Southwest Power Pool Takes Action to Expand Power Transfers Across the Eastern and Western Grids

Southwest Power Pool’s Board of Directors on Aug. 11 approved the Western and Eastern Interconnection Capacity Expansion High-Priority Study, or WE EXPAND, to evaluate opportunities to increase electricity transfers between the nation’s eastern and western grids as demand in its 17-state region is expected to nearly double over the next decade. The study will examine transmission options that could improve reliability, reduce wholesale energy costs, and defer future generation investments.

Electricity transfer between the Eastern and Western Interconnections is currently limited to a small number of transmission pathways with constrained capacity. Preliminary analysis indicates that increasing transfer capability by more than 5,500 megawatts could generate hundreds of millions of dollars in annual savings. The Energy Department’s draft 2026 National Transmission Needs Study also identified cross-interconnection links as having the highest potential transmission value nationally, citing wholesale price differences of $18 to $33 per megawatt-hour between the Western Interconnection and the grid operator’s eastern footprint.

The study follows SPP’s expansion into the Western Interconnection in April 2026, making it the first regional transmission organization to provide services spanning both major U.S. interconnections. The expanded footprint positions the grid operator to evaluate opportunities for greater energy sharing between regions and apply the findings to other areas.

The grid operator will work with stakeholders through the remainder of 2026 to establish the study scope and plans to conduct WE EXPAND in 2027. The results are also expected to inform future transmission cost allocation decisions by its Regional State Committee.

The findings are expected to provide a foundational assessment of long-term interconnection expansion needs and could support future regional planning efforts aimed at improving system flexibility, integrating diverse generation resources, and enhancing overall grid resilience across both interconnections.