On September 4, 2025, the Board of Directors of Southwest Power Pool (SPP), the regional transmission organization (RTO) responsible for much of the central United States, passed Revision Request 696 (RR 696), paving the way for SPP to propose that the Federal Energy Regulatory Commission (FERC) modify SPP’s Open Access Transmission Tariff (Tariff) to create a 90-day path to interconnection for large loads and supporting generation. SPP is expected to file this Tariff change proposal with FERC in the coming weeks. Pending FERC’s decision, SPP aims to administer one of the fastest interconnection study processes in the nation and allow expedited processing of new large loads on the SPP transmission system.
What is included in RR 696?
RR 696 provides for two integration study frameworks: (i) High Impact Large Load (HILL) and (ii) High Impact Large Load Generation Assessment (HILLGA). Under RR 696, a High Impact Large Load is defined as “a new commercial or industrial load, or increase in commercial or industrial load, at a single site connected through one or more shared Points of Interconnection (POIs) or delivery points, where such load is either (1) 10 MW or more if connected to the Transmission System at a voltage level less than or equal to 69 kV; or (2) 50 MW or more if connected to the Transmission System at a voltage greater than 69 kV.” Electric Storage Resources under the SPP Tariff are not considered HILLs. HILLs must register as such in accordance with SPP Tariff Attachment AE and follow the processes specified in new SPP Tariff Attachment BA – High Impact Large Load.
RR 696 processes are designed to add more certainty for HILLs attempting to interconnect to SPP’s grid while maintaining grid reliability and operational efficiency. RR 696 adds supplemental analysis on top of the studies that are already required to be conducted under Attachment AX – Provisional Load Process, or Attachment AQ – Delivery Point Assessment, as applicable, to address additional reliability elements presented by the large load. Note that Attachment AX was submitted to FERC on June 4, 2025, with a requested August 4, 2025 effective date in Docket No. ER25-2430-000. An order is still pending in that docket.
High Impact Large Load Generation Assessment
RR 696 also proposes the creation of Attachment BB to address HILLGA projects by creating an expedited process to review and approve the interconnection of a new or existing generator that supports generation of a HILL. The process that is created is separate from Attachment V – Generator Interconnection Procedures, as interconnection requests processed though Attachment V will not be subject to the provisions of HILLGA, and a HILLGA request is only subject to Attachment V if explicitly noted in Attachment BB.
Attachment BB is not a request for transmission service, but rather a way for generation resources to be studied where that generation is directly supporting a HILL. The HILL supported by that generation would still need to execute a Deliverability Point Study Agreement. A HILLGA customer may select either the Common Bus or Local Area pathway for the interconnection studies to be conducted. Common Bus is applicable when the HILL and supporting generation are behind the same point of interconnection and the Local Area pathway is applicable when the HILL and supporting generation are within two buses of each other. Both pathways include certain requirements and limitations that should be considered.
Removal of Conditional High Impact Large Load Service and HILLGA Path Three
Notably, the Conditional High Impact Large Load Service (CHILLS) was removed from this revision request. The CHILLS product would have allowed HILLs to interconnect with conditional transmission service. One of the three original paths under HILLGA (which had been applicable to HILLs and associated generation resources in the same deliverability area) was also removed from the proposal. However, SPP is currently drafting language for a separate revision request addressing CHILLS, targeting approval by the SPP Markets and Operating Policy Committee in October 2025. Revisions to the original CHILLS policy proposed in RR 696 are expected.
Please reach out to Michael Blackwell and Brittney Beetcher for more information.