Document:

<PAGE>

                                                                    EXHIBIT 10.1

                                  $25,000,000

                           364-DAY CREDIT AGREEMENT

                                  dated as of

                                August 15, 2001

                                     among

                           SIERRA PACIFIC RESOURCES,

                                  as Borrower

                                      and

                             THE BANK OF NEW YORK,

                                    as Bank
<PAGE>

                               TABLE OF CONTENTS

<TABLE>
<S>                                                                                                <C>
ARTICLE I DEFINITIONS; CONSTRUCTION...............................................................   1

 SECTION 1.01   DEFINED TERMS.....................................................................   1
 SECTION 1.02   CLASSIFICATION OF LOANS AND BORROWINGS............................................  15
 SECTION 1.03   TERMS GENERALLY...................................................................  15
 SECTION 1.04   ACCOUNTING TERMS; GAAP............................................................  15

ARTICLE II THE CREDITS............................................................................  15

 SECTION 2.01   THE COMMITMENT....................................................................  15
 SECTION 2.02   LOANS AND BORROWINGS..............................................................  16
 SECTION 2.03   REQUESTS FOR REVOLVING BORROWINGS.................................................  16
 SECTION 2.04   FUNDING OF BORROWINGS.............................................................  17
 SECTION 2.05   CONVERSIONS.......................................................................  17
 SECTION 2.06   TERMINATION OR REDUCTION OF COMMITMENT............................................  18
 SECTION 2.07   REPAYMENT OF LOANS................................................................  19
 SECTION 2.08   NOTE..............................................................................  20
 SECTION 2.09   PREPAYMENT........................................................................  20
 SECTION 2.10   FEES..............................................................................  21
 SECTION 2.11   INTEREST..........................................................................  21
 SECTION 2.12   ALTERNATE RATE OF INTEREST........................................................  22
 SECTION 2.13   INCREASED COSTS...................................................................  22
 SECTION 2.14   BREAK FUNDING PAYMENTS............................................................  23
 SECTION 2.15   TAXES.............................................................................  24
 SECTION 2.16   ILLEGALITY........................................................................  25
 SECTION 2.17   PAYMENTS GENERALLY................................................................  25

ARTICLE III REPRESENTATIONS AND WARRANTIES........................................................  25

 SECTION 3.01   CORPORATE STATUS..................................................................  25
 SECTION 3.02   CORPORATE POWER AND AUTHORIZATION.................................................  26
 SECTION 3.03   EXECUTION AND BINDING EFFECT......................................................  26
 SECTION 3.04   GOVERNMENTAL APPROVALS AND FILINGS................................................  26
 SECTION 3.05   ABSENCE OF CONFLICTS..............................................................  26
 SECTION 3.06   AUDITED FINANCIAL STATEMENTS......................................................  27
 SECTION 3.07   INTERIM FINANCIAL STATEMENTS......................................................  27
 SECTION 3.08   ABSENCE OF UNDISCLOSED LIABILITIES................................................  27
 SECTION 3.09   ABSENCE OF MATERIAL ADVERSE CHANGE................................................  28
 SECTION 3.10   ACCURATE AND COMPLETE DISCLOSURE..................................................  28
 SECTION 3.11   MARGIN REGULATIONS................................................................  28
 SECTION 3.12   LITIGATION........................................................................  28
 SECTION 3.13   ABSENCE OF EVENTS OF DEFAULT......................................................  29
 SECTION 3.14   ABSENCE OF OTHER CONFLICTS........................................................  29
 SECTION 3.15   INSURANCE.........................................................................  29
</TABLE>

                                      -i-
<PAGE>

<TABLE>
<S>                                                                                                <C>
 SECTION 3.16   TITLE TO PROPERTY; NO LIENS.......................................................  29
 SECTION 3.17   TAXES.............................................................................  30
 SECTION 3.18   BORROWER NOT AN INVESTMENT COMPANY OR A REGISTERED PUBLIC UTILITY HOLDING
                COMPANY...........................................................................  30
 SECTION 3.19   ENVIRONMENTAL MATTERS.............................................................  30
 SECTION 3.20   ERISA.............................................................................  31
 SECTION 3.21   PARI PASSU STATUS.................................................................  32

