Southern Co. and three Missouri utilities told FERC that MISO has billed them more than $21 million in excessive transmission rates since Entergy joined the RTO in December 2013.

FERC said last week that SPP must engage in interregional coordination and cost allocation with SERTP, rejecting the RTO’s request for a limited waiver of Order 1000 requirements.

SPP members last week approved spending $270 million on transmission improvements over the next five years but not before stakeholders expressed misgivings.

A summary of measures approved by the SPP Markets & Operations Policy Committee at its quarterly meeting Jan. 12-13.