EXHIBIT 12 NORTHWEST NATURAL GAS COMPANY Computation of Ratio of Earnings to Fixed Charges January 1, 1993 - September 30, 1998 Twelve Months Ended Year Ended December 31, Sept 30, ---------------------------------------------------- 1993 1994 1995 1996 1997 1998 ---------------------------------------------------------------- Fixed Charges, as Defined: Interest on Long- Term Debt ...................... $ 22,578 $ 21,921 $ 23,141 $ 23,176 $ 24,918 $ 27,366 Other Interest .................. 1,906 2,473 2,252 3,448 4,500 4,986 Amortization of Debt Discount and Expense ........... 775 850 882 865 730 698 Interest Portion of Rentals ...................... 1,701 1,697 1,764 1,798 2,111 2,111 -------- -------- -------- -------- -------- -------- Total Fixed Charges, as defined .................... $ 26,960 $ 26,941 $ 28,039 $ 29,287 $ 32,259 $ 35,161 ======== ======== ======== ======== ======== ======== Earnings, as defined: Net Income ...................... $ 37,647 $ 35,461 $ 38,065 $ 46,793 $ 43,059 $ 39,753 Taxes on Income ................. 22,096 20,473 22,120 27,347 21,106 17,699 Fixed Charges, as above ..................... 26,960 26,941 28,039 29,287 32,259 35,161 -------- -------- -------- -------- -------- -------- Total Earnings, as defined ................... $ 86,703 $ 82,875 $ 88,224 $103,427 $ 96,424 $ 92,613 ======== ======== ======== ======== ======== ======== Ratio of Earnings to Fixed Charges ....................... 3.22 3.08 3.15 3.53 2.99 2.63 ======== ======== ======== ======== ======== ========