Regulatory Matters (Tables)

3 Months Ended

Mar. 31, 2012

Regulatory Matters

Components of regulatory assets and liabilities

	March 31, 2012		December 31, 2011
Regulatory Assets:
Under recovered purchased gas costs — gas segment - current	$	224	$	211
Under recovered electric fuel and purchased power costs — current	3,661		7,513
Regulatory assets, current(1)	3,885		7,724
Pension and other postretirement benefits(2)	118,417		121,058
Income taxes	49,330		49,631
Deferred construction accounting costs(3)	17,087		17,095
Unamortized loss on reacquired debt	11,333		11,610
Unsettled derivative losses — electric segment	10,117		7,839
System reliability — vegetation management	7,218		6,569
Storm costs(4)	5,025		5,303
Asset retirement obligation	4,568		3,571
Customer programs	3,718		3,408
Unamortized loss on interest rate derivative	1,383		1,462
Other	696		1,420
Under recovered purchased gas costs — gas segment	627		1,281
Deferred operating and maintenance expense	1,676		1,444
Under recovered electric fuel and purchased power costs	233		231
Regulatory assets, long-term	231,428		231,922
Total Regulatory Assets	$	235,313	$	239,646

	March 31, 2012		December 31, 2011
Regulatory Liabilities:
Costs of removal	75,923		73,562
SWPA payment for Ozark Beach lost generation	24,418		25,074
Income taxes	12,270		12,337
Deferred construction accounting costs — fuel(3)	8,266		8,304
Unamortized gain on interest rate derivative	3,669		3,711
Pension and other postretirement benefits(5)	2,675		2,939
Over recovered electric fuel and purchased power costs	4,446		2,513
Other	—		—
Regulatory liabilities, long-term	131,667		128,440
Total Regulatory Liabilities	$	131,667	$	128,440

(1)  Reflects over and under recovered costs expected to be returned or recovered, as applicable, within the next 12 months in Missouri, Kansas and Oklahoma rates.

(2) Primarily reflects regulatory assets resulting from the unfunded portion of our pension and OPEB liabilities and regulatory accounting for EDG acquisition costs. Approximately $0.1 million in pension and other postretirement benefit costs have been recognized since January 1, 2012 to reflect the amortization of the regulatory assets that were recorded at the time of the EDG acquisition of the Aquila, Inc. gas properties.

(3)  Reflects the deferral of depreciation, operations and maintenance and carrying costs relating to Iatan 1 and Iatan 2 in accordance with our 2005 regulatory plan, as well as Plum Point construction costs incurred subsequent to February 28, 2010. All of these deferrals ended when recovery in rates began and these costs are now being amortized over the life of the plants. The regulatory plan also required us to continue to defer the fuel and purchased power expense impacts of Iatan 2, which are recorded in Non-Current Regulatory Liabilities.

Balances as of March 31, 2012	Deferred Carrying Charges		Deferred O&M	Depreciation	Total
Iatan 1	$	2,715	1,358	1,645	$	5,718
Iatan 2	$	3,873	4,279	2,718	$	10,870
Plum Point	$	65	276	158	$	499
Total					$	17,087

Balances as of December 31, 2011	Deferred Carrying Charges		Deferred O&M	Depreciation	Total
Iatan 1	$	2,728	1,363	1,652	$	5,743
Iatan 2	$	3,891	4,271	2,728	$	10,890
Plum Point	$	65	239	158	$	462
Total					$	17,095

(4)  Reflects ice storm costs incurred in 2007 and costs incurred as a result of the May 2011 tornado.

(5) Includes the effect of costs incurred that are more or less than those allowed in rates for the Missouri (EDE and EDG) and Kansas (EDE) portion of pension and other postretirement benefit costs. Since January 1, 2012, regulatory liabilities and corresponding expenses have been reduced by less than $0.1 million as a result of ratemaking treatment.