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



|                                                                                |  |                             |   |  |                      |   |  |        |   |  |        |   |  |        |   |  |        |   |  |       
|------------------------------------------------------------------------------- |  | --------------------------- | - |  | -------------------- | - |  | ------ | - |  | ------ | - |  | ------ | - |  | ------ | - |  | ------
|                                                                                |  | Three MonthsEnded March 31, |   |  | Years Ended Dec. 31,
|                                                                                |  | 2010                        |   |  | 2009                 |   |  | 2009   |   |  | 2008   |   |  | 2007   |   |  | 2006   |   |  | 2005  
|                                                                                |  | (dollars in millions)      
|EARNINGS:                                                                       |  |                             |   |  |                      |   |  |        |   |  |        |   |  |        |   |  |        |   |  |       
|Net income                                                                      |  | $37.0                       |   |  | $31.3                |   |  | $89.5  |   |  | $118.4 |   |  | $113.5 |   |  | $105.3 |   |  | $105.1
|Income taxes (a)                                                                |  | 25.0                        |   |  | 13.7                 |   |  | 45.8   |   |  | 68.4   |   |  | 59.3   |   |  | 62.2   |   |  | 60.9  
|                                                                                |  |                             |   |  |                      |   |  |       
|Income before income taxes                                                      |  | 62.0                        |   |  | 45.0                 |   |  | 135.3  |   |  | 186.8  |   |  | 172.8  |   |  | 167.5  |   |  | 166.0 
|                                                                                |  |                             |   |  |                      |   | 
|Fixed charges as defined                                                        |  | 22.2                        |   |  | 21.3                 |   |  | 99.9   |   |  | 90.7   |   |  | 84.8   |   |  | 81.9   |   |  | 73.9  
|                                                                                |  |                             |   |  |                      |   | 
|Adjustment for undistributed equity earnings                                    |  | (1.0                        | ) |  | (2.2                 | ) |  | (7.1   | ) |  | (6.1   | ) |  | (6.7   | ) |  | (3.8   | ) |  | (1.6) 
|                                                                                |  |                             |   |  |                      |   |  |       
|                                                                                |  |                             |   |  |                      |   | 
|Total earnings as defined                                                       |  | $83.2                       |   |  | $64.1                |   |  | $228.1 |   |  | $271.4 |   |  | $250.9 |   |  | $245.6 |   |  | $238.3
|                                                                                |  |                             |   |  |                      |   |  |       
|FIXED CHARGES:                                                                  |  |                             |   |  |                      |   |  |        |   |  |        |   |  |        |   |  |        |   |  |       
|Interest expense                                                                |  | $19.8                       |   |  | $17.5                |   |  | $74.8  |   |  | $62.2  |   |  | $49.6  |   |  | $48.3  |   |  | $40.4 
|Estimated interest component of rent expense                                    |  | 2.4                         |   |  | 3.8                  |   |  | 25.1   |   |  | 28.5   |   |  | 35.2   |   |  | 33.6   |   |  | 33.5  
|                                                                                |  |                             |   |  |                      |   |  |       
|Total fixed charges as defined                                                  |  | $22.2                       |   |  | $21.3                |   |  | $99.9  |   |  | $90.7  |   |  | $84.8  |   |  | $81.9  |   |  | $73.9 
|                                                                                |  |                             |   |  |                      |   |  |       
|                                                                                |  |                             |   |  |                      |   | 
|Ratio of Earnings to Fixed Charges                                              |  | 3.75                        |   |  | 3.01                 |   |  | 2.28   |   |  | 2.99   |   |  | 2.96   |   |  | 3.00   |   |  | 3.22  
|                                                                                |  |                             |   |  |                      |   |  |       
|                                                                                |  |                             |   |  |                      |   | 
|Preferred dividend requirements (pre-tax basis) (b)                             |  | $1.3                        |   |  | $1.2                 |   |  | $5.0   |   |  | $5.2   |   |  | $5.0   |   |  | $5.2   |   |  | $5.2  
|                                                                                |  |                             |   |  |                      |   |  |       
|                                                                                |  |                             |   |  |                      |   | 
|Fixed charges and preferred dividend requirements                               |  | $23.5                       |   |  | $22.5                |   |  | $104.9 |   |  | $95.9  |   |  | $89.8  |   |  | $87.1  |   |  | $79.1 
|                                                                                |  |                             |   |  |                      |   |  |       
|                                                                                |  |                             |   |  |                      |   | 
|Ratio of Earnings to Combined Fixed Charges and Preferred Dividend Requirements |  | 3.54                        |   |  | 2.85                 |   |  | 2.17   |   |  | 2.83   |   |  | 2.79   |   |  | 2.82   |   |  | 3.01  
|                                                                                |  |                             |   |  |                      |   |  |       

(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.