Option Name: Flowgate Allocation
Work Group (Indicate Work Group Lead with an asterisk ‘*’)
Work Group Member Organization
Advena, Chris PJM
Johnson, Alan NRG
Bressers, Bert SPP
Erhardt, Blaine Basin Electric
Desocio, Mike New York ISO
Muller, Nelson OATI
Taylor, Ben TVA
Luong, Thanh FERC
Skiba, Ed Midwest ISO
Wesley, Cathy PJM
Mallinger, Tom* Midwest ISO
Nelson, Emilie New York ISO
Sanders, Steve WAPA
Colby, Mike PJM
Danis, Deral Constellation
Problem Statement:
Each work group will develop a mechanism to assign priorities of generation to load impacts that will be used in the IDC to assign relief obligations during TLR. The NERC ORS has approved modifications to the IDC to collect data and make a centralized generation to load impact calculation. In order for the IDC to curtail these impacts on a pro-rata basis along with tags, appropriate priorities must be assigned to these generation-to-load impacts.
Overview Description of Solution:
The flowgate allocation process allocates the total capacity of the flowage for firm usage based on day-ahead and hour-ahead predicted firm usage. The predicted firm usage includes generation-to-load (GTL) impacts from generators considered to have firm transmission service and firm point-to-point (PTP) impacts (day-ahead impacts will be based on firm reservations and hour-ahead impacts will be based on firm schedules). As a starting point, the flowgate allocation process needs to have the set of generators with firm transmission service that will be used to determine GTL impacts and the set of firm PTP reservations/schedules to determine PTP impacts for the period under review.
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On a day-ahead basis, 24 hourly allocations will be performed to determine firm rights in the forward and reverse directions. Each hourly allocation will be based on the predicted load, topology of the system and transactions. Load will be reduced for imports to avoid double counting the impact of reservations (while load will be decreased for import reservations, generation will not be increased for export reservations). Merit order/block loading files that take into account units off for maintenance will be used to dispatch generators (see third major bullet in Detailed Description of Solution). Since these hourly allocations only consider generators with firm transmission service, they do not represent the actual dispatch of generators expected to occur in real-time. Consequently, this dispatch will be considered a fictitious dispatch and ramp rates will not be applied in the day-ahead and hour-ahead allocations.
On an hourly basis, an hour-ahead allocation will be performed but will use schedules in place of reservations and will use the latest information on loads and outages to make a next-hour allocation. Both the day-ahead and the hour-ahead allocations will follow a similar process to determine firm
1allocations that will be assigned to each Aggregate Entity. There will be a single allocation of firm GTL
and firm PTP impacts down to 0% in the forward and reverse directions. All Aggregate Entities will receive their 5% and greater impacts on the flowgate. If the flowgate is not over allocated (the sum of the 5% and greater impacts exceed the capacity of the flowgate), the Aggregate Entities will receive either a portion or their full impacts down to 0%. If there is still flowgate capacity remaining after assigning impacts down to 0%, any remaining flowgate capacity will be assigned to Aggregate Entities on a proportional basis (based on total impacts down to 0%).
To obtain 5% allocations, impacts between 0% and 5% will be removed from the down to 0% allocation. This will leave the impacts greater than 5% and excess capacity (if any) in the 5% allocation. The higher-of logic will be applied between the day-ahead allocation and the hour-ahead allocation. This means that to the extent the day-ahead allocation is greater than the hour-ahead allocation, you use the day-ahead allocation in real-time to set priorities. This is being done to avoid the situation where an error in the hour-ahead allocation could drive the allocation to zero and there is no time to correct this error before allocations are used to set priorities used in real-time to assign curtailments. Even after applying the higher-of logic, it is likely that the real-time firm GTL impacts and firm PTP impacts (from generators considered to have firm transmission service and from firm PTP schedules) will exceed the firm allocation. When this happens, OATI has proposed to make pro-rata curtailments where proportional amounts of firm PTP impacts and firm GTL impacts will be placed into a lowest level of firm bucket that will be curtailed first during TRL 5 (first to curtail firm service). The following process will be used by OATI to make pro-rata curtailments when real-time firm PTP impacts and firm GTL impacts exceed the firm allocation.
