Derivative instruments: (Tables)

12 Months Ended

Dec. 31, 2012

Derivative instruments:

Schedule of volume activity of natural gas derivatives that is expected to settle or mature each year

The following table reflects the volume activity of our natural gas derivatives as of December 31, 2012 that is expected to settle or mature each year:

	Natural Gas Swaps
Year	(MMBTUs)
	(in millions)
2013	4.4
2014	1.0
Total	5.4

Schedule of notional amount of forecasted debt issuances hedged in each year with LIBOR swaptions

The following table reflects the notional amount of forecasted debt issuances we have hedged in each year with LIBOR swaptions as of December 31, 2012.

Year		LIBOR Swaption Notional Dollar Amount
		(in thousands)
2013	$	754,452
2014		563,425
2015		470,625
2016		310,533
2017		80,169
Total	$	2,179,204

Schedule of fair value of derivative instruments and their effect on consolidated balance sheets.

	Balance Sheet Location		Fair Value
			2012		2011
			(dollars in thousands)
Designated as hedge:
Liabilities
Natural gas swaps	Other current liabilities	$	–	$	7,220
Not designated as hedge:
Assets
Nuclear decommissioning trust	Nuclear Decommissioning trust fund	$	–	$	(982	)
Interest rate options	Other deferred charges	$	25,783	$	69,446
Liabilities
Natural gas swaps	Other current liabilities	$	1,085	$	–

Schedule of the realized gains and (losses) on derivative instruments recognized in margin

	Consolidated Statement of Revenues and Expenses Location		2012			2011			2010
			(dollars in thousands)
Designated as hedge:
Natural Gas Swaps	Fuel	$	–		$	195		$	–
Natural Gas Swaps	Fuel		–			(4,151	)		(19,734	)
		$	–		$	(3,956	)	$	(19,734	)
Not designated as hedge:
Natural Gas Swaps	Fuel	$	2,338		$	–		$	–
Natural Gas Swaps	Fuel		(10,483	)		–			–
		$	(8,145	)	$	–		$	–

Schedule of unrealized gains and (losses) on derivative instruments deferred on the balance sheet

	Consolidated Balance Sheet Location		2012			2011			2010
Designated as hedge:
Natural Gas Swaps	Accounts receivable	$	–		$	(7,220	)	$	(2,054	)
Total designated as hedge
Not designated as hedge:
Natural Gas Swaps	Regulatory asset	$	(1,085	)	$	–		$	–
Nuclear Decommissioning Trust	Regulatory asset		–			3,602			2,689
Nuclear Decommissioning Trust	Regulatory asset		–			(2,557	)		(2,564	)
Interest Rate Options	Regulatory asset		(74,217	)		(30,554	)		–
Total not designated as hedge		$	(75,302	)	$	(29,509	)	$	125