MARKET NOTIFICATION OF SYSTEM CHANGE

PIP Number(s):        144, 200



PRR Number(s):       294



Protocol Section(s):   4.4.4, 6.3.1, 11.4.1.1



Implementation Date:     January 18, 2002



Description of System Change:

ERCOT plans to implement PIP 144/PRR 294 (Load Ratio Shares per LSE) and
PIP 200 (LSE Load Ratio and Loss Allocation) on January 18, 2002.   The
Protocol revision for PIP 144 impacts sections 4.4.4 and 6.3.1 of the
Protocols.  The revision for PIP 200 is documented in section 11.4.1.1
of the protocols.

Currently, ERCOT calculates ancillary service obligations for each QSE
for a given trade day based on the QSE's aggregated Load Ratio Share as
of the same day of the prior week.  This results in the use of QSE/LSE
relationships from one week prior to calculate ancillary service
obligations.  When an LSE switches from one QSE to another, the
obligation associated with its load continue to be allocated to the old
QSE for one week after the effective date of the switch.  The same
obligation does not get allocated to the new QSE for the first week
after the switch.  QSEs also do not have access to Load Ratio Share data
per LSE that makes up their ancillary service obligations.

This modification will alter the way the QSE Load Ratio Shares are
aggregated so that ancillary service obligations are calculated based on
the QSE/LSE relationships that will be effective on the trade day for
which obligations are being posted.  Load Ratio Shares will be
calculated and saved by LSE during the data aggregation process run for
initial settlement of the trade day in question.  QSE Load Ratio Share
will then be aggregated and posted for a given trade day based on the
sum of LSE Load Ratio Shares calculated as described above corresponding
to the most current QSE/LSE relationships for that trade day.

Scheduled Extract Changes:  Billing determinants for LSE Load Ratio
Shares called LRSLSE will be added to the load extract.  Each QSE will
have the LRSLSE fields added to its load extract for each LSE it
represents.  Each LSE will also have the LRSLSE field added to its load
extract with its Load Ratio Share information.

Dynamic Extract:  The Settlement and Billing folder within the archive
extracts area of the portal will have an additional dynamic extract
folder added called "Obligations".  This dynamic extract folder will
have two extracts called "QSE obligations" and "LSE obligations" which
can be used to query Load Ratio Shares by QSE and LSE.  The following
ERCOT total quantities will also be added to the dynamic extracts above:

?        Total obligated non-spinning quantity (NSOTOT)

?        Total obligated regulation down quantity (RDOTOT)

?        Total obligated responsive reserve quantity (RROTOT)

?        Total obligated regulation up quantity (RUOTOT)



You can find details of PRR-294 at the following link:
http://www.ercot.com/AboutERCOT/PublicDisclosure/ProtocolRev.htm .

If you have any questions, please call your ERCOT client service
representative.