| POWER      OF ATTORNEY                                    |
|-----------------------------------------------------------|
| Annual      Report on Form 10-K for the Fiscal Year Ended |
| December      31, 2007                                    |

| Company                                  |   | State of Incorporation |
|------------------------------------------|--------|------------------------|
| Public      Service Company of Oklahoma  |   | Oklahoma               |
| Southwestern      Electric Power Company |   | Delaware               |

| /s/ Nicholas K.      Akins                                                                                                                                                                                                                                                                                                                                                                                               | /s/ Holly K.      Koeppel                                                         |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Nicholas      K. Akins                                                                                                                                                                                                                                                                                                                                                                                                   | Holly      K. Koeppel                                                                                                                                                                                                                                                                                                                                                |
|                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                 |
| /s/ Carl L.      English                                                                 | /s/ Michael G.      Morris                                                        |
| Carl      L. English                                                                                                                                                                                                                                                                                                                                                                                                     | Michael      G. Morris                                                                                                                                                                                                                                                                                                                                               |
|                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                 |
| /s/ Thomas M.      Hagan                                                                                                                                                                                                                                                                                                                                                                                                 | /s/ Stephen P.      Smith                                                         |
| Thomas      M. Hagan                                                                                                                                                                                                                                                                                                                                                                                                     | Stephen      P. Smith                                                                                                                                                                                                                                                                                                                                                |
|                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                 |
| /s/ John B.      Keane                                                                   | /s/ Susan      Tomasky                                                            |
| John      B. Keane                                                                                                                                                                                                                                                                                                                                                                                                       | Susan      Tomasky                                                                                                                                                                                                                                                                                                                                                   |
|                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                 |
|                                                                                                                                                                                                                                                                                                                                                                                                                     | /s/ Dennis E.      Welch                                                                         |
|                                                                                                                                                                                                                                                                                                                                                                                                                     | Dennis      E. Welch                                                                                                                                                                                                                                                                                                                                                 |