On March 12, 2024, the US Court of Appeals for the Third Circuit vacated, in part, a FERC order that allowed PJM Interconnection, L.L.C. (PJM) to implement new rules in the middle of a capacity auction—and to apply those rules to capacity bids that had already been submitted.1 The case explains what it means for a regulatory rule to be retroactive and emphasizes the importance of the filed rate doctrine in FERC cases.2 PJM's existing tariff required it to calculate an amount of capacity that...
