EXHIBIT 12.2 PUBLIC SERVICE COMPANY OF OKLAHOMA (CONSOLIDATED) RATIO OF EARNINGS TO FIXED CHARGES FOR THE TWELVE MONTHS ENDED MARCH 31, 2000 (Thousands Except Ratio) (Unaudited) Operating Income $98,653 Adjustments Income taxes 14,133 Provision for deferred income taxes 19,178 Deferred investment tax credits (1,791) Other income and deductions 1,570 Allowance for borrowed and equity funds used during construction 1,990 ----------- Earnings $133,733 =========== Fixed Charges: Interest on long-term debt $26,444 Interest on short-term debt and other 8,406 Distributions on Trust Preferred Securities 6,000 ----------- Fixed Charges $40,850 =========== Ratio of Earnings to Fixed Charges 3.27 =========== 75