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

 
Years Ended December 31,
 
2012
2011
2010
2009
2008
 
(dollars in millions)
EARNINGS:
 
 
 
 
 
Net income

$150.2


$139.3


$143.4


$153.0


$141.6

Income tax expense (benefit) (a)
(19.8
)
(3.6
)
42.3

27.0

52.6

Income before income taxes
130.4

135.7

185.7

180.0

194.2

Fixed charges as defined
79.3

79.6

83.1

77.5

63.7

Total earnings as defined

$209.7


$215.3


$268.8


$257.5


$257.9

 
 
 
 
 
 
FIXED CHARGES:
 
 
 
 
 
Interest expense

$78.5


$78.7


$82.2


$76.5


$61.9

Estimated interest component of rent expense
0.8

0.9

0.9

1.0

1.8

Total fixed charges as defined

$79.3


$79.6


$83.1


$77.5


$63.7

 
 
 
 
 
 
Ratio of Earnings to Fixed Charges
2.64

2.70

3.23

3.32

4.05

 
 
 
 
 
 
Preferred dividend requirements (pre-tax basis) (b)

$10.9


$14.6


$19.9


$18.1


$21.1

 
 
 
 
 
 
Fixed charges and preferred dividend requirements

$90.2


$94.2


$103.0


$95.6


$84.8

 
 
 
 
 
 
Ratio of Earnings to Combined Fixed Charges and Preferred Dividend Requirements
2.32

2.29

2.61

2.69

3.04


(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 annual effective income tax rate.