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                                   PACIFICORP
                            (AN OREGON CORPORATION)
 
                                       TO
 
                            THE CHASE MANHATTAN BANK
                            (A NEW YORK CORPORATION)
                       (FORMERLY KNOWN AS CHEMICAL BANK)
 
                                AS TRUSTEE UNDER PACIFICORP'S
                                  MORTGAGE AND DEED OF TRUST,
                                  DATED AS OF JANUARY 9, 1989
 
                             ---------------------
 
                         Twelfth Supplemental Indenture
                         DATED AS OF SEPTEMBER 1, 1996
 
            SUPPLEMENTAL TO PACIFICORP'S MORTGAGE AND DEED OF TRUST
                          DATED AS OF JANUARY 9, 1989
 
                             ---------------------
 
      THIS INSTRUMENT GRANTS A SECURITY INTEREST BY A TRANSMITTING UTILITY
          THIS INSTRUMENT CONTAINS AFTER-ACQUIRED PROPERTY PROVISIONS
 
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                         TWELFTH SUPPLEMENTAL INDENTURE
 
    THIS INDENTURE, dated as of the 1st day of September, 1996, made and entered
into by and between PACIFICORP, a corporation of the State of Oregon, whose
address is 700 NE Multnomah, Portland, Oregon 97232 (hereinafter sometimes
called the "Company"), and THE CHASE MANHATTAN BANK (formerly known as Chemical
Bank), a New York corporation whose address is 450 West 33rd Street, New York,
New York 10001 (the "Trustee"), as Trustee under the Mortgage and Deed of Trust,
dated as of January 9, 1989, as heretofore amended and supplemented (hereinafter
called the "Mortgage"), is executed and delivered by PacifiCorp in accordance
with the provisions of the Mortgage, this indenture (hereinafter called the
"Twelfth Supplemental Indenture") being supplemental thereto.
 
    WHEREAS, the Mortgage was or is to be recorded in the official records of
the States of Arizona, California, Colorado, Idaho, Montana, New Mexico, Oregon,
Utah, Washington and Wyoming and various counties within such states, which
counties include or will include all counties in which this Twelfth Supplemental
Indenture is to be recorded; and
 
    WHEREAS, by the Mortgage the Company covenanted that it would execute and
deliver such supplemental indenture or indentures and such further instruments
and do such further acts as might be necessary or proper to carry out more
effectually the purposes of the Mortgage and to make subject to the Lien of the
Mortgage any property thereafter acquired, made or constructed and intended to
be subject to the Lien thereof; and
 
    WHEREAS, in addition to the property described in the Mortgage, the Company
has acquired certain other property, rights and interests in property; and
 
    WHEREAS, the Company has executed, delivered, recorded and filed
Supplemental Indentures as follows:


                    DATED AS OF                              DATED AS OF
             --------------------------               --------------------------
                                             
First        March 31, 1989              Seventh      March 15, 1993
Second       December 29, 1989           Eighth       November 1, 1993
Third        March 31, 1991              Ninth        June 1, 1994
Fourth       December 31, 1991           Tenth        August 1, 1994, and
Fifth        March 15, 1992              Eleventh     December 1, 1995;
Sixth        July 31, 1992

 
and

                                       2
 
    WHEREAS, the Company has heretofore issued, in accordance with the
provisions of the Mortgage, bonds entitled and designated First Mortgage and
Collateral Trust Bonds, of the series and in the principal amounts as follows:
 


                                                                AGGREGATE         AGGREGATE
                                                             PRINCIPAL AMOUNT  PRINCIPAL AMOUNT
                          SERIES                DUE DATE          ISSUED         OUTSTANDING
               -----------------------------  -------------  ----------------  ----------------
                                                                   
First          --10.45%                          1/9/90       $      500,000                 0
Second         --Medium-Term Notes, Series A     various         250,000,000    $  240,000,000
Third          --Medium-Term Notes, Series B     various         200,000,000       138,500,000
Fourth         --Medium-Term Notes, Series C     various         300,000,000       253,705,118
Fifth          --Medium-Term Notes, Series D     various         250,000,000       250,000,000
Sixth          --C-U                             various         250,432,000       185,288,000
Seventh        --Medium-Term Notes, Series E     various         500,000,000       500,000,000
Eighth         --6 3/4%                         4/1/2005         150,000,000       150,000,000
Ninth          --Medium-Term Notes, Series F     various         500,000,000       500,000,000
Tenth          --E-L                             various          71,200,000        71,200,000
Eleventh       --Medium-Term Notes, Series G     various         500,000,000       300,000,000
Twelfth        --1994-1                          various         216,470,000       216,470,000
Thirteenth     --Adjustable Rate Replacement      2002            13,234,000        13,234,000
                Series
Fourteenth     --9 3/8% Replacement Series        1997            50,000,000        50,000,000
Fifteenth      --Bond Credit Series              various         498,589,753                 0;

 
and
 
    WHEREAS, Section 2.03 of the Mortgage provides that the form or forms, terms
and conditions of and other matters not inconsistent with the provisions of the
Mortgage, in connection with each series of bonds (other than the First Series)
issued thereunder, shall be established in or pursuant to one or more
Resolutions and/or shall be established in one or more indentures supplemental
to the Mortgage, prior to the initial issuance of bonds of such series; and

