<PAGE>

                                                                    Exhibit 4(d)




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


                                 AMENDMENT NO. 1

                            Dated as of May 13, 2003

                          EXTENDING THE EXPIRATION DATE


                                     of the

                                CREDIT AGREEMENT

                            dated as of May 21, 2002


                                      among


                               AVISTA CORPORATION,

                             THE BANKS PARTY HERETO,

                             WASHINGTON MUTUAL BANK,
                               as Managing Agent,

               FLEET NATIONAL BANK, KEYBANK NATIONAL ASSOCIATION,
              U.S. BANK, NATIONAL ASSOCIATION and WELLS FARGO BANK,
                            as Documentation Agents,

                         UNION BANK OF CALIFORNIA, N.A.,
                              as Syndication Agent,

                                       and

                              THE BANK OF NEW YORK,
                    as Administrative Agent and Issuing Bank



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

          BNY CAPITAL MARKETS, INC. and UNION BANK OF CALIFORNIA, N.A.
                        Lead Arrangers and Book Managers


--------------------------------------------------------------------------------
<PAGE>
                                 AMENDMENT NO. 1
                            Dated as of May 13, 2003

                                       to

                                CREDIT AGREEMENT
                            Dated as of May 21, 2002

      AVISTA CORPORATION, a Washington corporation, the Banks listed on the
signature pages hereof, WASHINGTON MUTUAL BANK, as Managing Agent, FLEET
NATIONAL BANK, KEYBANK NATIONAL ASSOCIATION, U.S. BANK, NATIONAL ASSOCIATION and
WELLS FARGO BANK, as Documentation Agents, UNION BANK OF CALIFORNIA, N.A., as
Syndication Agent, and THE BANK OF NEW YORK, as Administrative Agent and Issuing
Bank, agree as follows:

      1.    Credit Agreement. Reference is made to the Credit Agreement, dated
as of May 21, 2002, among Avista Corporation, a Washington corporation, the
Banks listed in Schedule 2.01 thereto, KeyBank National Association and
Washington Mutual Bank, as Co-Agents, U.S. Bank, National Association, as
Managing Agent, Fleet National Bank and Wells Fargo Bank, as Documentation
Agents, Union Bank of California, N.A., as Syndication Agent, and The Bank of
New York, as Administrative Agent and Issuing Bank (the "Credit Agreement").
Terms defined in the Credit Agreement and not otherwise defined herein are used
herein as therein defined. As used herein, the terms "Bond Delivery Agreement",
"First Mortgage Bond" and "Supplemental Indenture" have the meanings ascribed to
such terms in Section 2 hereof and the term "Amendment Documents" means this
Amendment, the Bond Delivery Agreement, the First Mortgage Bond and the
Supplemental Indenture.

      2.    Amendments. Subject to satisfaction of the conditions precedent set
forth in Section 4 below, effective as of the date hereof (the "Effective
Date"), the Credit Agreement shall be amended as follows:

      (a)   The definition of "Applicable Rate" contained in Section 1.01 of the
Credit Agreement shall be amended by replacing the table contained therein with
the following table:

<TABLE>
<CAPTION>
                                       Commitment Fee
Pricing       Commitment Fee            (> 33.33% but       Commitment Fee     Eurodollar   LC Participation      ABR
  Levels     (< or = 33.33% Usage)    < or = 50.0% Usage)   (> 50.0% Usage)      Margin           Fee            Margin
  ------     ---------------------    -------------------   ---------------      ------           ---            ------
<S>          <C>                      <C>                   <C>                <C>          <C>                 <C>
    I             0.250%                 0.200%                 0.150%           1.250%          1.250%         0.250%
    II            0.275%                 0.225%                 0.200%           1.375%          1.375%         0.375%
   III            0.400%                 0.350%                 0.250%           1.625%          1.625%         0.625%
    IV            0.525%                 0.475%                 0.375%           1.875%          1.875%         0.875%
    V             0.750%                 0.625%                 0.500%           2.500%          2.500%         1.500%
</TABLE>

      (b)   The definition of "Bond Delivery Agreement" contained in Section
1.01 of the Credit Agreement shall be amended to read as follows:


                                       1
<PAGE>
            "Bond Delivery Agreement" shall mean (i) the Twenty-Ninth Series
      Bond Delivery Agreement or (ii) any comparable bond delivery agreement
      relating to the delivery of a first mortgage bond issued under the First
      Mortgage in substitution for a First Mortgage Bond in connection with a
      Commitment Increase pursuant to Section 2.10(d).

