ATTACHMENT Y STUDY REPORT

Transcription

1 Dynegy Marketing and Trade, LLC Wood River Units 4 & 5: 473 MW Retirement: June 1, 2016 ATTACHMENT Y STUDY REPORT March 23, 2016 PUBLIC / REDACTED

2 PUBLIC VERSION EXECUTIVE SUMMARY An Attachment Y notification submitted by Dynegy Marketing and Trade, LLC was received by MISO on December 1, The request was for retirement of Wood River Units 4 & 5 beginning June 1, Ameren and MISO performed a transmission system reliability assessment of the impact of the retirement. Initial analysis determined that the retirement of Wood River Units 4 & 5 would result in thermal loading issues on the Transmission System unless mitigation plans are implemented prior to the retirement date. Analysis of area voltages indicated slightly degraded voltage conditions, but would not decline to a level that requires mitigation. In subsequent evaluation of alternative mitigation plans, solutions were identified that eliminated the need to retain the Wood River Units 4 & 5 as System Support Resource units. Transmission System upgrades needed to alleviate thermal overloads are planned to be completed by Ameren prior to the planned retirement date which includes the replacement of the Roxford 345/138kV transformer with a 700MVA rated bank and installation of a new 345kV circuit breaker to move the transformer to a new bus position. Additionally Ameren plans to complete the reconductor of the Madison State Street Madison Industrial line 1359 by end of 2016 and reconductor of the Belleville 17 th Street Centerville line 1586 by June Until these projects are completed, mitigation may include re dispatch of available generation or will require short term ratings to allow post contingent switching or load shedding as allowed by planning criteria. Other thermal overloads observed in the analysis are addressed available mitigation plans and future transmission upgrades that can be implemented prior to the need. Therefore, based on the expected completion of transmission upgrades and available mitigation plans, Wood River Units 4 & 5 will not be required as System Support Resource units and may Retire effective June 1,

3 PUBLIC VERSION Contents I. Introduction... 4 II. Study objectives... 4 III. Models and Assumptions... 5 a. Model Assumptions... 5 b. Table of Models... 6 c. Monitoring and Contingencies... 6 IV. Study Criteria and Methodology... 6 a. Steady State Thermal Criteria... 7 b. Steady State Voltage Criteria... 7 c. MISO Transmission Planning BPM SSR Criteria... 7 d. Contingencies... 7 e. Import Capability Assessment... 8 V. Study Results... 8 a Summer Peak Analysis... 8 b Shoulder Analysis... 9 c Summer Peak Analysis... 9 d Summer Peak Import Capability Analysis... 9 VI. SSR Agreement Cost Allocation VII. Alternatives Analysis a. New Generation or Generation Re dispatch b. System Reconfiguration and Operating Guides c. Demand Response or Load Curtailment d. Transmission Projects VIII. Conclusion IX. Appendices

4 PUBLIC VERSION I. INTRODUCTION The Market Participant Dynegy Marketing and Trade, LLC submitted an Attachment Y Notice to MISO dated November 24, 2015 for the retirement of the Wood River Units 4 & 5 effective June 1, The Wood River Units 4 & 5 are coal fired generators with a total capacity of 473 MW and are connected to the Ameren 138kV Transmission System. The plant is located near the city of Alton, Illinois. Figure 1.0: Location of Wood River Generating Plant in Alton, Illinois. II. STUDY OBJECTIVES Under Section of MISO s Tariff, SSR procedures maintain system reliability by providing a mechanism for MISO to enter into agreements with Market Participants (MP) that own or operate Generation Resources or Synchronous Condenser Units (SCUs) that have requested to either Retire or Suspend, but are required to maintain system reliability. 4

5 PUBLIC VERSION The principal objective of an Attachment Y study is to determine if the unit(s) for which a change in status is requested is necessary for system reliability based on the criteria set forth in the MISO Business Practices Manuals. The study work included monitoring and identifying the steady state branch/voltage violations on transmission facilities due to the unavailability of the Generation Resource or SCU. The relevant MISO Transmission Owner and/or regional reliability criteria are used for monitoring such violations. III. MODELS AND ASSUMPTIONS Corresponding to the anticipated retirement of [unit name][unit id], the following power system analysis models were used for the study: 2016 Summer Peak (MTEP Summer Peak Model) 2016 Shoulder (MTEP Shoulder Model) 2020 Summer Peak (MTEP Summer Peak Model) The Attachment Y study models were created in accordance with the MISO Transmission Planning Business Practice Manual (BPM 020 r12) Section This includes creating a set of Security Constrained Economic Dispatch (SCED) models from each source model in which the units being studied are taken out of service to represent the After retirement scenario. To create the Before retirement scenario, generation in MISO was scaled down in each model and then the to be retired unit was fully dispatched. a. Model Assumptions 1. Generation Approved Attachment Y Units are modelled offline 2. Transmission The following transmission projects in service prior to the change of status date are included models: MTEP Project 2996 Montgomery Hills 345kV clearance MTEP Project 1538 Pana Ramsey 138kV reconductor MTEP Project 3013 Turkey Hill Cahokia 345kV conversion MTEP Project 3339 Pana Taylorville 138kV reconductor MTEP Project 2472 Maple Ridge Fargo 345kV line addition The following transmission projects were excluded in the 2016SP and 2016SH models due to later in service date MTEP Project 2302 Madison Madison State St 138kV reconductor, ISD 12/1/2016 5

