Exhibit 12 Tucson Electric Power Company Computation of Ratio of Earnings to Fixed Charges <Table> 12 Months Ended ---------------------------------------------------------- Dec. 31, Dec. 31, Dec. 31, Dec. 31, Dec. 31, 2003 2002 2001 2000 1999 - ------------------------------------------------------------------------------------------------------ - Thousands of Dollars - Fixed Charges: Interest on Long-Term Debt $ 76,585 $ 65,620 $ 68,678 $ 75,076 $ 78,220 Other Interest (1) 1,820 273 441 211 1,696 Interest on Capital Lease Obligations 84,053 87,783 90,506 92,815 82,414 - ------------------------------------------------------------------------------------------------------ Total Fixed Charges 162,458 153,676 159,625 168,102 162,330 Net Income 128,913 55,390 77,778 52,762 76,371 Less: Extraordinary Income & Accounting Change - Net of Tax 67,471 - 470 - 22,597 - ------------------------------------------------------------------------------------------------------ Net Income from Continuing Operations 61,442 55,390 77,308 52,762 53,774 Add (Deduct): (Income) Losses from Equity Investees (2) (76) 17 700 1,543 - Income Taxes 21,090 36,434 57,545 27,610 24,249 Total Fixed Charges 162,458 153,676 159,625 168,102 162,330 - ------------------------------------------------------------------------------------------------------ Total Earnings before Taxes and Fixed Charges $ 244,914 $ 245,517 $ 295,178 $ 250,017 $ 240,353 ====================================================================================================== Ratio of Earnings to Fixed Charges 1.508 1.598 1.849 1.487 1.481 <fn> (1) Excludes recognition of Allowance for Borrowed Funds Used During Construction. (2) (Income) losses of Truepricing and Inncom. </fn> </table>