      (c)   Clause (a) of the definition of "Commitment" contained in Section
1.01 of the Credit Agreement shall be amended by inserting immediately after the
words "Section 2.10(b)," the words "increased from time to time pursuant to
Section 2.10(d),".

      (d)   The definition of "Expiration Date" contained in Section 1.01 of the
Credit Agreement shall be amended by replacing the date "May 20, 2003" with the
date "May 11, 2004".

      (e)   The definition of "First Mortgage Bond" contained in Section 1.01 of
the Credit Agreement shall be amended to read as follows:

            "First Mortgage Bond" shall mean (i) the Twenty-Ninth Series First
      Mortgage Bond or (ii) any first mortgage bond under the First Mortgage
      issued in substitution for a First Mortgage Bond in connection with a
      Commitment Increase pursuant to Section 2.10(d).

      (f)   Clause (a) of the definition of "Interest Period" contained in
Section 1.01 of the Credit Agreement shall be amended to read as follows:

      (a) as to any Eurodollar Borrowing, the period commencing on the date of
      such Borrowing and ending on, as the Borrower may elect, the date 2 weeks
      thereafter or the numerically corresponding day (or, if there is no
      numerically corresponding day, on the last day) in the calendar month that
      is 1, 2, 3 or 6 months thereafter, and

      (g)   The definition of "Supplemental Indenture" contained in Section 1.01
of the Credit Agreement shall be amended to read as follows:

            "Supplemental Indenture" shall mean (i) the Thirty-First
      Supplemental Indenture or (ii) any supplemental indenture to the First
      Mortgage pursuant to which a first mortgage bond under the First Mortgage
      is issued in substitution for a First Mortgage Bond in connection with a
      Commitment Increase pursuant to Section 2.10(d).

      (h)   The following new definitions shall be inserted in the proper
alphabetical order in Section 1.01 of the Credit Agreement:

            "Evergreen Letter of Credit" shall mean a Letter of Credit that, by
      its terms, provides that it shall be automatically renewed or extended for
      a stated period of time at the end of its then-scheduled expiration date
      unless the Issuing Bank notifies the beneficiary thereof prior to such
      expiration date that the Issuing Bank elects not to renew or extend such
      Letter of Credit.

                                       2
<PAGE>
            "First Amendment" shall mean Amendment No. 1 dated as of May 13,
      2003 to this Agreement.

            "Thirty-First Supplemental Indenture" shall mean the Thirty-First
      Supplemental Indenture, dated as of May 1, 2003, between the Borrower and
      Citibank, N.A., as trustee under the First Mortgage.

            "Twenty-Ninth Series Bond Delivery Agreement" shall mean the Bond
      Delivery Agreement, dated the date of the First Amendment, between the
      Borrower and the Administrative Agent.

            "Twenty-Ninth Series First Mortgage Bond" shall mean a bond of the
      Twenty-Ninth Series issued under the Supplemental Indenture, in a
      principal amount equal to the total Commitments on the date of the First
      Amendment, payable to the Administrative Agent.

      (i)   The last sentence of Section 2.05(b) of the Credit Agreement shall
be amended by replacing the dollar amount "$50,000,000" with the dollar amount
"$75,000,000".

      (j)   Section 2.05(c) of the Credit Agreement shall be amended to read as
follows:

            (c)   Expiration Date. Each Letter of Credit shall expire (or, in
      the case of an Evergreen Letter of Credit, shall expire if the Issuing
      Bank gives the required notice of non-renewal or non-extension) not later
      than the close of business on the date that is five Business Days prior to
      the first anniversary of the Expiration Date.