1 Aggregate Entity refers to a group of BAs and TPs that can be rolled-up for the purposes of the allocation process. For example, all of the Midwest ISO LBA GTL impacts can be aggregated into Midwest ISO.
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; The GTL impacts will be placed into one of three buckets in real-time:
o 7 FN firm service – will be curtailed on a pro-rata basis with all other firm.
o 7 FCN first to curtail firm service – will be curtailed on a pro-rata basis with other first to
curtail firm service. First to curtail firm service will be entirely curtailed before firm
service is curtailed.
o 6 NN non-firm service – highest priority of non-firm service.
; The firm PTP impacts will be placed into one of two buckets in real-time:
o 7 F firm service - will be curtailed on a pro-rata basis with all other firm. o 7 FC first to curtail firm service - will be curtailed on a pro-rata basis with other first to
curtail firm service. First to curtail firm service will be entirely curtailed before firm
service is curtailed.
; The size of the GTL buckets and the PTP buckets for each Aggregate Entity will be determined based on the Aggregate Entity’s firm allocations versus the Aggregate Entity’s impacts from the hour-ahead allocation. The following review will be performed for each Aggregate Entity: o The firm GTL impacts down to 0% in the forward direction and the firm PTP impacts
down to 0% in the forward direction from the hour-ahead allocation will be summed
and compared to the firm allocation
o If the summed value is less than the Aggregate Entity’s allocation, no pro-rata
curtailments will be made between firm PTP impacts and firm GTL impacts. In real-time,
all firm PTP schedules will be assigned a firm curtailment priority and all GTL impacts will
be assigned first to the firm GTL bucket that is remaining after reducing it for firm PTP
service. Any GTL remaining after filling the firm GTL bucket will be assigned to the non-
firm GTL bucket.
o If the summed value is greater than the Aggregate Entity’s allocation, the firm allocation
will be proportionally assigned to GTL and PTP based on impacts down to 0%. This
proportional assignment of firm allocation represents the size of the firm bucket (7 FN
for GTL and 7 F for PTP). The remaining impacts down to 0% will be assigned a first to
be curtailed firm service and will establish the size of the first to be curtailed firm bucket
(7 FCN for GTL and 7 FC for PTP). In real-time, all firm PTP schedules will be assigned a
proportional amount of 7 F and 7 FC for use during TLR 5. In real-time, all GTL impacts
will first be assigned to the firm GTL bucket. Any GTL impacts remaining after filling the
firm GTL bucket will then be assigned to the first to be curtailed firm GTL bucket. Any
GTL impacts still remaining after filing both firm GTL buckets will be assigned to the non-
firm GTL bucket.
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Detailed Description of Solution:
; The total capacity of a coordinated flowgate will be allocated to Aggregate Entities on a day-
ahead basis using estimated next-day conditions.
o Aggregate Entities refers to a group of BAs and TSPs that can be “rolled-up” for the
purposes of the allocation process. For example, all of the Midwest ISO LBA GTL
impacts can be aggregated into Midwest ISO.
o Day- Ahead – 24 Hour Profile one-time run
; Provides an opportunity to review results and make corrections, if needed.
; Day ahead will use reservations except for IESO, NY ISO, and ISO NE, which will
use input from the day ahead market to calculate allocations at 12:00 pm
; (Verify when Day-Ahead firm reservation window closes.)
; Verify whether IESO can provide day-ahead schedules.
; Reservations on the Midwest ISO and PJM OASIS that source or sink in one of
the three entities that do not have reservation systems will have the total
impacts split between Midwest ISO and PJM for allocation purposes and real-
time assignment of priorities.
; Example 1: If the reservation is from NY ISO to PJM (no wheel through),
PJM would receive 100% of the impacts.
; Example 2: If the reservation is from PJM to Midwest ISO to IESO (wheel
through), Midwest ISO and PJM would each receive 50% of the impacts.
