Document:

EXHIBIT 4.13

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                               IDAHO POWER COMPANY

                                       TO

                      DEUTSCHE BANK TRUST COMPANY AMERICAS

                                       AND

                                  STANLEY BURG,

                As Trustees under its Mortgage and Deed of Trust
                          dated as of October 1, 1937.

                                 _______________

                     _______________ Supplemental Indenture
           providing among other things for Bonds of __________ Series
                          Dated as of __________, 200_

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                               TABLE OF CONTENTS\1
                                                                            Page

ARTICLE I  DESCRIPTION OF BONDS OF _________ SERIES............................6
       SECTION 1  General Terms and Redemption Provisions......................6
       SECTION 2  Exchange and Transfers of Bonds..............................9
       SECTION 3  Form of Bonds...............................................10
       SECTION 4  Temporary Bonds.............................................10

ARTICLE II  ISSUE OF BONDS OF __________ SERIES...............................10
       SECTION 5  Issue of Bonds..............................................10

ARTICLE III  COVENANTS........................................................10
       SECTION 6  Application of Original Indenture...........................10
       SECTION 7  Lawful Ownership............................................10
       SECTION 8  Annual Certificate as to Defaults...........................11

ARTICLE IV  THE TRUSTEES......................................................11

ARTICLE V  MISCELLANEOUS PROVISIONS...........................................11

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1/  This table of contents shall not have any bearing upon the interpretation
   of this Supplemental Indenture.

                                      -i-

<PAGE>

          SUPPLEMENTAL INDENTURE, dated as of the _____ day of __________, 200_
made and entered into by and between IDAHO POWER COMPANY, a corporation of the
State of Idaho (successor by merger to Idaho Power Company, a corporation of the
State of Maine, hereinafter sometimes called the "Maine Company"), whose address
is 1221 West Idaho Street, Boise, Idaho 83702-5627 (hereinafter sometimes called
the "Company"), party of the first part, and DEUTSCHE BANK TRUST COMPANY
AMERICAS, formerly known as Bankers Trust Company, a corporation of the State of
New York whose post office address is 60 Wall Street, New York, N.Y. 10005
(hereinafter sometimes called the "Corporate Trustee"), and Stanley Burg
(hereinafter sometimes called the "Individual Trustee"), parties of the second
part (the Corporate Trustee and the Individual Trustee being hereinafter
together sometimes called the "Trustees"), as Trustees under the Mortgage and
Deed of Trust dated as of October 1, 1937 hereinafter referred to;

          WHEREAS, the Maine Company has heretofore executed and delivered to
the Trustees its Mortgage and Deed of Trust (hereinafter sometimes referred to
as the "Original Indenture"), dated as of October 1, 1937, to secure the payment
both of the principal of and interest and premium, if any, on all Bonds at any
time issued and outstanding thereunder and to declare the terms and conditions
upon which Bonds are to be issued thereunder; and

          WHEREAS, the Maine Company was merged into the Company on June 30,
1989; and

          WHEREAS, in order to evidence the succession of the Company to the
Maine Company and the assumption by the Company of the covenants and conditions
of the Maine Company in the Bonds and in the Original Indenture, as
supplemented, contained, and to enable the Company to have and exercise the
powers and rights of the Maine Company under the Original Indenture, as
supplemented, in accordance with the terms thereof, the Company executed and
delivered to the Trustees a Twenty-eighth Supplemental Indenture, dated as of
June 30, 1989 (which supplemental indenture is hereinafter sometimes called the
"Twenty-eighth Supplemental Indenture"); and

          WHEREAS, said Twenty-eighth Supplemental Indenture was recorded in the
records of the County of Elko, Nevada; the Counties of Baker, Grant, Harney,
Malheur, Union and Wallowa, Oregon; the Counties of Ada, Adams, Bannock, Bear
Lake, Bingham, Blaine, Boise, Bonneville, Butte, Camas, Canyon, Caribou, Cassia,
Clark, Elmore, Gem, Gooding, Idaho, Jefferson, Jerome, Lemhi, Lincoln, Minidoka,
Oneida, Owyhee, Payette, Power, Twin Falls, Valley and Washington, Idaho; the
Counties of Lincoln and Sweetwater, Wyoming; and with the Secretary of State of
Montana; and

          WHEREAS, in accordance with the terms of the Original Indenture the
Maine Company or the Company has executed and delivered to the Trustees the
following supplemental indentures in addition to the Twenty-eighth Supplemental
Indenture:

         Designation                                            Dated as of
         -----------                                            -----------
First Supplemental Indenture...................................July 1, 1939
Second Supplemental Indenture..................................November 15, 1943

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         Designation                                          Dated as of
         -----------                                          -----------
Third Supplemental Indenture..................................February 1, 1947
Fourth Supplemental Indenture.................................May 1, 1948
Fifth Supplemental Indenture..................................November 1, 1949
Sixth Supplemental Indenture..................................October 1, 1951
Seventh Supplemental Indenture................................January 1, 1957
Eighth Supplemental Indenture.................................July 15, 1957
Ninth Supplemental Indenture..................................November 15, 1957
Tenth Supplemental Indenture..................................April 1, 1958
Eleventh Supplemental Indenture...............................October 15, 1958
Twelfth Supplemental Indenture................................May 15, 1959
Thirteenth Supplemental Indenture.............................November 15, 1960
Fourteenth Supplemental Indenture.............................November 1, 1961
Fifteenth Supplemental Indenture..............................September 15, 1964
Sixteenth Supplemental Indenture..............................April 1, 1966
Seventeenth Supplemental Indenture............................October 1, 1966
Eighteenth Supplemental Indenture.............................September 1, 1972
Nineteenth Supplemental Indenture.............................January 15, 1974
Twentieth Supplemental Indenture..............................August 1, 1974
Twenty-first Supplemental Indenture...........................October 15, 1974
Twenty-second Supplemental Indenture..........................November 15, 1976
Twenty-third Supplemental Indenture...........................August 15, 1978
Twenty-fourth Supplemental Indenture..........................September 1, 1979
Twenty-fifth Supplemental Indenture...........................November 1, 1981
Twenty-sixth Supplemental Indenture...........................May 1, 1982
Twenty-seventh Supplemental Indenture.........................May 1, 1986
Twenty-ninth Supplemental Indenture...........................January 1, 1990
Thirtieth Supplemental Indenture..............................January 1, 1991
Thirty-first Supplemental Indenture...........................August 15, 1991
Thirty-second Supplemental Indenture..........................March 15, 1992
Thirty-third Supplemental Indenture...........................April 1, 1993
Thirty-fourth Supplemental Indenture..........................December 1, 1993
Thirty-fifth Supplemental Indenture...........................November 1, 2000
Thirty-sixth Supplemental Indenture\2.........................October 1, 2001