      (k)   Section 2.05 of the Credit Agreement shall be further amended by
adding the following new paragraph (j) to the end thereof:

            (j)   In the event that any Letters of Credit are outstanding on the
      Expiration Date and shall have an expiration date thereafter, the Borrower
      shall either (i) deposit in an account with the Administrative Agent an
      amount in cash equal to the LC Exposure as of such date, to be held and
      applied as provided in Section 2.05(i), or (ii) enter into an agreement
      with the Issuing Bank (which the Issuing Bank may do in its sole and
      absolute discretion) effective as of the Expiration Date whereby such
      Letters of Credit shall thereafter be governed by another agreement and
      shall cease to be governed by this Agreement, whereupon all participations
      of the Banks in such Letters of Credit shall automatically terminate,
      provided that such agreement and termination shall not affect the
      obligation of the Borrower with respect to amounts accrued or owing at
      such time under the Loan Documents with respect to such Letters of Credit.

      (l)   The caption to Section 2.10 of the Credit Agreement shall be amended
by adding the words "; Increase in Commitments" to the end thereof.


                                       3
<PAGE>
      (m)   Section 2.10 of the Credit Agreement shall be further amended by
adding the new paragraph (d) to the end thereof:

            (d)   At any time following the date of this Agreement and prior to
      the Expiration Date, the aggregate amount of the Commitments may, at the
      option of the Borrower, be increased by an amount not in excess of
      $30,000,000, either by new Banks establishing Commitments or by one or
      more then-existing Banks increasing their Commitments (each such increase
      by either means, a "Commitment Increase," and each such new Bank or Bank
      increasing its Commitment, an "Additional Commitment Bank"); provided that
      (a) each Additional Commitment Bank shall be selected or approved by the
      Borrower and shall be reasonably acceptable to the Administrative Agent
      and the Issuing Bank, (b) no Bank shall have an obligation to become an
      Additional Commitment Bank, (c) no Default or Event of Default shall exist
      immediately prior to or after the effective date of the Commitment
      Increase, (d) each Commitment Increase shall be in an aggregate amount not
      less than $10,000,000 and multiples of $5,000,000 in excess thereof, (e)
      the aggregate amount of the Commitment Increases after the date of this
      Agreement shall not exceed $30,000,000, and (f) no Commitment Increase
      shall become effective unless and until (i) the Borrower, the
      Administrative Agent, the Issuing Bank and each Additional Commitment Bank
      shall have executed and delivered an agreement substantially in the form
      of Exhibit D (a "Commitment Increase Supplement") and (ii) the
      Administrative Agent shall have received a substitute First Mortgage Bond
      in an amount equal to the total Commitments after giving effect to the
      Commitment Increase, together with a supplemental indenture, bond delivery
      agreement, mortgage title insurance, legal opinions and other certificates
      and documents with respect thereto comparable to those delivered pursuant
      to Section 4.02(a) with respect to the Twenty-Eighth Series First Mortgage
      Bond issued under the First Mortgage, in each case in form and substance
      satisfactory to the Administrative Agent. On the effective date of a
      Commitment Increase, each Additional Commitment Bank shall purchase, as an
      assignment from each other existing Bank, the portion of such other Bank's
      Loans, unreimbursed LC Disbursements and participations in Letters of
      Credit outstanding at such time such that, after giving effect to such
      assignments, the respective aggregate amount of Loans, unreimbursed LC
      Disbursements and participations in Letters of Credit of each Bank shall
      be equal to such Bank's Pro Rata Share of the aggregate Loans,
      unreimbursed LC Disbursements and participations in Letters of Credit
      outstanding. The purchase price for the Loans, unreimbursed LC
      Disbursements and participations in Letters of Credit so assigned shall be
      the sum of (i) the principal amount of the Loans and unreimbursed LC
      Disbursements so assigned plus the amount of accrued and unpaid interest
      thereon as of the date of assignment and (ii) the amount of accrued and
      unpaid LC Participation Fees as of the date of assignment on the
      participations in Letters of Credit so assigned. Each Additional
      Commitment Bank shall pay the aggregate purchase price payable by it to
      the Administrative Agent on the effective date of the Commitment Increase
      and the Administrative Agent shall promptly forward to each other Bank the
      portion thereof payable to it. Upon payment of such purchase price, each
      other Bank shall be automatically deemed to have sold and made such an
      assignment to such Additional Commitment Bank and shall, to the extent of
      the interest assigned, be released from its obligations under the Loan
      Documents, and such Additional Commitment Bank shall be