; In BAs that do not have reservation systems the allocations would be on Gen-to-
Load.
o Hour-Ahead – 1 Hour sent 24 times per day
; Address possible change in ratings, transmission and generation outages,
change in load, new temporary flowgates, changes in unit commitment and
changes between reservations and schedules.
; For Hour-Ahead will use schedules for determining allocations submitted 45
minutes prior to the start of the next hour.
; Allocations will be performed at 35 minutes prior to the start of the next hour
; TLR will be issued for next hour at 30 minutes prior to the start of the next hour. o Will do a Day Ahead and then do an Hour Ahead. The Day-Ahead will be used as a back
stop.
; Will use the higher-of either the Day Ahead allocation or the Hour Ahead
allocation.
; What if there is not enough generation to serve firm load (potential options not listed in any
priority)
o Ramp online generation with firm transmission service
o Ramp offline non-outage generation with firm transmission service o Ramp generation with non-firm transmission service
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o Ramp outaged generation with firm transmission service
o Curtail load
o Ramp above pmax
; Scenario 1 (with prioritized order)
1. Ramp online generation with firm transmission service
2. Ramp offline non-outage generation with firm transmission service
3. Curtail load
; Scenario 2 (with prioritized order)
1. Ramp online generation with firm transmission service
2. Ramp offline non-outage generation with firm transmission service
3. Ramp generation with non-firm transmission service
; Scenario 3 (with prioritized order)
1. Ramp online generation with firm transmission service
2. Ramp offline non-outage generation with firm transmission service
3. Ramp above pmax
; Merit order/Block Loading should be made in conjunction with IDC model updates or with
approvals by the IDCWG. This should only include firm generation with firm transmission service
usage.
; If an hourly generation dispatch file (energy dispatch file) option is used by an entity, this should
only include generation with firm transmission service usage. The following requirements must
be followed:
o 24 hour hourly generation dispatch file must be submitted at a minimum of once a day.
o More frequent updates could be submitted.
o Will provide Pmax, Pmin, and Ramp
o If there is a problem with the hourly generation dispatch file submitted, there will be a
pro-rata adjustment to the hourly generation dispatch by the IDC.
o If there is a problem with the file submittal and there is no data available, the IDC will go
back to the previous hour for the first hour. (or previous day)
; The impact of other entities are considered in the allocation process but the other entities do
not receive an allocation since this is not a coordinated flowgate for them. ; Because flowgate capacity is allocated among Aggregate Entities based on their projected next
day usage of firm GTL and firm transmission service, still need to know which generators have
firm transmission service usage to make the allocation.
; The firm allocations are then used by the IDC to assign pro-rata curtailments to the real-time
GTL impacts and PTP impacts.
Detail Explanation for Implementing Solution (What is required to implement the solution?) ; Impact Calculation and Allocation Calculation
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1. An OATI change order is needed to make the firm GTL and firm PTP impact calculation on all coordinated flowgates. This will be both a day-ahead and an hour-ahead impact calculation. ; It will require the following data to make the calculation:
o List of generators by BA with firm transmission service.
o Merit order/block loading file for generators.
o Load plus losses for each BA.
o Topology of transmission system to calculate response factors.
o Firm reservations for day-ahead impact calculation.
o List of coordinated flowgates and the Aggregate Entities that have significant
impacts on these flowgates.
; Impacts will be calculated down to 0% and 5% and greater in both the forward and
reverse directions. GTL impacts and PTP impacts will be calculated separately. ; The details on how load/generation will be adjusted for firm import/export transactions,
how intra-BA PTP impacts will be determined, and what steps will be taken when there
is not sufficient firm generation available to serve load will be documented in the
change order requirements.
2. An OATI change order is needed to provide an allocation calculation based on the rating of the flowgate, TRM, CBM and Aggregate Entity impacts.
; An allocation calculation will be performed using impacts down to 0% to allocate the full
capacity of the flowgate. The allocation down to 0% will then be used to determine the
5% allocation by removing impacts between 0% and 5% that were included in the 0%
allocation. The 0% and 5% allocation calculation will determine allocations for all
Aggregate Entities on the flowgate and will be made in the forward and reverse
directions. OATI will calculate both a day-ahead allocation that include a 24 hourly
profile and a hour-ahead allocation.
