Enhanced Day Ahead Commitment
Project: Enhancements to the DACP
IESOTP 244-3d
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What is Day Ahead Commitment Process?
A mechanism for:
• Developing a dependable view of the next day’s available supply and anticipated Ontario demand
• The economic commitment of certain dispatchable generators the day before dispatch in return for a financial guarantee
• The economic scheduling of imports the day before dispatch in return for a financial guarantee
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DACP Enhancements
• New calculation engine performing 24 hour optimization for energy and operating reserve while considering:– Three-part offers and commitment parameters– Combined cycle plant modeling– Inclusion of exports and linked wheel
transactions
• Revised cost guarantee principles
• Revised/new failure charges
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24 Hour Optimization
• The objective of the engine is to minimize the total cost for scheduling of energy and reserve over the entire day
• Scheduling decisions are made that benefit the entire day over that of a single hour
• Examples include – committing a not QS resource that may be more
expensive than an import in a single hour but has a benefit for several hours over other alternatives
– committing a not QS resource that may be more expensive than another not QS resource who has a longer run time
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Multi-Pass Run
Pass 1: determines initial set of schedules required to satisfy average hourly forecast demand.
Pass 2: determines additional schedules required to satisfy peak hourly forecast demand (utilizing pass 1 results).
Pass 3: determines final set of schedules for all resources based on average hourly forecast demand (utilizing pass 2 results).
Pass 1Commitment
Pass 2Reliability
Pass 3Scheduling
AverageForecast
AverageForecast
PeakForecast
Fixed cost associated with starting a resource in a given hour. 6
Resource Scheduling According to Three Part Offers
2. Speed-no-load costs
Minimum Loading Point
Start-Up Synchronize
3. Energy Offer
1.Start-up Costs
Three Part Offer = 1 + 2 + 3
t
MW
Fixed cost associated with scheduling a resource in a given hour.
Variable cost associated with scheduled quantity in a given hour.
*three part offers are applicable to not quick start resources
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Scheduling Accordingto Commitment Parameters
Minimum Generation Block Run Time
1st Start
Minimum Generation Block Down Time
Synchronize
Minimum Loading Point
SynchronizeDe-Synchronize2nd Start
Maximum number of starts/day = 2
*commitment parameters are applicable to not quick start resources
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Pseudo Unit Modeling
PSU1 = CT1 + 1/3 ST
PSU2 = CT2 + 1/3 ST
PSU3 = CT3 + 1/3 ST
PSU1 PSU2 PSU3
Physical Units Pseudo Units
• For a combined cycle plant, modeling allows scheduling of a combustion turbine in parallel with the associated portion of the steam turbine
• Scheduling is done in proportion to the gas/steam relationship at the facility
CT1 CT2 CT3 ST
Line A Line B
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Offer Resubmission for Cascading Hydroelectric Resources
GEN A
GEN B
3 Hour Delay
Same River System
• Hydroelectric resources that are energy limited and have a cascading dependency with a resource owned by the same market participant
• May resubmit offers for the second run of the DACP in order to receive schedules that reflect the hydraulic time lag between adjacent resources
HE1 HE2 HE3 HE4 HE5 HE6 HE7 HE8 HE9
GEN A
25MW
27MW
32MW
22MW
GEN B
17MW
19MW
24MW
14MW
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Inclusion of Export and Linked Wheel Transactions
IMPORT
EXPORT
LIN
KED
WH
EEL
• All transaction types can participate in the day-ahead.
- Imports- Exports- Linked Wheels
• Scheduling of internal resources accounts for intertie traffic and its impact to internal power flow.
• Commitments reflect both internal and external demands.
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New Generator Commitment Guarantee
• Guarantees a generator its day-ahead costs for the total amount and duration of its day-ahead schedule.– guarantee is based entirely on day-ahead offer– revenue shortfall is assessed by comparing the day-
ahead cost versus real-time revenue (energy, operating reserve, CMSC)
• Guarantee structure encourages:– punctual start-up for the first hour of a commitment
start– close compliance with real-time dispatch– a real-time offer strategy that aims to fully utilize
day-ahead schedule
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New Withdrawal Charge for Committed Generators
• Committed generators have their entire day-ahead costs guaranteed.
• Withdrawals of commitments impacts the least cost solution attained in the day-ahead.
• New withdrawal charge applies to committed generators who withdraw due to financial decisions.– Reasons outside of market participant control are
exempt (ie. generator outage)
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New Import Offer Guarantee
• Guarantees the day-ahead costs for arranging an import.– guarantee is based entirely on day-ahead offer– revenue shortfall is assessed by comparing the day-
ahead cost versus real-time revenue (energy and CMSC)
• Guarantee structure encourages:– a real-time offer strategy that aims to fully utilize
day-ahead schedule
• Excludes import legs of a linked wheel transaction.
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New/Revised Day-Ahead Intertie Failure Charges
• Import, export and linked wheel transactions that do not match their day-ahead schedules impact the least cost solution attained in the day-ahead.
• Assessed on scheduled quantities between day-ahead and the final pre-dispatch.
Day-Ahead Failure Charge
Real-Time Failure Charge
Day-Ahead Schedule
Pre-Dispatch Schedule
Real-Time Schedule
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Net Result of Enhancement
• Operational efficiency• Efficient resource commitment• Meaningful day-ahead results• Guarantees & charges that encourage
wanted behaviors
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