Joint Plant Ownership (Tables)

12 Months Ended

Dec. 31, 2017

Columbia Units [Member]

Jointly Owned Utility Plant Interests [Line Items]

Schedule of Joint Plant Ownership

MGE's interest in Columbia's gross utility plant in service, and the related accumulated depreciation reserves at December 31 were as follows:

(In thousands)		2017		2016
Utility plant	$	274,450	$	270,898
Accumulated depreciation		(87,144)		(81,935)
Property, plant, and equipment, net		187,306		188,963
Construction work in progress		20,382		21,120
Total property, plant, and equipment	$	207,688	$	210,083

Elm Road Units [Member]

Jointly Owned Utility Plant Interests [Line Items]

Schedule of Joint Plant Ownership

MGE Power Elm Road's interest in the portion of the Elm Road Units in-service and the related accumulated depreciation reserves at December 31 were as follows:

(In thousands)		2017		2016
Nonregulated plant	$	206,063	$	204,292
Accumulated depreciation		(30,061)		(28,790)
Property, plant, and equipment, net		176,002		175,502
Construction work in progress		1,225		3,241
Total property, plant, and equipment	$	177,227	$	178,743

West Campus [Member]

Jointly Owned Utility Plant Interests [Line Items]

Schedule of Joint Plant Ownership

MGE Power West Campus' interest in WCCF and the related accumulated depreciation reserves at December 31 were as follows:

(In thousands)		2017		2016
Nonregulated plant	$	111,386	$	111,330
Accumulated depreciation		(31,104)		(29,742)
Property, plant, and equipment, net		80,282		81,588
Construction work in progress		610		1,009
Total property, plant, and equipment	$	80,892	$	82,597