                                       3
 
    WHEREAS, Section 22.04 of the Mortgage provides, among other things, that
any power, privilege or right expressly or impliedly reserved to or in any way
conferred upon the Company by any provision of the Mortgage, whether such power,
privilege or right is in any way restricted or is unrestricted, may be in whole
or in part waived or surrendered or subjected to any restriction if at the time
unrestricted or to additional restriction if already restricted, and the Company
may enter into any further covenants, limitations, restrictions or provisions
for the benefit of any one or more series of bonds issued thereunder and provide
that a breach thereof shall be equivalent to a Default under the Mortgage, or
the Company may cure any ambiguity contained therein, or in any supplemental
indenture, or may (in lieu of establishment in or pursuant to Resolution in
accordance with Section 2.03 of the Mortgage) establish the forms, terms and
provisions of any series of bonds other than said First Series, by an instrument
in writing executed by the Company; and
 
    WHEREAS, no Class "A" Bonds are Outstanding under either the Pacific
Mortgage or the Utah Mortgage, and said Pacific Mortgage and said Utah Mortgage
have been cancelled and discharged; and
 
    WHEREAS, said Pacific Mortgage and said Utah Mortgage no longer constitute
liens upon the properties of the Company described therein; and the Lien hereof
is now a lien on all of the properties of the Company intended to be subject to
the Lien hereof which were previously subject to the liens of said Pacific
Mortgage and said Utah Mortgage, free of any lien prior or equal to the Lien
hereof except Qualified Liens and Excepted Encumbrances; and
 
    WHEREAS, the properties of the Company that were previously subject to the
liens of said Pacific Mortgage and said Utah Mortgage were more specifically
described in the Pacific Mortgage and the Utah Mortgage, and in indentures
supplemental thereto, which such descriptions are incorporated herein by
reference to the dates and places at which such instruments were recorded and
filed, as listed in Exhibit A and/or Exhibit 1 attached hereto and by this
reference made a part hereof; and
 
    WHEREAS, the Company now desires to create a new series of bonds and
(pursuant to the provisions of Section 22.04 of the Mortgage) to add to its
covenants and agreements contained in the Mortgage certain other covenants and
agreements to be observed by it; and

                                       4
 
    WHEREAS, the execution and delivery by the Company of this Twelfth
Supplemental Indenture, and the terms of the bonds of the Sixteenth Series
herein referred to, have been duly authorized by the Board of Directors in or
pursuant to appropriate Resolutions;
 
    NOW, THEREFORE, THIS INDENTURE WITNESSETH:
 
    That PACIFICORP, an Oregon corporation, in consideration of the premises and
of good and valuable consideration to it duly paid by the Trustee at or before
the ensealing and delivery of these presents, the receipt and sufficiency
whereof is hereby acknowledged, and in order to secure the payment of both the
principal of and interest and premium, if any, on the bonds from time to time
issued under the Mortgage, according to their tenor and effect and the
performance of all provisions of the Mortgage (including any instruments
supplemental thereto and any modification made as in the Mortgage provided) and
of such bonds, and to confirm the Lien of the Mortgage on certain after-acquired
property, hereby mortgages, pledges and grants a security interest in (subject,
however, to Excepted Encumbrances as defined in Section 1.06 of the Mortgage),
unto The Chase Manhattan Bank, as Trustee, and to its successor or successors in
said trust, and to said Trustee and its successors and assigns forever, all
properties of the Company real, personal and mixed, owned by the Company as of
the date of the Mortgage and acquired by the Company after the date of the
Mortgage, subject to the provisions of Section 18.03 of the Mortgage, of any
kind or nature (except any herein or in the Mortgage expressly excepted), now
owned or, subject to the provisions of Section 18.03 of the Mortgage, hereafter
acquired by the Company (by purchase, consolidation, merger, donation,
construction, erection or in any other way) and wheresoever situated, including
the properties described in Article V hereof and the properties described in the
documents to which reference is made in Exhibits A and/or 1 hereto (except such
of such properties as had previously been released from the liens of the Pacific
Mortgage or the Utah Mortgage and except such of such properties as are excluded
by name or nature from the Lien hereof), and further including (without
limitation) all real estate, lands, easements, servitudes, licenses, permits,
franchises, privileges, rights of way and other rights in or relating to real
estate or the occupancy of the same; all power sites, flowage rights, water