6 PUBLIC VERSION MTEP Project 4494 Galesburg 161/138kV transformer replacement at Sandburg, ISD 12/1/2016 MTEP Project 4471 Cahokia Dupo Ferry 138kV line reconductor, ISD 12/1/2017 MTEP Project 2237 Pana Faraday 345kV line addition, ISD 12/1/2016 MTEP Project 3017 Meredosia 345/138kV transformer, ISD 12/1/2016 MTEP Project 3022 Sandburg 345kV substation and line addition, ISD 12/1/2016 MTEP Project 3169 Pana Austin area work, ISD 12/1/2018 MTEP Project 3170 Zachary Maywood line addition, ISD 12/1/2018 MTEP Project 2248 Ottumwa Zachary 345kV line addition, 12/1/2018 b. Table of Models Table 1: Table of Models Topology Loads Source Model Wood River Contingencies Units 4 & Summer Peak MTEP SP On P1,P2,P4,P5,P7,select ed P3, P6 * Summer Peak MTEP SP Off P1,P2,P4,P5,P7,select ed P3, P6 * Shoulder MTEP SH On P1,P2,P4,P5,P7,select ed P3, P6 * Shoulder MTEP SH Off P1,P2,P4,P5,P7,select ed P3, P6 * Summer Peak MTEP SP On P1,P2,P4,P5,P7,select ed P3, P6 * Summer Peak MTEP SP Off P1,P2,P4,P5,P7,select ed P3, P6 * *NERC Category P4,P5 events simulated using Category P2 contingencies c. Monitoring and Contingencies Monitor: AMMO (356), AMIL (357) local balancing areas, kV bus voltages Contingencies: AMMO, AMIL NERC Category P1, P2, P4, P5, P7 and selected P3, P6 events for nearby 100 kv 345 kv facilities, CE selected single and bus double (P2) contingencies 345kV IV. STUDY CRITERIA AND METHODOLOGY PSS/E was used to perform AC contingency analysis. Cases were solved with automatic control of LTCs, phase shifters, DC taps, switched shunts enabled (regulating), and area interchange 6

7 PUBLIC VERSION disabled. Contingency analysis was performed on before and after cases. The results were compared to find if there were any criteria violations due to the unit(s) change of status. a. Steady State Thermal Criteria Ameren Transmission Planning Criteria applied for thermal analysis (effective 3/24/2015): For System Intact (NERC Category P0), all thermal loadings exceeding 100% of the normal rating. For NERC Category P1 P7 contingencies, all thermal loadings exceeding 100% of the emergency rating. b. Steady State Voltage Criteria Ameren Transmission Planning Criteria applied for voltage analysis (effective 3/24/2015): For System Intact (NERC Category P0), transmission bus voltages less than 95% or above 105% For NERC Category P1 P7 contingencies, transmission bus voltages less than 95% or above 105% c. MISO Transmission Planning BPM SSR Criteria As specified in the MISO BPM 020 r12, the System Support Resource criteria for determining if an identified facility is impacted by the generator change of status is: Under system intact and category P1 contingencies, branch thermal violations are only valid if the flow increase on the element in the after retirement scenario is equal to or greater than: a) 5% of the to be retired unit(s) MW amount (i.e. 5% PTDF) for a base violation compared with the before retirement scenario, or b) 3% of the to be retired unit(s) amount (i.e. 3% OTDF) for a contingency violation compared with the before retirement scenario. Under system intact and category P1 contingencies, high and low voltage violations are only valid if the change in voltage is greater than 1% as compared to the before retirement voltage calculation. Under category P1 P7 contingencies, for the valid thermal and voltage violations as specified above, generation re dispatch, system reconfiguration, and/or load shedding will be considered if applicable. d. Contingencies A subset of the MISO Transmission Expansion Plan (MTEP) contingencies in Ameren and neighboring ComEd system was used for AC contingency analysis. 7

8 PUBLIC VERSION The following NERC Categories of contingencies were evaluated: 1. Category P0 when the system is under normal conditions. 2. Category P1 contingencies resulting in the loss of a single element. 3. Category P2, P3, P4, P5, P6, P7 contingencies resulting in the loss of two or more (multiple) elements. 4. Maintenance outage condition with forced outage during shoulder load conditions. e. Import Capability Assessment A study of simultaneous import capability (FCITC) was performed. An import capability of 2000 MW, as limited by an Ameren transmission element, was used as a proxy to maintain transmission capability related to generation reserves in the Ameren Missouri or Ameren Illinois footprint, considering the 2020 summer peak model. Import capabilities for the AMMO and AMIL systems were developed considering the Wood River Plant retirement scenario as well as the Wood River Plant in service. Results were compared to determine if there is any significant change to import capability or if there are any criteria violations due to the proposed suspension of study units. V. STUDY RESULTS Appendix A to this report includes all constrained elements found to be affected by the retirement of Wood River Units 4 & 5. a Summer Peak Analysis Analysis of the 2016 summer peak conditions identified a number of NERC Category P2 contingency events which result in thermal overloads that would not be addressed with the SSR units. The study identified three NERC Category P3 events that result in thermal violations on two transmission facilities and nine NERC Category P6 events that cause thermal violations on four transmission facilities. The NERC Category P3 and Category P6 events are mitigated by proposed transmission upgrades or by redispatch following the first contingent event or post contingent load shedding where permitted. Analysis of the 2016 summer peak model indicated that NERC Category P1 and Category P3 events result in marginal voltage violations in the Wood River and significant voltage decline below 95% for NERC Category P2, Category P3 (Generator+Line) and Category P6 contingency events. To address concerns over the level of modeling details in the study models, additional voltage comparisons were performed using the Ameren 2020 summer peak model containing the more detailed representation of the Ameren subtransmission system. The MISO model used in the Wood River Attachment Y analysis includes an equivalent representation of these subtransmission facilities, while the Ameren model, which was used to support Ameren s compliance with NERC standard TPL 001 4, includes explicit representation of kv LTC bulk substation transformers and 34 kv capacitor banks, and equivalent representation of the 8

