EXHIBIT 12.4 WEST TEXAS UTILITIES COMPANY RATIO OF EARNINGS TO FIXED CHARGES FOR THE TWELVE MONTHS ENDED MARCH 31, 2000 (Thousands Except Ratio) (Unaudited) Operating Income $56,999 Adjustments Income taxes 10,822 Provision for deferred income taxes 7,869 Deferred investment tax credits (1,074) Other income and deductions 1,954 Allowance for borrowed and equity funds used during construction 1,089 ----------- Earnings $77,659 =========== Fixed Charges: Interest on long-term debt $20,352 Interest on short-term debt and other 4,580 ----------- Fixed Charges $24,932 =========== Ratio of Earnings to Fixed Charges 3.11 =========== 77