                                       5
 
rights, water locations, water appropriations, ditches, flumes, reservoirs,
reservoir sites, canals, raceways, waterways, dams, dam sites, aqueducts, and
all other rights or means for appropriating, conveying, storing and supplying
water; all rights of way and roads; all plants for the generation of electricity
and other forms of energy (whether now known or hereafter developed) by steam,
water, sunlight, chemical processes and/or (without limitation) all other
sources of power (whether now known or hereafter developed); all power houses,
gas plants, street lighting systems, standards and other equipment incidental
thereto; all telephone, radio, television and other communications, image and
data transmission systems, air-conditioning systems and equipment incidental
thereto, water wheels, water works, water systems, steam and hot water plants,
substations, lines, service and supply systems, bridges, culverts, tracks, ice
or refrigeration plants and equipment, offices, buildings and other structures
and the equipment thereof; all machinery, engines, boilers, dynamos, turbines,
electric, gas and other machines, prime movers, regulators, meters,
transformers, generators (including, but not limited to, engine-driven
generators and turbogenerator units), motors, electrical, gas and mechanical
appliances, conduits, cables, water, steam, gas or other pipes, gas mains and
pipes, service pipes, fittings, valves and connections, pole and transmission
lines, towers, overhead conductors and devices, underground conduits,
underground conductors and devices, wires, cables, tools, implements, apparatus,
storage battery equipment and all other fixtures and personalty; all municipal
and other franchises, consents or permits; all lines for the transmission and
distribution of electric current and other forms of energy, gas, steam, water or
communications, images and data for any purpose including towers, poles, wires,
cables, pipes, conduits, ducts and all apparatus for use in connection therewith
and (except as herein or in the Mortgage expressly excepted) all the right,
title and interest of the Company in and to all other property of any kind or
nature appertaining to and/or used and/or occupied and/or enjoyed in connection
with any property hereinbefore described;
 
    TOGETHER WITH all and singular the tenements, hereditaments, prescriptions,
servitudes and appurtenances belonging or in anywise appertaining to the
aforesaid property or any part thereof, with the reversion and reversions,
remainder and remainders and (subject to the provisions of Section 13.01 of the
Mortgage) the tolls, rents, revenues, issues, earnings, income,

                                       6
 
product and profits thereof, and all the estate, right, title and interest and
claim whatsoever, at law as well as in equity, which the Company now has or may
hereafter acquire in and to the aforesaid property and franchises and every part
and parcel thereof.
 
    IT IS HEREBY AGREED by the Company that, subject to the provisions of
Section 18.03 of the Mortgage, all the property, rights and franchises acquired
by the Company (by purchase, consolidation, merger, donation, construction,
erection or in any other way) after the date hereof, except any herein or in the
Mortgage expressly excepted, shall be and are as fully mortgaged and pledged
hereby and as fully embraced within the Lien of the Mortgage as if such
property, rights and franchises were now owned by the Company and were
specifically described herein or in the Mortgage and mortgaged hereby or
thereby.
 
    PROVIDED THAT the following are not and are not intended to be now or
hereafter mortgaged or pledged hereunder, nor is a security interest therein
hereby granted or intended to be granted, and the same are hereby expressly
excepted from the Lien and operation of the Mortgage, namely: (1) cash, shares
of stock, bonds, notes and other obligations and other securities not hereafter
specifically pledged, paid, deposited, delivered or held under the Mortgage or
covenanted so to be; (2) merchandise, equipment, apparatus, materials or
supplies held for the purpose of sale or other disposition in the usual course
of business or for the purpose of repairing or replacing (in whole or part) any
rolling stock, buses, motor coaches, automobiles or other vehicles or aircraft
or boats, ships or other vessels, and any fuel, oil and similar materials and
supplies consumable in the operation of any of the properties of the Company;
rolling stock, buses, motor coaches, automobiles and other vehicles and all
aircraft; boats, ships and other vessels; all crops (both growing and
harvested), timber (both growing and harvested), minerals (both in place and
severed), and mineral rights and royalties; (3) bills, notes and other
instruments and accounts receivable, judgments, demands, general intangibles and
choses in action, and all contracts, leases and operating agreements not
specifically pledged under the Mortgage or covenanted so to be; (4) the last day
of the term of any lease or leasehold which may be or become subject to the Lien
of the Mortgage; (5) electric energy, gas, water, steam, ice and other
materials, forms of energy or products generated, manufactured,

                                       7
 
produced or purchased by the Company for sale, distribution or use in the
ordinary course of its business; (6) any natural gas wells or natural gas leases
or natural gas transportation lines or other works or property used primarily
and principally in the production of natural gas or its transportation,
primarily for the purpose of sale to natural gas customers or to a natural gas
distribution or pipeline company, up to the point of connection with any
distribution system; (7) the Company's franchise to be a corporation; (8) any
interest (as lessee, owner or otherwise) in the Wyodak Facility, including,
without limitation, any equipment, parts, improvements, substitutions,
replacements or other property relating thereto; and (9) any property heretofore
released pursuant to any provision of the Mortgage and not heretofore disposed
of by the Company; provided, however, that the property and rights expressly
excepted from the Lien and operation of the Mortgage in the above subdivisions
(2) and (3) shall (to the extent permitted by law) cease to be so excepted in
the event and as of the date that the Trustee or a receiver for the Trustee
shall enter upon and take possession of the Mortgaged and Pledged Property in
the manner provided in Article XV of the Mortgage by reason of the occurrence of
a Default;
 
