**Exhibit        12(a)**

**UniSource          Energy Corporation**

**Computation            of Ratio of Earnings to Fixed Charges**

|                                                                                                      |   | 6                  Months                  Ended |    |   | 12                  Months                  Ended |   |    | 12                  Months                  Ended(2)       |   |
|-----------------------------------------------------------------------------------------------------------|--------|--------------------------------------------------|---------|--------|---------------------------------------------------|--------|---------|------------------------------------------------------------|--------|
|                                                                                                      |   | Jun.                  30                         |    |   | Jun.                  30                          |   |    | Dec.                  31,                                  |   |   | Dec.                  31, |   |   | Dec.                  31, |   |   | Dec.                  31, |   |   | Dec.                  31, |   |
|                                                                                                      |   | 2007                                             |    |   | 2007                                              |   |    | 2006                                                       |   |   | 2005 |   |   | 2004 |   |   | 2003 |   |   | 2002 |   |
|                                                                                                      |   |                                             |    |   |                                              |   |    | -                  Thousands                  of Dollars - |   |
| **Fixed                  Charges:**                                                                       |   |                                             |    |   |                                              |   |    |                                                       |   |   |   |   |   |   |   |   |   |   |   |   |   |
|   Interest                  on Long-Term Debt                                                   |   | $                                                | 36,265  |   |                                              | $      | 74,492  |                                                       |   | $ | 75,039 |   |   | $ | 76,762 |   |   | $ | 80,968 |   |   | $ | 80,844 |   |   | $ | 65,620 |   |
|   Other                  Interest (1)                                                           |   |                                             | 3,412   |   |                                              |   | 8,760   |                                                       |   |   | 7,922 |   |   |   | 3,153 |   |   |   | 1,947 |   |   |   | 3,709 |   |   |   | 2,123 |   |
|   Interest                  on Capital Lease Obligations                                        |   |                                             | 32,278  |   |                                              |   | 67,790  |                                                       |   |   | 72,586 |   |   |   | 79,098 |   |   |   | 85,912 |   |   |   | 84,080 |   |   |   | 87,801 |   |
| **Total                  Fixed Charges**                                                                  |   |                                             | 71,955  |   |                                              |   | 151,042 |                                                       |   |   | 155,547 |   |   |   | 159,013 |   |   |   | 168,827 |   |   |   | 168,633 |   |   |   | 155,544 |   |
|                                                                                                      |   |                                             |    |   |                                              |   |    |                                                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| **Net                  Income**                                                                           |   |                                             | 16,749  |   |                                              |   | 57,376  |                                                       |   |   | 67,447 |   |   |   | 46,144 |   |   |   | 45,919 |   |   |   | 113,941 |   |   |   | 34,928 |   |
|                                                                                                      |   |                                             |    |   |                                              |   |    |                                                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| **Less:**                                                                                                 |   |                                             |    |   |                                              |   |    |                                                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|    Discontinued                  Operations - Net of Tax                                   |   |                                             | -       |   |                                              |   | 873     |                                                       |   |   | (1,796 | ) |   |   | (5,483 | ) |   |   | (5,063 | ) |   |   | (7,472 | ) |   |   | (12,919 | ) |
|    Accounting                  Change - Net of Tax                                         |   |                                             | -       |   |                                              |   | -       |                                                       |   |   | - |   |   |   | (626 | ) |   |   | - |   |   |   | 67,471 |   |   |   | - |   |
| **Net                  Income from Continuing Operations**                                                |   |                                             | 16,749  |   |                                              |   | 56,503  |                                                       |   |   | 69,243 |   |   |   | 52,253 |   |   |   | 50,982 |   |   |   | 53,942 |   |   |   | 47,847 |   |
|                                                                                                      |   |                                             |    |   |                                              |   |    |                                                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| **Add                  (Deduct):**                                                                        |   |                                             |    |   |                                              |   |    |                                                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|   (Income)                  Losses from Equity Investees                                        |   |                                             | 174     |   |                                              |   | (60     | )                                                          |   |   | (210 | ) |   |   | (2,113 | ) |   |   | (7,121 | ) |   |   | 3,051 |   |   |   | 3,047 |   |
|   Income                  Taxes                                                                 |   |                                             | 11,947  |   |                                              |   | 35,072  |                                                       |   |   | 43,936 |   |   |   | 37,623 |   |   |   | 37,186 |   |   |   | 16,531 |   |   |   | 26,432 |   |
|   Total                  Fixed Charges                                                          |   |                                             | 71,955  |   |                                              |   | 151,042 |                                                       |   |   | 155,547 |   |   |   | 159,013 |   |   |   | 168,827 |   |   |   | 168,633 |   |   |   | 155,544 |   |
|                                                                                                      |   |                                             |    |   |                                              |   |    |                                                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| **Total                    Earnings before Taxesand                    Fixed                    Charges** |   | $                                                | 100,825 |   |                                              | $      | 242,557 |                                                       |   | $ | 268,516 |   |   | $ | 246,776 |   |   | $ | 249,874 |   |   | $ | 242,157 |   |   | $ | 232,870 |   |
|                                                                                                      |   |                                             |    |   |                                              |   |    |                                                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                                                                                      |   |                                             |    |   |                                              |   |    |                                                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| **Ratio                  of Earnings to Fixed Charges**                                                   |   |                                             | 1.401   |   |                                              |   | 1.606   |                                                       |   |   | 1.726 |   |   |   | 1.552 |   |   |   | 1.480 |   |   |   | 1.436 |   |   |   | 1.497 |   |
|                                                                                                      |   |                                             |    |   |                                              |   |    |                                                       |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |