Definition
Required all transmission providers to implement Ambient-Adjusted Ratings (AARs) and Seasonal Line Ratings (replacing static ratings that often understated true line capacity regardless of actual weather conditions) and added Attachment M to the pro forma OATT. The order was driven by evidence that conservative, fixed seasonal ratings were artificially suppressing ATC and forcing unnecessary curtailments — particularly during cooler weather when conductors can safely carry significantly more current. By requiring temperature-responsive ratings, Order 881 unlocks latent grid capacity without building new infrastructure, reducing congestion costs and improving interconnection outcomes for renewable developers seeking near-term transmission access.
Topic Deck
FERC Orders
Source
FERC Order Index →Explore more
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