    AND PROVIDED FURTHER, that as to any property of the Company that, pursuant
to the after-acquired property provisions thereof, is now or hereafter becomes
subject to the lien of a mortgage, deed of trust or similar indenture that may
in accordance with the Mortgage hereafter become designated as a Class "A"
Mortgage, the Lien hereof shall at all times be junior and subordinate to the
lien of such Class "A" Mortgage;
 
    TO HAVE AND TO HOLD all such properties, real, personal and mixed, mortgaged
and pledged, or in which a security interest has been granted by the Company as
aforesaid, or intended so to be (subject, however, to Excepted Encumbrances as
defined in Section 1.06 of the Mortgage), unto The Chase Manhattan Bank, as
Trustee, and its successors and assigns forever;
 
    IN TRUST NEVERTHELESS, for the same purposes and upon the same terms, trusts
and conditions and subject to and with the same provisos and covenants as are
set forth in the Mortgage, this Twelfth Supplemental Indenture being
supplemental to the Mortgage;
 
    AND IT IS HEREBY COVENANTED by the Company that all the terms, conditions,
provisos, covenants and provisions contained in the Mortgage

                                       8
 
shall affect and apply to the property hereinbefore described and conveyed, and
to the estates, rights, obligations and duties of the Company and the Trustee
and the beneficiaries of the trust with respect to said property, and to the
Trustee and its successor or successors in the trust, in the same manner and
with the same effect as if the said property had been owned by the Company at
the time of the execution of the Mortgage, and had been specifically and at
length described in and conveyed to said Trustee by the Mortgage as a part of
the property therein stated to be conveyed.
 
    The Company further covenants and agrees to and with the Trustee and its
successor or successors in such trust under the Mortgage, as follows:
 
                                   ARTICLE I
 
                           SIXTEENTH SERIES OF BONDS
 
    SECTION 1.01. There shall be a series of bonds designated "Secured
Medium-Term Notes, Series H" (herein sometimes referred to as the Sixteenth
Series), each of which shall also bear the descriptive title "First Mortgage
Bond," and the form thereof, which shall be established by or pursuant to a
Resolution, shall contain suitable provisions with respect to the matters
hereinafter in this Section specified.
 
    (I)  Bonds of the Sixteenth Series shall mature on such date or dates nine
months or more from the date of issue as shall be set forth in or determined in
accordance with a Resolution filed with the Trustee and, unless otherwise
established by or pursuant to a Resolution, shall be issued as fully registered
bonds in the denomination of One Thousand Dollars and, at the option of the
Company, of any multiple or multiples of One Thousand Dollars (the exercise of
such option to be evidenced by the execution and delivery thereof).
 
    The Company reserves the right to establish, at any time, by or pursuant to
a Resolution filed with the Trustee, a form of coupon bond, and or appurtenant
coupons, for the Sixteenth Series and to provide for exchangeability of such
coupon bonds with the bonds of the Sixteenth Series issued hereunder in fully
registered form and to make all appropriate provisions for such purpose.

                                       9
 
    (II)  Bonds of the Sixteenth Series shall bear interest at such rate or
rates (which may either be fixed or variable), payable on such dates, and have
such other terms and provisions not inconsistent with the Mortgage as may be set
forth in or determined in accordance with a Resolution filed with the Trustee.
Bonds of the Sixteenth Series shall be dated and shall accrue interest as
provided in Section 2.06 of the Mortgage.
 
    Interest payable on any bond of the Sixteenth Series and punctually paid or
duly provided for on any interest payment date for such bond will be paid to the
person in whose name the bond is registered at the close of business on the
Record Date (as hereinafter specified) for such bond next preceding such
interest payment date; provided, however, that the first payment of interest on
any bond with an Issue Date (as hereinafter specified) between a Record Date and
an interest payment date will be made on the interest payment date following the
next succeeding Record Date to the registered owner on such next Record Date
(unless the Company elects, in its sole discretion, to pay such interest on the
first interest payment date after the Issue Date, in which case such interest
will be paid to the person in whose name the bond is originally issued),
provided, further, that interest payable at maturity or upon earlier redemption
will be payable to the person to whom principal shall be payable. The "Record
Date" with respect to bonds of the Sixteenth Series of a designated interest
rate and maturity shall be determined by or in accordance with the Resolution
filed with the Trustee. "Issue Date" with respect to bonds of the Sixteenth
Series of a designated interest rate and maturity shall mean the date of first
authentication of bonds of such designated interest rate and maturity.
 
