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REGULATORY MATTERS (Tables)
 12 Months Ended
Dec. 31, 2022
Regulated Operations [Abstract]  
Schedule of regulatory assets
Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2022 and 2021 are provided in the following tables:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2022
AROs(a)(u)
$6,096 $1,971 $3,829 $242 $— 
Retiree benefit plans(b)(u)
2,517 675 848 113 114 
Remaining net book value of retired assets(c)
1,543 562 962 19 — 
Under recovered regulatory clause revenues(d)
953 788 — 31 134 
Deferred income tax charges(e)
866 250 583 30 — 
Environmental remediation(f)(u)
294 — 25 — 269 
Loss on reacquired debt(g)
257 38 213 5 1 
Vacation pay(h)(u)
212 82 108 10 12 
Regulatory clauses(i)
142 142 — — — 
Software and cloud computing costs(j)
111 46 59 — 6 
Nuclear outage(k)
82 52 30 — — 
Long-term debt fair value adjustment(l)
69 — — — 69 
Fuel-hedging (realized and unrealized) losses(m)
60 15 45 — — 
Storm damage(n)
44 — — 44 — 
Plant Daniel Units 3 and 4(o)
27 — — 27 — 
Kemper County energy facility assets, net(p)
20 — — 20 — 
Other regulatory assets(q)
197 36 27 16 118 
Deferred income tax credits(e)
(5,251)(1,925)(2,244)(269)(788)
Other cost of removal obligations(a)
(1,430)11 462 (196)(1,707)
Storm/property damage reserves(r)
(216)(97)(83)(36)— 
Reliability reserves(r)
(191)(166)— (25)— 
Customer refunds(s)
(183)(62)(121)— — 
Fuel-hedging (realized and unrealized) gains(m)
(83)(38)(21)(24)— 
Over recovered regulatory clause revenues(d)
(64)— (38)— (26)
Other regulatory liabilities(t)
(239)(40)(21)(3)(93)
Total regulatory assets (liabilities), net$5,833 $2,340 $4,663 $4 $(1,891)
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2021
AROs(a)(u)
$5,685 $1,576 $3,866 $236 $— 
Retiree benefit plans(b)(u)
2,998 747 962 145 95 
Remaining net book value of retired assets(c)
1,050 574 455 21 — 
Deferred income tax charges(e)
829 240 555 31 — 
Under recovered regulatory clause revenues(d)
806 225 — 49 532 
Environmental remediation(f)(u)
302 — 35 — 267 
Loss on reacquired debt(g)
281 42 231 6 2 
Vacation pay(h)(u)
207 81 102 10 14 
Regulatory clauses(i)
142 142 — — — 
Storm damage(n)
97 — 48 49 — 
Long-term debt fair value adjustment(l)
79 — — — 79 
Nuclear outage(k)
75 41 34 — — 
Software and cloud computing costs(j)
73 35 33 — 5 
Kemper County energy facility assets, net(p)
35 — — 35 — 
Plant Daniel Units 3 and 4(o)
28 — — 28 — 
Other regulatory assets(q)
168 38 29 7 94 
Deferred income tax credits(e)
(5,636)(1,968)(2,537)(288)(816)
Other cost of removal obligations(a)
(1,826)(192)278 (195)(1,683)
Customer refunds(s)
(189)(181)(8)— — 
Fuel-hedging (realized and unrealized) gains(m)
(176)(50)(72)(54)— 
Storm/property damage reserves(r)
(133)(103)— (30)— 
Over recovered regulatory clause revenues(d)
(63)(1)(59)— (3)
Other regulatory liabilities(t)
(121)(29)(24)(4)(57)
Total regulatory assets (liabilities), net$4,711 $1,217 $3,928 $46 $(1,471)
Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency:
(a)AROs and other cost of removal obligations generally are recorded over the related property lives, which may range up to 53 years for Alabama Power, 57 years for Georgia Power, 55 years for Mississippi Power, and 80 years for Southern Company Gas. AROs and cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information.
(b)Recovered and amortized over the average remaining service period, which may range up to 13 years for Alabama Power, Georgia Power, and Mississippi Power and up to 14 years for Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information.
(c)Alabama Power: Primarily represents the net book value of Plant Gorgas Units 8, 9, and 10 ($492 million at December 31, 2022) being amortized over remaining periods not exceeding 15 years (through 2037). Balance at December 31, 2022 also includes approximately $42 million related to Plant Barry Unit 4 being amortized over the unit's remaining useful life (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information.
