System, that is lower than the must offer obligation described in Section 69.A.5.a.
MISO will manually grant these exemptions during the Exemption Review Request Period outlined in BPM-008 Outage Operations:
BPM-008 Outage Operations -> 4. Generation Outage Coordination -> 4.1.1 Generation Outage Exemption Requirements
Generator Owner or Generator Operator may request a review of the CROW Time Requirement Exemption (TRE) and/or Maintenance Margin Exemption (MME) within fourteen (14) calendar days following the actual end date of the outage associated with exemption(s) ("Exemption Review Request Period").
Schedule 53 ->II. Tier 1 and Tier 2 Planned Outage Exemption Requirements -> D. Limitation Provided by Transmission Provider or Transmission Operator.
The Transmission Provider will grant the equivalent of a Tier 2 Planned Outage exemption if a Schedule 53A Resource is provided an operating limitation, such as thermal, voltage, or stability limits referenced in the BPM - 008 Outage Operations, provided by the Transmission Provider or the Transmission Operator to preserve the reliability of the Transmission System, that is lower than the must offer obligation described in Section 69.A.5.a.
MISO will manually grant these exemptions during the Exemption Review Request Period outlined in BPM-008 Outage Operations:
BPM-008 Outage Operations -> 4. Generation Outage Coordination -> 4.1.1 Generation Outage Exemption Requirements
Generator Owner or Generator Operator may request a review of the CROW Time Requirement Exemption (TRE) and/or Maintenance Margin Exemption (MME) within fourteen (14) calendar days following the actual end date of the outage associated with exemption(s) ("Exemption Review Request Period").
- The request must be submitted through the MISO Help Center. Only requests submitted via the MISO Help Center will be considered. Submission instructions can be found in the Knowledge Article: How to Submit an Outage Exemption Review.
- The request must contain sufficient data and the reason review is requested.
- The MISO Operations Planning team will review all requests submitted through the MISO Help Center during the Exemption Review Request Period and update the exemption status, as required, based on the outcome of the review. MISO may issue a decision on the request for review during or after the Exemption Review Request Period.
- Once the Exemption Review Request Period ends, no further requests for review will be accepted.
- All exemptions will be considered final upon expiration of the Exemption Review Request Period, if no request for review is submitted during that period through the MISO Help Center, or upon MISO issuing a decision based on a properly submitted request for review.
Granting these exemptions after the unit outage is complete allows MISO to verify the transmission outage limiting the unit and ensures that unplanned outages do not automatically lose their exemption when the outage ticket changes status. These transmission system limited generation outages should use Cause Code 126 "Transmission System Limitation" and list the Transmission Outage in the Requestor Notes section of the outage ticket.