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Cost-Benefit Analysis
Founded as an 11-member tight power pool in 1941, Southwest Power Pool (SPP) achieved RTO status in 2004, ensuring reliable power supplies, adequate transmission infrastructure, and competitive wholesale electricity prices for its members. Based in Little Rock, Ark., SPP manages transmission in portions of fourteen states: Arkansas, Iowa, Kansas, Louisiana, Minnesota, Missouri, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas and Wyoming. Its membership is comprised of investor-owned utilities, municipal systems, generation and transmission cooperatives, state authorities, independent power producers, power marketers and independent transmission companies.
List of Orders Click on the categories below to view additional information.
Docket No. Date Issued Company Title ER26-1861-001 09/10/2026 Southwest Power Pool, Inc. Order Addressing Arguments Raised on Rehearing ER16-1341-005 07/16/2026 Southwest Power Pool, Inc. Order on Compliance EL26-68-000 06/18/2026 Southwest Power Pool, Inc. Order Instituting Proceeding Under Section 206 of the Federal Power Act | News Release | Fact Sheet | Presentation ER26-407-001 05/21/2026 Southwest Power Pool, Inc. Order Addressing Arguments Raised on Rehearing ER25-177-000 03/19/2026 Southwest Power Pool, Inc. The order accepts Southwest Power Pool, Inc.’s proposed revisions to its tariff to implement a System Support Resource program to ensure the reliability of the transmission system when a generating resource seeks to retire. EL25-106-000 01/22/2026 New England Power Generators Association v. ISO New England Order Addressing Arguments Raised on Rehearing ER24-2026-001 01/22/2026 Southwest Power Pool Order on Compliance
Docket No. Date Issued Company Title ER16-1341-003 09/18/25 Southwest Power Pool, Inc Order on Refund Plan ER22-1697-003 09/18/25 Southwest Power Pool, Inc Order on Compliance Filing ER24-2026-000 06/26/25 Southwest Power Pool Order on Compliance ER24-1658-003 04/17/25 Southwest Power Pool, Inc. Letter Order Accepting Proposed Tariff Revisions ER24-2184-000 03/20/25 Southwest Power Pool, Inc. Order Accepting Tariff Revisions, Subject to Condition ER24-2906-000 03/20/25 Southwest Power Pool, Inc. Order Accepting Tariff Revisions ER24-2397-001 03/20/25 Southwest Power Pool, Inc. Order Addressing Arguments Raised on Rehearing ER24-1658-000 01/16/25 Southwest Power Pool, Inc. Order Accepting Proposed Tariff, Subject to Condition ER24-1317-000 01/16/25 Southwest Power Pool, Inc. Order Accepting and Suspending Proposed Tariff Revisions, Consolidating Proceedings, and Establishing Paper Hearing Procedures ER25-138-000 01/16/25 Southwest Power Pool, Inc Order Accepting Tariff Revisions
Docket No. Date Issued Company Title ER24-1221-001 10/17/24 Southwest Power Pool, Inc. Order on Compliance Filing ER24-2570-000 09/19/24 Southwest Power Pool, Inc Order Accepting Tariff Revisions ER24-289-000 07/25/24 Southwest Power Pool, Inc. Order on Compliance Filing ER24-1775-000 07/25/24 Southwest Power Pool, Inc. Letter Order accepting proposed Tariff Revisions ER24-1775-000 07/25/24 Southwest Power Pool, Inc. Letter Order accepting proposed Tariff Revisions ER22-1697-002 06/27/24 Southwest Power Pool, Inc Order Addressing Arguments Raised On Rehearing And Granting Clarification In Part ER24-1221-000 05/23/24 Southwest Power Pool, Inc. Order on Compliance Filing
