This gets even better.  On Tuesday, April 3, I had our California prescheduler ask the ISO Day Ahead personnel why the COB S/N ATC had been decreased so much.  There reply was that the ATC is calculated by taking the TTC less Existing Transmission Contracts less FTRs less Capacity Benefit Margin.  Normally, and up until January 1 of this year, they haven't used a Capacity Benefit Margin when calculating ATC leaving the state.  So the amount of ATC they had at COB S/N is normally in the 700 to 800 MW range, rather than the 35 to 60 MW of ATC they are using now.

We asked what this Capacity Benefit Margin was, and they said it's not in their tariff, it's in the NERC Operating Manual.  I went to the NERC web site, and sure enough, Capacity Benefit Margin is a defined term.  It reads : "Capacity Benefit Margin is the amount of TTC reserved by load serving entities to ensure access to generation from interconnected systems to meet generation reliability requirements".

The ISO's use of this language is outrageous.  This is language to ensure that load has transmission access to remote generation.  I can see them using this argument with respect to COB N/S but no way COB S/N!!  In fact, one could very easily argue that they are VIOLATING this criteria.  If we have load in the Northwest, and have purchased generation in California, we should have access to available transmission.