9 PUBLIC VERSION 34 kv lines between the kv bulk substations. The additional analysis confirmed that equivalent representation of the Ameren kv LTC transformers, 34 kv subtransmission lines, and 34 kv capacitor banks produced more conservative voltage results than the Ameren 2020 summer model with its explicit representation of kv transformers with LTC and 34 kv capacitor banks. Further, it is concluded that transmission level bus voltages that are identified as less than 95% in the MISO models used for the Wood River Attachment Y study are not true voltage concerns that require mitigation. b Shoulder Analysis In the 2016 shoulder study no thermal overloading issues were identified for base case or contingency conditions. Analysis of the 2016 shoulder model indicated several marginal voltage violations in the Wood River area as a result of NERC Category P2 and P3 events. Based on the comparison analysis of voltages in the equivalent and explicitly detailed models, it was determined that transmission level bus voltages that are identified as less than 95% in the MISO models used for the Wood River Attachment Y study are not true voltage concerns that require mitigation. c Summer Peak Analysis Analysis of the 2020 summer peak conditions identified four NERC Category P2 contingency events that cause thermal violations on four transmission facilities that would not be addressed by the SSR units. The study indicated that two NERC Category P3 contingency events cause thermal overloading of one transmission facility and six NERC Category P6 events cause thermal overloading on six transmission facilities. The NERC Category P3 and Category P6 events are mitigated by proposed transmission projects and by re dispatch following the first contingent event or post contingent load shedding where permitted. Analysis of the 2020 summer peak model indicated that NERC Category P1 contingency events result in marginal voltage violations in the Wood River area and significant voltage decline below 95% for NERC Category P2, Category P3 (Generator + Line) and Category P6 contingency events. Additional voltage comparisons were performed using the Ameren 2020 summer peak model containing the more detailed representation of the Ameren subtransmission system which confirmed that the equivalent models used for the Attachment Y study produce more conservative voltage results. Analysis of the more detailed model concluded that transmission level bus voltages that are identified as less than 95% in the MISO models used for the Wood River Attachment Y study are not true voltage concerns that require mitigation. d Summer Peak Import Capability Analysis The AmerenMO and AmerenIL transmission systems were tested for simultaneous incremental transfer (import) capability considering the MISO 2020 summer peak model with Wood River generating units 4 and 5 on 473 MW) and Wood River generating units 4 and 5 off (retired). Four simultaneous export subsystems were considered, with power coming from North, East, South, and West for each combination of generation deficiencies. The export 9

10 PUBLIC VERSION participation was varied over the four directions, with one direction assumed to provide 40% of the export, while each of the other three directions were assumed to provide 20% of the export. The analysis monitored only Ameren transmission facilities. Import subsystems considered were as follows: All on line AmerenIL generation All on line AmerenIL coal fired generation All on line AmerenIL generation in the Metro St. Louis East area All on line AmerenMO generation All on line AmerenMO coal fired generation All on line AmerenMO generation in the Metro St. Louis area The retirement of Wood River generating units 4 and 5 would not impact simultaneous import capability to AmerenIL generation as all calculated import FCITC from all test directions was MW with no limit found up to the test level. However, the retirement of the Wood River generators has a significant impact on the simultaneous import capability to AmerenMO generation as all calculated import FCITC from all test directions decreased by 585 MW to 1862 MW (33.5% to 46.5%) compared to the import FCITC with Wood River generation on. The retirement of the Wood River generation shifts the limit from the Cahokia 138 kv bus tie 3 4 for the outage of the [REDACTED] and [REDACTED] to the Roxford 345/138 kv transformer for the outage of the [REDACTED] and [REDACTED]. Although the import capabilities are above 2000 MW for two of the three import tests to AmerenMO generation, and the proxy would be maintained to ensure that there is transmission capability needed for generation reserves, please note that significant margin would be removed from the system to handle the unexpected transmission contingency and/or generation dispatch scenarios that could impact transmission operations on a daily basis. Therefore, upgrades would likely be pursued over time to assure that transmission capability needed for future generation reserve requirements would be available. VI. SSR AGREEMENT COST ALLOCATION MISO Cost Allocation Methodology utilizes bus distribution factors for the load buses to determine the impacted Elemental Pricing Nodes (EP Nodes) that are associated with the customers responsible for the costs of the SSR Unit. Using the quarterly MISO Network and Commercial model, the analysis determines the load buses that contribute to the constraints identified in the Attachment Y study using linear power flow techniques. The Commercial Model is used to allocate costs to the affected Load Serving Entities (LSE s) in each monthly settlement cycle based on the peak hour energy withdrawal. The SSR Cost allocation information was calculated for the constraints identified in the Attachment Y analysis based on the initial determination of need for the SSR Units. However, 10