ARTICLE IV CONDITIONS.............................................................................  32

 SECTION 4.01   EFFECTIVE DATE....................................................................  32
 SECTION 4.02   CONDITIONS TO ALL LOANS...........................................................  34

ARTICLE V AFFIRMATIVE COVENANTS...................................................................  35

 SECTION 5.01   BASIC REPORTING REQUIREMENTS......................................................  35
 SECTION 5.02   INSURANCE.........................................................................  38
 SECTION 5.03   PAYMENT OF TAXES AND OTHER POTENTIAL CHARGES AND PRIORITY CLAIMS..................  38
 SECTION 5.04   PRESERVATION OF CORPORATE STATUS AND FRANCHISES...................................  39
 SECTION 5.05   GOVERNMENTAL APPROVALS AND FILINGS................................................  39
 SECTION 5.06   MAINTENANCE OF PROPERTIES.........................................................  39
 SECTION 5.07   AVOIDANCE OF OTHER CONFLICTS......................................................  40
 SECTION 5.08   FINANCIAL ACCOUNTING PRACTICES....................................................  40
 SECTION 5.09   USE OF PROCEEDS...................................................................  40
 SECTION 5.10   END OF FISCAL PERIODS.............................................................  41

ARTICLE VI NEGATIVE COVENANTS.....................................................................  41

 SECTION 6.01   INDEBTEDNESS......................................................................  41
 SECTION 6.02   LIENS.............................................................................  41
 SECTION 6.03   MERGERS...........................................................................  43
 SECTION 6.04   DISPOSITIONS OF PROPERTIES........................................................  43
 SECTION 6.05   INVESTMENTS AND ACQUISITIONS......................................................  44
 SECTION 6.06   DIVIDENDS AND STOCK REPURCHASES...................................................  44
 SECTION 6.07   TRANSACTIONS WITH AFFILIATES......................................................  44
 SECTION 6.08   EQUAL AND RATABLE LIEN............................................................  45
 SECTION 6.09   RESTRICTIVE AGREEMENTS............................................................  45
 SECTION 6.10   DEBT TO CAPITALIZATION RATIO......................................................  45

ARTICLE VII DEFAULTS..............................................................................  45

 SECTION 7.01   EVENTS OF DEFAULT.................................................................  45
 SECTION 7.02   CONSEQUENCES OF AN EVENT OF DEFAULT...............................................  48

ARTICLE VIII MISCELLANEOUS........................................................................  49

 SECTION 8.01   AMENDMENTS AND WAIVERS............................................................  49
</TABLE>

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<TABLE>
<S>                                                                                                <C>
 SECTION 8.02   NO IMPLIED WAIVER; CUMULATIVE REMEDIES............................................  49
 SECTION 8.03   NOTICES...........................................................................  49
 SECTION 8.04   EXPENSES; TAXES; INDEMNITY........................................................  50
 SECTION 8.05   SEVERABILITY......................................................................  51
 SECTION 8.06   PRIOR UNDERSTANDINGS..............................................................  51
 SECTION 8.07   DURATION; SURVIVAL................................................................  51
 SECTION 8.08   COUNTERPARTS......................................................................  52
 SECTION 8.09   LIMITATION ON PAYMENTS............................................................  52
 SECTION 8.10   SET-OFF...........................................................................  52
 SECTION 8.11   SUCCESSORS AND ASSIGNS; ASSIGNMENTS; PARTICIPATIONS...............................  53
 SECTION 8.12   GOVERNING LAW; CONSENT TO JURISDICTION............................................  54
 SECTION 8.13   SERVICE OF PROCESS................................................................  54
 SECTION 8.14   NO LIMITATION ON SERVICE OR SUIT..................................................  54
 SECTION 8.15   WAIVER OF TRIAL BY JURY...........................................................  55
 SECTION 8.16   NO CONSEQUENTIAL DAMAGES..........................................................  55
</TABLE>

                                     -iii-
<PAGE>

     364-DAY CREDIT AGREEMENT, dated as of August 15, 2001, between SIERRA
PACIFIC RESOURCES, a Nevada corporation (the "Borrower") and THE BANK OF NEW
YORK (the "Bank" or "BNY").

