Exhibit 12.1 Public Service Company of Oklahoma Consolidated Ratio of Earnings to Fixed Charges For Years Ended June 30, 2001 Twelve Months Ended 06/30/01 2000 1999 1998 1997 1996 -------- ------------------------------------------------- (thousands, except ratios) Operating Income $ 91,591 $ 96,669 $ 98,713 $115,074 $ 82,024 $ 99,738 Adjustments Income Taxes 37,116 10,291 18,562 52,494 12,313 25,257 Provision for Deferred Income Taxes (4,016) 25,453 14,521 (1,651) 8,615 (2,526) Deferred Investment Tax Credits (1,791) (1,791) (1,791) (1,795) (2,278) (2,784) Charges for Investments and Plant Development Costs, Net of Tax - - - - (75) (35,708) Other Income and Deductions 8,015 8,739 745 (951) 729 (95) Allowance for Borrowed and Equity Funds Used During Construction 8,004 4,631 1,636 2,029 2,317 1,722 -------- -------- -------- -------- -------- --------- Earnings $138,919 $143,992 $132,386 $165,200 $103,645 $ 85,604 ======== ======== ======== ======== ======== ======== Fixed Charges: Interest on Long-term Debt $28,902 $26,473 $26,528 $29,136 $30,474 $30,555 Interest on Short-term Debt 11,545 10,902 7,058 4,107 4,100 5,623 Distributions on Trust Preferred Securities 6,000 6,000 6,000 6,000 3,967 - ------- ------- ------- ------- ------- -------- Fixed Charges $46,447 $43,375 $39,586 $39,243 $38,541 $36,178 ======= ======= ======= ======= ======= ======= Ratio of Earnings to Fixed Charges 2.99 3.31 3.34 4.20 2.68 2.36