Regulatory Assets and Liabilities

12 Months Ended

Dec. 31, 2019

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory Assets and Liabilities

gulatory 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. NSP-Minnesota would be required to recognize the write-off of regulatory assets and liabilities in net income or other comprehensive income if changes in the utility industry no longer allow for the application of regulatory accounting guidance under GAAP.

Components of regulatory assets:

(Millions of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2019				Dec. 31, 2018
Regulatory Assets			Current		Noncurrent		Current		Noncurrent
Pension and retiree medical obligations	9	Various	$	27.5	$	377.7	$	28.1	$	424.3
Excess deferred taxes — TCJA	7	Various	10.4		132.2		—		153.3
Net AROs (a)	1, 10	Plant lives	—		117.9		—		323.4
Recoverable deferred taxes on AFUDC recorded in plant		Plant lives	—		114.8		—		117.6
Benson biomass PPA termination and asset purchase		Ten years	9.4		72.7		9.8		85.8
Contract valuation adjustments (b)	1, 8	Term of related contract	15.5		62.1		14.1		76.0
Laurentian biomass PPA termination		Five years	19.2		53.9		18.1		73.3
PI extended power update		Sixteen years	3.1		52.6		3.1		55.8
Purchased power contracts costs		Term of related contract	2.7		36.5		2.8		36.6
Nuclear refueling outage costs	1	One to two years	43.3		16.9		36.3		13.5
Sales true-up and revenue decoupling		One to two years	53.8		16.3		38.3		6.7
Losses on reacquired debt		Term of related debt	1.7		13.8		2.1		15.5
Conservation programs (c)	1	One to two years	18.1		13.5		34.5		21.1
Environmental remediation costs	1, 10	Pending future rate cases	1.3		11.8		1.3		14.3
Deferred purchased natural gas and electric energy costs		One to three years	6.2		5.7		5.6		12.6
State commission adjustments		Plant lives	—		3.4		—		3.4
Renewable resources and environmental initiatives		One to two years	72.2		0.6		39.2		0.4
Gas pipeline inspection and remediation costs		Less than one year	26.2		—		27.4		—
Other		Various	9.5		22.6		19.6		20.5
Total regulatory assets			$	320.1	$	1,125.0	$	280.3	$	1,454.1

^(a)  Includes amounts recorded for future recovery of AROs, less amounts recovered through nuclear decommissioning accruals and gains from decommissioning investments.

^(b)  Includes the fair value of certain long-term PPAs used to meet energy capacity requirements and valuation adjustments on natural gas commodity purchases.

^(c)  Includes costs for conservation programs, as well as incentives allowed in certain jurisdictions.

Components of regulatory liabilities:

(Millions of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2019				Dec. 31, 2018
Regulatory Liabilities			Current		Noncurrent		Current		Noncurrent
Deferred income tax adjustments and TCJA refunds (a)	7	Various	$	12.8	$	1,388.9	$	153.7	$	1,465.1
Plant removal costs	1, 10	Plant lives	—		520.3		—		484.6
ITC deferrals (b)	1	Various	—		8.3		—		8.9
DOE Settlement		Less than one year	27.0		—		13.0		—
Deferred electric energy costs		Less than one year	24.2		—		22.8		—
Contract valuation adjustments (c)	1, 8	Less than one year	7.8		—		10.4		—
Renewable resources and environmental initiatives		Less than one year	—		—		8.8		—
Other		Various	69.2		19.6		53.7		26.1
Total regulatory liabilities (d)			$	141.0	$	1,937.1	$	262.4	$	1,984.7

^(a)  Includes the revaluation of recoverable/regulated plant ADIT and revaluation impact of non-plant ADIT due to the TCJA.

^(b)  Includes impact of lower federal tax rate due to the TCJA.

^(c)  Includes the fair value of certain long-term PPAs used to meet energy capacity requirements and valuation adjustments on natural gas commodity purchases.

^(d)  Revenue subject for refund of $23.8 million and $12.5 million for 2019 and 2018, respectively, is included in other current liabilities.

At Dec. 31, 2019 and 2018, NSP-Minnesota’s regulatory assets not earning a return primarily included the unfunded portion of pension and retiree medical obligations, net AROs and Laurentian biomass PPA termination costs/obligations. In addition, regulatory assets included $235.1 million and $190.2 million at Dec. 31, 2019 and 2018, respectively, of past expenditures not earning a return. Amounts primarily related to sales true-up and revenue decoupling, purchased natural gas and electric energy costs, various renewable resources and certain environmental initiatives.