EXHIBIT 12.4 West Texas Utilities Company Ratio of Earnings to Fixed Charges For Years Ended December 31 1996 1995 1994 1993(2) 1992 --------- --------- --------- -------- -------- (thousands, except ratios) Operating income $51,734 $59,486 $54,763 $46,576 $57,302 Adjustments: Income taxes 6,547 6,456 7,900 10,869 12,387 Provision for deferred income taxes 5,718 1,971 8,377 3,593 6,426 Deferred investment tax credits (1,321) (1,321) (1,321) (1,321) (1,515) Reserve for utility plant costs, net of tax (10,946) -- -- -- -- Other income and deductions 601 (463) 4,210 1,907 1,114 Allowance for borrowed and equity funds used during construction 1,276 1,031 474 247 156 ======== ======== ======== ======== ======== Earnings $53,609 $67,160 $74,403 $61,871 $75,870 ======== ======== ======== ======== ======== Fixed charges: Interest on long-term debt $21,169 $21,413 $18,547 $19,225 $21,368 Interest on short-term debt and other 4,925 4,111 3,534 2,988 2,197 ======== ======== ======== ======== ======== Fixed charges $26,094 $25,524 $22,081 $22,213 $23,565 ======== ======== ======== ======== ======== Ratio of earnings to fixed charges 2.05 (1) 2.63 3.37 2.79 (3) 3.22 (1) Earnings in 1996 reflect a $10.9 million one-time charge, net of tax, associated with certain investments for plant sites, engineering studies and lignite reserves. (2) Earnings in 1993 were significantly affected by restructuring charges and the $4 million cumulative effect of changes in accounting principles. (3) The ratio of earnings to fixed charges for 1993 was calculated before cumulative effect of change in accounting principles.