Georgia Power: Net book values of Plant Wansley Units 1 and 2 (totaling $562 million at December 31, 2022) are being amortized over a remaining period of eight years (through 2030) and net book values of Plant Hammond Units 1 through 4 and Plant Branch Units 3 and 4 (totaling $396 million at December 31, 2022) are being amortized over remaining periods of between one and 13 years (between 2023 and 2035). Balance at December 31, 2022 also includes unusable materials and supplies inventories, as discussed further under "Georgia Power – Integrated Resource Plans" herein.
Mississippi Power: Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over a 10-year period through 2030 and the wholesale portion is being amortized over a 14-year period through 2035. See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information.
(d)Alabama Power: Balances are recorded monthly and expected to be recovered over periods of up to eight years, with the majority expected to be recovered within two years. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information.
Georgia Power: Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information.
Mississippi Power: At December 31, 2022, $12 million is being amortized over a three-year period ending in 2023 and the remaining $18 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information.
Southern Company Gas: Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs.
(e)Deferred income tax charges are recovered and deferred income tax credits are amortized over the related property lives, which may range up to 53 years for Alabama Power, 57 years for Georgia Power, 55 years for Mississippi Power, and 80 years for Southern Company Gas. See Note 10 for additional information. As a result of the Tax Reform Legislation, these accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below:
Alabama Power: Related amounts at December 31, 2022 include excess federal deferred income tax liabilities that are being returned to customers through bill credits of up to approximately $318 million in 2023, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. The Alabama PSC will determine the treatment of any remaining excess federal accumulated deferred income taxes at a future date. Remaining amounts are being recovered and amortized ratably over the related property lives.
Georgia Power: Related amounts at December 31, 2022 include $145 million of deferred income tax assets related to CWIP for Plant Vogtle Units 3 and 4, the recovery of which is expected to be determined in a future regulatory proceeding.
Mississippi Power: Related amounts at December 31, 2022 include $33 million of retail deferred income tax liabilities generally being amortized over three years through 2025.
Southern Company Gas: Related amounts at December 31, 2022 include $1 million of deferred income tax liabilities being amortized through 2024. See "Southern Company Gas – Rate Proceedings" herein for additional information.
(f)Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information.
(g)Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2022, the remaining amortization periods do not exceed 25 years for Alabama Power, 30 years for Georgia Power, 19 years for Mississippi Power, and five years for Southern Company Gas.
(h)Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable.
(i)Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027.
(j)Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years. See "Alabama Power – Software Accounting Order" herein for additional information. For Georgia Power, costs incurred through 2022 will be amortized over five years starting in 2023 and the recovery period for all future costs will be determined in its next base rate case. For Southern Company Gas, costs began being amortized ratably in July 2022 over the life of the related software, which ranges up to 10 years.
(k)Nuclear outage costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information.
(l)Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 16 years at December 31, 2022.
(m)Fuel-hedging assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power.
(n)Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over an eight-year period through 2029.
(o)Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2022, consists of the $18 million retail portion being amortized through 2039 over the remaining life of the related property and the $9 million wholesale portion being amortized through 2035.
(p)Includes $26 million of regulatory assets and $6 million of regulatory liabilities at December 31, 2022. The retail portion includes $17 million of regulatory assets and $6 million of regulatory liabilities that are expected to be fully amortized by 2023 and 2025, respectively. The wholesale portion includes $10 million of regulatory assets that are expected to be fully amortized by 2035.
(q)Comprised of numerous immaterial components with remaining amortization periods generally not exceeding 21 years for Alabama Power, 10 years for Georgia Power, 14 years for Mississippi Power, and 20 years for Southern Company Gas at December 31, 2022.
(r)Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information.
(s)Primarily includes approximately $62 million and $181 million at December 31, 2022 and 2021, respectively, for Alabama Power and $119 million and $5 million at December 31, 2022 and 2021, respectively, for Georgia Power as a result of each company exceeding its allowed retail return range. Georgia Power's balances also include immaterial amounts related to refunds for transmission service customers. See "Alabama Power – Rate RSE" and "Georgia Power – Rate Plans" herein for additional information.
(t)Comprised of numerous immaterial components with remaining amortization periods generally not exceeding 11 years for Alabama Power, 10 years for Georgia Power, four years for Mississippi Power, and 20 years for Southern Company Gas at December 31, 2022.
(u)Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability.
The following table illustrates Southern Company Gas' authorized ratemaking amounts that are not recognized on its balance sheets. These amounts are primarily composed of an allowed equity rate of return on assets associated with certain regulatory infrastructure programs. These amounts will be recognized as revenues in Southern Company Gas' financial statements in the periods they are billable to customers, the majority of which will be recovered by 2025.
