SOUTHERN CO
For the period ended Dec 31, 2023. Filed Feb 15, 2024.
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FY2023 · Filed Feb 15, 2024
SO$92.34-1.1%Stored close · as of Nov 6, 2026
Extracted filing text, with the paragraph anchors used by the comparison.
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Definitionsii
When used in this Form 10-K, the following terms will have the meanings indicated.
| Term | Meaning |
|---|---|
| ARP | Georgia Power's Alternate Rate Plans approved by the Georgia PSC; 2019 ARP for the years 2020 through 2022 and 2022 ARP for the years 2023 through 2025 |
| AFUDC | Allowance for funds used during construction |
| Alabama Power | Alabama Power Company |
| AMEA | Alabama Municipal Electric Authority |
| Amended and Restated Loan Guarantee Agreement | Loan guarantee agreement entered into by Georgia Power with the DOE in 2014, as amended and restated in March 2019, under which the proceeds of borrowings may be used to reimburse Georgia Power for Eligible Project Costs incurred in connection with its construction of Plant Vogtle Units 3 and 4 |
| AOCI | Accumulated other comprehensive income |
| ARO | Asset retirement obligation |
| ASU | Accounting Standards Update |
| Atlanta Gas Light | Atlanta Gas Light Company, a wholly-owned subsidiary of Southern Company Gas |
| Bcf | Billion cubic feet |
| Bechtel | Bechtel Power Corporation, the primary contractor for the remaining construction activities for Plant Vogtle Units 3 and 4 |
| Bechtel Agreement | The 2017 construction completion agreement between the Vogtle Owners and Bechtel |
| CCN | Certificate of convenience and necessity |
| CCR | Coal combustion residuals |
| CCR Rule | Disposal of Coal Combustion Residuals from Electric Utilities final rule published by the EPA in 2015 |
| Chattanooga Gas | Chattanooga Gas Company, a wholly-owned subsidiary of Southern Company Gas |
| Clean Air Act | Clean Air Act Amendments of 1990 |
| CO2 | Carbon dioxide |
| COD | Commercial operation date |
| Contractor Settlement Agreement | The December 31, 2015 agreement between Westinghouse and the Vogtle Owners resolving disputes between the Vogtle Owners and the EPC Contractor under the Vogtle 3 and 4 Agreement |
| Cooperative Energy | Electric generation and transmission cooperative in Mississippi |
| COVID-19 | The novel coronavirus disease declared a pandemic by the World Health Organization and the Centers for Disease Control and Prevention in March 2020 |
| CPCN | Certificate of public convenience and necessity |
| CWIP | Construction work in progress |
| Dalton | City of Dalton, Georgia, an incorporated municipality in the State of Georgia, acting by and through its Board of Water, Light, and Sinking Fund Commissioners |
| Dalton Pipeline | A pipeline facility in Georgia in which Southern Company Gas has a 50% undivided ownership interest |
| DOE | U.S. Department of Energy |
| ECCR | Georgia Power's Environmental Compliance Cost Recovery tariff |
| ECO Plan | Mississippi Power's environmental compliance overview plan |
| ELG | Effluent limitations guidelines |
| Eligible Project Costs | Certain costs of construction relating to Plant Vogtle Units 3 and 4 that are eligible for financing under the loan guarantee program established under Title XVII of the Energy Policy Act of 2005 |
| EMC | Electric membership corporation |
| EPA | U.S. Environmental Protection Agency |
| EPC Contractor | Westinghouse and its affiliate, WECTEC Global Project Services Inc.; the former engineering, procurement, and construction contractor for Plant Vogtle Units 3 and 4 |
| FASB | Financial Accounting Standards Board |
| FCC | Federal Communications Commission |
| FERC | Federal Energy Regulatory Commission |
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| Term | Meaning |
|---|---|
| FFB | Federal Financing Bank |
| FFB Credit Facilities | Note purchase agreements among the DOE, Georgia Power, and the FFB and related promissory notes which provide for two multi-advance term loan facilities |
| Fitch | Fitch Ratings, Inc. |
| FP&L | Florida Power and Light Company |
| GAAP | U.S. generally accepted accounting principles |
