Regulatory Assets and Liabilities

NSP-Wisconsin’s consolidated financial statements are prepared in accordance with the applicable accounting guidance, as discussed in Note 1. Under this guidance, regulatory assets and liabilities are created for amounts that regulators may allow to be collected, or may require to be paid back to customers in future electric and natural gas rates. Any portion of the business that is not rate regulated cannot establish regulatory assets and liabilities. If changes in the utility industry or the business of NSP-Wisconsin no longer allow for the application of regulatory accounting guidance under GAAP, NSP-Wisconsin would be required to recognize the write-off of regulatory assets and liabilities in net income or OCI.

The components of regulatory assets shown on the consolidated balance sheets of NSP-Wisconsin at Dec. 31, 2017 and 2016 are:



(Thousands of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2017				Dec. 31, 2016
Regulatory Assets			Current		Noncurrent		Current		Noncurrent
Environmental remediation costs	1, 11	Various	$	16,006	$	136,146	$	10,669	$	148,880
Pension and retiree medical obligations ^(a)	7	Various	5,674		87,505		5,989		93,160
Excess deferred taxes - TCJA	6	Various	—		22,605		—		—
State commission adjustments	1	Plant lives	716		15,932		703		14,008
Recoverable deferred taxes on AFUDC recorded in plant ^(b)	1	Plant lives	—		14,286		—		22,345
Losses on reacquired debt	4	Term of related debt	655		2,678		801		3,333
Other		Various	62		3,065		—		4,462
Total regulatory assets			$	23,113	$	282,217	$	18,162	$	286,188


^(a)	Includes the non-qualified pension plan.


^(b)	Includes a write-down of $11.3 million as a result of the revaluation of deferred tax gross up at the new federal tax rate at Dec. 31, 2017.

The components of regulatory liabilities shown on the consolidated balance sheets of NSP-Wisconsin at Dec. 31, 2017 and 2016 are:



(Thousands of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2017				Dec. 31, 2016
Regulatory Liabilities			Current		Noncurrent		Current		Noncurrent
Excess deferred taxes - TCJA ^(a)	6	Various	$	—	$	236,589	$	—	$	—
Plant removal costs	11	Plant lives	—		146,370		—		139,735
Deferred electric production and natural gas costs	1	Less than one year	13,950		—		11,377		—
DOE settlement	11	Less than one year	5,261		—		4,822		—
Other		Various	1,501		3,848		1,229		8,454
Total regulatory liabilities			$	20,712	$	386,807	$	17,428	$	148,189


^(a)	Primarily relates to the revaluation of recoverable/regulated plant ADIT and $41.0 million revaluation impact of non-plant ADIT at Dec. 31, 2017.