December 31, 2022December 31, 2021
(in millions)
Atlanta Gas Light$35 $47 
Virginia Natural Gas10 10 
Chattanooga Gas2 4 
Nicor Gas3 — 
Total$50 $61 
Schedule of regulatory liabilities
Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2022 and 2021 are provided in the following tables:
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2022
AROs(a)(u)
$6,096 $1,971 $3,829 $242 $— 
Retiree benefit plans(b)(u)
2,517 675 848 113 114 
Remaining net book value of retired assets(c)
1,543 562 962 19 — 
Under recovered regulatory clause revenues(d)
953 788 — 31 134 
Deferred income tax charges(e)
866 250 583 30 — 
Environmental remediation(f)(u)
294 — 25 — 269 
Loss on reacquired debt(g)
257 38 213 5 1 
Vacation pay(h)(u)
212 82 108 10 12 
Regulatory clauses(i)
142 142 — — — 
Software and cloud computing costs(j)
111 46 59 — 6 
Nuclear outage(k)
82 52 30 — — 
Long-term debt fair value adjustment(l)
69 — — — 69 
Fuel-hedging (realized and unrealized) losses(m)
60 15 45 — — 
Storm damage(n)
44 — — 44 — 
Plant Daniel Units 3 and 4(o)
27 — — 27 — 
Kemper County energy facility assets, net(p)
20 — — 20 — 
Other regulatory assets(q)
197 36 27 16 118 
Deferred income tax credits(e)
(5,251)(1,925)(2,244)(269)(788)
Other cost of removal obligations(a)
(1,430)11 462 (196)(1,707)
Storm/property damage reserves(r)
(216)(97)(83)(36)— 
Reliability reserves(r)
(191)(166)— (25)— 
Customer refunds(s)
(183)(62)(121)— — 
Fuel-hedging (realized and unrealized) gains(m)
(83)(38)(21)(24)— 
Over recovered regulatory clause revenues(d)
(64)— (38)— (26)
Other regulatory liabilities(t)
(239)(40)(21)(3)(93)
Total regulatory assets (liabilities), net$5,833 $2,340 $4,663 $4 $(1,891)
Southern CompanyAlabama PowerGeorgia PowerMississippi PowerSouthern Company Gas
(in millions)
At December 31, 2021
AROs(a)(u)
$5,685 $1,576 $3,866 $236 $— 
Retiree benefit plans(b)(u)
2,998 747 962 145 95 
Remaining net book value of retired assets(c)
1,050 574 455 21 — 
Deferred income tax charges(e)
829 240 555 31 — 
Under recovered regulatory clause revenues(d)
806 225 — 49 532 
Environmental remediation(f)(u)
302 — 35 — 267 
Loss on reacquired debt(g)
281 42 231 6 2 
Vacation pay(h)(u)
207 81 102 10 14 
Regulatory clauses(i)
142 142 — — — 
Storm damage(n)
97 — 48 49 — 
Long-term debt fair value adjustment(l)
79 — — — 79 
Nuclear outage(k)
75 41 34 — — 
Software and cloud computing costs(j)
73 35 33 — 5 
Kemper County energy facility assets, net(p)
35 — — 35 — 
Plant Daniel Units 3 and 4(o)
28 — — 28 — 
Other regulatory assets(q)
168 38 29 7 94 
Deferred income tax credits(e)
(5,636)(1,968)(2,537)(288)(816)
Other cost of removal obligations(a)
(1,826)(192)278 (195)(1,683)
Customer refunds(s)
(189)(181)(8)— — 
Fuel-hedging (realized and unrealized) gains(m)
(176)(50)(72)(54)— 
Storm/property damage reserves(r)
(133)(103)— (30)— 
Over recovered regulatory clause revenues(d)
(63)(1)(59)— (3)
Other regulatory liabilities(t)
(121)(29)(24)(4)(57)
Total regulatory assets (liabilities), net$4,711 $1,217 $3,928 $46 $(1,471)
Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency:
(a)AROs and other cost of removal obligations generally are recorded over the related property lives, which may range up to 53 years for Alabama Power, 57 years for Georgia Power, 55 years for Mississippi Power, and 80 years for Southern Company Gas. AROs and cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information.
(b)Recovered and amortized over the average remaining service period, which may range up to 13 years for Alabama Power, Georgia Power, and Mississippi Power and up to 14 years for Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information.
