Deliverability Study
October 2015
SPP Staff
Southwest Power Pool, Inc.
Revision History
Revision History
Date or Version
Number
Author
Change Description
Version 0.0
February, 2015
Michael Odom
Initial Draft
Version 3.0
June, 2015
SPP Staff
Proposed new study
concept
Version 5.0
July, 2015
SPP Staff
Modified study
assumptions
Version 6.0
August, 2015
SPP Staff
Provided options for
reporting deliverability
results
Version 9.0
October, 2015
SPP Staff
Updated language per
Stakeholder feedback
Deliverability
Study
1
Comments
Southwest Power Pool, Inc.
Table of Contents
Revision History ...........................................................................................................................................1
Background and Introduction ....................................................................................................................3
Deliverability Study .....................................................................................................................................4
Deliverables ..................................................................................................................................................8
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Background and Introduction
Firm transmission service needed to deliver power from generation to load has historically been required
by SPP in order for that generating capacity to count toward meeting a load’s reserve margin requirements.
SPP is now developing an option to rely upon a pre-established determination of deliverability to allow the
Load Responsible Entity (LRE) to meet its reserve margin requirements in excess of its peak load,
including losses, without having request and obtain firm transmission service. A confirmed firm
transmission service request, whether for network or point-to-point service, will still be required, consistent
with the existing SPP Criteria, in order for an LRE to obtain the firm transmission necessary to serve load.
Acquisition of firm transmission will continue to be necessary to acquire Auction Revenue Rights (ARRs).
The approach described below will allow an LRE to rely on transmission capacity being developed in SPP
transmission planning processes for its reserve margin requirements, in excess of its peak load plus losses,
without sacrificing reliability. This process would allow an LRE to obtain capacity necessary to meet its
reserve margin requirements in a quicker manner that is more consistent with the potential needs of the
proposed Reliability Assurance policy, in comparison to the timing associated with the current process
used to obtain long-term firm transmission service.
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Deliverability Study
Study Purpose
Reserve margin allows for reserve capacity to be readily available in the situation of unexpected loss of
generation or unexpected significant increase of demand. Annually, each LRE in SPP must report capacity
committed to supply its load and reserve margin obligations. Under the existing SPP Criteria, firm
transmission service must be secured for the delivery of capacity, including reserves, to meet each LREs
peak load obligation. In the future, it has been proposed that the deliverability of capacity resources needed
to meet only the required reserve margins, not the load itself, could be assured through either the
acquisition of appropriate firm transmission service through the acceptance and confirmation of a request
for firm transmission service or by being obtained from generating facilities with capacity that is deemed to
be deliverable to the load through the performance of a deliverability study. It is proposed that the
deliverability study should take the form of analyzing all reported generation registered in the Integrated
Marketplace in order to determine if the associated capacity is deliverable to the SPP Consolidated
Balancing Authority (CBA).
Study Models
SPP develops CBA models as part of the ITPNT process by performing a security constrained economic
dispatch treating SPP as a single Balancing Authority in an effort to simulate a dispatch similar to the
Integrated Marketplace. Transmission projects are developed through the ITPNT process to address
thermal and voltage needs in each CBA model. The CBA models will be the base models for deliverability
analysis.
Analysis
The current-year summer ITPNT CBA model will be used to evaluate deliverability of each plant
participating in the Integrated Marketplace. The initial assumption is that any resource generating in the
CBA model is automatically deliverable to the SPP BA for the dispatched output. Each eligible plant that
was not committed or dispatched at its maximum output is then evaluated individually to determine that
plant’s total deliverability. A transfer level equal to the difference between the nameplate capacity and
CBA dispatched amount is determined for each plant. The transfer will be analyzed as a generation to load
transfer sinking into SPP CBA so as the output of the generator is increased, the SPP CBA load uniformly
increases. A First Contingency Incremental Transfer Capability (FCITC) analysis of each transfer will be
performed to determine the deliverability of the resources. If the FCITC is equal to the transfer amount
then the resource is fully deliverable to the SPP CBA. SPP facilities 100 kV and above will be included in
the FCITC analysis. Limits associated with invalid contingencies and Transmission Operating Guides
(TOGs) will be excluded as constraints. A three percent transfer distribution factor will be used to analyze
constraints impacted by the transfer.
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Plant
Max
Cap
MW
CBA
Output
MW
Study
Transfer
MW
FCITC
Deliverability % of
Plant PMAX to
SPP CBA
Plant 1
Plant 2
Plant 3
Plant 4
128
200
140
1348
119.7
0
138.6
0
8.3
200
1.4
1348
8.3
200
1.4
997.5
100%
100%
100%
74%
Table 1: Example of Deliverability Results
Applicability
The CBA Deliverability percentage allows an entity to use the SPP CBA deliverability percentage amount
to contract capacity. This is an Integrated Marketplace simulated approach so that as load increases across
the SPP CBA, individual plant generation increases accordingly to serve the incremental CBA load.
Examples:
Plant 2 is offline in the CBA powerflow model and has a max capacity of 200MW. An FCITC analysis
showed that Plant 2 is could deliver 200MW without breaching a transmission constraint. Therefore,
Plant 2 is 100% deliverable to the SPP CBA region, and the Generator Owner and an LRE could
contract capacity up to 100 % of the Plant 2 maximum capacity (MW) amount.
Plant 4 is offline in the CBA powerflow model and has a max capacity of 1348MW. An FCITC
analysis showed that Plant 4 is could deliver 997.5MW until breaching a transmission constraint.
Therefore, Plant 4 is 74% deliverable to the SPP CBA region, and the Generator Owner and an LRE
could contract capacity up to 74 % of the Plant 4 maximum capacity (MW) amount.
Jointly Owned Units (JOUs)
For generators that have more than one owner, the percentage of ownership will be determined based on
the data submitted in the Resource Adequacy Workbook. The ownership percentage will then be
multiplied by the deliverability amount (MW) to determine each Generator Owner’s percentage of
deliverability.
Example:
Plant 4 is a JOU with 25% ownership by GO 1 and 75% ownership by GO 2. Plant 4 has a
deliverability amount of 74% to the SPP CBA. PMAX for Plant 4 is 1348 MW and 74% of 1348 is
997.5 MW.
GO 1 would have 0.25 * 997.5 MW which equates to 249.3 MW total available for contract capacity.
GO 2 would have 0.75 * 997.5 MW which equates to 748.1 MW total available for contract capacity.
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Figure 1: Regional map indicating the dispatch boundary for deliverability analysis
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Study Timeline
Deliverability Study Timeline
4/16/2016
SPP Board
approves NTCs
2/1/2016
3/1/2016
6/17/2016
CBA model finalized
4/1/2016
5/1/2016
7/1/2016
Deliverability Study
Performed (1 & 2 year out look)
6/1/2016
7/1/2016
8/1/2016
10/1/2016
Deliverability Study
Results provided to GOs
9/1/2016
10/1/2016
11/1/2016 12/1/2016
1/1/2016
12/31/2016
8/1/2016 - 10/1/2016
Internal review of Deliverability Study results
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Deliverables
The findings of the Deliverability study results for each plant will be provided to each appropriate
Generator Owner in the last quarter of the current year. Based upon these results, each GO can work with
applicable LREs to develop a plan for acquiring the necessary capacity for reserve margin requirements.
The results of each annual study will extend for two consecutive summer periods. Each LRE may obtain a
capacity contract based on the latest results for no more than two summer periods.
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