Overview
- The Natural Resources Defense Council and the Sierra Club filed the petition for review on Nov. 17 in the U.S. Court of Appeals for the D.C. Circuit, represented by Earthjustice.
- The groups argue SPP’s approach over-credits coal- and gas-fired units by not fully accounting for correlated outages and performance during high‑risk hours.
- FERC’s approval found SPP’s explanations persuasive and rejected claims that the thermal methodology inadequately reflects risk compared with ELCC-based methods.
- SPP says the plan will better indicate which resources are available when needed based on historical performance; the grid operator serves a 14-state region from eastern New Mexico to Montana.
- The case unfolds as other regional operators, including MISO, PJM and ISO New England, revise capacity accreditation to address reliability with a changing resource mix.