EXHIBIT 99.453
ISO CHANGE MANAGEMENT FORM
CHANGE CONTROL #: 1007
CROSS REF:
SUBSYSTEM: SA
ORIGINATOR: Name: W. Strong DATE: 05/20/97
CHANGE REQUEST
CHANGE SUMMARY: Ancillary Services management - Bid Change #1
CHANGE DETAILS: Under the requested change, ancillary services bid evaluation
will not take into account the energy bid for the resource; if the resource is
dispatched in real time, its energy will be settled at real time balancing
energy clearing prices
BENEFIT ANALYSIS: A London Economics study sponsored by the Trustee has
concluded that the current AS market design in DSOW could produce inefficient
outcomes; and recommended revising the ancillary services market design as
outlined in this change order.
ANALYSIS
ASSIGNED TO: NAME: Ali Vojdani DATE: 04/29/97
DUE DATE: 06/04/97
CHANGE DESCRIPTION (CLICK HERE TO OPEN)
NEED FOR CHANGE:
A study sponsored by the Trustee has concluded that the current AS market design
in the DSOW could produce inefficient outcomes, and recommended to revise the
ancillary services market design as outlined in this change request. The
requested change in the AS market design was approved by the ISO Trust Advisory
Committee on 5/8/97.
DETAILED CHANGE DESCRIPTION:
The following lists changes and clarifications to the Ancillary Service
requirements given in the DSOW:
1. Form of A/S price curves:
o The energy bid price is a piecewise linear curve ($/MWH vs MW); however,
this price is not used by the ASM subsystem in determining the A/S
schedules.
o The Capacity reservation price for each service is a single ($/MW) entry
for each resource (it is not a curve).
o The regulation adder for regulation reserve is a single ($/MW) entry and is
used (along with the regulation capacity reservation price) in determining
the regulation schedules.
o The energy bid (ENBID) and the expected energy output (ExpEn) are no longer
used for the scheduling of black start.
2. Price determination and payment:
o The output prices will consist of the marginal cost of ancillary service
for each congestion zone. Output prices by resource will no longer be
calculated since all resources in a congestion zone will pay the same
price. This also applies to black start.
o If multiple resources have market prices resulting from an ancillary
services auction, and if the sum of resources with price less than or equal
to the market price is greater than the net requirement to be supplied by
the ISO, then the resources with the market price will be prorated based on
their capacity so that the total of the scheduled resources equals the
requirement.
3. Reserve auctions:
o Reserve auctions will be done in the following order: regulation,
spinning, non-spinning and replacement.
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o in the sequential auctions, the capacity scheduled from prior auctions
subtracts from subsequent auctions. For example, suppose a SC bid the
following from a resource: 10 MW regulation, 40 MW spinning, 0 MW
non-spinning and 100 MW replacement. If the 10 MW were selected for
regulation, then only 30 MW is available for the spinning auction and 90 MW
for the replacement auction. If the 30 MW were selected for spinning, then
only 60 MW would be available for replacement. If the 30 MW were not
selected, then 90 MW would be available for replacement. No capacity would
be available for non-spinning, in this example, under any conditions.
o Reserve auctions would be done for specified reserve regions where the
reserve regions are disjointed and made up of one or more congestion zones.
The reserve regions will be a function of time specified by the operator.
The same reserve regions apply to all reserve types. Additionally, the
operator will specify which external areas (companies) can supply each
reserve region. Self provided reserves can only be used to provide reserves
in a region if the resource is in the particular region or if the resource
is in an external area that can supply that region.
4. Hour-ahead auction:
o The hour-ahead auction procures additional A/S resources to cover
additional scheduled energy resources (beyond that specified in the
day-ahead market) and to cover reductions in bid capacities previously
scheduled in the day-ahead auctions.
o Any A/S services scheduled in the day-ahead market that are not reduced
will continue to be scheduled.
5. Two day-ahead reserve requirements:
o The reserve requirements that are output two-days ahead (as part of the
day-ahead processing) will be based on the ISO load forecast. Forecasts
will only be supplied for regulation, spinning and non-spinning (not
replacement) reserves. The percent of load supplied by thermal and hydro
will be input constants set by the operator.
6. Black start is dispatched on operator demand for the entire system. There
are no regional auction. The schedule is good from the start of the next
hour and remains active until black start is redispatched.
7. Several parameters, enterable on ASM displays, are used to define the A/S
requirements.
A single value for each of the following parameters is used for all time
points and all reserve regions:
o % load that is hydro (used for two-day ahead reserve calculations)
o % load that is thermal (used for two-day ahead reserve calculations)
o % hydro load (used for calculating operating reserve requirement)
o % thermal load (used for calculating operating reserve requirement)
o % operating reserve (used for calculating spinning reserve
requirement)
o % of ISO and SC load forecast difference (used for calculating
replacement reserve)
The following are entered by zone and time point:
o Most severe contingency (MW)
o Additional replacement reserve requirement (MW)
The following is entered by time point:
o % SC load forecast (used for calculating regulation requirement)
IMPACT ANALYSIS
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OPEN DATE: 05/20/97 BY: Ali Vojdani
REJECTION DATE:
APPROVAL DATE: 05/08/97
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