                                       4
<PAGE>
      automatically deemed to have purchased and assumed such an assignment from
      each other Bank and, if not already a Bank hereunder, shall be a party
      hereto and, to the extent of the interest assigned, have the rights and
      obligations of a Bank under the Loan Documents.

      (n)   The first sentence of Section 2.11 of the Credit Agreement shall be
amended by replacing the words "upon at least three Business Days' prior notice
to the Administrative Agent" with the words "upon at least three Business Days'
prior notice to the Administrative Agent in the case of a prepayment of a
Eurodollar Borrowing and upon at least one Business Day's prior notice in the
case of a prepayment of an ABR Borrowing".

      (o)   Sections 3.05, 3.06, 3.07 and 3.12 of the Credit Agreement shall be
amended by replacing all references therein to the date "December 31, 2001" with
references to the date "December 31, 2002".

      (p)   Section 3.11 of the Credit Agreement shall be amended by replacing
the dollar amount "$10,000,000" with the dollar amount "$25,000,000".

      (q)   Clause (z) of Section 6.01 of the Credit Agreement shall be amended
by replacing the dollar amount "$150,000,000" with the dollar amount
"$234,000,000".

      (r)   Section 6.09 of the Credit Agreement shall be amended by replacing
the references to the years "2002" and "2003" with references to the years
"2003" and "2004", respectively.

      (s)   Schedule 2.01 to the Credit Agreement shall be replaced by Schedule
2.01 attached hereto.

      (t)   The Credit Agreement shall be amended by adding Exhibit D attached
hereto as Exhibit D thereto.

      3.    Representations and Warranties. In order to induce the each Bank and
the Issuing Bank to enter into this Amendment, the Borrower represents and
warrants as follows:

      (a)   The Borrower has the corporate power and authority (i) to execute
and deliver the Amendment Documents, (ii) to perform its obligations under the
Amendment Documents and the Loan Documents as amended thereby and (iii) to
borrow Loans and have Letters of Credit issued in the maximum amount available
under the Credit Agreement as amended hereby.

      (b)   The execution and delivery by the Borrower of the Amendment
Documents, the performance by the Borrower of its obligations under the
Amendment Documents and the Loan Documents as amended thereby, and the borrowing
of Loans and procurement of Letters of Credit in the maximum amount available
under the Credit Agreement as amended hereby (collectively, the "Transactions")
(a) have been duly authorized by all requisite corporate and, if required,
stockholder action and (b) will not (i) violate (A) any provision of law,
statute, rule or regulation the violation of which could reasonably be expected
to impair the validity and


                                       5
<PAGE>
enforceability of any Amendment Document or any Loan Document as amended thereby
or materially impair the rights of or benefits available to the Banks or the
Issuing Bank under the Amendment Documents or the Loan Documents as amended
thereby, or of the certificate or articles of incorporation or other
constitutive documents or by laws of the Borrower or any Significant Subsidiary,
(B) any order of any Governmental Authority the violation of which could
reasonably be expected to impair the validity or enforceability of any Amendment
Document or any Loan Document as amended thereby, or materially impair the
rights of or benefits available to the Banks or the Issuing Bank under the
Amendment Documents or the Loan Documents as amended thereby, or (C) any
provision of any indenture or other material agreement or instrument evidencing
or relating to borrowed money to which the Borrower or any Significant
Subsidiary is a party or by which any of them or any of their property is or may
be bound in a manner which could reasonably be expected to impair the validity
and enforceability of any Amendment Document or any Loan Document as amended
thereby or materially impair the rights of or benefits available to the Banks or
the Issuing Bank under any Amendment Document or any Loan Document as amended
thereby, (ii) be in conflict with, result in a breach of or constitute (alone or
with notice or lapse of time or both) a default under any such indenture,
agreement or other instrument in a manner which could reasonably be expected to
impair the validity and enforceability of any Amendment Document or any Loan
Document as amended thereby or materially impair the rights of or benefits
available to the Banks or the Issuing Bank under any Amendment Document or any
Loan Document as amended thereby or (iii) result in the creation or imposition
under any such indenture, agreement or other instrument of any Lien upon or with
respect to any property or assets now owned or hereafter acquired by the
Borrower.

