SPP Sets 36% Winter Planning Reserve Margin
- Capacity & Wholesale Markets News Policy & Markets
Marin Holt
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- 4 minutes read
- Winter Planning Reserve Margin (PRM): 36%
- Summer PRM: 16%
- Capacity Season: 2026-27
- Reference CONE: $139.85/kW-year
Southwest Power Pool (SPP) set a 36% Winter Planning Reserve Margin (PRM) for the 2026-27 capacity season. The Summer PRM will be 16%. This change impacts load-serving entities in the SPP region. This region covers parts of Arkansas, Iowa, Kansas, Louisiana, Minnesota, Missouri, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, and Wyoming. The new PRM values begin June 1, 2026, for the 2026-27 capacity season. SPP also reports the reference CONE increased to $139.85/kW-year, from $85.61. SPP announced these changes on March 12, 2026. They form part of the organization’s seasonal Resource Adequacy (RA) framework.
What Changed
The Winter PRM increased to 36%, and the Summer PRM rose to 16%. This marks a major shift in SPP’s RA framework. This change is notable as it represents the largest seasonal divergence in U.S. RTO history. The reference CONE also climbed to $139.85/kW-year. This is a key factor in the change. CES Ltd explained on April 2, 2026, that SPP faces a critical capacity gap. The Effective Load Carrying Capability (ELCC) accreditation method will still ensure resources meet required standards.
Why It Matters
New PRM values and the reference CONE will significantly impact load-serving entities in the SPP region. These entities must secure enough capacity to meet higher PRM requirements. They will do this through bilateral contracting, backed by ELCC-accredited resources. Modo Energy noted on April 10, 2026, that market participants must understand the SPP resource adequacy framework. These changes to PRM values and reference CONE will require load-serving entities to reassess capacity needs. They will also adjust their contracting strategies.
Critical Perspective
The Winter PRM’s significant increase to 36% raises questions. It concerns the potential market impact. It also asks about load-serving entities’ ability to secure enough capacity. CES Ltd states that SPP’s capacity gap is a pressing concern. This gap needs addressing. Using ELCC-accredited resources will be critical to meet the required capacity. The 2026-27 capacity season approaches. Market participants will closely watch developments in the SPP region. They want to understand the implications of these changes. SPP’s decision to increase the Winter PRM to 36% will face close scrutiny. Regulators, market participants, and load-serving entities will carefully monitor its market impact.