Docket No. Date Issued Company Title ER22-2339-001 12/19/23 Southwest Power Pool, Inc. Order on Compliance Filing ER22-1846-004 12/19/23 Southwest Power Pool, Inc. Order Addressing Arguments Raised on Rehearing ER23-2183-000 12/19/23 Southwest Power Pool, Inc. Order Rejecting Tariff Revisions ER22-2339-000 05/18/23 Southwest Power Pool, Inc. Order on Compliance Filing EL22-59-001 04/20/23 Tenaska Clear Creek Wind, LLC v. Southwest Power Pool, Inc. Order Addressing Arguments Raised on Rehearing ER22-2371-001 02/16/23 Southwest Power Pool, Inc. Letter Order Approving Settlement EL21-77-003 02/16/23 Tenaska Clear Creek Wind, LLC v. Southwest Power Pool, Inc. Order Addressing Arguments Raised on Rehearing and Denying Motion for Stay EL22-30-001 02/16/23 Southwestern Public Service Company v. Southwest Power Pool, Inc. Order Addressing Arguments Raised on Rehearing ER22-709-003 02/16/23 Southwest Power Pool, Inc. Order Addressing Arguments Raised on Rehearing EL22-54-001 01/19/23 Southwest Power Pool, Inc. Order Addressing Arguments Raised on Rehearing RM22-3-000 ER18-2358-006 ER19-1357-004 ER20-1313-001 01/19/23 Southwest Power Pool, Inc. Order Addressing Arguments Raised on Rehearing and Granting Clarification
Docket No. Date Issued Company Title EL22-59-000 12/15/22 Tenaska Clear Creek Wind, LLC v. Southwest Power Pool, Inc., Midcontinent Independent System Operator, Inc., Associated Electric Cooperative, Inc. and Tennessee Valley Authority Order Denying Complaint and Petition EL19-77-00 11/17/22 Oklahoma Gas and Electric Company v. Southwest Power Pool, Inc. Order on Complaint ER18-2404-001 11/17/22 Southwest Power Pool, Inc. Order Addressing Arguments Raised On Rehearing And Denying Request For Remedial Relief EL19-93-000 11/17/22 Western Farmers Electric Cooperative v. Southwest Power Pool, Inc. Order on Complaint EL19-96-000 11/17/22 Cimarron Windpower II, LLC v. Southwest Power Pool, Inc. Order on Complaint EL19-93-00 11/17/22 Western Farmers Electric Cooperative v. Southwest Power Pool, Inc. Order on Complaint
2021
Docket No.
Date Issued
Company
Title
ER18-2404-000 03/18/2021
Southwest Power Pool, Inc.
Order Denying Waiver Request
ER19-477-000 03/18/2021
Southwest Power Pool, Inc.
Order Denying Waiver Request
ER18-99-004 02/18/2021
Southwest Power Pool, Inc. Settlement
Order Rejecting Contested Settlement
ER20-945-002 02/18/2021
Southwest Power Pool, Inc.
Letter Order on Compliance Filing
ER15-2115-008 02/18/2021
Southwest Power Pool, Inc.
Letter Order Approving Uncontested Settlement Agreement
2020
Docket No.
Date Issued
Company
Title
ER18-2358-004 11/19/20
Southwest Power Pool, Inc
Order Addressing Arguments Raised on Rehearing
ER20-644-000 07/16/20
Southwest Power Pool, Inc.
Order on Compliance
ER20-1617-000 07/16/20
Southwest Power Pool, Inc.
Order Accepting Tariff Revisions
ER19-460-005 07/16/20
Southwest Power Pool, Inc.
Order on Compliance
ER19-2522-002 07/16/20
Southwest Power Pool, Inc.
Order on Compliance
ER19-1954-001 06/18/20
Southwest Power Pool, Inc.
Order on Compliance
EL19-92-000 06/18/20
Southwest Power Pool, Inc.
Order on Section 206 Investigation
EL16-91-001 05/21/20
Southwest Power Pool, Inc.
Order Granting Rehearing and Dismissing Compliance Filing
ER15-2115-004 02/20/20
Southwest Power Pool, Inc.
Order on Rehearing and Clarification
ER15-2028-003 02/20/20
Southwest Power Pool, Inc.
Order on Rehearing and Clarification
ER16-1341-003 02/20/20
Southwest Power Pool, Inc.
Order Denying Motion
ER16-1341-004 02/20/20
Southwest Power Pool, Inc.