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2/  Here will be inserted additional, executed supplemental indentures.

                                      -2-

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each of which is supplemental to the Original Indenture (the Original Indenture
and all indentures supplemental thereto together being hereinafter sometimes
referred to as the "Indenture"); and

          WHEREAS, the Original Indenture and said Supplemental Indentures
(except said Fifteenth Supplemental Indenture) have each been recorded in the
records of the County of Elko, Nevada; the Counties of Baker, Grant, Harney,
Malheur, Union and Wallowa, Oregon; the Counties of Ada, Adams, Bannock, Bear
Lake, Bingham, Blaine, Boise, Bonneville, Butte, Camas, Canyon, Caribou, Cassia,
Clark, Elmore, Gem, Gooding, Idaho, Jefferson, Jerome, Lemhi, Lincoln, Minidoka,
Oneida, Owyhee, Payette, Power, Twin Falls, Valley and Washington, Idaho; the
Counties of Lincoln and Sweetwater, Wyoming; and with the Secretary of State of
Montana; and

          WHEREAS, the Maine Company or the Company has heretofore issued Bonds,
under and in accordance with the terms of the Indenture in the following series
and aggregate principal amounts:

<TABLE>
<CAPTION>
                                                          Principal          Principal
                                                            Amount             Amount
Series                                                      Issued           Outstanding
------                                                -----------------   ----------------
<S>                                                   <C>                 <C>
3-3/4% Series due 1967............................... $   18,000,000           None
3-1/8% Series due 1973...............................     18,000,000           None
2-3/4% Series due 1977...............................      5,000,000           None
3% Series due 1978...................................     10,000,000           None
2-3/4% Series due 1979...............................     12,000,000           None
3-1/4% Series due 1981...............................     15,000,000           None
4-1/2% Series due 1987...............................     20,000,000           None
4-3/4% Series due 1987...............................     15,000,000           None
4% Series due April 1988.............................     10,000,000           None
4-1/2% Series due October 1988.......................     15,000,000           None
5% Series due 1989...................................     15,000,000           None
4-7/8% Series due 1990...............................     15,000,000           None
4-1/2% Series due 1991...............................     10,000,000           None
5-1/4% Series due 1996...............................     20,000,000           None
6-1/8% Series due 1996...............................     30,000,000           None
7-3/4% Series due 2002...............................     30,000,000           None
8-3/8% Series due 2004...............................     35,000,000           None
10% Series due 2004..................................     50,000,000           None
8-1/2% Series due 2006...............................     30,000,000           None
9% Series due 2008...................................     60,000,000           None
10-1/4% Series due 2003..............................     62,000,000           None

                                      -3-

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                                                          Principal          Principal
                                                            Amount             Amount
Series                                                      Issued           Outstanding
------                                                -----------------   ----------------
First Mortgage Bonds, 1984 Series....................     10,100,000           None
16.10% Series due 1991-1992..........................     50,000,000           None
Pollution Control Series A...........................     49,800,000          49,800,000
8.65% Series due 2000................................     80,000,000           None
9.50% Series due 2021................................     75,000,000           None
9.52% Series due 2031................................     25,000,000           None
8% Series due 2004                                        50,000,000          50,000,000
8 3/4% Series due 2027...............................     50,000,000           None
Secured Medium-Term Notes, Series A..................    190,000,000         160,000,000
Secured Medium-Term Notes, Series B..................    197,000,000         140,000,000
Secured Medium-Term Notes, Series C..................    200,000,000         200,000,000
Secured Medium-Term Notes, Series D..................    200,000,000         200,000,000\3
</TABLE>

which bonds are hereinafter sometimes called bonds of the First through
__________ Series; and

          WHEREAS, the Company, in accordance with the provisions of the
Indenture and pursuant to appropriate resolutions of its Board of Directors, has
duly determined to make, execute and deliver to the Trustees this __________
Supplemental Indenture for the purposes herein provided, including the issuance
of a __________ Series of Bonds under the Indenture, in the aggregate principal
amount of up to __________ Million Dollars ($__________), to be designated as
"First Mortgage Bonds, _____% Series due __________" ["First Mortgage Bonds,
Secured Medium-Term Notes, Series _____"]\4 (herein sometimes called the "Bonds
of __________ Series"); and

          WHEREAS, it is also now desired, for the purpose of more effectually
carrying out the purposes of the Original Indenture, to confirm specifically the
subjection to the lien thereof and of the Indenture of the certain property
acquired by the Company in addition to the property specifically described in
the Original Indenture and in said First, Second, Third, Fourth, Fifth, Sixth,
Seventh, Ninth, Tenth, Eleventh, Twelfth, Thirteenth, Fourteenth, Sixteenth,
Seventeenth, Eighteenth, Nineteenth, Twenty-first, Twenty-second, Twenty-third,
Twenty-fourth, Twenty-fifth, Twenty-sixth, Twenty-seventh, Twenty-eighth,
Twenty-ninth, Thirtieth, Thirty-first, Thirty-second, Thirty-third,
Thirty-fourth, Thirty-fifth and Thirty-sixth\5 Supplemental Indentures; and

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3/  Here will be inserted additional outstanding series of bonds.

4/  Bracketed language will be inserted in lieu of words "First Mortgage Bonds,
   _____% Series due __________" in any supplemental indenture relating to the
   issuance of First Mortgage Bonds which are designated "Secured Medium-Term
   Notes, Series _____".

5/  Here will be inserted additional, executed supplemental indentures.

                                      -4-

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          WHEREAS, all things necessary to make said Bonds of _________ Series,
when duly authenticated by the Corporate Trustee and issued by the Company,
valid and legally binding obligations of the Company and to make the Original
Indenture, as heretofore supplemented and as supplemented hereby, a valid and
legally binding instrument for the security thereof, have been performed, and
the execution and delivery of this __________ Supplemental Indenture and the
issue of said Bonds as in this __________ Supplemental Indenture provided have
been in all respects duly authorized:

          NOW, THEREFORE, THIS INDENTURE WITNESSETH:

          That in consideration of the premises and of One Dollar to it duly
paid by the Trustees at or before the ensealing and delivery of these presents,
the receipt whereof is hereby acknowledged, and in order to secure the payment
both of the principal of and interest and premium, if any, on all Bonds at any
time issued and outstanding under the Indenture, according to their tenor and
effect, and the performance of all the provisions of the Indenture and of said
Bonds, the Company has duly executed and delivered to the Trustees this
__________ Supplemental Indenture and has granted, bargained, sold, released,
conveyed, assigned, transferred, mortgaged, pledged, set over and confirmed and
by these presents does grant, bargain, sell, release, convey, assign, transfer,
mortgage, pledge, set over and confirm unto Stanley Burg and (to the extent of
its legal capacity to hold the same for the purposes hereof) unto Deutsche Bank
Trust Company Americas, as Trustees as aforesaid, and to their successor or
successors in said trust, and to them and their successors, heirs and assigns
forever, all property, whether real, personal or mixed (except any hereinafter
expressly excepted), and wheresoever situated, acquired since the date of said
Original Indenture by and now or hereafter owned by the Company including the
following described properties, rights and interests in property (in addition to
all other properties heretofore subjected to the lien of the Indenture and not
heretofore released from the lien thereof)--that is to say:\6

          All other property, whether real, personal or mixed (except any
hereinafter expressly excepted), and wheresoever situated, acquired since the
date of said Original Indenture by and now or hereafter owned by the Company.

          TOGETHER with all and singular the tenements, hereditaments and
appurtenances belonging or in any wise appertaining to the aforesaid property or
any part thereof, with the reversion and reversions, remainder and remainders,
and (subject to the provisions of Section 57 of the Original Indenture) the
tolls, rents, revenues, issues, earnings, income, 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 not intended herein or hereby to include in or subject to the
lien of the Indenture, and the granting clauses hereof shall not be deemed to
apply to, (1) any revenues, earnings, rents, issues, income or profits of the
mortgaged and pledged property, or any bills, notes or accounts receivable,
contracts or choses in action, except to the extent permitted by law in case a
completed default specified in Section 65 of the Indenture shall have occurred
and be

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6/  Here will be inserted property descriptions.

                                      -5-

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continuing and either or both of the Trustees, or a receiver or trustee, shall
have entered upon or taken possession of the mortgaged and pledged property, or
(2) in any case, unless specifically subjected to the lien thereof, any bonds,
notes, evidences of indebtedness, shares of stock, or other securities or any
cash (except cash deposited with the Corporate Trustee pursuant to any
provisions of the Indenture) or any goods, wares, merchandise, equipment or
apparatus manufactured or acquired for the purpose of sale or resale in the
usual course of business.

          TO HAVE AND TO HOLD all such properties, real, personal and mixed,
granted, bargained, sold, released, conveyed, assigned, transferred, mortgaged,
pledged, set over or confirmed by the Company as aforesaid, or intended so to
be, unto the Individual Trustee and (to the extent of its legal capacity to hold
the same for the purposes hereof) unto the Corporate Trustee, and their
successors, heirs 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 provisions and covenants
as are set forth in the Original Indenture, as amended or modified by said
First, Second, Third, Fourth, Fifth, Sixth, Seventh, Eighth, Ninth, Tenth,
Eleventh, Twelfth, Thirteenth, Fourteenth, Fifteenth, Sixteenth, Seventeenth,
Eighteenth, Nineteenth, Twentieth, Twenty-first, Twenty-second, Twenty-third,
Twenty-fourth, Twenty-fifth, Twenty-sixth, Twenty-seventh, Twenty-eighth,
Twenty-ninth, Thirtieth, Thirty-first, Thirty-second, Thirty-third,
Thirty-fourth, Thirty-fifth and Thirty-sixth Supplemental Indentures and this
_________\7 Supplemental Indenture.

          And it is hereby covenanted, declared and decreed by and between the
parties hereto, for the benefit of those who shall hold the Bonds and interest
coupons, or any of them, issued and to be issued under the Indenture, as
follows:

                                   ARTICLE I

                   DESCRIPTION OF BONDS OF __________ SERIES.

          SECTION 1. The __________ Series of Bonds to be executed,
authenticated and delivered under and secured by the Indenture shall be Bonds of
__________ Series, designated as "First Mortgage Bonds, _____% Series due
__________" of the Company. The Bonds of __________ Series shall be executed,
authenticated and delivered in accordance with the provisions of, and shall in
all respects be subject to, all of the terms, conditions and covenants of the
Original Indenture, except insofar as the terms and provisions of the Original
Indenture have been or are amended or modified by said First through __________
Supplemental Indentures or by this __________ Supplemental Indenture. Bonds of
__________ Series shall mature on __________, and shall be issued as registered
Bonds without coupons in denominations of $1,000 and in any multiple thereof,
and shall bear interest, payable on __________ and __________ of each year, at
the rate of _____% per annum until the principal shall have become due and
payable, and, if default shall be made in the payment of said principal when due
and payable, at the rate of _____% per annum thereafter until the Company's
obligation with respect to payment of said principal shall have been discharged
as provided in the Indenture; provided, however, that if Bonds of __________
Series shall have been declared due and payable prior to

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7/  Here will be inserted additional, executed supplemental indentures.

                                      -6-

<PAGE>

their stated maturity and such declaration shall have been annulled as provided
in the Indenture, the principal of such Bonds shall not be deemed to have been
so declared due and payable. The principal of and interest and premium, if any,
on the Bonds of __________ Series shall be payable at the office or agency of
the Company in the Borough of Manhattan, The City of New York, and, at the
option of the Company, interest on each said Bond may also be payable at the
office of the Company in Boise, Idaho, in such coin or currency of the United
States of America as at the time of payment shall be legal tender for public and
private debts. The interest on the Bonds of __________ Series, whether in
temporary or definitive form, shall be payable without presentation of such
Bonds and (subject to the provisions of this Section 1) only to or upon the
written order of the registered holders thereof.

          Except as provided in the next succeeding sentence of this Section 1,
each Bond of __________ Series shall be dated the date of its authentication and
interest shall be payable on the principal represented thereby from the
__________ or __________, as the case may be, next preceding the date thereof to
which interest has been paid, unless the date thereof is a __________ or
__________ to which interest has been paid, in which case such interest shall be
payable from such date or unless such date is prior to __________, in which case
interest shall be payable from __________. Each Bond of __________ Series
authenticated between the record date for any interest payment date and such
interest payment date shall be dated the date of its authentication, but
interest shall be payable from such interest payment date; provided, however,
that if the Company shall default in the payment of the interest due on such
interest payment date, any Bond of __________ Series so authenticated shall bear
interest from the __________ or __________, as the case may be, next preceding
the date of such Bond, to which interest has been paid.

          Interest on any Bond of __________ Series shall be paid to the
registered holder of such Bond of __________ Series, or, notwithstanding the
cancellation thereof, the Bond of __________ Series in exchange or substitution
for which such Bond shall have been issued, at the close of business on the
applicable record date; provided, however, that if the Company shall default in
the payment of the interest due on any interest payment date on the principal
represented by any Bond of __________ Series, such defaulted interest shall be
paid to the registered holder of such Bond (or any Bond or Bonds of __________
Series issued upon transfer or exchange thereof) on the date of payment of such
defaulted interest or, at the election of the Company, to the person in whose
name such Bond (or any Bond or Bonds of __________ Series issued upon transfer
or exchange thereof) is registered on a subsequent record date established by
notice given by mail by or on behalf of the Company to the holders of Bonds of
__________ Series not less than ten (10) days preceding such subsequent record
date. The term "record date" as used in this Section 1 shall mean, with respect
to any semi-annual interest payment date, the close of business on __________ or
__________, as the case may be, next preceding such interest payment date or, in
the case of defaulted interest, the close of business on any subsequent record
date established as provided above.

          The Bonds of __________ Series, in definitive form, shall be, at the
option of the Company, fully engraved or shall be lithographed or printed on
steel engraved borders or shall be partially lithographed or printed and
partially engraved on steel engraved borders or shall be printed on safety paper
or shall be typewritten.

                                      -7-

<PAGE>

          8/[SECTION 1. The __________ Series of Bonds to be executed,
authenticated and delivered under and secured by the Indenture shall be Secured
Medium-Term Notes, Series _____, designated as "First Mortgage Bonds, Secured
Medium-Term Notes, Series _____ "of the Company. The Bonds of __________ Series
shall be executed, authenticated and delivered in accordance with the provisions
of, and shall in all respects be subject to, all of the terms, conditions and
covenants of the Original Indenture, except insofar as the terms and provisions
of the Original Indenture have been or are amended or modified by said First
through __________ Supplemental Indentures or by this __________ Supplemental
Indenture. Bonds of __________ Series shall be issued from time to time in an
aggregate principal amount not to exceed $__________, be issued as registered
Bonds without coupons in the denominations of $1,000 or in any multiple thereof;
each Bond of __________ Series shall mature on such date not less than
__________ nor more than __________ from date of issue, shall bear interest at
such rate or rates (which may be either fixed or variable) and have such other
terms and provisions not inconsistent with the Indenture as the Board of
Directors may determine in accordance with a resolution filed with the Corporate
Trustee and a written order referring to this __________ Supplemental Indenture;
the principal of and interest on each said Bond to be payable at the office or
agency of the Company in the Borough of Manhattan, The City of New York and, at
the option of the Company, interest on each said Bond may also be payable at the
office of the Company in Boise, Idaho, 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. Interest on Bonds of __________ Series which bear interest at a
fixed rate shall be payable semiannually on __________ and __________ of each
year and at maturity (each an interest payment date). Interest on Bonds of
__________ Series which bear interest at a variable rate shall be payable on the
dates (each an interest payment date) set forth in a resolution filed with the
Corporate Trustee referring to this __________ Supplemental Indenture.

          Notwithstanding the foregoing, so long as there is no existing default
in the payment of interest on the Bonds of __________ Series, all Bonds of
__________ Series authenticated by the Corporate Trustee after the Record Date
hereinafter specified for any interest payment date, and prior to such interest
payment date (unless the date of first authentication of Bonds of such
designated interest rate and maturity is after such Record Date), shall be dated
the date of authentication, but shall bear interest from such interest payment
date, and the person in whose name any Bond of __________ Series is registered
at the close of business on any Record Date with respect to any interest payment
date shall be entitled to receive the interest payable on such interest payment
date, notwithstanding the cancellation of such Bond of __________ Series, upon
any transfer or exchange thereof subsequent to the Record Date and on or prior
to such interest payment date. If the date of first authentication of the Bonds
of __________ Series of a designated interest rate and maturity is after such
Record Date and prior to the corresponding interest payment date, such Bonds
shall bear interest from the Original Interest Accrual Date but payment of
interest shall commence on the second interest payment date succeeding the
Original Interest Accrual Date. "Record Date" for Bonds of __________ Series
which bear interest at a fixed rate shall mean the last day of the calendar
month preceding such interest payment date if such interest payment date is the
fifteenth day of a calendar month

------------------------
8/ These provisions will be inserted in lieu of Section 1 above in any
   supplemental indenture relating to the issuance of First Mortgage Bonds
   which are designated "Secured Medium-Term Notes, Series _____".

                                      -8-

<PAGE>

and shall mean the fifteenth day of the calendar month preceding such interest
payment date if such interest payment date is the first day of a calendar month,
unless otherwise determined by the Board of Directors and set forth in a
resolution filed with the Corporate Trustee referring to this ____________
Supplemental Indenture, and for Bonds of __________ Series which bear interest
at a variable rate, the date 15 calendar days prior to any interest payment
date, provided that, interest payable on the maturity date will be payable to
the person to whom the principal thereof shall be payable. "Original Interest
Accrual Date" with respect to Bonds of __________ Series of a designated
interest rate and maturity shall mean the date of first authentication of Bonds
of such designated interest rate and maturity unless a written order filed with
the Corporate Trustee on or before such date shall specify another date from
which interest shall accrue, in which case "Original Interest Accrual Date"
shall mean such other date specified in the written order for Bonds of such
designated interest rate and maturity.

          The Bonds of __________ Series, in definitive form, shall be, at the
option of the Company, fully engraved or shall be lithographed or printed on
steel engraved borders or shall be partially lithographed or printed and
partially engraved on steel borders or shall be printed on safety paper or shall
be typewritten.]

          The holders of the Bonds of __________ Series consent that the Company
may, but shall not be obligated to, fix a record date for the purpose of
determining the holders of Bonds of __________ Series entitled to consent to any
amendment, supplement or waiver. If a record date is fixed, those persons who
are holders at such record date (or their duly designated proxies), and only
those persons, shall be entitled to consent to such amendment, supplement or
waiver or to revoke any consent previously given, whether or not such persons
continue to be holders after such record date. No such consent shall be valid or
effective for more than 90 days after such record date.

                 [Here will be inserted redemption provisions.]

          SECTION 2. At the option of the registered holder, any Bonds of
__________ Series, upon surrender thereof for cancellation at the office or
agency of the Company in the Borough of Manhattan, The City of New York,
together with a written instrument of transfer (if so required by the Company or
by the Trustees) in form approved by the Company duly executed by the registered
holder or by his duly authorized attorney, shall be exchangeable for a like
aggregate principal amount and maturity of Bonds of __________ Series of other
authorized denominations. Bonds of __________ Series may bear such legends as
may be necessary to comply with any law or with any rules or regulations made
pursuant thereto or with the rules or regulations of any stock exchange or to
conform to usage with respect thereto.

          Bonds of __________ Series shall be transferable at the office or
agency of the Company in the Borough of Manhattan, The City of New York.

          Notwithstanding the foregoing provisions of this Section 2, the
Company shall not be required to make any transfers or exchanges of Bonds of
__________ Series for a period of fifteen (15) days next preceding any mailing
of notice of redemption, and the Company shall not be required to make transfers
or exchanges of the principal amount of any Bonds of __________ Series so called
or selected for redemption.

                                      -9-

<PAGE>

          SECTION 3. The Bonds of __________ Series shall be substantially of
the tenor and purport recited in the Original Indenture, and the form thereof
shall be as established by resolution of the Board of Directors or the Executive
Committee of the Board of Directors of the Company, which resolution may provide
that any provisions of such form of Bond may appear on the reverse of such form.

          SECTION 4. Until Bonds of __________ Series in definitive form are
ready for delivery, the Company may execute, and upon its request in writing,
the Corporate Trustee shall authenticate and deliver, in lieu thereof, Bonds of
__________ Series in temporary form, as provided in Section 15 of the Original
Indenture.

                                   ARTICLE II

                       ISSUE OF BONDS OF __________ SERIES

          SECTION 5. The Bonds of __________ Series for the aggregate principal
amount of up to __________ Million Dollars ($___________) may be executed by the
Company and delivered to the Corporate Trustee and shall be authenticated by the
Corporate Trustee and delivered to or upon the order or orders of the Company,
evidenced by a writing or writings signed by the Company by its President or a
Vice President and its Treasurer or an Assistant Treasurer, pursuant to and upon
compliance with the provisions of Article V, Article VI or Article VII of the
Indenture.

                                   ARTICLE III

                                    COVENANTS

          The Company hereby covenants, warrants and agrees:

          SECTION 6. That all the terms, conditions, provisos, covenants and
provisions contained in the Indenture shall affect and apply to the property
hereinabove described and conveyed and to the estate, rights, obligations and
duties of the Company and Trustees and the beneficiaries of the trust with
respect to said property, and to the Trustees and their successors as trustees
of said property, 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
Original Indenture and had been specifically and at length described in and
conveyed to the Individual Trustee and (to the extent of its legal capacity to
hold the same for the purposes of the Indenture) the Corporate Trustee by the
Original Indenture as a part of the property therein stated to be conveyed.

          SECTION 7. That it is lawfully seized and possessed of all of the
mortgaged and pledged property described in the granting clauses of the
Indenture, which has not heretofore been released from the lien thereof; that it
had or has, at the respective times of execution and delivery of the Original
Indenture, the First, Second, Third, Fourth, Fifth, Sixth, Seventh, Eighth,
Ninth, Tenth, Eleventh, Twelfth, Thirteenth, Fourteenth, Fifteenth, Sixteenth,
Seventeenth, Eighteenth, Nineteenth, Twentieth, Twenty-first (as corrected by
the Twenty-second), Twenty-second, Twenty-third, Twenty-fourth, Twenty-fifth,
Twenty-sixth, Twenty-seventh, Twenty-eighth, Twenty-ninth, Thirtieth,
Thirty-first, Thirty-second, Thirty-third, Thirty-fourth,

                                      -10-

<PAGE>

Thirty-fifth and Thirty-sixth Supplemental Indentures, and this __________\9
Supplemental Indenture, good right and lawful authority to mortgage and pledge
the mortgaged and pledged property described therein, as provided in and by the
Indenture; and that such mortgaged and pledged property is, at the actual date
of the initial issue of the Bonds of __________ Series, free and clear of any
mortgage, lien, charge or encumbrance thereon or affecting the title thereto
(other than excepted encumbrances) prior to the lien of the Indenture, except as
set forth in the granting clauses of the Indenture.

          SECTION 8. That it will deliver to the Corporate Trustee annually,
within ninety (90) days after the close of each fiscal year, commencing with the
fiscal year 200_, a certificate from the principal executive officer, principal
financial officer or principal accounting officer as to his or her knowledge of
the Company's compliance with all conditions and covenants under the Indenture.
For purposes of this Section 8, such compliance shall be determined without
regard to any period of grace or requirement of notice provided under the
Indenture.

                                   ARTICLE IV

                                  THE TRUSTEES

          The Trustees hereby accept the trust hereby declared and provided and
agree to perform the same upon the terms and conditions in the Original
Indenture, as heretofore supplemented and as supplemented by this __________
Supplemental Indenture, and in this __________ Supplemental Indenture set forth,
and upon the following terms and conditions:

          The Trustees shall not be responsible in any manner whatsoever for or
in respect of the validity or sufficiency of this ____________ Supplemental
Indenture or the due execution hereof by the Company or for or in respect of the
recitals contained herein, all of which recitals are made by the Company only.

                                   ARTICLE V

                            MISCELLANEOUS PROVISIONS

          All terms contained in the __________ Supplemental Indenture shall,
for all purposes hereof, have the meanings given to such terms in Article I of
the Original Indenture, as amended by Article IV of the Second Supplemental
Indenture.

          Except as hereby expressly amended and supplemented, the Original
Indenture heretofore amended and supplemented is in all respects ratified and
confirmed, and all the terms and provisions thereof shall be and remain in full
force and effect.

          This __________ Supplemental Indenture may be executed in any number
of counterparts, each of which when so executed shall be deemed to be an
original; but such counterparts together constitute but one and the same
instrument.

------------------------
9/  Here will be inserted additional, executed supplemental indentures.

                                      -11-

<PAGE>

          IN WITNESS WHEREOF, Idaho Power Company, party hereto of the first
part, caused its corporate name to be hereunto affixed and this instrument to be
signed and sealed by its President or a Vice President and its corporate seal to
be attested by its Secretary or an Assistant Secretary for and on its behalf,
and Deutsche Bank Trust Company Americas, one of the parties hereto of the
second part, in token of its acceptance of the trust hereby created has caused
its corporate name to be hereunto affixed and this instrument to be signed and
sealed by a Vice President and its corporate seal to be attested by an Associate
and Stanley Burg, one of the parties hereto of the second part, has for all like
purposes hereunto set his hand and affixed his seal, each on the date
hereinafter acknowledged, as of the day and year first above written.

                                              IDAHO POWER COMPANY

                                              By
                                                --------------------------------

Attest:

--------------------------------

Executed, sealed and delivered by
        IDAHO POWER COMPANY
        in the presence of:

--------------------------------

--------------------------------

                                      -12-

<PAGE>

                                              DEUTSCHE BANK TRUST COMPANY
                                              AMERICAS

                                                By
                                                  ------------------------------

Attest:

--------------------------------

Executed,sealed and delivered by
       DEUTSCHE BANK TRUST COMPANY AMERICAS,
       in the presence of:

--------------------------------

--------------------------------

                                          --------------------------------[L.S.]
                                                  Stanley Burg

Executed, sealed and delivered by
           STANLEY BURG,
        in the presence of:

--------------------------------

--------------------------------

                                      -13-

<PAGE>

STATE OF IDAHO      )
                    ) ss.:
COUNTY OF ADA       )

          On the _____ day of __________ , in the year 200_, before me
personally came ____________________, to me known, who being by me duly sworn
did depose and say that he resides at _____________________________; that he is
the ___________________ of Idaho Power Company, one of the corporations
described in and which executed the above instrument; that he knows the seal of
said corporation; that the seal affixed to said instrument is such corporate
seal; that it was so affixed by order of the Board of Directors of said
corporation, and that he signed his name thereto by like order; the said
____________________, having personally appeared and known to me to be the
___________________ of said corporation that executed the instrument,
acknowledged to me that said corporation executed the same.

          IN WITNESS WHEREOF, I have hereunto subscribed my name and affixed my
official seal the day and year in this certificate first above written.

                                              ----------------------------------
                                              Notary Public, State of Idaho

                                       -14-
<PAGE>

STATE OF NEW YORK   )
                    ) ss.:
COUNTY OF NEW YORK  )

          On the _____ day of __________ , in the year 200_, before me
personally came ____________________, to me known, who being by me duly sworn
did depose and say that he resides at _____________________________; that he is
an ___________________ of Deutsche Bank Trust Company Americas, one of the
corporations described in and which executed the above instrument; that he knows
the seal of said corporation; that the seal affixed to said instrument is such
corporate seal; that it was so affixed by order of the Board of Directors of
said corporation, and that he signed his name thereto by like order; the said
____________________, having personally appeared and known to me to be an
___________________ of said corporation that executed the instrument,
acknowledged to me that said corporation executed the same.

          IN WITNESS WHEREOF, I have hereunto subscribed my name and affixed my
official seal the day and year in this certificate first above written.

                                          -------------------------------------
                                          Notary Public, State of New York
                                          No. __________
                                          Qualified in __________ County
                                          Certificate filed in New York County
                                          Commission Expires __________

                                       -15-
<PAGE>

STATE OF NEW YORK   )
                    ) ss.:
COUNTY OF NEW YORK  )

          On the _____ day of __________, in the year 200_, before me,
_______________, a Notary Public in and for the State of New York in the County
of New York, personally appeared and came STANLEY BURG, to me known and known to
me to be the person described in and who executed the within and foregoing
instrument and whose name is subscribed thereto and acknowledged to me that he
executed the same.

          IN WITNESS WHEREOF, I have hereunto subscribed my name and affixed my
official seal the day and year in this certificate first above written.

                                          -------------------------------------
                                          Notary Public, State of New York
                                          No. __________
                                          Qualified in __________ County
                                          Certificate filed in New York County
                                          Commission Expires __________

                                       -16-
<PAGE>

STATE OF IDAHO      )
                    ) ss.:
COUNTY OF ADA       )

          __________, being first duly sworn, upon oath, deposes and says: that
he is an officer, to wit, the __________ of Idaho Power Company, a corporation,
the mortgagor described in the foregoing indenture or mortgage, and makes this
affidavit on behalf of said Idaho Power Company; that said indenture or mortgage
is made in good faith without any design to hinder, delay or defraud creditors,
to secure the indebtedness mentioned to be thereby secured.

                                          -------------------------------------

Subscribed and sworn to before me
this _____ day of __________, 200_.

-------------------------------------

Notary Public, State of Idaho

                                       -17-
<PAGE>

STATE OF NEW YORK   )
                    ) ss.:
COUNTY OF NEW YORK  )

          __________, being first duly sworn, upon oath, deposes and says: that
he is an officer, to wit, an __________ of Deutsche Bank Trust Company Americas,
a corporation, one of the mortgagees and trustees named in the foregoing
indenture or mortgage, and makes this affidavit on behalf of said Deutsche Bank
Trust Company Americas that said indenture or mortgage is made in good faith
without any design to hinder, delay or defraud creditors, to secure the
indebtedness mentioned or provided for therein.

                                          -------------------------------------

Subscribed and sworn to before me
this _____ day of __________, 200_.

-------------------------------------

Notary Public, State of New York
No. __________
Qualified in __________ County
Certificate filed in New York County
Commission Expires __________

                                       -18-
<PAGE>

STATE OF NEW YORK   )
                    ) ss.:
COUNTY OF NEW YORK  )

          STANLEY BURG, being first duly sworn, upon oath, deposes and says:
that he is one of the mortgagees and trustees named in the foregoing indenture
or mortgage; that said indenture or mortgage is made in good faith without any
design to hinder, delay or defraud creditors, to secure the indebtedness
mentioned or provided for therein.

                                          -------------------------------------
                                                      Stanley Burg

Subscribed and sworn to before me
this _____ day of __________, 200_.

-------------------------------------

Notary Public, State of New York
No. __________
Qualified in __________ County
Certificate filed in New York County
Commission Expires __________

                                       -19-Exhibit 4.15

================================================================================

                               IDAHO POWER COMPANY

                                       TO

                      DEUTSCHE BANK TRUST COMPANY AMERICAS,

                                     Trustee

                                 ---------------

                          ______ SUPPLEMENTAL INDENTURE

                            Dated as of ____________

                                       TO

                                    INDENTURE

                           Dated as of August 1, 2001

                                 DEBT SECURITIES
                                 ---------------

================================================================================

<PAGE>

          _____ SUPPLEMENTAL INDENTURE dated as of ___________ made and entered
into by and between IDAHO POWER COMPANY, a corporation of the State of Idaho
(hereinafter, subject to Article XI of the Indenture, called the "Issuer" or the
"Company"), having its principal office at 1221 West Idaho Street, Boise, Idaho
83702-5627, and Deutsche Bank Trust Company Americas (formerly known as Bankers
Trust Company), a banking corporation organized and existing under the laws of
the State of New York, as Trustee (hereinafter, subject to Article VII of the
Indenture, called the "Trustee"), having its principal office at 60 Wall Street,
New York, New York 10005, as Trustee under the Indenture for Debt Securities
dated as of August 1, 2001 executed and delivered by Idaho Power Company.

          WHEREAS the Indenture dated as of August 1, 2001 (herein with all
indentures supplemental thereto called the "Indenture"), provides for the
issuance of notes, debentures or other evidences of its indebtedness in one or
more series (hereinafter called the "Securities"), unlimited in aggregate
principal amount;

          WHEREAS the Indenture provides in Article III thereof that, prior to
the issuance of Securities of any series, the form of such Securities and the
terms applicable to such series shall be established in, or pursuant to, the
authority granted in a resolution of the Board of Directors (delivered to the
Trustee in the form of a Board Resolution) or established in one or more
indentures supplemental thereto;

          WHEREAS the Issuer desires by this Supplemental Indenture, among other
things, to establish the form of the Securities of a series, to be titled
"__________ Notes, Series __" of the Issuer, and to establish the terms
applicable to such series, pursuant to Sections 3.1 and 10.1(e) of the
Indenture;

          WHEREAS the execution and delivery of this Supplemental Indenture by
the parties hereto are in all respects authorized by the provisions of the
Indenture; and

          WHEREAS all things necessary have been done to make this Supplemental
Indenture a valid agreement of the Issuer, in accordance with its terms.