                             W I T N E S S E T H:

     WHEREAS, the Borrower has requested, and the Bank has agreed to make
available, the credit facility described below upon the terms and conditions
contained herein.

     NOW, THEREFORE, in consideration of the premises and of the mutual
covenants herein contained and intending to be legally bound hereby, the parties
hereto agree as follows:

                                   ARTICLE I
                           DEFINITIONS; CONSTRUCTION

     SECTION 1.01   DEFINED TERMS.
                    -------------

     As used in this Agreement, the following terms have the following meanings:

     "ABR" when used in reference to any Loan or Borrowing, refers to whether
      ---
such Loan, or the Loans comprising such Borrowing, are bearing interest at a
rate determined by reference to the Alternate Base Rate.

     "Acquisition" means any transaction, or any series of related transactions,
      -----------
consummated after the Effective Date, by which the Borrower and/or any of its
Subsidiaries directly or indirectly (a) acquires any ongoing business or all or
substantially all of the assets of any Person engaged in any ongoing business,
whether through purchase of assets, merger or otherwise, (b) acquires control of
securities of a Person engaged in an ongoing business representing more than 50%
of the ordinary voting power for the election of directors or other governing
position if the business affairs of such Person are managed by a board of
directors or other governing body; or (c) acquires control of more than 50% of
the ownership interest in any partnership, joint venture, limited liability
company, business trust or other Person engaged in an ongoing business that is
not managed by a board of directors or other governing body.

     "Affiliate" means any Person that directly or indirectly Controls, or is
      ---------
under common Control with, or is Controlled by, another Person, provided that,
in any event, any Person that owns directly or indirectly securities having 20%
or more of the voting power for the election of directors or other governing
body of a corporation or 20% or more of the partnership or other ownership
interests of any other Person (other than as a limited partner of such other
Person) will be deemed to Control such corporation or other Person.
<PAGE>

     "Alternate Base Rate" means, for any day, a rate per annum equal to the
      -------------------
greater of (a) the BNY Rate in effect on such day and (b) the Federal Funds Rate
in effect on such day plus 1/2 of 1%.  Any change in the Alternate Base Rate due
                      ----
to a change in the BNY Rate or the Federal Funds Rate shall be effective from
and including the effective date of such change in the BNY Rate or the Federal
Funds Rate, respectively.

     "Applicable Margin" means, at any time, with respect to Loans of any Type
      -----------------
at any time, the percentage rate per annum which is applicable at such time with
respect to Loans of such Type, as set forth on the Pricing Table attached
hereto.

     "Bankruptcy Code" means Title 11 of the United States Code entitled
      ---------------
"Bankruptcy," as now or hereafter in effect or any successor thereto.

     "BNY Rate" means a rate of interest per annum equal to the prime commercial
      --------
lending rate of BNY as publicly announced by BNY to be in effect from time to
time, such rate to be adjusted automatically (without notice) on the effective
date of any change in such rate.

     "Board" means the Board of Governors of the Federal Reserve System of the
      -----
United States of America.

     "Borrowing" means advances under the Facility, made, converted or continued
      ---------
on the same date and, in the case of Eurodollar Loans, as to which a single
Interest Period is in effect.

     "Borrowing Date" means any date specified in a Borrowing Request delivered
      --------------
pursuant to Section 2.03 as a date on which the Borrower requests the Bank to
make a Loan.

