On December 21, 2017, FERC issued an order accepting a proposal
from the Midcontinent Independent System Operator, Inc.
("MISO") to revise its Open Access Transmission, Energy,
and Operating Reserve Markets Tariff ("Tariff") and
establish Dynamic Narrow Constrained Areas ("Dynamic
NCAs"). FERC found that MISO's proposal would strengthen
existing market power mitigation measures in MISO and help ensure
that the potential exercise of market power during such transitory
conditions would be properly mitigated.
MISO's existing Tariff applies mitigation measures to curb
market power that may arise due to transmission congestion at two
types of locations on its transmission system. The first such
congestion area is the Narrow Constrained Area ("NCA"),
which is defined as, among other things, an area having binding
transmission constraints for at least 500 hours during a 12-month
period. The second type of congestion area is called the Broad
Constrained Are ("BCA"), which is