Order on Rehearing and Clarification
ER19-1954-000 01/23/20
Southwest Power Pool, Inc.
Order on Complaints
EL19-62-001 01/23/20
City Utilities of Springfield, Missouri
Order on Rehearing and Clarification
2019
Docket No.
Date Issued
Company
Title
EL19-11-001 12/19/19
American Wind Energy Association and The Wind Coalition
Order on Rehearing, Compliance, and Section 205 Filing
ER19-2681-000 11/21/19
Southwest Power Pool, Inc.
Order Accepting Tariff Revisions
ER19-1910-000 11/21/19
Southwest Power Pool, Inc.
Letter Order Approving Uncontested Settlement Agreement
ER19-1357-000, 10/17/19
GridLiance High Plains LLC, and Southwest Power Pool, Inc.
Order Establishing Hearing and Settlement Judge Procedures and Consolidating Proceedings
ER19-460-001 10/17/19
Southwest Power Pool, Inc.
Order on Compliance Filing and Instituting Section 206 Proceeding
ER19-2273-000 09/19/19
Southwest Power Pool, Inc. and Sunflower Electric Power Corporation
Order Accepting Proposed Tariff Revisions and Establishing Hearing and Settlement Judge Procedures
EL17-89-000 09/19/19
American Electric Power Service Corporation v. Midcontinent Independent System Operator, Inc. and Southwest Power Pool, Inc.
Order Establishing Briefing Procedures
EL18-26-000 09/19/19
EDF Renewable Energy, Inc. v. Midcontinent Independent System Operator, Inc., Southwest Power Pool, Inc. and PJM Interconnection, L.L.C
Order on Complaint and Technical Conference
EL17-89-000 09/19/19
American Electric Power Service Corporation v. Midcontinent Independent System Operator, Inc. and Southwest Power Pool, Inc.
Order On Complaint And Establishing Refund Effective Date
ER15-2115-000 06/20/19
Southwest Power Pool, Inc.
Order on Contested Settlement
ER15-2028-000 06/20/19
Southwest Power Pool, Inc.
Order on Contested Settlement
ER17-1568-002 04/18/19
Southwest Power Pool, Inc.
Order Granting Requests for Extension of Effective Dates
EL19-11-000 04/18/19
American Wind Energy Association The Wind Coalition v. Southwest Power Pool, Inc.
Order on Complaint
ER18-2318-000 03/21/19
Southwest Power Pool, Inc.
Order on Compliance filing for Order No. 844
ER16-204-004 01/17/19
Southwest Power Pool, Inc.
Opinion No. 562-A; Order Denying Rehearing
2018
Docket No.
Date Issued
Company
Title
ER19-166-000 12/20/18
Southwest Power Pool, Inc.
Letter Order on Tariff Revisions
EL18-194-000 12/20/18
Nebraska Public Power District
Order Denying Complaint
ER18-1632-001 10/18/18
Southwest Power Pool, Inc.
Order Accepting Tariff Revisions
EL16-110-002, EL17-69-001 05/17/18
Buffalo Dunes Wind Project, LLC, Enel Green Power North America, Inc., Alabama Power Company, and Southern Company Services, Inc. v. Southwest Power Pool, Inc.
Order Denying Rehearing
ER17-1575-002 05/17/18
Southwest Power Pool, Inc.
Order Denying Rehearing
ER16-204-001 05/17/18
Southwest Power Pool, Inc.
Opinion No. 562
ER17-2229-001 04/19/18
Southwest Power Pool, Inc.
Order Denying Rehearing
ER18-99-000 03/15/18
Southwest Power Pool, Inc.
Order Accepting Proposed Tariff Revisions, Subject to Refund, and Establishing Hearing and Settlement Judge Procedures
EL18-20-000 03/15/18
Indicated SPP Transmisson Owners
Order Denying Complaint
ER17-2495-000 01/18/18
Southwest Power Pool, Inc.
Letter Order Approving Repricing Request
2017
Docket No.
Date Issued
Company
Title
ER17-426-000, ER17-426-002 12/21/17
Southwest Power Pool, Inc.