     "Borrowing Request" means a request by the Borrower for a Borrowing made in
      -----------------
accordance with Section 2.03.

     "Business Day" means, for all purposes other than as set forth in clause
      ------------
(b) below, (a) any day other than a Saturday, Sunday or other day on which
commercial banks located in New York City are authorized or required by law or
other governmental action to close and (b) with respect to all notices and
determinations in connection with, and payments of principal and interest on,
Eurodollar Loans, any day which is a Business Day described in clause (a) above
and which is also a day on which dealings in foreign currency and exchange and
Eurodollar funding between banks may be carried on in London, England.

     "Capital Lease Obligations" of any Person, means all obligations of such
      -------------------------
Person to pay rent or other amounts under a lease of (or other agreement
conveying the right to use) Property to the extent such obligations are required
to be classified and accounted for as a capital lease on a balance sheet of such
Person under GAAP (including Statement

                                      -2-
<PAGE>

of Financial Accounting Standards No. 13 of the Financial Accounting Standards
Board), and, for purposes of this Agreement, the amount of such obligations
shall be the capitalized amount thereof, determined in accordance with GAAP
(including such Statement No. 13).

     "Change in Control" means (a) the acquisition of ownership, directly or
      -----------------
indirectly, beneficially or of record, by any Person or group (within the
meaning of the Securities Exchange Act of 1934 and the rules of the Securities
and Exchange Commission thereunder as in effect on the date hereof) of shares
representing more than 20% of the aggregate ordinary voting power represented by
the issued and outstanding capital stock of the Borrower; (b) for any period of
12 consecutive calendar months, a majority of the Board of Directors of  the
Borrower shall no longer be composed of individuals (i) who were members of said
Board on the first day of such period, (ii) whose election or nomination to said
Board was approved by individuals referred to in clause (i) above constituting
at the time of such election or nomination at least a majority of said Board or
(iii) whose election or nomination to said Board was approved by individuals
referred to in clauses (i) and (ii) above constituting at the time of such
election or nomination at least a majority of said Board; (c) the failure of the
Borrower to own, legally and beneficially, 100% of the aggregate ordinary voting
power represented by the issued and outstanding capital stock of either NPC or
SPPC; or (d) any reduction in Borrower's ownership, either legal or beneficial,
of a Significant Subsidiary.

     "Change in Law" means (a) the adoption of any Law after the date of this
      -------------
Agreement, (b) any change in any Law or in the interpretation or application
thereof by any Governmental Authority after the date of this Agreement or (c)
compliance by Bank (or, for purposes of Section 2.13(b), by any lending office
of Bank or by Bank's holding company) with any request, guideline or directive
(whether or not having the force of Law) of any Governmental Authority made or
issued after the date of this Agreement.

     "Code" means the Internal Revenue Code of 1986 and the regulations
      ----
promulgated and rulings issued thereunder.  Section references to the Code are
to the Code, as in effect at the date of this Agreement and any subsequent
provisions of the Code, amendatory thereof, supplemental thereto or substituted
therefor.

     "Commitment" means the Bank's undertaking to make Loans from time to time
      ----------
to the Borrower in an aggregate principal amount, subject to Section 2.01, not
to exceed $25,000,000, as the Commitment may be reduced from time to time
pursuant to Section 2.06.

     "Commitment Fee" has the meaning assigned to such term in Section 2.10.
      --------------

     "Commitment Period" means the period from and including the Effective Date
      -----------------
to the Termination Date or such earlier date as the Commitment shall terminate
as provided herein.

                                      -3-
<PAGE>

     "Compliance Certificate" means a certificate of the Borrower in
      ----------------------
substantially the form of Exhibit D, duly executed by a Responsible Officer or
such other officer of the Company as shall be acceptable to the Bank.

     "Consolidated Indebtedness" means all Indebtedness of the Borrower and its
      -------------------------
Subsidiaries eliminating intercompany items.