; OATI will then apply the higher-of logic to determine the firm allocation down to 0%.
Once the higher-of value for the down to 0% allocation has been determined (based on
either the day-ahead or the hour-ahead allocation), the 5% allocation corresponding to
the higher-of down to 0% allocation will be used. OATI will not apply the higher-of logic
to both the down to 0% allocation and the 5% allocation such that the down to 0%
allocation could come from the day-ahead allocation calculation and the 5% allocation
could come from the hour ahead allocation calculation (or vice versa).
; The higher-of comparison is made immediately after completing the hour-ahead
allocation calculation and it identifies the next-hour firm allocation for the Aggregate
Entity. Before using these allocations to set the priorities of the GTL impacts, there will
be a check performed whether there needs to be pro-rata curtailments assigned to both
the firm GTL impacts and the firm PTP impacts from the hour-ahead allocation
calculation. This means the next hour impacts down to 0% will be summed (both firm
GTL impacts and firm PTP impacts). If this summed value is less than the firm allocation
from the higher-of comparison (down to 0%), there is no need for pro-rata curtailments
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and there is no first to be curtailed firm allocation assigned to the Aggregate Entity of
this flowgate. If the summed value is greater than the firm allocation from the higher-of
comparison (down to 0%), the firm allocation from the higher-of comparison will be split
into a firm GTL allocation and a firm PTP allocation on a pro-rata basis using firm GTL
impacts and firm PTP impacts from the hour-ahead allocation calculation. The amount
of the short-fall needed to cover impacts down to 0% from the hour-ahead allocation
calculation will be assigned to the Aggregate Entity in the first to be curtailed firm
service category. Once this is done, the firm allocation plus the first to be curtailed firm
allocation will match the sum of the firm GTL impacts and firm PTP impacts from the
hour-ahead allocation calculation.
; OATI will then assign the real-time GTL flows and PTP impacts into the correct priority
buckets before reporting them to the IDC.
o Where there were no pro-rata curtailments assigned between firm GTL and firm
PTP, the firm allocation will be reduced by impacts from firm PTP schedules.
The remainder will then be used to set firm priority of the real-time GTL flows.
If there is more real-time GTL flow than the remainder of the firm allocation,
this will be assigned a non-firm curtailment priority (6 NN).
o Where there were pro-rata curtailments, the firm allocation from the higher-of
comparison has been split between firm GTL and firm PTP. This split along with
the amount of first to be curtailed firm allocation will be used to assign the
priorities of real-time GTL flows and PTP impacts.
; Change Order 283
1. Rather than calculate a GTL flow for each generator and assign it to a priority bucket based
on the priority of the generator, will calculate the combined GTL flows of all generators
inside the BA (in the forward and reverse direction and for those generators with impacts
below 5% versus above 5%).
2. Will have an interface with the allocation calculation that provides BA GTL flows that then
get assigned the correct priority bucket.
; Change Order 310
1. Change Order 310 will be required for all internal point-to-point tagged transactions, so that
all point-to-point (inter and intra) transmission service is tagged.
Review of solution to “Directions for the Work Groups” document (Does the solution address the issues
and concerns? Does the solution take into account the consideration items?)
; The work group reviewed the Directions for the Work Groups and believes that the solution outlined in this option addresses the directions provided to the work groups.
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; The work group reviewed the directions prior to developing its solution and added another
assumption for the solution. (See the first assumption in the next section.)
Assumptions:
; Any generating resources in the EMS model have to be reported. If a generator is in the EMS
model it should also be in the IDC model. This will include pseudo-ties.
; NERC will approve INT-012-1 requiring intra-BA transactions to be tagged for point-to-point
transactions. These transactions will be recognized by the IDC subject to curtailment based on
the tag transmission service priority and will not be included in the gen-to-load impacts. Impacted Entities (e.g. Marketer/Brokers, Transmission Service Providers/Transmission Providers, Generators, Balancing Authorities, Reliability Coordinators)
Impacted Entity Description of Impact(s)
Transmission Service Will need to identify generators with firm transmission service and firm
Providers PTP reservations to be used in the impact calculation process.