11 PUBLIC VERSION with the subsequent resolution of reliability issues, the allocation of costs is no longer applicable and retained only for completeness. The initial cost allocation was calculated to include EP Nodes listed in Appendix B. VII. ALTERNATIVES ANALYSIS a. New Generation or Generation Re dispatch A review of the generation interconnection queue identified no new generation that has been proposed in the neighboring counties. Analysis of available generation re dispatch was performed for constraints caused by NERC Category P3 and P6 contingency events where load shedding is not allowed under Ameren local planning criteria. The results indicate that redispatch of nearby generation can effectively manage the constraints. Table 2 contains results of the generation re dispatch analysis. Table 2: Generation Re dispatch Estimates for Selected Contingencies Case Contingency Reliability Issue Madison State Street Tap-Madison Industrial 2016 Summer [REDACTED] section of Venice- Peak Madison Industrial 138 kv line Summer Peak 2020 Summer Peak [REDACTED] [REDACTED] Belleville 17th Street Jct-Centerville section of S Belleville-Centerville 138 kv line 1586 Cahokia 345/138 kv Xfmr #8 Generation Redispatch Venice: -150 MW Baldwin: -97 MW Baldwin: -137 MW b. System Reconfiguration and Operating Guides No existing operating guides are available to address the thermal issues. No new operating guides were developed to provide mitigation for constraints. c. Demand Response or Load Curtailment Evaluation of demand response was performed using load sensitivities to determine the amount of load that could alleviate the thermal overloading and voltage issues as a hypothetical solution. Although no customers have offered to provide demand response service, the analysis is intended to provide a general indication of the amount of load curtailment required to avoid the need for an SSR. Since the estimate is based on the most 11

12 PUBLIC VERSION effective locations for load shedding, the actual demand response will vary depending on the location of the customer load. The minimum amount of load shed is estimated to be 55 MW to fully mitigate the reliability issues resulting from NERC Category P3 and P6 contingent events that would otherwise be alleviated by the SSR generation. Table 3 contains results of the demand response analysis including the associated bus locations. Table 3: Demand Response Estimates for Selected Contingencies Case Contingency Reliability Issue Madison State Street Tap-Madison 2016 Summer Industrial section of [REDACTED] Peak Venice-Madison Industrial 138 kv line Summer Peak 2020 Summer Peak [REDACTED] [REDACTED] Belleville 17th Street Jct-Centerville section of S Belleville- Centerville 138 kv line 1586 Cahokia 345/138 kv Xfmr #8 Demand Response Bus Locations 30 MW 4MADSN INDUS MW 4CENTERVILLE MW 4CAHOK RUSL d. Transmission Projects Transmission projects already planned are expected to address many of the thermal issues identified in the analysis with three projects to be completed prior to summer Project Roxford 345/138kV Transformer & Breaker, ISD: 6/1/2016 Project 2302 Madison State St. Madison Industrial Reconductor, ISD: 12/1/2016 Project Belleville 17 th St. Centerville Reconductor, ISD: 6/1/2019 Project 9741 Porter Road Highland Upgrade, ISD: 6/1/2016 Project Cahokia Ridge 138kV Upgrade, ISD: 6/1/2018 Project 7801 Cahokia Ashley Upgrade, ISD: 6/1/2018 Reconductoring the Belleville 17th Street Junction Centerville section of South Belleville Centerville 138 kv line 1586 is needed to address the failure of [REDACTED] and other multiple outage conditions, and was earlier proposed for completion in This project will be advanced to 2019 to address the thermal loading concerns caused by the retirement of Wood River generation. A short term emergency rating would need to be developed for the nearterm to allow time for post contingency load shedding or switching in the Centerville area until the line reconductoring could be completed. 12

13 PUBLIC VERSION Rather than reconductor the Venice Madison State Street Tap section of Venice Madison Industrial 138 kv line 1359, which was reconductored just a few years ago, it is proposed to install a new 345 kv breaker in the Roxford ring bus and connect the Roxford 345/138 kv transformer to its own ring bus position. This system connection modification would keep the Roxford 345/138 kv transformer in service for the outage of the [REDACTED] and eliminate the thermal loading concern on the Venice Madison State Street Tap line section for 345kV breaker failure conditions at the [REDACTED] Substation. This project is proposed for completion before summer Reconductoring the Madison State Street Tap Madison Industrial section of Venice Madison Industrial 138 kv line 1359 (MISO Project ID 2302) is planned for completion in late 2016, after the proposed retirement date of June 1, 2016 for the Wood River generators. This project is needed to address thermal loading concerns for 345 kv breaker failure events at the [REDACTED] Substation, which result in the outage of the [REDACTED]. The critical contingency loading on this line section would be reduced by maintaining the Roxford 345/138 kv transformer in service for these[redacted] breaker failure events, allowing for a short term emergency rating to be developed for the near term to allow time for post contingency load shedding or switching in the Madison Industrial/Granite City 23 rd Street area until the line reconductoring could be completed. Post contingency load shedding or subtransmission switching would also be required in the Granite City area for the coincident outage of [REDACTED] and the [REDACTED]. Assuming the completion of the project to reconnect the Roxford 345/138 kv transformer to the Roxford 345 kv ring bus, there is no need to replace the 477 kcmil ACSR bus conductor at the O Fallon Porter Road kv Substation to address the thermal loading concerns during circuit breaker failure events at the [REDACTED] Substation. The critical contingency loading on this line section would be eliminated by maintaining the Roxford 345/138 kv transformer in service for [REDACTED] breaker failure events. However, this project (MISO project ID 9741) will be completed by June, 2016 to address P6 outage events Replacement of the Roxford 345/138 kv 560 MVA transformer with a 700 MVA transformer is recommended to address thermal loading concerns with Wood River generation retired. The critical outage event is the coincident outage of [REDACTED] or [REDACTED] with the [REDACTED]. Work is underway to replace this transformer before summer The replacement of the Ridge and Cahokia 138 kv bus conductors in the Cahokia Ridge kv circuit would be needed to increase ratings on this facility as a result of the Wood River generation retirement. The critical contingency is the [REDACTED], or the coincident outage of the [REDACTED] and the [REDACTED]. Upgrade of the Cahokia 138 kv bus tie 3 4 is presently planned for The critical contingency is the failure of [REDACTED]. 13

