Segment Information

12 Months Ended

Dec. 31, 2022

Segment Reporting [Abstract]

Segment Reporting Disclosure [Text Block]

22.Segment Information - MGE Energy and MGE.

The electric utility business purchases, generates and distributes electricity, and contracts for transmission service. The gas utility business purchases and distributes natural gas and contracts for the transportation of natural gas. Both the electric and gas segments operate through MGE Energy's principal subsidiary, MGE.

The nonregulated energy operations are conducted through MGE Energy's subsidiaries: MGE Power, MGE Power Elm Road, and MGE Power West Campus. These subsidiaries own electric generating capacity that they lease to MGE to assist MGE. MGE Power Elm Road has an ownership interest in two coal-fired generating units in Oak Creek, Wisconsin, which are leased to MGE, and MGE Power West Campus owns a controlling interest in the electric generation plant of a natural gas-fired cogeneration facility on the UW campus. MGE Power West Campus's portion is also leased to MGE.

The transmission investment segment invests in ATC, a company that provides electric transmission services primarily in Wisconsin, and ATC Holdco, a company formed to pursue electric transmission development and investments outside of Wisconsin. These investments are held in MGE Transco and MGEE Transco, respectively. See Footnote 7 for further discussion.

The "All Others" segment includes: corporate, CWDC, MAGAEL, MGE State Energy Services, MGE Services, and North Mendota. These entities' operations consist of investing in companies and property which relate to the regulated operations, financing the regulated operations.

General corporate expenses include the cost of executive management, corporate accounting and finance, information technology, risk management, human resources and legal functions, and employee benefits that are allocated to electric and gas segments based on formulas prescribed by the PSCW. Identifiable assets are those used in MGE's operations in each segment.

Sales between our electric and gas segments are based on PSCW approved tariffed rates. Additionally, intersegment operations related to the leasing arrangement between our electric segment and MGE Power Elm Road/MGE Power West Campus are based on terms previously approved by the PSCW. Consistent with internal reporting, management has presented the direct financing capital leases between MGE and MGE Power Elm Road/MGE Power West Campus based on actual lease payments included in rates. Lease payments made by MGE to MGE Power Elm Road and MGE Power West Campus are shown as operating expenses. The lease payments received by MGE Power Elm Road and MGE Power West Campus from MGE are shown as lease income in interdepartmental revenues. The depreciation expense associated with the Elm Road Units and WCCF is reflected in the nonregulated energy segment.

The following table shows segment information for MGE Energy's and MGE's operations:

(In thousands) MGE Energy	Electric			Gas			Non-Regulated Energy			Transmission Investment			All Others			Consolidation/ Elimination Entries			Consolidated Total
Year Ended December 31, 2022
Operating revenues	$	465,167		$	248,672		$	680		$	—		$	—		$	—		$	714,519
Interdepartmental revenues		(44	)		34,073			41,555			—			—			(75,584	)		—
Total operating revenues		465,123			282,745			42,235			—			—			(75,584	)		714,519
Depreciation and amortization		(62,897	)		(15,261	)		(7,391	)		—			—			—			(85,549	)
Operating income (loss)		77,672			26,261			34,683			—			(873	)		—			137,743
Interest (expense) income, net		(17,578	)		(4,787	)		(4,322	)		—			40			—			(26,647	)
Income tax (provision) benefit		(7,299	)		(8,492	)		(8,272	)		(2,490	)		329			—			(26,224	)
Equity in earnings of investments		—			—			—			9,136			—			—			9,136
Net income (loss)		65,187			18,215			22,090			6,647			(1,187	)		—			110,952
Year Ended December 31, 2021
Operating revenues	$	420,286		$	185,620		$	678		$	—		$	—		$	—		$	606,584
Interdepartmental revenues		556			22,728			40,866			—			—			(64,150	)		—
Total operating revenues		420,842			208,348			41,544			—			—			(64,150	)		606,584
Depreciation and amortization		(56,672	)		(12,852	)		(7,459	)		—			—			—			(76,983	)
Operating income (loss)		58,993			25,133			33,936			—			(768	)		—			117,294
Interest (expense) income, net		(15,261	)		(4,315	)		(4,577	)		—			41			—			(24,112	)
Income tax (provision) benefit		10,672			(4,922	)		(7,998	)		(2,486	)		619			—			(4,115	)
Equity in earnings of investments		—			—			—			9,339			(69	)		—			9,270
Net income (loss)		63,910			15,511			21,361			6,852			(1,873	)		—			105,761
Year Ended December 31, 2020
Operating revenues	$	393,692		$	144,261		$	680		$	—		$	—		$	—		$	538,633
Interdepartmental revenues		765			12,157			40,402			—			—			(53,324	)		—
Total operating revenues		394,457			156,418			41,082			—			—			(53,324	)		538,633
Depreciation and amortization		(54,658	)		(12,049	)		(7,481	)		—			—			—			(74,188	)
Operating income (loss)		57,847			19,674			33,460			(1	)		(983	)		—			109,997
Interest (expense) income, net		(14,446	)		(4,370	)		(4,826	)		—			121			—			(23,521	)
Income tax (provision) benefit		(4,230	)		(4,805	)		(7,800	)		(2,786	)		198			—			(19,423	)
Equity in earnings of investments		—			—			—			10,221			—			—			10,221
Net income (loss)		50,522			14,167			20,834			7,434			(539	)		—			92,418