(c)Alabama Power: Primarily represents the net book value of Plant Gorgas Units 8, 9, and 10 ($492 million at December 31, 2022) being amortized over remaining periods not exceeding 15 years (through 2037). Balance at December 31, 2022 also includes approximately $42 million related to Plant Barry Unit 4 being amortized over the unit's remaining useful life (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information.
Georgia Power: Net book values of Plant Wansley Units 1 and 2 (totaling $562 million at December 31, 2022) are being amortized over a remaining period of eight years (through 2030) and net book values of Plant Hammond Units 1 through 4 and Plant Branch Units 3 and 4 (totaling $396 million at December 31, 2022) are being amortized over remaining periods of between one and 13 years (between 2023 and 2035). Balance at December 31, 2022 also includes unusable materials and supplies inventories, as discussed further under "Georgia Power – Integrated Resource Plans" herein.
Mississippi Power: Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over a 10-year period through 2030 and the wholesale portion is being amortized over a 14-year period through 2035. See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information.
(d)Alabama Power: Balances are recorded monthly and expected to be recovered over periods of up to eight years, with the majority expected to be recovered within two years. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information.
Georgia Power: Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information.
Mississippi Power: At December 31, 2022, $12 million is being amortized over a three-year period ending in 2023 and the remaining $18 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information.
Southern Company Gas: Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs.
(e)Deferred income tax charges are recovered and deferred income tax credits are amortized over the related property lives, which may range up to 53 years for Alabama Power, 57 years for Georgia Power, 55 years for Mississippi Power, and 80 years for Southern Company Gas. See Note 10 for additional information. As a result of the Tax Reform Legislation, these accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below:
Alabama Power: Related amounts at December 31, 2022 include excess federal deferred income tax liabilities that are being returned to customers through bill credits of up to approximately $318 million in 2023, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. The Alabama PSC will determine the treatment of any remaining excess federal accumulated deferred income taxes at a future date. Remaining amounts are being recovered and amortized ratably over the related property lives.
Georgia Power: Related amounts at December 31, 2022 include $145 million of deferred income tax assets related to CWIP for Plant Vogtle Units 3 and 4, the recovery of which is expected to be determined in a future regulatory proceeding.
Mississippi Power: Related amounts at December 31, 2022 include $33 million of retail deferred income tax liabilities generally being amortized over three years through 2025.
Southern Company Gas: Related amounts at December 31, 2022 include $1 million of deferred income tax liabilities being amortized through 2024. See "Southern Company Gas – Rate Proceedings" herein for additional information.
(f)Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information.
(g)Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2022, the remaining amortization periods do not exceed 25 years for Alabama Power, 30 years for Georgia Power, 19 years for Mississippi Power, and five years for Southern Company Gas.
(h)Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable.
(i)Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027.
(j)Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years. See "Alabama Power – Software Accounting Order" herein for additional information. For Georgia Power, costs incurred through 2022 will be amortized over five years starting in 2023 and the recovery period for all future costs will be determined in its next base rate case. For Southern Company Gas, costs began being amortized ratably in July 2022 over the life of the related software, which ranges up to 10 years.
(k)Nuclear outage costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information.
(l)Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 16 years at December 31, 2022.
(m)Fuel-hedging assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power.
(n)Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over an eight-year period through 2029.
(o)Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2022, consists of the $18 million retail portion being amortized through 2039 over the remaining life of the related property and the $9 million wholesale portion being amortized through 2035.
(p)Includes $26 million of regulatory assets and $6 million of regulatory liabilities at December 31, 2022. The retail portion includes $17 million of regulatory assets and $6 million of regulatory liabilities that are expected to be fully amortized by 2023 and 2025, respectively. The wholesale portion includes $10 million of regulatory assets that are expected to be fully amortized by 2035.
(q)Comprised of numerous immaterial components with remaining amortization periods generally not exceeding 21 years for Alabama Power, 10 years for Georgia Power, 14 years for Mississippi Power, and 20 years for Southern Company Gas at December 31, 2022.
(r)Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information.
(s)Primarily includes approximately $62 million and $181 million at December 31, 2022 and 2021, respectively, for Alabama Power and $119 million and $5 million at December 31, 2022 and 2021, respectively, for Georgia Power as a result of each company exceeding its allowed retail return range. Georgia Power's balances also include immaterial amounts related to refunds for transmission service customers. See "Alabama Power – Rate RSE" and "Georgia Power – Rate Plans" herein for additional information.
(t)Comprised of numerous immaterial components with remaining amortization periods generally not exceeding 11 years for Alabama Power, 10 years for Georgia Power, four years for Mississippi Power, and 20 years for Southern Company Gas at December 31, 2022.