      (c)   This Amendment has been duly executed and delivered by the Borrower
and constitutes, and each other Amendment Document when executed and delivered
by the Borrower, and the Loan Documents as amended thereby, will constitute,
legal, valid and binding obligations of the Borrower enforceable against the
Borrower in accordance with its terms.

      (d)   No action, consent or approval of, registration or filing with or
any other action by any Governmental Authority is or will be required in
connection with the Transactions, except such as have been made or obtained and
are in full force and effect.

      (e)   Each representation and warranty made in the Loan Documents is true
and correct at and as of the date hereof after giving effect to the Amendment
Documents, except to the extent such representations and warranties expressly
relate to an earlier date.

      (f)   No Default or Event of Default has occurred and is continuing after
giving effect to the Amendment Documents.

      4.    Conditions to Effectiveness. The amendments provided for in Section
2 above shall become effective as of the Effective Date, but shall not become
effective as of such date unless and until each of the following conditions
precedent shall have been satisfied:

      (a)   The Administrative Agent shall have received each of the following,
in form and substance satisfactory to it:

                                       6
<PAGE>
            (i)   Opinion of Heller Ehrman White & McAuliffe, LLP, counsel to
      the Borrower, dated the date of this Amendment and addressed to the
      Administrative Agent, the Banks and the Issuing Bank, with respect to such
      matters relating to the Borrower, the Amendment Documents and the Loan
      Documents as amended thereby, as the Administrative Agent, the Issuing
      Bank or any Bank may reasonably request. The Borrower hereby instructs
      such counsel to deliver such opinion to the Administrative Agent.

            (ii)  Evidence satisfactory to the Administrative Agent that the
      Borrower shall have obtained all consents and approvals of, and shall have
      made all filings and registrations with, any Governmental Authority
      required in order to consummate the Transactions, in each case without the
      imposition of any condition which, in the judgment of the Banks or the
      Issuing Bank, could adversely affect their rights or interests under the
      Amendment Documents or the Loan Documents as amended thereby.

            (iii) A copy of the certificate or articles of incorporation,
      including all amendments thereto, of the Borrower, certified as of a
      recent date by the Secretary of State of the state of its organization,
      and a certificate as to the good standing of the Borrower as of a recent
      date, from such Secretary of State.

            (iv)  A certificate of the Secretary or Assistant Secretary of the
      Borrower dated the date of this Amendment and certifying (A) that attached
      thereto is a true and complete copy of the by-laws of the Borrower as in
      effect on the date of this Amendment and at all times since a date prior
      to the date of the resolutions described in clause (B) below, (B) that
      attached thereto is a true and complete copy of resolutions duly adopted
      by the board of directors of the Borrower authorizing the Transactions,
      and that such resolutions have not been modified, rescinded or amended and
      are in full force and effect, (C) that the certificate or articles of
      incorporation of the Borrower have not been amended since the date of the
      last amendment thereto shown on the certificate of good standing furnished
      pursuant to clause (iii) above, and (D) as to the incumbency and specimen
      signature of each officer executing any Amendment Document or any other
      document delivered in connection therewith on behalf of the Borrower.

            (v)   A certificate of another officer as to the incumbency and
      specimen signature of the Secretary or Assistant Secretary executing the
      certificate pursuant to clause (iv) above.