14 PUBLIC VERSION VIII. CONCLUSION While analysis of the retirement of Wood River Units 4 & 5 indicates that a number of thermal loading issues will occur on the Transmission System without the units, mitigation options are available to alleviate the concerns. Area voltages slightly degrade as a result of the retirement, but would not decline to a level that requires mitigation. Evaluation of alternative mitigation plans identified solutions that eliminate the need to retain the Wood River Units 4 & 5 as System Support Resource units. Transmission System upgrades needed to alleviate thermal overloads are planned to be completed by Ameren prior to the planned retirement date which includes the replacement of the Roxford 345/138kV transformer with a 700MVA rated bank and installation of a new 345kV circuit breaker to move the transformer to a new bus position. Additionally Ameren plans to complete the reconductor of the Madison State Street Madison Industrial line 1359 by end of 2016 and reconductor of the Belleville 17 th Street Centerville line 1586 by June Until these projects are completed, mitigation may include re dispatch of available generation or will require short term ratings to allow post contingent switching or load shedding as allowed by planning criteria. Other thermal overloads observed in the analysis are addressed available mitigation plans and future transmission upgrades that can be implemented prior to the need. Therefore, based on the expected completion of transmission upgrades and available mitigation plans, Wood River Units 4 & 5 will not be required as System Support Resource units and may Retire effective June 1, IX. APPENDICES Appendix A: Table 1 Thermal Analysis Results Table 2 Voltage Analysis Results Appendix B: Table 1 SSR Cost Allocation 14

15 Appendix A Steady-State AC Contingency Analysis Results

16 Appendix A, Table 1 Thermal Analysis Results Wood River Attachment Y Study Compare Thermal Results Model Type Contingency Branch Rating B (MVA) % Loading with Wood River Off % Loading with Wood River On Comments 2016SP P23 [REDACTED] 2016SP P23 [REDACTED] 2016SP P23 [REDACTED] 2016SP P23 [REDACTED] 2016SP P23 [REDACTED] 2016SP P23 [REDACTED] 2016SP P23 [REDACTED] 2016SP P23 [REDACTED] 2016SP P23 [REDACTED] 2016SP P23 [REDACTED] Belleville 17th Street Jct Centerville section of S Belleville Centerville post contingent load shedding; MTEP App B Project 138 kv line , ISD: 6/1/2019 Madison State Street Tap Madison Industrial section of Venice post contingent load shedding; MTEP App A Project Madison Industrial 138 kv line , ISD: 12/1/2016 Venice Madison State Street Tap section of Venice Madison Industrial 138 kv line MTEP App A Project 10884, ISD: 6/1/2016 Porter Road Highland Tap section of E Collinsville Porter Rd 138 kv MTEP App A Project 10884, ISD 6/1/2016; MTEP line App A Project 9741, ISD 6/1/2016 Madison Industrial Granite City 23rd Street section of Madison Industrial Wood River 138 kv line confirmed corrected rating: 333MVA, not an issue Madison State Street Tap Madison Industrial section of Venice post contingent load shedding; MTEP App A Project Madison Industrial 138 kv line , ISD: 12/1/2016 Venice Madison State Street Tap section of Venice Madison Industrial 138 kv line MTEP App A Project 10884, ISD: 6/1/2016 Porter Road Highland Tap section of E Collinsville Porter Rd 138 kv MTEP App A Project 10884, ISD 6/1/2016; MTEP line App A Project 9741, ISD 6/1/2016 Madison Industrial Granite City 23rd Street section of Madison Industrial Wood River 138 kv line confirmed corrected rating: 333MVA, not an issue Madison State Street Tap Madison Industrial section of Venice post contingent load shedding; MTEP App A Project Madison Industrial 138 kv line , ISD: 12/1/ SP P3 [REDACTED] Roxford 345/138 kv Xfmr MTEP App A Project 10884, ISD 6/1/ SP P3 [REDACTED] Roxford 345/138 kv Xfmr MTEP App A Project 10884, ISD 6/1/ SP P3 [REDACTED] Roxford 345/138 kv Xfmr MTEP App A Project 10884, ISD 6/1/ SP P3 [REDACTED] 2016SP P6 [REDACTED] 2016SP P6 [REDACTED] Madison State Street Tap Madison Industrial section of Venice redispatch or post contingent load shedding; MTEP Madison Industrial 138 kv line App A Project 2302, ISD: 12/1/2016 Porter Road Highland Tap section of E Collinsville Porter Rd 138 kv MTEP App A Project 10884, ISD 6/1/2016; MTEP line App A Project 9741, ISD 6/1/2016 Madison Industrial Granite City 23rd Street section of Madison Industrial Wood River 138 kv line confirmed corrected rating: 333MVA, not an issue

