Property, Plant, and Equipment (Tables)

12 Months Ended

Dec. 31, 2021

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant, and Equipment

Property, plant, and equipment consisted of the following as of December 31:

	MGE Energy				MGE
(In thousands)	2021		2020		2021		2020
Utility:
Electric(a)(b)	$	1,516,533	$	1,608,658	$	1,516,550	$	1,608,675
Plant anticipated to be retired early(a)		158,983		—		158,983		—
Gas		546,390		496,450		546,401		496,461
Utility property, plant, and equipment, gross		2,221,906		2,105,108		2,221,934		2,105,136
Less: Accumulated depreciation and amortization(a)		636,804		721,382		636,804		721,382
Utility property, plant, and equipment, net		1,585,102		1,383,726		1,585,130		1,383,754
Nonregulated:
Nonregulated		317,881		320,691		317,881		320,691
Less: Accumulated depreciation and amortization		74,812		74,131		74,812		74,131
Nonregulated property, plant, and equipment, net		243,069		246,560		243,069		246,560
Construction work in progress:
Utility construction work in progress(b)		49,211		137,725		49,211		137,725
Nonregulated construction work in progress		1,392		1,374		1,392		1,374
Total property, plant, and equipment	$	1,878,774	$	1,769,385	$	1,878,802	$	1,769,413

(a)An asset that will be retired in the near future and substantially in advance of its previously expected retirement date is subject to abandonment accounting. In the second quarter of 2021, the operator of Columbia received approval from MISO to retire Columbia Units 1 and 2. The co-owners intend to retire Unit 1 by the end of 2023 and Unit 2 by the end of 2024. Final timing and retirement dates are subject to change depending on operational, regulatory, and other factors. As of December 31, 2021, early retirement of Columbia was probable. "Plant anticipated to be retired early" in table above is the net book value of these generating units. Assets for Columbia Unit 1 and Unit 2 are currently included in rate base, and MGE continues to depreciate them on a straight-line basis using the composite depreciation rates approved by the PSCW that included retirement dates of 2029 for Unit 1 and 2038 for Unit 2. If it becomes probable that regulators will disallow full recovery or a return on the remaining net book value of a generating unit that is either abandoned or probable of being abandoned, an impairment loss would be required. An impairment loss would be recorded for the difference of the remaining net book value of the generating unit that is greater than the present value of the amount expected to be recovered from ratepayers. No impairment was recorded as of December 31, 2021.

(b)Three major projects were placed in service in 2021. Electric only utility projects were O'Brien Solar Fields completed in May and Badger Hollow I completed in November. Implementation of a new Customer Information System, an electric and gas utility project, went live in September.