            (vi)  A certificate, dated the date of this Amendment and signed by
      a Financial Officer of the Borrower, confirming compliance with the
      conditions precedent set forth in paragraphs (e) and (f) of Section 3
      hereof.

            (vii) Evidence satisfactory to the Administrative Agent that the
      Amendment Documents have been executed and delivered by all parties
      thereto.

            (viii) A certificate, dated the date of this Amendment and signed by
      the Secretary or an Assistant Secretary of the Borrower, certifying that
      the First Mortgage


                                       7
<PAGE>
      has not been amended or supplemented since the certified copy thereof
      delivered by the Borrower pursuant to Section 4.02(a)(viii) of the Credit
      Agreement, except as supplemented by the Supplemental Indenture.

            (ix)  A paid endorsement to title insurance policy No. NSL 31426-SEA
      issued by First American Title Insurance Company, which endorsement (A)
      provides that the insured is the trustee under the First Mortgage
      including all supplemental indentures through the Supplemental Indenture,
      (B) increases the amount of insurance to not less than $395,000,000, (C)
      updates the list of insured properties to conform to the list of
      properties subject to the First Mortgage, (D) insures against loss from
      the failure of the Supplemental Indenture to modify the First Mortgage and
      (E) updates the insurance as to the priority of the First Mortgage.

            (x)   Such other documents as the Administrative Agent, the Banks,
      the Issuing Bank or their respective legal counsel may reasonably request.

      (b)   All fees payable by the Borrower to the Administrative Agent, the
Issuing Bank, the Banks or any of their Affiliates on or prior to the date of
this Amendment with respect to this Amendment, and all amounts payable by the
Borrower pursuant to Section 9.05 of the Credit Agreement for which invoices
have been delivered to the Borrower on or prior to such date, shall have been
paid in full or arrangements satisfactory to the Administrative Agent shall have
been made to cause them to be paid in full concurrently with the disbursement of
the proceeds of any Borrowing to be made on such date.

      (c)   All legal matters incident to the Amendment Documents and the Loan
Documents as amended thereby and the transactions contemplated thereby shall be
reasonably satisfactory to the Administrative Agent, the Banks, the Issuing Bank
and their respective legal counsel.

      5.    Assignment of Loans, LC Disbursements and LC Participations to
Reflect Amended Commitments. On the Effective Date, the Banks whose Pro Rata
Shares after giving effect to this Amendment are greater than their Pro Rata
Shares prior to giving effect to this Amendment (each an "Increasing Bank")
shall purchase, as an assignment from the Banks whose Pro Rata Shares after
giving effect to this Amendment are less than their Pro Rata Shares prior to
giving effect to this Amendment (each a "Decreasing Bank"), such portions of the
Decreasing Banks' Loans, unreimbursed LC Disbursements and participations in
Letters of Credit outstanding at such time such that, after giving effect to
such assignments, the respective aggregate amount of Loans, unreimbursed LC
Disbursements and participations in Letters of Credit of each Bank shall be
equal to such Bank's Pro Rata Share of the aggregate Loans, unreimbursed LC
Disbursements and participations in Letters of Credit outstanding. The purchase
price for the Loans, unreimbursed LC Disbursements and participations in Letters
of Credit so assigned shall be the sum of (i) the principal amount of the Loans
and unreimbursed LC Disbursements so assigned plus the amount of accrued and
unpaid interest thereon as of the date of assignment and (ii) the amount of
accrued and unpaid LC Participation Fees as of the date of assignment on the
participations in Letters of Credit so assigned. Each Increasing Bank shall pay
the aggregate purchase price payable by it to the Administrative Agent on the
Effective Date and the Administrative Agent shall promptly forward to each
Decreasing Bank the portion


                                       8
<PAGE>
thereof payable to it. Upon payment by an Increasing Bank of the purchase price
payable by it to a Decreasing Bank, such Decreasing Bank shall be automatically
deemed to have sold and made the applicable assignments to such Increasing Bank
and shall, to the extent of the interest assigned, be released from its
obligations under the Loan Documents, and such Increasing Bank shall be
automatically deemed to have purchased and assumed such assignments from such
Decreasing Bank and, if not already a Bank hereunder, shall be a party hereto
and, to the extent of the interest assigned, have the rights and obligations of
a Bank under the Loan Documents.

