• Proposes new Consolidated Planning Process for 20-year transmission planning.
• Keeps highway/byway cost allocation but adds subregional allocation and generation-customer upgrade charges

After a yearlong delay, the Southwest Power Pool (SPP) submitted a proposed compliance filing revising its open access transmission tariff (OATT) to comply with FERC’s Order 1920 reforms to long-term regional transmission planning.

That 2024 order requires transmission providers to engage in long-term regional transmission planning over a 20-year planning horizon to identify long-term transmission needs and determine cost allocation methodology, among other requirements. The order initially required providers like SPP to submit compliance filings by June 2025, but SPP successfully obtained extensions, pushing the deadline by a full year.

The new filing describes SPP’s new Consolidating Planning Process (CPP), which it aims to use to replace its existing Integrated Transmission Planning Process (ITPP) it has used since 2010. The new system is expected to conduct multiple transmission assessments over recurring three-year periods to evaluate SPP’s transmission system’s long-term performance, economic, policy and interconnection needs via 20-year forward-looking assessments broken up into 2, 5, 10 and 20-year evaluations.

SPP says the new assessment paradigm “is expected to identify transmission solutions to deliver energy across the region while accommodating industry uncertainties and promoting optimal generation siting.”

SPP is currently conducting its ITPP and CPP transition study, the first integrating its former and current processes. It is scheduled to conclude in “late 2026” and “provide information regarding reliability and economic transmission needs across multiple planning horizons and futures.”

A follow-up 2027 study is scheduled to run for the majority of next year.

NPM Interconnection queue data is tracking 676 pre-operational projects within SPP, of which 181 projects reached an advanced stage in the past 12 months, of which NextEra Energy Resources, Savion, Xcel Energy and ENGIE each have 1 GW or higher of projects that have reached that metric.

Cost Allocation

The CPP proposes to continue cost allocation via an existing highway/byway methodology based on voltage level with facilities operating above 300 kV fully allocating costs on a region-wide basis, 100 kV – 300 kV projects allocating 33 percent of costs regionally and 67 percent to the zone in which it is located, and sub-100 kV projects instead allocating its 67 -percent figure to its applicable subregion.

New revisions seek to replace existing legacy pricing zones with a new subregional allocation structure that SPP argues “better reflects the regional nature of transmission planning because byway facilities provide benefits beyond a single zone.”

Under the new framework, generation customers will also be allocated a portion of upgrade costs while load continues to fund transmission upgrades though the established methodology. SPP says revenues collected through this new GRID-C methodology for generation customers will be credited back to them and reduce net transmission charges.

Breaking with FERC

Notably, however, SPP’s proposal does propose to deviate somewhat from FERC’s proposed seven-point benefit metric expected to guide selected regional transmission portfolios including such metrics as cost reduction via avoided or delayed transmission investments as well as incorporation of loss of load projections, production cost savings and reduced transmission energy losses and congestion while measuring extreme weather mitigation.

While FERC illustrated the expectation that transmission owners apply these metrics during the portfolio selection process, SPP has argued doing so “would create unmanageable and frankly impossible modeling burdens making the planning cycle administratively infeasible and significantly slow SPP’s transmission planning process leading to unnecessary delays.”

As such, SPP is proposing to perform is benefit metric analysis on a single final portfolio following its selection, a framework it argues is “intentionally iterative” and “more technically sound and administratively workable.”