Transcript CMWG20080428_mw

Congestion Management
Work Group 2008 Overview
CMWG 4-28-08
Marguerite Wagner, Reliant Energy Inc.
2008 Activities
• Competitiveness Constraint Test Support
• Nodal Shadow Price Cap Development
• CSCs for 2009
Constraint Competitiveness Test (CCT)
• Used to determine mitigation in RT SCED
• All energy offers in SCED are subject to Offer
Caps and Floors in PUCT Rule 25.505 and the
Protocols
• SCED Texas Two Step uses Energy Offers to
dispatch energy to serve load and solve
congestion
– Energy Offers used to solve congestion on
competitive constraints are not mitigated through
SCED
– Energy Offers used to solve congestion on noncompetitive constraints are mitigated under Protocols
4.4.9.4.1
Identification of Competitive Constraints
• Section 3.19 of the Nodal Protocols
describes process
• Test evaluates capacity availability and
concentration of control
– Constraint is competitive if there are sufficient
Generation Resource MW to resolve
constraint, controlled by a sufficient number of
different QSEs
CMWG will work with ERCOT to:
• Understand process used to set up base
case for CCT annual evaluation
• Ensure that QSE - Resource mappings
are up to date so that the Resource
‘control’ can be identified
• Develop list of potential Competitive
Constraints
• Timeline Now-Summer
Competitive Constraints Must be
Approved by TAC
• At the absolute latest: November TAC
– (3.19(5) also says CCs must be approved by TAC one month
prior to annual CRR auction. Nodal begins with one month
CRR auctions…to support the one month CRR auctions we
would need to target a September TAC—meaning August
WMS)
• Need ERCOT support to develop CSCs
for 2009
• To Support 168 hour test need to
recommend Competitive Constraints to
WMS by 8/16
CCT Methodology
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Also need business process documents from ERCOT about CCT assumptions
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Will any upgrades will be included in annual CCT?
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What about generation additions?
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Same assumptions (month after interconnection) as transmission upgrades?
3.19.9(2)(a)(i): “…The monthly peak case must include planned transmission and generation outages
for the month.” Does this mean all outages? What, if anything, does this mean for outage scheduling
calendar?
3.19.9(2)(a)(i): “For voltage, stability, and thermal-limited constraints, as well as
interfaces represented by thermal limits on monitored Transmission Elements, the
“Base Shift Factors,” which are the shift factors used from the monthly peak case with
no other contingencies included, must be used. For contingency-limited constraints,
the outage shift factors relative to the import terminal of the limiting Transmission
Element must be used.”
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Or would upgrades only be part of monthly evaluations?
Should upgrades match those for CRR auctions? (CRR auction model does not include upgrades until
the month after they go into service)
How are the two sets of SFs managed?
What is the ongoing process for validating Resource “management”?
3.19.9(2)(c)(i): “Managed Capacity for an Entity is a Resource or portion of a
Resource for which the Entity or its Affiliates has the decision-making authority over
how the Resource or portion of the Resource is offered or scheduled.”
CCT Methodology, ctd.
• What is the ongoing process for validating Resource
“management”?
– 3.19.9(2)(c)(i): “Managed Capacity for an Entity is a Resource or
portion of a Resource for which the Entity or its Affiliates has the
decision-making authority over how the Resource or portion of
the Resource is offered or scheduled.”
• Test requires dispatch at Resource HSL, except for wind
– 3.19.9(1)(b): “For wind generation, the expected on-peak wind
generation output,”
– Does this mean ERCOT should use Wind Forecast Tool to
develop an average on peak output for the month? What
assumptions should go into development of this forecast?
• Other assumptions?
Backstop for CCT
• Backstop: CSCs are deemed to be competitive 3.19(1)
need to determine CSCs for 2009
• Timeline: late Summer 2008
• Timing may require PRRs to amend timeline for CSC
determination
• Zonal Protocols (Section 7.2) require:
– ERCOT analysis complete: 8/1
– CSCs & CREs determined by 11/1 (means Oct TAC & BOD)
• Likely will not have analysis done by 8/1, targeting 9/1
with CMWG consideration early Sept and Sept WMS
• May need PRR to change timeframe for consideration to
9/1
Nodal Shadow Price Cap
• Protocols 6.5.7.1.11 require ERCOT to “establish
a maximum Shadow Price for each constraint…”
• Each contingency used in SCED must have a
max SP cap
• CMWG will develop proposals for how to
establish SP cap and bring to WMS for
consideration and recommendation to TAC
• Target completion of draft by start of 168 hr test
• TAC approval by Oct  Sept WMS consideration
Nodal Protocols Definitions
• Shadow Price: A price for a commodity that
measures the marginal value of this commodity,
that is, the rate at which system costs could be
decreased or increased by slightly increasing or
decreasing, respectively, the amount of the
commodity being made available.
• Locational Marginal Price (LMP): The offerbased marginal cost of serving the next
increment of Load at an Electrical Bus, which
marginal cost is produced by the DAM process
or by the SCED process.
High Level--Why SP Cap Matters:
• At a high level, a locational price can be
considered as:
system marginal cost + congestion component
• Congestion component varies by location
“i” and can be calculated as
– SUMc (SFi * SPc)
– Where SP is the shadow price of constrained
element, “c”
• Choice of shadow price cap bounds range
for system production of LMPs
CMWG Work Products for WMS
• Recommended list of Competitive
Constraints for 2009
• Recommended CSCs for 2009
• Proposal for developing SP Cap in SCED