      6.    Effect of Interest and Fee Rate Amendments. Any changes in interest
or fees rates effected by this Amendment shall apply with respect to interest
and fees accruing for the Effective Date and periods thereafter, while interest
and fees rates in effect prior to the effectiveness of such amendments shall
continue to be applicable for accruals for periods prior to the Effective Date.

      7.    Confirmation of Amended Agreement. The Credit Agreement as amended
by this Amendment is and shall continue to be in full force and effect and is
hereby in all respects confirmed, approved and ratified.

      8.    Governing Law. This Amendment shall be construed in accordance with
and governed by the law of the State of New York.

      9.    Counterparts. This Amendment may be signed in any number of
counterparts, each of which shall be an original, with the same effect as if the
signatures thereto were upon the same instrument.

      10.   Headings. Section headings in this Amendment are included herein for
convenience and reference only and shall not constitute a part of this Amendment
for any other purpose.

                      [The next page is the signature page]



                                       9
<PAGE>
WITNESS the due execution hereof as of the date first above written.

                                   AVISTA CORPORATION

                                   By:
                                      ------------------------------------------
                                   Name:
                                   Title:
<PAGE>
                                   THE BANK OF NEW YORK,
                                       as Administrative Agent, Issuing Bank and
                                       a Bank

                                   By:
                                      ------------------------------------------
                                   Name:
                                   Title:
<PAGE>
                                   UNION BANK OF CALIFORNIA, N.A.,
                                       as Syndication Agent and a Bank

                                   By:
                                      ------------------------------------------
                                   Name:
                                   Title:
<PAGE>
                                   FLEET NATIONAL BANK,
                                       as Documentation Agent and a Bank

                                   By:
                                      ------------------------------------------
                                   Name:
                                   Title:
<PAGE>
                                   KEYBANK NATIONAL ASSOCIATION,
                                      as Documentation Agent and a Bank

                                   By:
                                      ------------------------------------------
                                   Name:
                                   Title:
<PAGE>
                                   U.S. BANK, NATIONAL ASSOCIATION,
                                        as Documentation Agent and a Bank

                                   By:
                                      ------------------------------------------
                                   Name:
                                   Title:
<PAGE>
                                   WELLS FARGO BANK,
                                      as Documentation Agent and a Bank

                                   By:
                                      ------------------------------------------
                                   Name:
                                   Title:
<PAGE>
                                   WASHINGTON MUTUAL BANK,
                                      as Managing Agent and a Bank

                                   By:
                                      ------------------------------------------
                                   Name:
                                   Title:
<PAGE>
                                   BANK HAPOALIM B.M.,
                                      as a Bank

                                   By:
                                      ------------------------------------------
                                   Name:
                                   Title:


                                   By:
                                      ------------------------------------------
                                   Name:
                                   Title:
<PAGE>
                                  SCHEDULE 2.01

                 Names, Commitments, Addresses for Initial Banks

<TABLE>
<CAPTION>
Bank                                                           Commitment
----                                                           ----------
<S>                                                            <C>
The Bank of New York.                                          $45,000,000
One Wall Street, 19th Floor
New York, New York 10286
Attention:  Steven Kalachman
Telecopy: 212-635-7923

Union Bank of California, N.A.                                 $45,000,000
445 S. Figueroa Street
Los Angeles, CA  90071
Attention:  Karen Elliott
Telecopy: (213) 236-4096

Fleet National Bank                                            $30,000,000
Global Energy
100 Federal Street
Boston, MA  02110
Attention:  Stephen Hoffman
Telecopy:  (617) 434-3652

KeyBank National Association                                   $30,000,000
127 Public Square
Cleveland, OH  10286
Attention:  Sherrie Manson
Telecopy:  (216) 689-4981