(u)Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability.
Public utilities general disclosures Georgia Power will recover estimated adjustments through its existing tariffs as follows:
Tariff202320242025
(in millions)
Traditional base$194 $275 $315 
ECCR(21)66 81 
DSM37 27 (2)
MFF6 9 9 
Total$216 $377 $403 
The Georgia PSC approved the following tariff adjustments under the 2019 ARP effective January 1, 2021 and 2022, respectively:
Tariff20212022
(in millions)
Traditional base$120 $192 
ECCR2 (12)
DSM(15)(25)
MFF4 2 
Total$111 $157 
The following table provides regulatory information for Southern Company Gas' natural gas distribution utilities:
Nicor GasAtlanta Gas LightVirginia Natural GasChattanooga Gas
Authorized ROE at December 31, 2022
9.75%10.25%9.50%9.80%
Weather normalization mechanisms(a)
üü
Decoupled, including straight-fixed-variable rates(b)
üüü
Regulatory infrastructure program rates(c)
üüüü
Bad debt rider(d)
üüü
Energy efficiency plan(e)
üü
Annual base rate adjustment mechanism(f)
üü
Year of last base rate case decision2021201920212018
(a)Designed to help stabilize operating results by allowing recovery of costs in the event of unseasonal weather, but are not direct offsets to the potential impacts on earnings of weather and customer consumption.
(b)Allows for recovery of fixed customer service costs separately from assumed natural gas volumes used by customers and provides a benchmark level of revenue for recovery.
(c)Programs that update or expand distribution systems and LNG facilities. Atlanta Gas Light's infrastructure program, System Reinforcement Rider, is effective for 2022 through 2024. See "Rate Proceedings – Atlanta Gas Light" herein for additional information. Chattanooga Gas' pipeline replacement program costs are recovered through its annual base rate review mechanism.
(d)The recovery (refund) of bad debt expense over (under) an established benchmark expense. The gas portion of bad debt expense is recovered through purchased gas adjustment mechanisms. Nicor Gas also has a rider to recover the non-gas portion of bad debt expense.
(e)Recovery of costs associated with plans to achieve specified energy savings goals.
(f)Regulatory mechanism allowing annual adjustments to base rates up or down based on authorized ROE and/or ROE range.
The following table and discussions provide updates on the infrastructure replacement programs and capital projects at the natural gas distribution utilities at December 31, 2022. These programs are risk-based and designed to update and replace cast iron, bare steel, and mid-vintage plastic materials or expand Southern Company Gas' distribution systems to improve reliability and meet operational flexibility and growth.
UtilityProgramRecovery
Expenditures in 2022
Expenditures Since Project InceptionPipe
Installed Since
Project Inception		Scope of
Program		Program DurationLast
Year of Program
(in millions)(miles)(miles)(years)
Nicor Gas
Investing in Illinois(*)
Rider$437 $2,945 1,297 1,854 92023
Virginia Natural GasSteps to Advance Virginia's Energy (SAVE)Rider69 411 525 695 132024
Atlanta Gas LightSystem Reinforcement RiderRider76 76 10 N/A32024
Chattanooga GasPipeline Replacement ProgramRate Base5 7 5 73 72027
Total$587 $3,439 1,837 2,622 
(*)Includes replacement of pipes, compressors, and transmission mains along with other improvements such as new meters. Scope of program miles is an estimate and subject to change. Recovery of program costs is described under "Nicor Gas" herein.
Schedule of revised cost and schedule
Georgia Power's approximate proportionate share of the remaining estimated capital cost to complete Plant Vogtle Units 3 and 4, including contingency, through the end of the second quarter 2023 and the first quarter 2024, respectively, is as follows:
(in millions)
Base project capital cost forecast(a)(b)
$10,533 
Construction contingency estimate60 
Total project capital cost forecast(a)(b)
10,593 
Net investment at December 31, 2022(b)
(9,521)
Remaining estimate to complete$1,072 
(a)Includes approximately $610 million of costs that are not shared with the other Vogtle Owners, including $33 million of construction monitoring costs approved for recovery by the Georgia PSC in its nineteenth VCM order, and approximately $407 million of incremental costs under the cost-sharing and tender provisions of the joint ownership agreements described below. Excludes financing costs expected to be capitalized through AFUDC of approximately $421 million, of which $304 million had been accrued through December 31, 2022.
(b)Net of $1.7 billion received from Toshiba under the Guarantee Settlement Agreement and approximately $188 million in related customer refunds.