Interchange scheduling

The act of scheduling imports/exports across an intertie between two Balancing Authority Areas (BAAs), whether it is a static or dynamic schedule transfer (pseudo tie or dynamic).

Static scheduling

Static schedules represent a fixed amount of energy scheduled to flow across an intertie between Balancing Authority Areas (BAAs) for the hour. 

The sending or host BAA is responsible to provide all real time balancing energy needs for the source generator (including regulation) through its Energy Management System (EMS) and its Automated Generation Control (AGC) system to maintain the pre-arranged static or fixed megawatt interchange schedule, with the sink BAA. Ancillary services (capacity tags) on the interties may also be scheduled using static interchange schedules (e-Tags); however, the use of static capacity tags is generally limited to ancillary services (AS) capacity in the form of contingency reserves, which are only converted to energy in the event of a contingency that requires the dispatch of AS energy to respond to a sink BAA contingency event.

Mid-hour changes

An exception to static hourly interchange schedules is a process for intra-hour schedule changes across balancing authorities. These are done on an exception basis.  

Dynamic transfers

Dynamic transfers is a general term that applies to either dynamic schedules or pseudo-ties between two BAAs. Participants need to meet the minimum requirement set forth in the Dynamic Scheduling Protocol (DSP) in Appendix M of the ISO tariff for scheduling dynamic transfers of imports and exports in the California ISO BAA.

Dynamic schedule vs. pseudo-tie transfer

A dynamically scheduled resource remains under the control of the host balancing authority area (BAA) where the source of transfer is electrically located, and the host balancing authority includes the resource’s output in its balancing of supply and demand. A pseudo-tie effectively transfers the external generation resource into the ISO balancing authority area. In a pseudo-tie transfer, the energy source is accounted for in the ISO’s balance, and the ISO also performs other balancing area functions for the pseudo-tie resource. In essence, the pseudo-tie is modelled as an internal resource within the sink of the attaining BAA. For more assistance with dynamic transfers, please review the Help Center knowledge base. 

Dynamic transfer requirements and process

View the process and procedures for implementation of dynamic transfers.

Requirements

• Become a certified scheduling coordinator (SC) or retain the services of a certified SC to act on your behalf.
• Successfully complete the new resource implementation process prior to participating in the ISO market.
• Use the Dynamic or Pseudo-Tie Transfer Scheduling Points Letter template when notifying the ISO of the start date of a new scheduling point for a pseudo tie or dynamic transfer resource.
• Participants must meet the metering and telemetry requirements to participate in the ISO market. 

Process

1. Review and complete the Dynamic Transfer Pseudo-Tie Introductory Meeting Checklist. 
   1. If you are a scheduling coordinator, submit the completed checklist and request a dynamic transfer meeting via a CIDI inquiry ticket.
   2. If you are a generator owner, submit an inquiry on the Contact us page, with your request to set up a dynamic transfer meeting. A customer experience representative will reach out to obtain your completed checklist. 
2. Upon receipt of the completed checklist, customer experience will schedule a meeting with the dynamic transfer team. 
3. Fill out Pro forma agreements and information request sheets below once you have your coordination meeting

Dynamic transfer pro forma agreements and information request sheets

e-Tags

Consistent with North American Electric Reliability Corporation (NERC) standards, upon receiving an ISO market award involving interchange imports and exports, the responsible purchasing selling entity must submit a NERC e-Tag interchange schedule to physically schedule energy or capacity delivery.

For in-depth process and requirements about e-Tagging, refer to operating procedure 2510 NERC Tagging Requirements.

Preparing eTags

Each valid market award must be cross-referenced on each e-Tag, which is verified by the California ISO Interchange Transaction Scheduler. The Transaction ID that identifies your market transmission award must be provided in the OASIS field of the e-Tag Transmission Allocation section as follows:  Refer to operating procedures 2510B CAISO Tagging Templates and 2510C Allowable Tag and Market Award Combinations.

ISO Market IDs

There are two types of market IDs. The resources IDs registered in Master File upon request and Transaction IDs are automatically generated when market bids are submitted into SIBR application. Refer to 2510 NERC Tagging Requirements and 2510B ISO Tagging Templates to determine the location of market IDs on the E-Tag. 

For Resource IDs the following three data elements are required to facilitate confirmation of the market transmission award. Any extra or missing element(s) will result in automatic tag denial.