EXHIBIT 12 AVISTA CORPORATION Computation of Ratio of Earnings to Fixed Charges and Preferred Dividend Requirements Consolidated (Thousands of Dollars) 12 months ended Years Ended December 31 March 31, ------------------------------------------------------------ 2005 2004 2003 2002 2001 --------- --------- -------- -------- -------- Fixed charges, as defined: Interest expense $ 84,378 $ 84,746 $ 85,013 $ 96,005 $100,180 Amortization of debt expense and premium - net 8,318 8,301 7,972 8,861 5,639 Interest portion of rentals 2,156 2,443 4,452 6,140 5,140 --------- --------- -------- -------- -------- Total fixed charges $ 94,852 $ 95,490 $ 97,437 $111,006 $110,959 ========= ========= ======== ======== ======== Earnings, as defined: Income from continuing operations $ 33,119 $ 35,614 $ 50,643 $ 42,174 $ 68,241 Add (deduct): Income tax expense 19,292 21,592 35,340 34,849 40,585 Total fixed charges above 94,852 95,490 97,437 111,006 110,959 --------- --------- -------- -------- -------- Total earnings $ 147,263 $ 152,696 $183,420 $188,029 $219,785 ========= ========= ======== ======== ======== Ratio of earnings to fixed charges 1.55 1.60 1.88 1.69 1.98 Fixed charges and preferred dividend requirements: Fixed charges above $ 94,852 $ 95,490 $ 97,437 $111,006 $110,959 Preferred dividend requirements (1) -- -- 1,910 4,387 3,878 --------- --------- -------- -------- -------- Total $ 94,852 $ 95,490 $ 99,347 $115,393 $114,837 ========= ========= ======== ======== ======== Ratio of earnings to fixed charges and preferred dividend requirements 1.55 1.60 1.85 1.63 1.91 (1) Preferred dividend requirements have been grossed up to their pre-tax level. Effective July 1, 2003, preferred dividends are included in interest expense with the adoption of SFAS No. 150.