On October 10, 2025, FERC accepted Southwest Power Pool, Inc.’s (“SPP”) proposed revisions to its Open Access Transmission Tariff (“OATT”) to establish a provisional load interconnection process. SPP argued the provisional load interconnection process is driven by an increase in requests for load additions and will improve transmission planning and encourage new generation resources to come online by allowing SPP to study interconnection requests while accounting for planned generation. FERC accepted the tariff revisions subject to further compliance, finding the provisional load interconnection process will allow SPP to better understand the impacts of load requests and identify necessary network upgrades.

SPP’s current process for modifying “delivery points,” or the points on the SPP transmission system where capacity and energy are made available to transmission customers, analyzes necessary network upgrades associated with a load addition request and allocates such upgrade costs through rolled-in rates. The SPP OATT also requires that changes to delivery points be accompanied by a 10-year load forecast, which SPP uses to evaluate whether there are enough existing “Designated Resources” to satisfy the load forecast. Designated Resources are defined under the OATT as generation resources owned, purchased, or leased by transmission customers to serve load in the SPP region and do not include resources (or any portion thereof) committed for sale to third parties or that cannot otherwise be called upon to meet a transmission customer’s load on a non-interruptible basis.

SPP explained its proposal was driven by an increase in requests for load additions in part from data centers and industrial load. SPP further noted that many transmission customers had been proven unable to demonstrate there will be adequate Designated Resources to cover their 10-year load forecasts. To address these issues, SPP proposed to (i) add a new OATT Attachment AX, (ii) add two new “Provisional Load Process” agreements as pro forma service agreements under the SPP OATT, and (iii) revise OATT Attachment J. SPP explained that the new OATT Attachment AX will allow SPP to evaluate new load requests based on both planned and existing Designated Resources. As to the Provisional Load Process agreements, SPP explained that the two new pro forma service agreements will require the relevant transmission customer to demonstrate its planned generation has been assessed and granted Designated Resource status before the applicable transmission service agreements are modified to reflect such changes. Finally, SPP noted that its proposed OATT Attachment J revisions ensure the costs of any upgrades under the provisional load interconnection process will be directly assigned to the transmission customer based on the constructing transmission owner’s revenue requirement.

FERC accepted all three components of SPP’s proposal effective August 4, 2025. First, FERC found that the new OATT Attachment AX will help transmission customers more expeditiously plan to serve their future loads and will allow SPP to evaluate the impacts of connecting load before necessary Designated Resources become interconnected to the SPP transmission system. FERC also determined that the two new pro forma Provisional Load Process service agreements will provide just and reasonable terms for SPP to study new load requests. Finally, FERC accepted SPP’s proposed cost allocation method under SPP’s revised OATT Attachment J, finding SPP’s proposed method satisfies the cost causation principle because it appropriately accounts for the uncertain nature of the load and generation additions to SPP’s system contemplated under the Attachment AX study process and will thus protect other transmission customers by limiting cost shifts.

FERC ordered a further compliance filing within 30 days to address language inadvertently included in SPP’s proposal.

FERC’s order, issued in Docket Nos. ER25-2430-000 and ER25-2430-001, is available here.