|                                                                               |   |                     |    |    Twelve |   |  Three             |   |
|------------------------------------------------------------------------------------|--------|--------------------------|---------|--------------------------|--------|-------------------------|--------|
|                                                                               |   |                     |    |  Months             |   |  Months            |   |
|                                                                               |   | Years Ended December 31, |    |    Ended  |   |    Ended |   |
|                                                                               |   | 2006                     |    | 2007                     |   | 2008                    |   |   | 2009 |   |  2010 |   |   3/31/2011 |   |   3/31/2011 |   |
|  EARNINGS                                                                     |   |                |    |                |   |               |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Income Before Income Taxes and Equity Earnings                                |   | $                        | 138,289 |                     | $      | 87,333                  |   | $ | 129,489 |   | $ | 140,035 |   | $ | 208,484 |   | $ |  210,607 |   | $ |  42,643 |   |
| Fixed Charges (as below)                                                           |   |                     | 63,242  |                     |   | 79,435                  |   |   | 119,516 |   |   | 109,146 |   |   | 132,106 |   |   |  136,679 |   |   |  34,592 |   |
| Total Earnings                                                                     |   | $                        | 201,531 |                     | $      | 166,768                 |   | $ | 249,005 |   | $  | 249,181 |   | $ | 340,590 |   | $ |  347,286 |   | $ |  77,235 |   |
|                                                                               |   |                     |    |                     |   |                    |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| FIXED CHARGES                                                                      |   |                     |    |                     |   |                    |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Interest Expense                                                                   |   | $                        | 55,213  |                     | $      | 60,619                  |   | $ | 93,150 |   | $  | 70,500 |   | $ | 86,538 |   | $ |  90,419 |   | $ |  22,425 |   |
| Credit for Allowance for Borrowed Funds    Used During Construction |   |                     | 2,208   |                     |   | 9,795                   |   |   | 19,800 |   |   | 29,546 |   |   | 33,668 |   |   |  34,360 |   |   |  9,192 |   |
| Trust Dividends                                                                    |   |                     | (179    | )                        |   | (179                    | )      |   | (134 | )  |   | - |   |   | - |   |   |  - |   |   |  - |   |
| Estimated Interest Element in Lease Rentals                                        |   |                     | 6,000   |                     |   | 9,200                   |   |   | 6,700 |   |   | 9,100 |   |   | 11,900 |   |   |  11,900 |   |   |  2,975 |   |
| Total Fixed Charges                                                                |   | $                        | 63,242  |                     | $      | 79,435                  |   | $ | 119,516 |   | $  | 109,146 |   | $ | 132,106 |   | $ |  136,679 |   | $ |  34,592 |   |
|                                                                               |   |                     |    |                     |   |                    |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Ratio of Earnings to Fixed Charges                                                 |   |                     | 3.18    |                     |   | 2.09                    |   |   | 2.08 |   |   | 2.28 |   |   | 2.57 |   |   |  2.54 |   |   |  2.23 |   |