Asset Retirement Obligations

12 Months Ended

Dec. 31, 2016

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligations - MGE Energy and MGE.

MGE recorded an obligation for the fair value of its legal liability for asset retirement obligations (AROs) associated with removal of the West Campus Cogeneration Facility and the Elm Road Units, electric substations, combustion turbine generating units, wind generating facilities, and photovoltaic generating facilities, all of which are located on property not owned by MGE Energy and MGE and would need to be removed upon the ultimate end of the associated leases. The significant conditional AROs identified by MGE included the costs of abandoning in place gas services and mains, the abatement and disposal of equipment and buildings contaminated with asbestos and PCBs, and the proper disposal and removal of tanks, batteries, and underground cable. Changes in management's assumptions regarding settlement dates, settlement methods, or assigned probabilities could have a material effect on the liabilities recorded by MGE at December 31, 2016, as well as the regulatory asset recorded.

MGE also may have AROs relating to the removal of various assets, such as certain electric and gas distribution facilities. These facilities are generally located on property owned by third parties, on which MGE is permitted to operate by lease, permit, easement, license, or service agreement. The asset retirement obligations associated with these facilities cannot be reasonably determined due to the indeterminate life of the related agreements.

The following table summarizes the change in AROs. Amounts include conditional AROs.

(In thousands)		2016		2015
Balance at January 1,	$	24,360	$	19,744
Liabilities incurred^(a)		1,303		2,380
Accretion expense		1,269		1,131
Liabilities settled		(110)		(124)
Revisions in estimated cash flows^(a)		64		1,229
Balance at December 31,	$	26,886	$	24,360

(a) In the second quarter of 2015, MGE recorded an obligation of $2.3 million for the fair value of its legal liability for AROs associated with the effect of the final Coal Combustion Residual Rule at Columbia. An additional $1.3 million was recorded in the fourth quarter, associated with this ARO, based on revised estimates.