On December 10, 2025, FERC accepted Southwest Power Pool, Inc.’s (SPP) proposed tariff revision to extend its existing day-ahead market dispatchable transaction model into the real-time balancing market (RTBM). The Commission found the proposal to be just and reasonable and not unduly discriminatory or preferential, rejecting protests that raised concerns about market power, reliability, and transmission withholding.
SPP operates an Integrated Marketplace consisting of a day-ahead market and a real-time balancing market. As part of its expansion into the Western Interconnection, SPP plans to operate two balancing authority areas: the existing East Balancing Authority Area and the new West Balancing Authority Area. To support this structure, SPP proposed revisions to Attachment AE of its tariff to introduce Real-Time Dispatchable Interchange Transactions (RTDT).
Under the proposal, interchange transactions – previously dispatchable only in the day-ahead market – may also be submitted and dispatched in real time. SPP explains that RTDT would be implemented as Dynamic Schedules, allowing transactions to respond to real-time system conditions rather than remaining fixed. SPP argued that extending dispatchability into real time would improve economic efficiency by enabling price-sensitive interchange to respond to five-minute price signals in the RTBM. SPP requested an effective date of December 31, 9998 (this date is used when an applicant does not know or have a proposed effective date), with implementation expected in the second quarter of 2026, and sought waiver of the Commission’s 120-day prior notice requirement to allow time for necessary software development testing.
Several parties intervened and filed protests, arguing that the RTDT design lacked sufficient safeguards against the exercise of market power and transmission withholding, particularly in the smaller and less diverse SPP West Balancing Authority Area. Others raised concerns that RTDT could increase opportunities for economic withholding, transmission hoarding through Market Import Service (MIS), inadequate ramp availability, and price manipulation due to the absence of offer validation beyond the $2,000/megawatt hour offer cap. Protestors also contended that deviation charges applied to RTDT could be discriminatory and that RTDT’s ability to set prices warranted additional protections.
FERC accepted SPP’s proposal, finding it just and reasonable and supported by the record. FERC determined that the concerns raised by protesting parties were speculative and did not demonstrate that RTDT would result in unjust, unreasonable, or unduly discriminatory outcomes. FERC found that RTDT is governed by existing NERC Reliability Standards and market rules that address reliability, ramp capability, and interchange evaluation. FERC also concluded that RTDT’s five-minute clearing interval and treatment of deviation charges are consistent with other RTBM products.
FERC granted SPP’s request for waiver of the 120-day notice requirement for good cause and accepted the tariff revisions effective December 31, 9998. FERC directed SPP to submit a compliance filing to establish the effective date for the tariff records.
A copy of the order, filed in Docket No. ER25-2753-000, can be found here.