(In thousands) MGE	Electric			Gas			Non-Regulated Energy			Consolidation/ Elimination Entries			Consolidated Total
Year Ended December 31, 2022
Operating revenues	$	465,167		$	248,672		$	680		$	—		$	714,519
Interdepartmental revenues		(44	)		34,073			41,555			(75,584	)		—
Total operating revenues		465,123			282,745			42,235			(75,584	)		714,519
Depreciation and amortization		(62,897	)		(15,261	)		(7,391	)		—			(85,549	)
Operating income		77,672			26,261			34,683			—			138,616
Interest expense, net		(17,578	)		(4,787	)		(4,322	)		—			(26,687	)
Income tax provision		(7,299	)		(8,492	)		(8,272	)		—			(24,063	)
Net income attributable to MGE		65,187			18,215			22,090			(21,576	)		83,916
Year Ended December 31, 2021
Operating revenues	$	420,286		$	185,620		$	678		$	—		$	606,584
Interdepartmental revenues		556			22,728			40,866			(64,150	)		—
Total operating revenues		420,842			208,348			41,544			(64,150	)		606,584
Depreciation and amortization		(56,672	)		(12,852	)		(7,459	)		—			(76,983	)
Operating income		58,993			25,133			33,936			—			118,062
Interest expense, net		(15,261	)		(4,315	)		(4,577	)		—			(24,153	)
Income tax (provision) benefit		10,672			(4,922	)		(7,998	)		—			(2,248	)
Net income attributable to MGE		63,910			15,511			21,361			(22,391	)		78,391
Year Ended December 31, 2020
Operating revenues	$	393,692		$	144,261		$	680		$	—		$	538,633
Interdepartmental revenues		765			12,157			40,402			(53,324	)		—
Total operating revenues		394,457			156,418			41,082			(53,324	)		538,633
Depreciation and amortization		(54,658	)		(12,049	)		(7,481	)		—			(74,188	)
Operating income		57,847			19,674			33,460			—			110,981
Interest expense, net		(14,446	)		(4,370	)		(4,826	)		—			(23,642	)
Income tax provision		(4,230	)		(4,805	)		(7,800	)		—			(16,835	)
Net income attributable to MGE		50,522			14,167			20,834			(22,393	)		63,130

The following table shows segment information for MGE Energy's and MGE's assets and capital expenditures:

	Utility				Consolidated
(In thousands) MGE Energy	Electric		Gas		Non-regulated Energy		Transmission Investment(a)		All Others		Consolidation/ Elimination Entries			Total
Assets:
December 31, 2022	$	1,626,373	$	530,733	$	247,841	$	80,642	$	467,112	$	(435,101	)	$	2,517,600
December 31, 2021		1,525,163		485,345		252,584		75,990		467,954		(435,130	)		2,371,906
December 31, 2020		1,421,302		444,702		254,298		74,480		495,483		(436,614	)		2,253,651
Capital Expenditures:
Year ended Dec. 31, 2022	$	141,273	$	27,656	$	6,101	$	—	$	—	$	—		$	175,030
Year ended Dec. 31, 2021		115,234		34,071		3,864		—		—		—			153,169
Year ended Dec. 31, 2020		162,210		36,906		4,023		—		—		—			203,139

	Utility				Consolidated
(In thousands) MGE	Electric		Gas		Non-regulated Energy		Consolidation/ Elimination Entries			Total
Assets:
December 31, 2022	$	1,626,373	$	530,733	$	247,791	$	(258	)	$	2,404,639
December 31, 2021		1,525,163		485,345		252,534		(267	)		2,262,775
December 31, 2020		1,421,302		444,702		254,248		(281	)		2,119,971
Capital Expenditures:
Year ended Dec. 31, 2022	$	141,273	$	27,656	$	6,101	$	—		$	175,030
Year ended Dec. 31, 2021		115,234		34,071		3,864		—			153,169
Year ended Dec. 31, 2020		162,210		36,906		4,023		—			203,139

(a)The Transmission Investment segment represents MGE Energy's investment in equity method investees.