17 Appendix A, Table 1 Thermal Analysis Results Wood River Attachment Y Study Compare Thermal Results Model Type Contingency Branch 2016SP P6 [REDACTED] Rating B (MVA) % Loading with Wood River Off % Loading with Wood River On Comments post contingent load shedding; MTEP App A Project Madison State Street Tap Madison Industrial section of Venice Madison Industrial 138 kv line , ISD: 6/1/2016, MTEP App A Project 2302, 85 ISD: 12/1/ SP P6 [REDACTED] 2016SP P6 [REDACTED] 2016SP P6 [REDACTED] Venice Madison State Street Tap section of Venice Madison Industrial 138 kv line MTEP App A Project 10884, ISD: 6/1/2016 Belleville 17th Street Jct Centerville section of S Belleville Centerville redispatch or post contingent load shedding; MTEP 138 kv line App B Project 10886, ISD: 6/1/2019 Porter Road Highland Tap section of E Collinsville Porter Rd 138 kv line MTEP App A Project 9741, ISD 6/1/ SP P6 [REDACTED] Cottage Hills Wanda section of Wood River Stallings 138 kv line confirmed corrected rating: 333MVA, not an issue 2016SP P6 [REDACTED] 2016SP P6 [REDACTED] 2016SP P6 [REDACTED] 2016SP P6 [REDACTED] 2016SP P6 [REDACTED] 2016SP P6 [REDACTED] 2016SP P6 [REDACTED] 2016SP P6 [REDACTED] 2016SP P6 [REDACTED] 2020SP P23 [REDACTED] Madison State Street Tap Madison Industrial section of Venice post contingent load shedding; MTEP App A Project Madison Industrial 138 kv line , ISD: 12/1/2016 Madison State Street Tap Madison Industrial section of Venice post contingent load shedding; MTEP App A Project Madison Industrial 138 kv line , ISD: 12/1/2016 Madison Industrial Granite City 23rd Street section of Madison Industrial Wood River 138 kv line confirmed corrected rating: 333MVA, not an issue Madison State Street Tap Madison Industrial section of Venice post contingent load shedding; MTEP App A Project Madison Industrial 138 kv line , ISD: 12/1/2016 Venice Madison State Street Tap section of Venice Madison Industrial 138 kv line post contingent load shedding; Porter Road Highland Tap section of E Collinsville Porter Rd 138 kv MTEP App A Project 10884, ISD 6/1/2016; MTEP line App A Project 9741, ISD 6/1/2016 Madison State Street Tap Madison Industrial section of Venice post contingent load shedding; MTEP App A Project Madison Industrial 138 kv line , ISD: 12/1/2016 Madison State Street Tap Madison Industrial section of Venice post contingent load shedding; MTEP App A Project Madison Industrial 138 kv line , ISD: 12/1/2016 Madison State Street Tap Madison Industrial section of Venice post contingent load shedding; MTEP App A Project Madison Industrial 138 kv line , ISD: 12/1/2016 Porter Road Highland Tap section of E Collinsville Porter Rd 138 kv line at limit, not an issue 2020SP P23 [REDACTED] Cahokia Ridge kv line post contingent load shedding; MTEP App B Project 10885, ISD 6/1/2018

18 Appendix A, Table 1 Thermal Analysis Results Wood River Attachment Y Study Compare Thermal Results Model Type Contingency Branch Rating B (MVA) % Loading with Wood River Off % Loading with Wood River On Comments 2020SP P23 [REDACTED] 2020SP P23 [REDACTED] 2020SP P23 [REDACTED] 2020SP P23 [REDACTED] 2020SP P23 [REDACTED] 2020SP P23 [REDACTED] 2020SP P23 [REDACTED] Venice Madison State Street Tap section of Venice Madison Industrial 138 kv line < 85 MTEP App A Project 10884, ISD: 6/1/2016 Porter Road Highland Tap section of E Collinsville Porter Rd 138 kv MTEP App A Project 10884, ISD 6/1/2016; MTEP line App A Project 9741, ISD 6/1/2016 Madison Industrial Granite City 23rd Street section of Madison Industrial Wood River 138 kv line < 85 confirmed corrected rating: 333MVA, not an issue Venice Madison State Street Tap section of Venice Madison Industrial 138 kv line < 85 MTEP App A Project 10884, ISD: 6/1/2016 Porter Road Highland Tap section of E Collinsville Porter Rd 138 kv MTEP App A Project 10884, ISD 6/1/2016; MTEP line App A Project 9741, ISD 6/1/2016 Madison Industrial Granite City 23rd Street section of Madison Industrial Wood River 138 kv line < 85 confirmed corrected rating: 333MVA, not an issue Porter Road Highland Tap section of E Collinsville Porter Rd 138 kv line < 85 MTEP App A Project 9741, ISD 6/1/ SP P24 [REDACTED] Cahokia 138 kv Bus Tie at limit, not an issue 2020SP P32 [REDACTED] Roxford 345/138 kv Xfmr < 85 MTEP App A Project 10884, ISD 6/1/ SP P32 [REDACTED] Roxford 345/138 kv Xfmr < 85 MTEP App A Project 10884, ISD 6/1/ SP P32 [REDACTED] Cahokia Ashley kv line at limit, not an issue 2020SP P6 [REDACTED] Cottage Hills Wanda section of Wood River Stallings 138 kv line < 85 confirmed corrected rating: 333MVA, not an issue 2020SP P6 [REDACTED] Sioux Mississippi Tap section of Sioux Roxford kv line < 85 post contingent load shedding; 2020SP P6 [REDACTED] Venice Madison State Street Tap section of Venice Madison Industrial 138 kv line < 85 post contingent load shedding; MTEP App A Project 10884, ISD: 6/1/ SP P6 [REDACTED] 2020SP P6 [REDACTED] Madison Industrial Granite City 23rd Street section of Madison Industrial Wood River 138 kv line < 85 confirmed corrected rating: 333MVA, not an issue Porter Road Highland Tap section of E Collinsville Porter Rd 138 kv MTEP App A Project 10884, ISD 6/1/2016; MTEP line App A Project 9741, ISD 6/1/2016