| Georgia Power | Georgia Power Company |
| GHG | Greenhouse gas |
| GRAM | Atlanta Gas Light's Georgia Rate Adjustment Mechanism |
| Guarantee Settlement Agreement | The June 9, 2017 settlement agreement between the Vogtle Owners and Toshiba related to certain payment obligations of the EPC Contractor guaranteed by Toshiba |
| Gulf Power | Gulf Power Company, until January 1, 2019 a wholly-owned subsidiary of Southern Company; effective January 1, 2021, Gulf Power Company merged with and into FP&L, with FP&L remaining as the surviving company |
| Heating Degree Days | A measure of weather, calculated when the average daily temperatures are less than 65 degrees Fahrenheit |
| Heating Season | The period from November through March when Southern Company Gas' natural gas usage and operating revenues are generally higher |
| HLBV | Hypothetical liquidation at book value |
| IBEW | International Brotherhood of Electrical Workers |
| IGCC | Integrated coal gasification combined cycle, the technology originally approved for Mississippi Power's Kemper County energy facility |
| IIC | Intercompany Interchange Contract |
| Illinois Commission | Illinois Commerce Commission |
| Internal Revenue Code | Internal Revenue Code of 1986, as amended |
| IPP | Independent power producer |
| IRA | Inflation Reduction Act |
| IRP | Integrated resource plan |
| IRS | Internal Revenue Service |
| ITAAC | Inspections, Tests, Analyses, and Acceptance Criteria, standards established by the NRC |
| ITC | Investment tax credit |
| JEA | Jacksonville Electric Authority |
| KW | Kilowatt |
| KWH | Kilowatt-hour |
| LIBOR | London Interbank Offered Rate |
| LIFO | Last-in, first-out |
| LNG | Liquefied natural gas |
| LTSA | Long-term service agreement |
| Marketers | Marketers selling retail natural gas in Georgia and certificated by the Georgia PSC |
| MEAG Power | Municipal Electric Authority of Georgia |
| Mississippi Power | Mississippi Power Company |
| mmBtu | Million British thermal units |
| Moody's | Moody's Investors Service, Inc. |
| MPUS | Mississippi Public Utilities Staff |
| MRA | Municipal and Rural Associations |
| MW | Megawatt |
| natural gas distribution utilities | Southern Company Gas' natural gas distribution utilities (Nicor Gas, Atlanta Gas Light, Virginia Natural Gas, and Chattanooga Gas) |
| NCCR | Georgia Power's Nuclear Construction Cost Recovery tariff |
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| Term | Meaning |
|---|---|
| NDR | Alabama Power's Natural Disaster Reserve |
| NextEra Energy | NextEra Energy, Inc. |
| Nicor Gas | Northern Illinois Gas Company, a wholly-owned subsidiary of Southern Company Gas |
| NOX | Nitrogen oxide |
| NRC | U.S. Nuclear Regulatory Commission |
| NYMEX | New York Mercantile Exchange, Inc. |
| NYSE | New York Stock Exchange |
| OCI | Other comprehensive income |
| OPC | Oglethorpe Power Corporation (an EMC) |
| OTC | Over-the-counter |
| PennEast Pipeline | PennEast Pipeline Company, LLC, a joint venture in which Southern Company Gas has a 20% ownership interest |
| PEP | Mississippi Power's Performance Evaluation Plan |
| PowerSecure | PowerSecure, Inc., a wholly-owned subsidiary of Southern Company |
| PowerSouth | PowerSouth Energy Cooperative |
| PPA | Power purchase agreements, as well as, for Southern Power, contracts for differences that provide the owner of a renewable facility a certain fixed price for the electricity sold to the grid |
| PSC | Public Service Commission |
| PTC | Production tax credit |
| Rate CNP | Alabama Power's Rate Certificated New Plant, consisting of Rate CNP New Plant, Rate CNP Compliance, Rate CNP PPA, and Rate CNP Depreciation |
| Rate ECR | Alabama Power's Rate Energy Cost Recovery |
| Rate NDR | Alabama Power's Rate Natural Disaster Reserve |
| Rate RSE | Alabama Power's Rate Stabilization and Equalization |
| Registrants | Southern Company, Alabama Power, Georgia Power, Mississippi Power, Southern Power Company, and Southern Company Gas |
| ROE | Return on equity |
| S&P | S&P Global Ratings, a division of S&P Global Inc. |
| SAVE | Steps to Advance Virginia's Energy, an infrastructure replacement program at Virginia Natural Gas |