See Note Below Will need to identify the firm merit order/block loading file that can be
used in the impact calculation process.
Note: This applies to Load Serving Entities or entities responsible for operating a market on behalf of Load Serving Entities.
Benefits:
; Provides a better overall economic solution to congestion management in that once firm
allocations have been established, can use either firm or non-firm generation to serve load
without risk of curtailment during TLR 3 as long as do not exceed firm allocation.
; No longer have an issue of not receiving credit for firm redispatch or not receiving credit for
redispatch that was done for a first TLR event once you have a second TLR event.
; Treat firm GTL flows and firm PTP impacts on an equal basis and does not make one subordinate
to the other.
; Does not disrupt the priority of firm PTP service in that it still does not get curtailed until a TLR 5
is issued.
; Reduces the effects of non-jurisdictional entities that classify all of its generation as firm. With
an allocation process, some of that generation having firm transmission service may now be
classified as first to be curtailed firm service (even on the non-jurisdictional entity’s own
flowgates).
Drawbacks:
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; Requires additional change orders for impact calculation and allocation calculation. OATI
already has significant experience doing both.
; There is no requirement for non-FERC jurisdictional entities in the Eastern Interconnection to
follow the NAESB business practices.
; NERC has not yet committed to implement Change Order 310, secured funding or established an
implementation timeline.
; INT-012-1 has not been approved
; A situation can occur where an Aggregate Entity with only generation that has firm transmission
service finds that some of its GTL flows are non-firm. This could be caused by the load forecast
and merit order/block loading file used in the hour-ahead allocation calculation and not due to
GTL impacts being treated subordinate to PTP impacts. Also, the decision on how we will
determine GTL impacts when we run out of generation with firm transmission service in the
impact calculation of the allocation process (see Outstanding Issue 3 below) will affect the size
of the firm GTL impacts down to 0% and the first to be curtailed firm allocation for GTL flows. Impact on NERC Standards and NAESB WEQ Business Practice Standards
; Current NAESB Business Practice Standards – Include WEQ Business Practice Standard number
and section number with a description of what needs to change.
WEQ BPS Reference Description of Change
WEQ-008 Minor changes may have to be made to sections of WEQ-008 but the bulk
of the changes will be new sections.
; Current NERC Standards– Include NERC Standard and Requirement Number with a description of
what needs to change.
NERC Standard Description of Change
None Don’t foresee changes to the existing standards but do see changes to the
IDC Change Order 283 requirements.
; New NAESB Business Practice Standards – Include WEQ Business Practice Number where
changes would be applied and a description for each of the changes
WEQ BPS Reference New Standard Description
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WEQ BPS Reference New Standard Description
WEQ-008 – Transmission New language will have to be added to WEQ-008 to address the
Loading Relief requirements listed in the Detail Description of the Solution section.
tbd Study Criteria (Methodology posted on a public website)
; New NERC Standards– Include NERC Standards where changes would be applied and a
description for each of the changes.
NERC Standard Description of Change
INT-012-1 Intra BA point-to-point transactions will be tagged
Impact on IDC Change Order 283:
; Modifications are needed to the aggregation of GTL flows in the GTL flow calculation. Needs an
interface between the GTL flow calculation and the allocation calculation. Impact on IDC Change Order 310:
; None
Coordination with Other Groups (e.g. OASIS Subcommittee, Joint Electric Scheduling Subcommittee, IDC Working Group, Coordinate Interchange Standard Drafting Team, TLR Standard Drafting Team) - include the group and what coordination needs to occur.
Entity Name Coordination Required
NERC Group (Tbd) NERC will be responsible for determining the tests to identify coordinated
flowgates.
NERC - INT Standards Need to confirm that all internal point-to-point transactions will be tagged.
Drafting Team
IDCWG Will need to coordinate modifications to Change Order 283.
A new change order will need to be developed in support of TLR changes.
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