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Storage as Transmission-Only Asset (SATOA) PAC004

Last Modified - 11/17/2021
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The title of this issue was updated in March of 2021 from “Energy Storage as Transmission Reliability Asset” to “Storage As Transmission-Only Asset (SATOA)” to reflect FERC Order 172 FERC ¶ 61,132, which allows for the selection of a storage facility as a transmission-only asset (SATOA) in the MISO Transmission Expansion Plan (MTEP). 

2021 phase is to address required revisions in Business Practices Manuals (BPM) 20, 27, and 29 required to implement SATOA. The Planning Subcommittee (PSC) will initiate review in Q2 2021. 
Revisions will address:

  • BPM-020 Transmission Planning: Changes to conform to the approved SATOA Tariff language
  • BPM-027 Competitive Transmission Process: Revisions to the competitive process to evaluate and select a Proposal for a SATOA as an Eligible Project
  • BPM-029 Minimum Project Requirements for Competitive Transmission Projects: Technical requirements necessary to create the minimum design and performance requirements in a Request for Proposals for a SATOA project eligible for the competitive process

 The current MTEP Reliability Planning process includes the opportunity for Transmission Owners and other stakeholders to propose solutions to reliability issues identified as needed to meet applicable reliability planning criteria (NERC, Regional, Local). 

Today, such proposed solutions could include a battery storage device in the MTEP Reliability Planning study as a transmission solution to an identified transmission issue.  However, there are some challenges that should be addressed prior to the development of the MTEP19 Reliability Planning models and associated studies, in order to facilitate proper evaluation of these energy storage (ES) device solutions, should they be submitted in this upcoming planning cycle.  Among issues needing resolution:

  • Project proposal submission details - database technicalities
  • Interconnection requirements and process
  • Planning evaluation considerations / modeling (Includes Cost and Cost Recovery consideration necessary to evaluate ESR against alternative transmission asset solutions) 
  • Functional control / State of Charge 
  • Facility retirement 



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PAC presented with SATOA edits made to the following with the PSC: proposed edits to BPM-027 and 029. Feedback period opened until December 3.


PAC presented with SATOA edits made to the following with the PSC: proposed edits to BPM-020 and 015, SATOA eligibility checklist, and life cycle cost estimates worksheet. Feedback period opened until October 1.


PAC review of BPM-020 and 015 edits developed with PSC; feedback requested by September 3. Further BPM revisions under review with PSC currently will come forward later in Q4 or Q1 2022.


Feedback and redlines on BPM-020 revisions for Storage as Transmission-Only Asset (SATOA) were reviewed at the PSC. These revisions and BPM-015 will be discussed at the August 11 PAC. MISO introduces draft language for BPM-027 and BPM-029. Feedback was requested on the draft language. MISO anticipate having all revisions to BPM-020 and 015 related to SATOA completed by end of 2021 and revisions to BPL-027 and 029 completed in the first quarter of 2022.


A review of BPM-020 revisions was provided and can be seen in the posted materials. Stakeholder feedback was requested on the proposed changes presented. The draft language will be presented at the PCS and PAC in August.


A Joint Brief of Respondent Intervenors was filed in DC Circuit Court regarding DTE Electric Co versus FERC.


An overview was provided of the Business Practices Manual (BPM) 020 revisions for Storage as a Transmission-Only Asset (SATOA). FERC accepted Tariff revisions for SATOA in 2020, and MISO is revising its BPM’s in 2021 to enable SATOA. BPM-020 and supporting documents will be used to determine eligibility and selection of electric storage facilities as a SATOA. BPM-020 revisions, SATOA eligibility checklist, and SATOA life cycle cost estimate spreadsheet were reviewed and are included in the meeting materials for stakeholder review. Feedback was requested on the revisions and materials posted.


Issue title and description updated to reflect current scope from FERC Order 172.


MISO submitted a response to the comments filed regarding the post-technical conference on storage facility as a transmission-only asset proceeding.


Order accepted and suspended until August. FERC will hold a Technical Conference on May 4. (Docket ER20-588)


Storage as Transmission Only Asset (SATOA) Filing Submitted


MISO review of updated draft Tariff language; updates contained in Modules A and C, Attachment FF, and Attachment X. Language to be filed in 2019.


Summary of stakeholder feedback from the August meeting provided along with proposed adjustments to draft BPM and Tariff language. Tariff additions to Module A, Attachment X, and Attachment FF were described in the posted material for feedback by October 7.


Reviewed stakeholder feedback responses and updated draft BPM-020 language. Supplemental summary of key issues addressed in the BPM posted with meeting materials. Requested additional feedback on substantive section of BPM concepts by September 6.


Proposed redlines to BPM-020 sections 4.3 and 4.4 were reviewed; feedback requested by July 12.


Reviewed stakeholder comments on proposed tariff and BPM presented in April; discussed approach to registration and energy settlement treatment of SATOA.


Discussed stakeholder comments from March material and reviewed tariff and BPM drafts as well as registration requirements for both integrated and standalone Transmission Owners.


Revised proposal and partial draft tariff / BPM provided, along with more detailed MISO paper for feedback.


MISO presented revised revisions to the Phase I policy proposal. Also discussed was a DTE sponsored presentation of additional considerations and potential common assumptions of a Storage as a Non-Market/Non-Transmission Asset (SANTA) proposal.


MISO presented Phase I policy positions for discussion as well as potential Phase II elements to be addressed following approval of Phase I policies.


Reviewed possible phased approach to implementing Storage as a Transmission Asset (SATA). MISO proposed proceeding with policy development separated into two phases: 1) Transmission only usage; and then 2) mixed Transmission and Market Services operation. Further revisions to the proposal will be presented in January with additional feedback requested at that time.


MISO-hosted Storage as Transmission Asset (SATA) workshop to continue exploring "threshold" questions introduced in the September 26, 2018 PAC meeting. Feedback on a series of guiding questions was requested via the Feedback Tool by October 19.


Discussion with Planning Subcommittee (PSC): modeling and assumptions for Storage as a Transmission Asset (SATA) in MTEP studies.


Updated proposal and summary of stakeholder feedback presented.


Summary of stakeholder feedback presented. Due to lack of feedback, an additional request was extended through September 7.


MISO began to address the planning related issues assigned to the PAC by the Stakeholder Steering Committee.


MISO initiated the discussion on the planning issues assigned to the PAC from the Steering Committee.


Issue Submission Energy Storage as a Transmission Solution in the MTEP Reliability Planning Process was assigned to the Planning Advisory Committee (PAC) from the Steering Committee.