U.S.  Bank, N.A.                                               $30,000,000
1420 Fifth Avenue, 1lth Floor
Seattle, WA  98101
Attention:  Wilfred Jack
Telecopy:  (206) 344-3654

Wells Fargo Bank                                               $30,000,000
221 N. Wall Street, Suite 310
Spokane, WA  99201
Attention:  Tom Beil
Telecopy:  (509) 363-6875
</TABLE>
<PAGE>
<TABLE>
<S>                                                           <C>
Washington Mutual Bank                                         $25,000,000
1201 3rd Avenue
Seattle, WA  98101
Attention:  Bruce Kendrex
Telecopy:  (206) 377-3812

Bank Hapoalim B.M.                                             $10,000,000
1177 Avenue of the Americas
New York, NY  10036
Attention:  Marc Bosc
Telecopy:  (212) 782-2382

                                                              ------------
TOTAL                                                         $245,000,000
</TABLE>
<PAGE>
                                                                       EXHIBIT D


                         COMMITMENT INCREASE SUPPLEMENT


      THIS COMMITMENT INCREASE SUPPLEMENT is made and dated as of
_________________ ____, by and among [ADDITIONAL COMMITMENT BANK] (the
"Additional Commitment Bank"), AVISTA CORPORATION, a Washington corporation, and
THE BANK OF NEW YORK, as Administrative Agent and Issuing Bank under the Credit
Agreement, dated as of May 21, 2002, among Avista Corporation, the Banks listed
in Schedule 2.01 thereto, KeyBank National Association and Washington Mutual
Bank, as Co-Agents, U.S. Bank, National Association, as Managing Agent, Fleet
National Bank and Wells Fargo Bank, as Documentation Agents, Union Bank of
California, N.A., as Syndication Agent, and The Bank of New York, as
Administrative Agent and Issuing Bank, as amended (the "Credit Agreement").
Terms used and not otherwise defined herein are used herein with the meanings
therein ascribed thereto in the Credit Agreement.

      WHEREAS, the Borrower desires to have the aggregate amount of the
Commitments increased; and

      WHEREAS, the Additional Commitment Bank is willing to [become an
additional Bank](1)[increase its Commitment](2);

      NOW, THEREFORE, the parties hereto agree as follows:

      1.    Upon the effectiveness of this Commitment Increase Supplement, [the
Additional Commitment Bank shall be a party to the Credit Agreement and shall be
entitled to all of the rights, and be subject to all of the obligations, of a
Bank under the Credit Agreement](1) [the Commitment of the Additional Commitment
Bank shall be increased from $_____________ to $__________________.](2) [The
initial amount of the Additional Commitment Bank's Commitment shall be
$________________.](1)

      2.    The Additional Commitment Bank acknowledges, and agrees to comply
with, its obligation under Section 2.10(d) of the Credit Agreement to purchase
assignments of Loans, unreimbursed LC Disbursements and participations in
Letters of Credit from the other Banks on the effective date hereof.

      3.    This Commitment Increase Supplement shall become effective upon the
execution and delivery hereof by the Additional Commitment Bank, the Borrower,
the Administrative Agent and the Issuing Bank.

      4.    This Commitment Increase Supplement may be executed in any number of
counterparts and by the different parties hereto on separate counterparts, each
of which when so executed and delivered shall be an original, but all of which
shall together constitute one and the same instrument.


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(1) Include if Additional Commitment Bank is not an existing Bank.

(2) Include if Additional Commitment Bank is an existing Bank.
<PAGE>
      5.    This Commitment Increase Supplement shall be construed in accordance
with and governed by the law of the State of New York.



      IN WITNESS WHEREOF, the parties hereto have cause this Commitment Increase
Supplement to be executed as of the day and year first written above.

                              [ADDITIONAL COMMITMENT BANK]


                              By:
                                 ---------------------------------------
                               Name:
                               Title:



                              AVISTA CORPORATION


                              By:
                                 ---------------------------------------
                               Name:
                               Title:



                              THE BANK OF NEW YORK,
                                as Administrative Agent and Issuing Bank


                              By:
                                 ---------------------------------------
                               Name:
                               Title: