| Exhibit 12.3                                                                                                                            |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|-----------------------------------------------------------------------------------------------------------------------------------------|--------|-----------------------|--------|--------|----------------------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|
|                                                                                                                                    |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| WISCONSIN 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                                                                                                                              |   | $                     | 63.9   |   |                 | $      | 94.1   |   |   | $      | 118.4  |   |   | $      | 113.5  |   |   | $      | 105.3  |   |   | $ | 105.1 |   |   | $ | 113.7 |   |
| Income taxes (a)                                                                                                                        |   |                  | 31.6   |   |                 |   | 54.1   |   |   |   | 68.4   |   |   |   | 59.3   |   |   |   | 62.2   |   |   |   | 60.9 |   |   |   | 66.3 |   |
| Income before income taxes                                                                                                              |   |                  | 95.5   |   |                 |   | 148.2  |   |   |   | 186.8  |   |   |   | 172.8  |   |   |   | 167.5  |   |   |   | 166.0 |   |   |   | 180.0 |   |
|                                                                                                                                    |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Fixed charges as defined                                                                                                                |   |                  | 77.2   |   |                 |   | 69.0   |   |   |   | 90.7   |   |   |   | 84.8   |   |   |   | 81.9   |   |   |   | 73.9 |   |   |   | 56.6 |   |
|                                                                                                                                    |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Adjustment for undistributed equity earnings                                                                                            |   |                  | (5.2   | )      |                 |   | (4.0   | )      |   |   | (6.1   | )      |   |   | (6.7   | )      |   |   | (3.8   | )      |   |   | (1.6 | ) |   |   | (4.5 | ) |
|                                                                                                                                    |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Total earnings as defined                                                                                                               |   | $                     | 167.5  |   |                 | $      | 213.2  |   |   | $      | 271.4  |   |   | $      | 250.9  |   |   | $      | 245.6  |   |   | $ | 238.3 |   |   | $ | 232.1 |   |
|                                                                                                                                    |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| FIXED CHARGES:                                                                                                                          |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Interest expense                                                                                                                        |   | $                     | 54.6   |   |                 | $      | 44.5   |   |   | $      | 62.2   |   |   | $      | 49.6   |   |   | $      | 48.3   |   |   | $ | 40.4 |   |   | $ | 33.5 |   |
| Estimated interest component of rent expense                                                                                            |   |                  | 22.6   |   |                 |   | 24.5   |   |   |   | 28.5   |   |   |   | 35.2   |   |   |   | 33.6   |   |   |   | 33.5 |   |   |   | 23.1 |   |
| Total fixed charges as defined                                                                                                          |   | $                     | 77.2   |   |                 | $      | 69.0   |   |   | $      | 90.7   |   |   | $      | 84.8   |   |   | $      | 81.9   |   |   | $ | 73.9 |   |   | $ | 56.6 |   |
|                                                                                                                                    |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Ratio of Earnings to Fixed Charges                                                                                                      |   |                  | 2.17   |   |                 |   | 3.09   |   |   |   | 2.99   |   |   |   | 2.96   |   |   |   | 3.00   |   |   |   | 3.22 |   |   |   | 4.10 |   |
|                                                                                                                                    |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Preferred dividend requirements (pre-tax basis) (b)                                                                                     |   | $                     | 3.7    |   |                 | $      | 3.9    |   |   | $      | 5.2    |   |   | $      | 5.0    |   |   | $      | 5.2    |   |   | $ | 5.2 |   |   | $ | 5.2 |   |
|                                                                                                                                    |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Fixed charges and preferred dividend requirements                                                                                       |   | $                     | 80.9   |   |                 | $      | 72.9   |   |   | $      | 95.9   |   |   | $      | 89.8   |   |   | $      | 87.1   |   |   | $ | 79.1 |   |   | $ | 61.8 |   |
|                                                                                                                                    |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Ratio of Earnings to Combined Fixed Charges and                                                                                         |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|    Preferred Dividend Requirements                                                                                       |   |                  | 2.07   |   |                 |   | 2.92   |   |   |   | 2.83   |   |   |   | 2.79   |   |   |   | 2.82   |   |   |   | 3.01 |   |   |   | 3.76 |   |
|                                                                                                                                    |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| (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.                                                                            |   |                  |   |   |                 |   |   |   |   |   |   |   |   |   |   |   |   |