| SCS | Southern Company Services, Inc., the Southern Company system service company and a wholly-owned subsidiary of Southern Company |
| SEC | U.S. Securities and Exchange Commission |
| SEGCO | Southern Electric Generating Company, 50% owned by each of Alabama Power and Georgia Power |
| SEPA | Southeastern Power Administration |
| Sequent | Sequent Energy Management, L.P. and Sequent Energy Canada Corp., wholly-owned subsidiaries of Southern Company Gas through June 30, 2021 |
| SERC | SERC Reliability Corporation |
| SNG | Southern Natural Gas Company, L.L.C., a pipeline system in which Southern Company Gas has a 50% ownership interest |
| SO2 | Sulfur dioxide |
| SOFR | Secured Overnight Financing Rate |
| Southern Company | The Southern Company |
| Southern Company Gas | Southern Company Gas and its subsidiaries |
| Southern Company Gas Capital | Southern Company Gas Capital Corporation, a 100%-owned subsidiary of Southern Company Gas |
| Southern Company power pool | The operating arrangement whereby the integrated generating resources of the traditional electric operating companies and Southern Power (excluding subsidiaries) are subject to joint commitment and dispatch in order to serve their combined load obligations |
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| Term | Meaning |
|---|---|
| Southern Company system | Southern Company, the traditional electric operating companies, Southern Power, Southern Company Gas, SEGCO, Southern Nuclear, SCS, Southern Linc, PowerSecure, and other subsidiaries |
| Southern Holdings | Southern Company Holdings, Inc., a wholly-owned subsidiary of Southern Company |
| Southern Linc | Southern Communications Services, Inc., a wholly-owned subsidiary of Southern Company, doing business as Southern Linc |
| Southern Nuclear | Southern Nuclear Operating Company, Inc., a wholly-owned subsidiary of Southern Company |
| Southern Power | Southern Power Company and its subsidiaries |
| SouthStar | SouthStar Energy Services, LLC (a Marketer), a wholly-owned subsidiary of Southern Company Gas |
| SP Solar | SP Solar Holdings I, LP, a limited partnership indirectly owning substantially all of Southern Power's solar and battery energy storage facilities, in which Southern Power has a 67% ownership interest |
| SP Wind | SP Wind Holdings II, LLC, a holding company owning a portfolio of eight operating wind facilities, in which Southern Power is the controlling partner in a tax equity arrangement |
| SRR | Mississippi Power's System Restoration Rider, a tariff for retail property damage cost recovery and reserve |
| Subsidiary Registrants | Alabama Power, Georgia Power, Mississippi Power, Southern Power, and Southern Company Gas |
| Tax Reform Legislation | The Tax Cuts and Jobs Act, which became effective on January 1, 2018 |
| Toshiba | Toshiba Corporation, the parent company of Westinghouse |
| traditional electric operating companies | Alabama Power, Georgia Power, and Mississippi Power |
| VCM | Vogtle Construction Monitoring |
| VIE | Variable interest entity |
| Virginia Commission | Virginia State Corporation Commission |
| Virginia Natural Gas | Virginia Natural Gas, Inc., a wholly-owned subsidiary of Southern Company Gas |
| Vogtle 3 and 4 Agreement | Agreement entered into with the EPC Contractor in 2008 by Georgia Power, acting for itself and as agent for the Vogtle Owners, and rejected in bankruptcy in July 2017, pursuant to which the EPC Contractor agreed to design, engineer, procure, construct, and test Plant Vogtle Units 3 and 4 |
| Vogtle Owners | Georgia Power, OPC, MEAG Power, and Dalton |
| Vogtle Services Agreement | The June 2017 services agreement between the Vogtle Owners and the EPC Contractor, as amended and restated in July 2017, for the EPC Contractor to transition construction management of Plant Vogtle Units 3 and 4 to Southern Nuclear and to provide ongoing design, engineering, and procurement services to Southern Nuclear |
| Westinghouse | Westinghouse Electric Company LLC |
| Williams Field Services Group | Williams Field Services Group, LLC |
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