19 Appendix A, Table 1 Thermal Analysis Results Wood River Attachment Y Study Compare Thermal Results Model Type Contingency Branch Rating B (MVA) % Loading with Wood River Off % Loading with Wood River On Comments 2020SP P6 [REDACTED] Cahokia Ashley kv line post contingent load shedding; MTEP App B Project 7801, ISD 6/1/ SP P6 [REDACTED] Cahokia 345/138 kv Xfmr # redispatch or post contingent load shedding 2020SP P6 [REDACTED] 2020SP P6 [REDACTED] 2020SP P6 [REDACTED] Madison Industrial Granite City 23rd Street section of Madison Industrial Wood River 138 kv line < 85 confirmed corrected rating: 333MVA, not an issue Venice Madison State Street Tap section of Venice Madison Industrial 138 kv line < 85 post contingent load shedding; Highland Tap East Collinsville section of Porter Rd East Collinsville 138 kv line < 85 at limit, not an issue 2020SP P6 [REDACTED] Turkey Hill East Belleville 138 kv line post contingent load shedding; 2020SP P6 [REDACTED] East Belleville Porter Rd 138 kv line post contingent load shedding; 2020SP P6 [REDACTED] Porter Road Highland Tap section of E Collinsville Porter Rd 138 kv line MTEP App A Project 9741, ISD 6/1/2016

20 Appendix A, Table 2 Voltage Analysis Results Wood River Attachment Y Study Compare Voltage Results Model Type Contingency Bus Voltage with Wood River On Voltage with Wood River Off Comments 2016SP P1 [REDACTED] Wood River 138 kv marginally below limit, confirmed not an issue 2016SP P1 [REDACTED] Laclede kv marginally below limit, confirmed not an issue 2016SP P1 [REDACTED] Laclede kv marginally below limit, confirmed not an issue 2016SP P1 [REDACTED] Conoco Phillips 138 kv marginally below limit, confirmed not an issue 2016SP P1 [REDACTED] Cottage Hills 138 kv marginally below limit, confirmed not an issue 2016SP P1 [REDACTED] Wood River 138 kv marginally below limit, confirmed not an issue 2016SP P1 [REDACTED] Laclede kv marginally below limit, confirmed not an issue 2016SP P1 [REDACTED] Laclede kv marginally below limit, confirmed not an issue 2016SP P1 [REDACTED] Conoco Phillips 138 kv marginally below limit, confirmed not an issue 2016SP P1 [REDACTED] Cottage Hills 138 kv marginally below limit, confirmed not an issue 2016SP P2 [REDACTED] Gillespie 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] North Staunton 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Litchfield 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Laclede kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Conoco Phillips 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Gillespie 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] North Staunton 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Gillespie 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Litchfield 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Wood River 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Laclede kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Laclede kv voltages are adequate, not an issue

21 Appendix A, Table 2 Voltage Analysis Results Wood River Attachment Y Study Compare Voltage Results Voltage with Wood River On Voltage with Wood River Off Model Type Contingency Bus Comments 2016SP P2 [REDACTED] Conoco Phillips 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Cottage Hills 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] BOC Gases 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Roxford 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Wood River 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Laclede kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Laclede kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Conoco Phillips 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Cottage Hills 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] BOC Gases 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Roxford 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Wanda 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Mississippi 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Wood River 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Laclede kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Laclede kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Conoco Phillips 138 kv voltages are adequate, not an issue 2016SP P2 [REDACTED] Cottage Hills 138 kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Wood River 138 kv marginally below limit, confirmed not an issue 2016SP P3 [REDACTED] Laclede kv marginally below limit, confirmed not an issue 2016SP P3 [REDACTED] Laclede kv marginally below limit, confirmed not an issue 2016SP P3 [REDACTED] Conoco Phillips 138 kv marginally below limit, confirmed not an issue