Letter Order Approving Uncontested Settlement
ER17-1741-000, ER17-1741-001 12/21/17
Southwest Power Pool, Inc.
Letter Order Approving Uncontested Settlement
ER17-2027-000, ER17-2027-001 12/21/17
Southwest Power Pool, Inc.
Order Accepting Tariff Revisions
ER18-208-000 12/21/17
Southwest Power Pool, Inc.
Order Accepting Service Agreement
EL18-35-000 12/21/17
Southwest Power Pool, Inc.
Order Instituting Section 206 Proceeding and Paper Hearing
ER17-1482-000 11/16/17
Southwest Power Pool, Inc.
Order Accepting Tariff Revisions, Subject to Condition
ER17-889-000 11/16/17
Southwest Power Pool, Inc.
Order on Service Agreement
EL16-91-000, EL18-19-000 10/19/17
Southwest Power Pool, Inc.
Order On Paper Hearing And Instituting Section 206 Proceeding, Establishing Refund Effective Date, And Consolidating Proceedings
ER17-1575-000, -001 10/19/17
Southwest Power Pool, Inc.
Order Rejecting Tariff Revisions And Denying Request For Rehearing And Clarification
EL17-69-000 10/19/17
Buffalo Dunes Wind Project, LLC, Enel Green Power North America, Inc., Alabama Power Company, and Southern Company Services, Inc. Vs Southwest Power Pool, Inc.
Order on Complaint
EL17-11-000 10/19/17
Alabama Power Company v. Southwest Power Pool, Inc.
Order on Complaint
ER16-1286-002, EL16-110-001 10/19/17
Southwest Power Pool, Inc.
Order Granting Clarification
EL16-110-000 10/19/17
Southwest Power Pool, Inc.
Order on Paper Hearing
ER17-772-000, -001, -002 09/20/17
Southwest Power Pool, Inc.
Order On Compliance Filing
ER17-520-000 09/20/17
Southwest Power Pool, Inc.
Order Accepting Tariff Revisions
ER17-1333-000 09/20/17
Southwest Power Pool, Inc.
Order on Tariff Filing
ER16-204-001 02/23/17
Southwest Power Pool, Inc.
Initial Decision
2016
Docket No.
Date Issued
Company
Title
ER12-959-007 07/21/16
Southwest Power Pool, Inc.
Order On Remand
ER16-791-000 07/21/16
Southwest Power Pool, Inc.
Order Granting In Part, And Denying In Part, Motion For Clarification
EL16-91-000 07/21/16
Southwest Power Pool, Inc.
Order Instituting Section 206 Proceeding and Commencing Paper Hearing Procedures and Establishing Refund Effective Date
ER16-1774-000 07/21/16
Southwest Power Pool, Inc.
Order Accepting Tariff Revisions Implementing Formula Rates and Establishing Hearing and Settlement Judge Procedures
ER16-13-002 07/21/16
Southwest Power Pool, Inc.
Letter Order on Compliance Filing
ER16-209-001 06/16/16
Southwest Power Pool, Inc.
Order Granting Clarification and Denying Rehearing
ER14-2850-006 and ER14-2851-006 05/19/16
Southwest Power Pool, Inc.
Letter Order Approving Settlement
EL12-60-001 and ER12-1586-002, -003 04/21/16
Southwest Power Pool, Inc.,
Order on Clarification, Rehearing, and Compliance
ER14-2850-004 and ER14-2851-004 04/21/16
Southwest Power Pool, Inc.
Letter Order Approving Settlement
ER16-139-000, -001 03/17/16
Southwest Power Pool, Inc.
Letter Order Accepting Tariff Revisions
ER16-636-000 03/17/16
Southwest Power Pool, Inc.
Order Granting Tariff Waiver Request
ER14-1174-000, EL11-34-002, EL14-21-000 & EL14-30-000 01/21/16
Midcontinent Independent System Operator, Inc.
Letter Order on Uncontested Settlement
ER14-1174-001, EL11-34-003, EL14-21-001 & EL14-30-001 01/21/16
Midcontinent Independent System Operator, Inc.
Order Dismissing Requests For Rehearing As Moot