          NOW, THEREFORE, THIS _______ SUPPLEMENTAL INDENTURE WITNESSETH:

          For and in consideration of the premises, it is mutually covenanted
and agreed, as follows:

                                       2

<PAGE>

                                   ARTICLE I.

                         _____________ Notes, Series __

          SECTION 1. The title of the series of the Securities established by
this Supplemental Indenture shall be "________ Notes, Series __, due __________"
of the Issuer (hereinafter called the "Series __ Notes"). The Series __ Notes
shall bear interest (computed on the basis of a 360-day year of twelve 30-day
months) until the principal amount thereof has been duly paid or provided for in
full, at a rate per annum equal to ___% and at the same rate per annum on any
overdue principal or (to the extent legally enforceable) on any overdue
installment of interest (the "Overdue Rate").

          SECTION 2. The Series __ Notes shall be limited in aggregate principal
amount to $____________, and shall be issued substantially in the form set forth
in Exhibit A hereto (which is hereby incorporated herein and made a part
hereof), subject to changes in the form thereof made by the Issuer and
acceptable to the Trustee. The Series __ Notes shall mature on __________.

          Interest shall be payable [quarterly] in arrears on the _____ day of
__________, _________ and ______ (each, an "Interest Payment Date") and at
Maturity. If any Interest Payment Date would otherwise be a day that is not a
Business Day, such Interest Payment Date shall be postponed to the next day that
is a Business Day. If Maturity would otherwise be a day that is not a Business
Day, the payment of principal and interest due at Maturity shall be made on the
next day that is a Business Day and no interest shall accrue as a result of such
delayed payment.

          Each payment of interest with respect of an Interest Payment Date or
at Maturity shall include interest accrued to but excluding such Interest
Payment Date or Maturity, as the case may be (an "Interest Period").

          Interest on any Series __ Note that is payable, and is punctually paid
or duly provided for, on any Interest Payment Date shall be paid to the person
in whose name such Series __ Note is registered at the close of business on the
________ day of the month next preceding such Interest Payment Date (the
"Regular Record Date"). In the case of any Series __ Note issued between a
Regular Record Date and the initial Interest Payment Date, interest for the
period beginning on the date of issue and ending on the initial Interest Payment
Date shall be paid to the person to whom such Series __ Note shall have been
originally issued. Notwithstanding the foregoing, any interest that is payable
but not punctually paid or duly provided for on any Interest Payment Date shall
forthwith cease to be payable to the registered owner of such Series __ Note on
such Regular Record Date, and may be paid to the person in whose name such
Series __ Note is registered at the close of business on the Special Record Date
established by the Issuer pursuant to Section 3.8 of the Indenture or as
otherwise provided in Section 3.8 of the Indenture.

          Payments of interest on any Series __ Note (other than interest
payable at Maturity) will be made by mailing a check to the Holder at the
address of the Holder appearing on the Securities Register on the applicable
record date, unless otherwise agreed to by the Issuer.

                                       3

<PAGE>

The principal amount thereof and any premium and the interest payable at
Maturity will be paid at Maturity against presentation of a Series __ Note at
the office or agency of the Issuer maintained for that purpose in the Borough of
Manhattan, The City of New York, or as otherwise provided in the Indenture.

          The Series __ Notes are [not] redeemable prior to Maturity and the
provisions of Article XIV of the Indenture are inapplicable.

          The Series __ Notes are [not] entitled to any sinking fund and the
provisions of Article XV of the Indenture are inapplicable thereto.

          The Series __ Notes are subject to the provisions of Article XII of
the Indenture, which provide for the satisfaction and discharge of the Indenture
under the circumstances and on the conditions set forth therein.

          SECTION 3. The Series _ Notes may be issued in whole or in part as one
or more Global Securities and The Depository Trust Company, or a nominee
thereof, shall be the Depository for such Global Security or Global Securities,
except in each case as otherwise provided in a Company Order with respect to any
Series __ Notes. The Depository for such Global Security or Global Securities
representing Series __ Notes may surrender one or more Global Securities
representing Series __ Notes in exchange in whole or in part for individual
Series __ Notes on such terms as are acceptable to the Issuer and such
Depository and otherwise subject to the terms of Section 2.4 of the Indenture.

          SECTION 4. The Issuer hereby appoints, or confirms the appointment of,
Deutsche Bank Trust Company Americas as the initial Trustee, Securities
Registrar and Paying Agent, subject to the provisions of the Indenture with
respect to resignation, removal and succession, and subject, further, to the
right of the Issuer to appoint additional agents (including Paying Agents). An
Authenticating Agent may be appointed for the Series __ Notes under the
circumstances set forth in, and subject to the provisions of, the Indenture.

                                  ARTICLE II.

                            Miscellaneous Provisions

          SECTION 1. The recitals contained herein shall be taken as the
statements of the Issuer, and the Trustee assumes no responsibility for the
correctness of the same. The Trustee makes no representation as to the validity
of this supplemental indenture. The Indenture, as supplemented by this
supplemental indenture, is in all respects hereby adopted, ratified and
confirmed.

          SECTION 2. The titles of the several Articles of this _____
Supplemental Indenture shall not be deemed to be any part hereof.

          SECTION 3. This ______ Supplemental Indenture may be executed in any
number of counterparts, each of which so executed shall be deemed to be an
original, but all such counterparts shall together constitute but one and the
same instrument.

                                       4

<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused this _____
Supplemental Indenture to be duly executed.

                                           IDAHO POWER COMPANY

                                           By   ____________________________
                                                Name:
                                                Title:

                                           DEUTSCHE BANK TRUST COMPANY AMERICAS

                                           By ___________________________
                                                Name:
                                                Title:

                                       5

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