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, | ||||||||||||||
| 2007 | 2006 | 2006 | 2005 | 2004 | 2003 | 2002 | |||||||||
| (dollars in millions) | |||||||||||||||
| EARNINGS: | |||||||||||||||
| Net income | $133.6 | $133.7 | $172.4 | $165.1 | $125.7 | $100.7 | $90.9 | ||||||||
| Income taxes (a) | 74.9 | 65.6 | 69.4 | 80.8 | 61.7 | 71.3 | 62.3 | ||||||||
| Income before income taxes | 208.5 | 199.3 | 241.8 | 245.9 | 187.4 | 172.0 | 153.2 | ||||||||
| Fixed charges as defined | 49.6 | 53.9 | 73.3 | 72.5 | 72.3 | 69.4 | 68.1 | ||||||||
| Total earnings as defined | $258.1 | $253.2 | $315.1 | $318.4 | $259.7 | $241.4 | $221.3 | ||||||||
| FIXED CHARGES: | |||||||||||||||
| Interest expense | $48.5 | $52.8 | $71.8 | $67.7 | $67.9 | $65.4 | $63.7 | ||||||||
| Estimated interest component of rent expense | 1.1 | 1.1 | 1.5 | 4.8 | 4.4 | 4.0 | 4.4 | ||||||||
| Total fixed charges as defined | $49.6 | $53.9 | $73.3 | $72.5 | $72.3 | $69.4 | $68.1 | ||||||||
| Ratio of Earnings to Fixed Charges | 5.20 | 4.70 | 4.30 | 4.39 | 3.59 | 3.48 | 3.25 | ||||||||
| Preferred dividend requirements (pre-tax basis) (b) | $17.9 | $17.1 | $21.6 | $22.9 | $23.0 | $23.2 | $4.9 | ||||||||
| Fixed charges and preferred dividend requirements | $67.5 | $71.0 | $94.9 | $95.4 | $95.3 | $92.6 | $73.0 | ||||||||
| Ratio of Earnings to Combined Fixed Charges and | |||||||||||||||
| Preferred Dividend Requirements | 3.82 | 3.57 | 3.32 | 3.34 | 2.73 | 2.61 | 3.03 | ||||||||
(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.