    Any interest on any bond of the Sixteenth Series which is payable but is not
punctually paid or duly provided for, on any interest payment date for such bond
(herein called "Defaulted Interest"), shall forthwith cease to be payable to the
registered owner on the relevant Record Date for the payment of such interest
solely by virtue of such owner having been such owner; and such Defaulted
Interest may be paid by the Company, at its election in each case, as provided
in subsection (i) or (ii) below:
 
            (i)  The Company may elect to make payment of any Defaulted Interest
        on the bonds of the Sixteenth Series to the persons in whose names such
        bonds are registered at the close of business on

                                       10
 
        a Special Record Date (as hereinafter defined) for the payment of such
        Defaulted Interest, which shall be fixed in the following manner: The
        Company shall, at least 30 days prior to the proposed date of payment,
        notify the Trustee in writing (signed by an Authorized Financial Officer
        of the Company) of the amount of Defaulted Interest proposed to be paid
        on each bond of the Sixteenth Series and the date of the proposed
        payment (which date shall be such as will enable the Trustee to comply
        with the next sentence hereof), and at the same time the Company shall
        deposit with the Trustee an amount of money equal to the aggregate
        amount proposed to be paid in respect of such Defaulted Interest or
        shall make arrangements satisfactory to the Trustee for such deposit on
        or prior to the date of the proposed payment, such money when deposited
        to be held in trust for the benefit of the persons entitled to such
        Defaulted Interest as in this subsection provided and not to be deemed
        part of the Mortgaged and Pledged Property. Thereupon, the Trustee shall
        fix a record date (herein referred to as a "Special Record Date") for
        the payment of such Defaulted Interest which date shall be not more than
        15 nor less than 10 days prior to the date of the proposed payment and
        not less than 10 days after the receipt by the Trustee of the notice of
        the proposed payment. The Trustee shall promptly notify the Company of
        such Special Record Date and, in the name and at the expense of the
        Company, shall cause notice of the proposed payment of such Defaulted
        Interest and the Special Record Date therefor to be mailed, first-class
        postage prepaid, to each registered owner of a bond of the Sixteenth
        Series at his, her or its address as it appears in the bond register not
        less than 10 days prior to such Special Record Date. Notice of the
        proposed payment of such Defaulted Interest and the Special Record Date
        therefor having been mailed as aforesaid, such Defaulted Interest shall
        be paid to the persons in whose names the bonds of the Sixteenth Series
        are registered at the close of business on such Special Record Date and
        shall no longer be payable pursuant to the following subsection (ii).
 
            (ii)  The Company may make payment of any Defaulted Interest on the
        bonds of the Sixteenth Series in any other lawful manner not
        inconsistent with the requirements of any securities exchange on

                                       11
 
        which such bonds may be listed and upon such notice as may be required
        by such exchange, if, after notice given by the Company to the Trustee
        of the proposed payment pursuant to this subsection, such payment shall
        be deemed practicable by the Trustee.
 
    Subject to the foregoing provisions of this Section, each bond of the
Sixteenth Series delivered under the Mortgage upon transfer of or in exchange
for or in lieu of any other bond shall carry all rights to interest accrued and
unpaid, and to accrue, which were carried by such other bond and each such bond
shall bear interest from such date, that neither gain nor loss in interest shall
result from such transfer exchange or substitution.
 
    (III)  The principal of and interest on each bond of the Sixteenth Series
shall be payable at the office or agency of the Company in the Borough of
Manhattan, The City of New York, in such coin or currency of the United States
of America as at the time of payment is legal tender for public and private
debts or in such other currency or currency unit as shall be determined by or in
accordance with the Resolution filed with the Trustee.
 
    (IV)  Each bond of the Sixteenth Series may be redeemable prior to maturity
at the option of the Company, as determined by or in accordance with a
Resolution filed with the Trustee.
 
    (V)  Each bond of the Sixteenth Series may be subject to the obligation of
the Company to redeem such bond, as determined by or in accordance with a
Resolution filed with the Trustee.
 
    (VI)  Each bond of the Sixteenth Series may have such other terms as are not
inconsistent with Section 2.03 of the Mortgage, including, without limitation,
terms and conditions regarding interest rates and the payment thereof, place or
places for payment, exchange privileges, rights with respect to redemption,
prepayment or purchase, and default provisions, and as may be determined by or
in accordance with a Resolution filed with the Trustee.
 
    (VII)  At the option of the registered owner, any bonds of the Sixteenth
Series, upon surrender thereof for cancellation at the office or agency of the
Company in the Borough of Manhattan, The City of New York, shall be exchangeable
for a like aggregate principal amount of bonds of the same series and same terms
of other authorized denominations.

                                       12
 
    (VIII)  Bonds of the Sixteenth Series shall be transferable, subject to any
restrictions thereon set forth in any such bond of the Sixteenth Series, upon
the surrender therefor for cancellation, together with a written instrument of
transfer in form approved by the registrar duly executed by the registered owner
or by his duly authorized attorney, at the office or agency of the Company in
the Borough of Manhattan, The City of New York. Upon any transfer or exchange of
bonds of the Sixteenth Series, the Company may make a charge therefor sufficient
to reimburse it for any tax or taxes or other government charge, as provided in
Section 2.08 of the Mortgage, but the Company hereby waives any right to make a
charge in addition thereto for any exchange or transfer of bonds of the
Sixteenth Series.
 
    (IX)  After the execution and delivery of this Twelfth Supplemental
Indenture and upon compliance with the applicable provisions of the Mortgage and
this Twelfth Supplemental Indenture, it is contemplated that there shall be
issued from time to time bonds of the Sixteenth Series in an aggregate principal
amount not to exceed Five Hundred Million Dollars (U.S. $500,000,000).
 
                                   ARTICLE II
 
                    AMENDMENT OF ARTICLE II OF THE MORTGAGE
 
    SECTION 2.01. Article II of the Mortgage is hereby amended to add a Section
2.16 which shall read as follows:
 
            "Section 2.16.  Notwithstanding anything herein to the contrary, if
        the Company shall establish in accordance with Section 2.03 that bonds
        of a particular series are to be issued as a Global Security, then the
        Company shall execute and the Trustee shall, in accordance with Articles
        IV, V, VI, and VII, as applicable, authenticate and deliver a Global
        Security that (i) shall represent, and shall be denominated in an amount
        equal to the aggregate principal amount of, all or a portion of the
        Outstanding bonds of that series, (ii) shall be registered in the name
        of the Depository or its nominee, (iii) shall be delivered by the
        Trustee to the Depository or pursuant to the Depository's instruction
        and (iv) shall bear a legend substantially to the following effect:
        "Except as otherwise provided in Section 2.16 of

                                       13
 
        the Mortgage, this bond may be transferred, in whole but not in part,
        only to the Depository, another nominee of the Depository or to a
        successor Depository or to a nominee of such successor Depository." The
        term "Global Security" means, with respect to any series of bonds, a
        bond executed and delivered by the Company and delivered by the Trustee
        to the Depository or pursuant to the Depository's instruction, all in
        accordance with the Mortgage, which shall be registered in the name of
        the Depository or its nominee. The term "Depository" means, with respect
        to any series of bonds for which the Company shall determine that such
        bonds will be issued as a Global Security, The Depository Trust Company,
        New York, New York, another clearing agency or any successor registered
        as a clearing agency under the Securities Exchange Act of 1934, as
        amended, or other applicable statute or regulation, which in each case
        shall be designated by the Company pursuant to Section 2.03 or this
        Section 2.16. Except as set forth below in Section 2.16(a) or (b), the
        Global Security of a series may be transferred, in whole but not in part
        and in the manner provided in Section 2.09, only to the Depository,
        another nominee of the Depository for that series, a successor
        Depository for that series selected or approved by the Company or a
        nominee of that successor Depository.
 
        (a)    (i)  If so provided with respect to a particular series of bonds,
               an interest in any Global Security of such series shall be
               exchangeable at the option of the beneficial owner of such
               interest in such Global Security for a definitive bond or bonds
               registered in the name of any holder other than the Depository or
               its nominee at any time following issuance of such Global
               Security.
 
               (ii)  A beneficial owner of an interest in any Global Security of
               such series desiring to exchange such beneficial interest for a
               definitive bond or bonds shall instruct the Depository, through
               the Depository's direct or indirect participants or otherwise, to
               request such exchange on such beneficial owner's behalf and to
               provide a written order containing registration instructions to
               the Trustee. Upon receipt by the

                                       14
 
               Trustee of electronic or written instructions from the Depository
               on behalf of such beneficial owner, the Trustee shall cause, in
               accordance with the standing instructions and procedures existing
               between the Trustee and the Depository, the aggregate principal
               amount of such Global Security to be reduced by the principal
               amount of such beneficial interest so exchanged and shall
               appropriately reflect such reduction of the aggregate principal
               amount of this Global Security as described in paragraph (iii) of
               this Section 2.16(a). Following such reduction, the Trustee shall
               authenticate and deliver to such beneficial owner or the
               transferee, as the case may be, a definitive bond or bonds
               previously executed by the Company as described in Section 2.10
               and registered in such names and authorized denominations as the
               Depository, pursuant to such instructions of the beneficial
               owner, shall instruct the Trustee.
 
               (iii)  Upon any exchange of a portion of any Global Security for
               a bond or bonds, the Company shall reflect the reduction of the
               principal amount of such Global Security by the principal amount
               of such beneficial interest so exchanged on the books for
               registration and transfer of the bonds maintained pursuant to
               Section 2.09. Until exchanged in full for definitive bonds, such
               Global Security shall in all respects be entitled to the same
               benefits under the Indenture as the definitive bonds
               authenticated and delivered hereunder.
 
        (b)    (i)  If and so long as the bonds of any series are issued as a
               Global Security, any definitive bond or bonds of such series
               shall be exchangeable at the option of the registered holder
               thereof for a beneficial interest in such Global Security at any
               time following the exchange of such Global Security for such
               definitive bond or bonds pursuant to Section 2.16(a).
 
               (ii)  A registered holder of a definitive bond or bonds desiring
               to exchange such definitive bond or bonds for a beneficial
               interest in such Global Security shall instruct the

                                       15
 
               Depository, through the Depository's direct or indirect
               participants or otherwise, to request such exchange on such
               bondholder's behalf and to provide a written order containing
               registration instructions to the Trustee. Upon receipt by the
               Trustee of electronic or written instructions from the
               Depository, and upon presentation to the Trustee of such
               definitive bond or bonds, the Trustee shall cause, in accordance
               with the standing instructions and procedures existing between
               the Trustee and the Depository, the aggregate principal amount of
               such Global Security to be increased by the principal amount of
               such definitive bond or bonds so exchanged and shall
               appropriately reflect such increase of the aggregate principal
               amount of the Global Security as described in paragraph (iii) of
               this Section 2.16(b).
 
               (iii)  Upon any exchange of a definitive bond or bonds for a
               beneficial interest in such Global Security, the Company shall
               reflect the increase of the principal amount of such Global
               Security by the principal amount of such definitive bond or bonds
               so exchanged on the registration books maintained pursuant to
               Section 2.09.
 
    (c)  If at any time (i) the Depository for a series of bonds notifies the
Company that it is unwilling or unable to continue as Depository for that series
or if at any time the Depository for that series shall no longer be registered
or in good standing under the Securities Exchange Act of 1934, as amended, or
other applicable statute or regulation and a successor Depository for that
series is not appointed by the Company within 90 days after the Company receives
such notice or becomes aware of such condition, as the case may be, or (ii) if a
Default has occurred and is continuing with respect to the bonds of a series and
payment of principal thereof and interest thereon has been accelerated, this
Section 2.16 shall no longer apply to the bonds of that series and the Company
will execute and, subject to Section 2.08, the Trustee will authenticate and
deliver bonds of that series in definitive registered form without coupons, in
authorized denominations, and in an aggregate principal amount equal to the
principal amount of the Global Security of that series in exchange for such
Global Security. In addition, the Company

                                       16
 
may at any time in its sole discretion determine that the bonds of any series
shall no longer be represented by a Global Security and that the provisions of
this Section 2.16 shall no longer apply to the bonds of that series. In that
event the Company will execute and, subject to Section 2.08, the Trustee, upon
receipt of an Officers' Certificate evidencing such determination by the
Company, will authenticate and deliver bonds of that series in definitive
registered form without coupons, in authorized denominations, and in an
aggregate principal amount equal to the principal amount of the Global Security
of such series in exchange for such Global Security. Upon the exchange of the
Global Security for such bonds in definitive registered form without coupons, in
authorized denominations, the Global Security shall be canceled by the Trustee.
Such bonds in definitive registered form issued in exchange for the Global
Security pursuant to this Section 2.16(c) shall be registered in such names and
in such authorized denominations as the Depository, pursuant to instructions
from its direct or indirect participants or otherwise, shall instruct the
Trustee. The Trustee shall deliver such bonds to the Depository for delivery to
the persons in whose names such bonds are so registered.
 
                                  ARTICLE III
 
THE COMPANY RESERVES THE RIGHT TO AMEND PROVISIONS REGARDING PROPERTIES EXCEPTED
                             FROM LIEN OF MORTGAGE
 
    SECTION 3.01. The Company reserves the right, without any consent or other
action by holders of bonds of the Eighth Series, or any other series of bonds
subsequently created under the Mortgage (including the bonds of the Sixteenth
Series), to make such amendments to the Mortgage, as heretofore amended and
supplemented, as shall be necessary in order to amend the first proviso to the
granting clause of the Mortgage, which proviso sets forth the properties
excepted from the Lien of the Mortgage, to add a new exception (10) which shall
read as follows:
 
            "(10) allowances allocated to steam-electric generating plants owned
        by the Company or in which the Company has interests, pursuant to Title
        IV of the Clean Air Act Amendments of 1990, Pub. L. 101-549, Nov. 15,
        1990, 104 Stat. 2399, 42 USC 7651, et seq., as now in effect or as
        hereafter supplemented or amended."

                                       17
 
                                   ARTICLE IV
 
                            MISCELLANEOUS PROVISIONS
 
    SECTION 4.01. The right, if any, of the Company to assert the defense of
usury against a holder or holders of bonds of the Sixteenth Series or any
subsequent series shall be determined only under the laws of the State of New
York.
 
    SECTION 4.02. The terms defined in the Mortgage shall, for all purposes of
this Twelfth Supplemental Indenture, have the meanings specified in the
Mortgage.
 
    SECTION 4.03. The Trustee hereby accepts the trusts hereby declared,
provided, created or supplemented, and agrees to perform the same upon the terms
and conditions herein and in the Mortgage, as hereby supplemented, set forth,
including the following:
 
    The Trustee shall not be responsible in any manner whatsoever for or in
respect of the validity or sufficiency of this Twelfth Supplemental Indenture or
for or in respect of the recitals contained herein, all of which recitals are
made by the Company solely. Each and every term and condition contained in
Article XIX of the Mortgage shall apply to and form part of this Twelfth
Supplemental Indenture with the same force and effect as if the same were herein
set forth in full, with such omissions, variations and insertions, if any, as
may be appropriate to make the same conform to the provisions of this Twelfth
Supplemental Indenture.
 
    SECTION 4.04. Whenever in this Twelfth Supplemental Indenture either of the
Company or the Trustee is named or referred to, this shall, subject to the
provisions of Articles XVIII and XIX of the Mortgage, be deemed to include the
successors and assigns of such party, and all the covenants and agreements in
this Twelfth Supplemental Indenture contained by or on behalf of the Company, or
by or on behalf of the Trustee, shall, subject as aforesaid, bind and inure to
the respective benefits of the respective successors and assigns of such
parties, whether so expressed or not.
 
    SECTION 4.05. Nothing in this Twelfth Supplemental Indenture, expressed or
implied, is intended, or shall be construed to confer upon, or to give to, any
person, firm or corporation, other than the parties hereto and the

                                       18
 
holders of the bonds and coupons outstanding under the Mortgage, any right,
remedy or claim under or by reason of this Twelfth Supplemental Indenture or any
covenant, condition, stipulation, promise or agreement hereof, and all the
covenants, conditions, stipulations, promises and agreements in this Twelfth
Supplemental Indenture contained by or on behalf of the Company shall be for the
sole and exclusive benefit of the parties hereto, and of the holders of the
bonds and of the coupons outstanding under the Mortgage.
 
    SECTION 4.06. This Twelfth Supplemental Indenture shall be executed in
several counterparts, each of which shall be an original and all of which shall
constitute but one and the same instrument.
 
                                   ARTICLE V
 
                        SPECIFIC DESCRIPTION OF PROPERTY
 
    The properties of the Company, owned as of the date hereof, and used (or
held for future development and use) in connection with the Company's electric
utility systems, or for other purposes, as more particularly described in
Exhibit B attached hereto.
 
    IN WITNESS WHEREOF, PACIFICORP has caused its corporate name to be hereunto
affixed, and this instrument to be signed and sealed by an Authorized Executive
Officer of the Company, and its corporate seal to be attested to by its
Secretary or one of its Assistant Secretaries for and in its behalf, and The
Chase Manhattan Bank has caused its corporate name to be hereunto

                                       19
 
affixed, and this instrument to be signed and sealed by one of its Vice
Presidents or one of its Assistant Vice Presidents, and its corporate seal to be
attested to by one of its Senior Trust Officers, all as of the day and year
first above written.
 
[SEAL]                                  PACIFICORP
 
                                            By      RICHARD T. O'BRIEN
                                               -------------------------------
                                              Senior Vice President and
                                               Chief Financial Officer
Attest:
 
              LENORE M. MARTIN
  ----------------------------------
         Assistant Secretary
 
                                        THE CHASE MANHATTAN BANK
[SEAL]                                  as Trustee
 
                                             By           F.J. GRIPPO
                                               -------------------------------
                                                    Vice President
Attest:
 
             GLENN G. MCKEEVER
  ----------------------------------
         Senior Trust Officer
 

                                       20
 
STATE OF OREGON
COUNTY OF MULTNOMAH      SS.:
 
    On this 28th day of August, 1996, before me, SHERYL L. STRATTON, a Notary
Public in and for the State of Oregon, personally appeared RICHARD T. O'BRIEN
AND LENORE M. MARTIN, known to me to be a Senior Vice President and an Assistant
Secretary, respectively, of PACIFICORP, an Oregon corporation, who being duly
sworn, stated that the seal affixed to the foregoing instrument is the corporate
seal of said corporation and acknowledged this instrument to be the free,
voluntary and in all respects duly and properly authorized act and deed of said
corporation.
 
    IN WITNESS WHEREOF, I have hereunto set my hand and official seal the day
and year first above written.
 
[SEAL]                                            SHERYL L. STRATTON
                                          ----------------------------------
                                        My commission expires: May 25, 2000
                                        Residing at: Portland, Oregon
                                        Commission No. 053955
 
STATE OF NEW YORK
COUNTY OF NEW YORK       SS.:
 
    On this 29th day of August, 1996, before me, ROBERT J. STANISLARO, a Notary
Public in and for the State of New York, personally appeared F.J. GRIPPO AND
GLENN G. MCKEEVER, known to me to be a Vice President and a Senior Trust
Officer, respectively, of THE CHASE MANHATTAN BANK, a New York corporation, who
being duly sworn, stated that the seal affixed to the foregoing instrument is
the corporate seal of said corporation and acknowledged this instrument to be
the free, voluntary and in all respects duly and properly authorized act and
deed of said corporation.
 
    IN WITNESS WHEREOF, I have hereunto set my hand and official seal the day
and year first above written.
 
[SEAL]                                           ROBERT J. STANISLARO
                                          ----------------------------------
                                        Notary Public, State of New York
                                        No. 43-4968897
                                        Qualified in Richmond County
                                        Certificate Filed in New York County
                                        Commission expires: July 2, 1998