EXHIBIT 12 NORTHWEST NATURAL GAS COMPANY Computation of Ratio of Earnings to Fixed Charges January 1, 1991 - September 30, 1996 ($000) Twelve Months Year Ended December 31 Ended ------------------------------------------ Sept.30, 1991 1992 1993 1994 1995 1996 ------- ------- ------- ------- ------- -------- Fixed Charges, as defined: Interest on Long- Term Debt $21,977 $23,001 $22,578 $21,921 $23,141 $ 23,136 Other Interest 4,266 3,223 1,906 2,473 2,252 2,528 Amortization of Debt Discount and Expense 348 511 775 850 882 885 Interest Portion of Rentals 1,485 1,439 1,701 1,697 1,764 1,764 ------- ------- ------- ------- ------- ------- Total Fixed Charges, as defined $28,076 $28,174 $26,960 $26,941 $28,039 $28,313 ======= ======= ======= ======= ======= ======= Earnings, as defined: Net Income $14,377 $15,775 $37,647 $35,461 $38,065 $ 48,972 Taxes on Income 2,321 6,951 22,096 20,473 22,120 29,008 Fixed Charges, as above 28,076 28,174 26,960 26,941 28,039 28,313 ------- ------- ------- ------- ------- ------- Total Earnings, as defined $44,774 $50,900 $86,703 $82,875 $88,224 $106,293 ======= ======= ======= ======= ======= ======= Ratio of Earnings to Fixed Charges 1.59 1.81 3.22 3.08 3.15 3.75 ==== ==== ==== ==== ==== ====