EXHIBIT (12) NORTHWEST NATURAL GAS COMPANY Computation of Ratio of Earnings to Fixed Charges January 1, 1993 - December 31, 1998 ($000) Year Ended December 31 ---------------------------------------------- 1994 1995 1996 1997 1998 ---- ---- ---- ---- ---- Fixed Charges, as defined: Interest on Long-Term Debt $21,921 $23,141 $23,176 $ 24,918 $ 27,567 Other Interest 2,473 2,252 3,448 4,500 4,902 Amortization of Debt Discount and Expense 850 882 865 730 714 Interest Portion of Rentals 1,697 1,764 1,798 2,111 1,986 -------- -------- -------- --------- ------- Total Fixed Charges, as defined $26,941 $28,039 $29,287 $ 32,259 $ 35,169 ======= ======= ======= ======== ======== Earnings, as defined: Net Income $35,461 $38,065 $46,793 $ 43,059 $ 27,301 Taxes on Income 20,473 22,120 27,347 21,106 12,254 Fixed Charges, as above 26,941 28,039 29,287 32,259 35,169 ------- ------- -------- -------- -------- Total Earnings, $82,875 $88,224 $103,427 $ 96,424 $ 74,724 as defined ======= ======= ======== ======== ======== Ratio of Earnings to Fixed Charges 3.08 3.15 3.53 2.99 2.12 ==== ==== ==== ==== ====