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,
|                                                  |                       |        |                     
|                                                  | 2006                  | 2005   |                     
|                                                  |                       |        |                     
|                                                  | (dollars in millions)
|                                                 
|EARNINGS:                                         |                      
|Net income                                        | $73.2                 | $73.9  |                     
|Income taxes                                      | 44.1                  | 41.8   |                     
|                                                  |                       |        |                     
|Income before income taxes                        | 117.3                 | 115.7  |                     
|Fixed charges as defined                          | 65.5                  | 56.5   |                     
|Adjustment for undistributed equity earnings      | (3.5)                 | (0.5)  |                     
|                                                  |                       |        |                     
|Total earnings as defined                         | $179.3                | $171.7 |                     
|                                                  |                       |        |                     
|                                                 
|FIXED CHARGES:                                   
|Interest expense                                  | $36.3                 | $29.7  |                     
|Estimated interest component of rent expense      | 29.2                  | 26.8   |                     
|                                                  |                       |        |                     
|Total fixed charges as defined                    | $65.5                 | $56.5  |                     
|                                                  |                       |        |                     
|Ratio of Earnings to Fixed Charges (Unaudited)    | 2.74                  | 3.04   |                     
|                                                  |                       |        |                     
|Preferred dividend requirements (pre-tax basis) * | $4.0                  | $3.9   |                     
|                                                  |                       |        |                     
|Fixed charges and preferred dividend requirements | $69.5                 | $60.4  |                     
|                                                  |                       |        |                     
|Ratio of Earnings to Combined Fixed Charges and  
|Preferred Dividend Requirements (Unaudited)       | 2.58                  | 2.84   |                     
|                                                  |                       |        |                     

* 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.