22 Appendix A, Table 2 Voltage Analysis Results Wood River Attachment Y Study Compare Voltage Results Model Type Contingency Bus Voltage with Wood River On Voltage with Wood River Off Comments 2016SP P3 [REDACTED] Cottage Hills 138 kv marginally below limit, confirmed not an issue 2016SP P3 [REDACTED] Wanda 138 kv marginally below limit, confirmed not an issue 2016SP P3 [REDACTED] Wood River 138 kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Laclede kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Laclede kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Conoco Phillips 138 kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Cottage Hills 138 kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Roxford 138 kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Mississippi 138 kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Wanda 138 kv voltages are adequate, not an issue 2016SP P3 [REDACTED] BOC Gases 138 kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Wood River 138 kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Laclede kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Laclede kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Conoco Phillips 138 kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Cottage Hills 138 kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Roxford 138 kv voltages are adequate, not an issue 2016SP P3 [REDACTED] Mississippi 138 kv voltages are adequate, not an issue 2016SP P6 [REDACTED] Wood River 138 kv voltages are adequate, not an issue 2016SP P6 [REDACTED] Laclede kv voltages are adequate, not an issue 2016SP P6 [REDACTED] Laclede kv voltages are adequate, not an issue 2016SP P6 [REDACTED] Conoco Phillips 138 kv voltages are adequate, not an issue

23 Appendix A, Table 2 Voltage Analysis Results Wood River Attachment Y Study Compare Voltage Results Model Type Contingency Bus Voltage with Wood River On Voltage with Wood River Off Comments 2016SP P6 [REDACTED] BOC Gases 138 kv voltages are adequate, not an issue 2020SP P1 [REDACTED] Wood River 138 kv marginally below limit, confirmed not an issue 2020SP P1 [REDACTED] Laclede kv > marginally below limit, confirmed not an issue 2020SP P1 [REDACTED] Laclede kv > marginally below limit, confirmed not an issue 2020SP P1 [REDACTED] Conoco Phillips 138 kv marginally below limit, confirmed not an issue 2020SP P1 [REDACTED] BOC Gases 138 kv > marginally below limit, confirmed not an issue 2020SP P1 [REDACTED] Cottage Hills 138 kv marginally below limit, confirmed not an issue 2020SP P1 [REDACTED] Wood River 138 kv > marginally below limit, confirmed not an issue 2020SP P1 [REDACTED] Laclede kv > marginally below limit, confirmed not an issue 2020SP P1 [REDACTED] Laclede kv > marginally below limit, confirmed not an issue 2020SP P1 [REDACTED] Conoco Phillips 138 kv marginally below limit, confirmed not an issue 2020SP P1 [REDACTED] BOC Gases 138 kv > marginally below limit, confirmed not an issue 2020SP P1 [REDACTED] Cottage Hills 138 kv marginally below limit, confirmed not an issue 2020SP P1 [REDACTED] Roxford 138 kv > marginally below limit, confirmed not an issue 2020SP P2 [REDACTED] Gillespie 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] North Staunton 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Litchfield 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Wood River 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Laclede kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Laclede kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Conoco Phillips 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] BOC Gases 138 kv > voltages are adequate, not an issue

24 Appendix A, Table 2 Voltage Analysis Results Wood River Attachment Y Study Compare Voltage Results Voltage with Wood River On Voltage with Wood River Off Model Type Contingency Bus Comments 2020SP P2 [REDACTED] Cottage Hills 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Roxford 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Gillespie 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] North Staunton 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Gillespie 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Litchfield 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Wood River 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Laclede kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Laclede kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Conoco Phillips 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Cottage Hills 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] BOC Gases 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Roxford 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Wood River 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Laclede kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Laclede kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Conoco Phillips 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Cottage Hills 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] BOC Gases 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Roxford 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Wanda 138 kv voltages are adequate, not an issue 2020SP P2 [REDACTED] Wood River 138 kv > voltages are adequate, not an issue

25 Appendix A, Table 2 Voltage Analysis Results Wood River Attachment Y Study Compare Voltage Results Voltage with Wood River On Voltage with Wood River Off Model Type Contingency Bus Comments 2020SP P2 [REDACTED] Laclede kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Laclede kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Conoco Phillips 138 kv > voltages are adequate, not an issue 2020SP P2 [REDACTED] Cottage Hills 138 kv > voltages are adequate, not an issue 2020SP P3 [REDACTED] Cottage Hills 138 kv > voltages are adequate, not an issue 2020SP P3 [REDACTED] Wanda 138 kv > voltages are adequate, not an issue 2020SP P3 [REDACTED] Wood River 138 kv > voltages are adequate, not an issue 2020SP P3 [REDACTED] Laclede kv > voltages are adequate, not an issue 2020SP P3 [REDACTED] Laclede kv > voltages are adequate, not an issue 2020SP P3 [REDACTED] Conoco Phillips 138 kv > voltages are adequate, not an issue 2020SP P3 [REDACTED] Cottage Hills 138 kv > voltages are adequate, not an issue 2020SP P3 [REDACTED] Roxford 138 kv > voltages are adequate, not an issue 2020SP P3 [REDACTED] Mississippi 138 kv > voltages are adequate, not an issue 2020SP P3 [REDACTED] Wanda 138 kv > voltages are adequate, not an issue 2020SP P3 [REDACTED] BOC Gases 138 kv > voltages are adequate, not an issue 2020SP P3 [REDACTED] Wood River 138 kv voltages are adequate, not an issue 2020SP P3 [REDACTED] Laclede kv voltages are adequate, not an issue 2020SP P3 [REDACTED] Laclede kv voltages are adequate, not an issue 2020SP P3 [REDACTED] Conoco Phillips 138 kv voltages are adequate, not an issue 2020SP P3 [REDACTED] Cottage Hills 138 kv voltages are adequate, not an issue 2020SP P3 [REDACTED] Roxford 138 kv voltages are adequate, not an issue 2020SP P3 [REDACTED] Mississippi 138 kv voltages are adequate, not an issue