Exhibit 12.2
INTERSTATE POWER AND LIGHT COMPANY
RATIO OF EARNINGS TO FIXED CHARGES AND RATIO OF EARNINGS TO COMBINED FIXED CHARGES
AND PREFERRED DIVIDEND REQUIREMENTS
	Nine Months
	Ended Sep. 30,				Years Ended Dec. 31,
	2009		2008		2008		2007		2006		2005		2004
	(dollars in millions)
EARNINGS:
Net income	$	133.9	$	112.8	$	141.6	$	290.3	$	172.4	$	165.1	$	125.7
Income taxes (a)		16.7		46.9		52.6		186.8		69.4		80.8		61.7
Income before income taxes		150.6		159.7		194.2		477.1		241.8		245.9		187.4
Fixed charges as defined		57.2		45.7		63.7		65.8		73.3		72.5		72.3
Total earnings as defined	$	207.8	$	205.4	$	257.9	$	542.9	$	315.1	$	318.4	$	259.7
FIXED CHARGES:
Interest expense	$	56.4	$	44.2	$	61.9	$	64.3	$	71.8	$	67.7	$	67.9
Estimated interest component of rent expense		0.8		1.5		1.8		1.5		1.5		4.8		4.4
Total fixed charges as defined	$	57.2	$	45.7	$	63.7	$	65.8	$	73.3	$	72.5	$	72.3
Ratio of Earnings to Fixed Charges		3.63		4.49		4.05		8.25		4.30		4.39		3.59
Preferred dividend requirements (pre-tax basis) (b)	$	12.9	$	16.3	$	21.1	$	25.3	$	21.6	$	22.9	$	23.0
Fixed charges and preferred dividend requirements	$	70.1	$	62.0	$	84.8	$	91.1	$	94.9	$	95.4	$	95.3
Ratio of Earnings to Combined Fixed Charges and
Preferred Dividend Requirements		2.96		3.31		3.04		5.96		3.32		3.34		2.73
(a) Includes net interest related to unrecognized tax benefits.
(b) Preferred dividend requirements (pre-tax basis) are computed by dividing the preferred dividend requirements by one hundred percent minus the
respective year-to-date effective income tax rate.