Property, Plant, and Equipment

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property, Plant, and Equipment - MGE Energy and MGE.

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

		MGE Energy				MGE
(In thousands)		2017		2016		2017		2016
Utility:
Electric(a)	$	1,209,336	$	1,171,004	$	1,209,353	$	1,171,021
Gas		415,542		395,790		415,553		395,801
Total utility plant		1,624,878		1,566,794		1,624,906		1,566,822
Less: Accumulated depreciation and amortization(a)		599,469		579,965		599,469		579,965
In-service utility plant, net		1,025,409		986,829		1,025,437		986,857
Nonregulated:
Nonregulated		319,611		317,810		319,611		317,014
Less: Accumulated depreciation and amortization		61,707		59,370		61,707		59,223
In-service nonregulated plant, net		257,904		258,440		257,904		257,791
Construction work in progress:
Utility construction work in progress(a)		56,208		31,356		56,208		31,356
Nonregulated construction work in progress		1,836		5,434		1,836		5,434
Total property, plant, and equipment	$	1,341,357	$	1,282,059	$	1,341,385	$	1,281,438

(a)As of December 31,2017 and 2016, MGE has classified $8.8 million and $14.8 million, respectively,of Columbia assets as held-for-sale on the consolidated balance sheets related to the partial sale of plant assets to WPL. See Footnote 5.a. for further discussion.

MGE's utility plant is subject to the lien of its Indenture of Mortgage and Deed of Trust. As of December 31,2017 and 2016, there was $1.2 million of bonds outstanding under that indenture. See Footnote 9 for further discussion of the mortgage indenture.