NOTICE DATE:  June 6, 2008

NOTICE TYPE:  M-A060608-01  PRR

CLASSIFICATION: Public

SHORT DESCRIPTION:  Implementation of PRR764, Zonal Congestion and
CSCs/CREs

INTENDED AUDIENCE:  QSE Settlement and Operations personnel

DAY AFFECTED:  Operating Day June 9, 2008

LONG DESCRIPTION:  At an emergency meeting today, the ERCOT Board of
Directors approved Protocol Revision Request (PRR) 764, Zonal Congestion
and CSCs/CREs. PRR764 provides that zonal constraints are only those
constraints for which a Commercially Significant Constraint (CSC) or
Closely Related Element (CRE) is the base case or post-contingency
limiting element.

ERCOT Operations will implement PRR764 at 0800 CPT on Operating Day June
9, 2008.  ERCOT will immediately send an additional Notice if at any
point the implementation timeline slips, and will send an additional
Notice confirming implementation when it occurs.

ADDITIONAL INFORMATION:  The details of PRR764 may be found on the ERCOT
website at:

http://www.ercot.com/mktrules/issues/prr/750-774/764/

CONTACT:  If you have any questions, please contact your ERCOT Account
Manager. You may also call the general ERCOT Client Services phone
number at (512) 248-3900 or contact ERCOT Client Services via e-mail at
[log in to unmask] <mailto:[log in to unmask]> .

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