     "Consolidated Net Worth" means the amount of (a) Shareholders' Equity plus
      ----------------------                                               ----
(b) Preferred Securities.

     "Consolidated Total Capitalization" means Consolidated Indebtedness plus
      ---------------------------------                                  ----
Consolidated Net Worth.

     "Contingent Obligation" means, for the Borrower and its Subsidiaries, any
      ---------------------
direct or indirect Contractual Obligation with respect to any Indebtedness,
lease, dividend, letter of credit or other obligation (the "primary
obligations") of another Person (the "primary obligor"), including, without
limitation, any obligation of the Borrower or any Subsidiary, whether or not
contingent, (a) to purchase, repurchase or otherwise acquire such primary
obligations or any Property constituting direct or indirect security therefor,
or (b) to advance or provide funds (i) for the payment or discharge of any such
primary obligation, or (ii) to maintain working capital or equity capital of the
primary obligor or otherwise to maintain the net worth or solvency or any
balance sheet item, level of income or financial condition of the primary
obligor prior to such obligation being a stated or determinable amount, or (c)
to purchase Property, securities or services primarily for the purpose of
assuring the owner of any such primary obligation of the ability of the primary
obligor to make payment of such primary obligation, or (d) otherwise to assure
or hold harmless the holder of any such primary obligation against loss in
respect thereof. The amount of any Contingent Obligation shall be deemed to be
an amount equal to the stated or determinable amount of the primary obligation
in respect of which such Contingent Obligation is made or, if not stated or if
indeterminable, the maximum reasonably anticipated liability in respect thereof,
except as specified in clause (b)(ii) above.

     "Contractual Obligations" means, as to any Person, any provision of any
      -----------------------
security issued by such Person or of any agreement, undertaking, contract,
indenture, mortgage, deed of trust or other instrument, document or agreement to
which such Person is a party or by which it or any of its Property is bound.

     "Control" of a Person (including, with its correlative meanings,
      -------
"Controlled by" and "under common Control with"), means possession, directly or
indirectly, of the power to direct or cause the direction of management or
policies (whether through ownership of securities or partnership or other
ownership interests, by contract or otherwise) of such Person.

                                      -4-
<PAGE>

     "Conversion Date" means the date on which a Eurodollar Loan is converted to
      ---------------
an Alternate Base Rate Loan, or the date on which an Alternate Base Rate Loan is
converted to a Eurodollar Loan, or the date on which a Eurodollar Loan is
converted to a new Eurodollar Loan, all in accordance with Section 2.05.

     "Default" means any event, act or condition, which upon notice, lapse of
      -------
time or both would, unless cured or waived, become an Event of Default.

     "Default Interest" has the meaning assigned to such term in Section
      ----------------
2.11(c).

     "Dispose" has the meaning assigned to such term in Section 6.04.
      -------

     "Dollars" or "$" refers to freely transferable lawful money of the United
      -------      -
States of America.

     "Effective Date" means the date on which the conditions specified in
      --------------
Section 4.01 are satisfied (or waived in accordance with Section 8.01).

     "Environmental Claims" means any and all administrative, regulatory or
      --------------------
judicial actions, suits, demands, demand letters, directives, claims, liens,
notices of non-compliance or violation, investigations or proceedings relating
in any way to any Environmental Law or any permit issued, or any approval given,
under any such Environmental Law (hereafter, "Claims"), including, without
                                              ------
limitation, (a) any and all Claims by governmental or regulatory authorities for
enforcement, cleanup, removal, response, remedial or other actions or damages
pursuant to any applicable Environmental Law, and (b) any and all Claims by any
third party seeking damages, contribution, indemnification, cost recovery,
compensation or injunctive relief in connection with alleged injury or threat of
injury to health, safety or the environment due to the presence of Hazardous
Materials.

     "Environmental Law" means any Federal, state, foreign or local statute,
      -----------------
Law, rule, regulation, ordinance, code, guideline, written policy and rule of
common law now or hereafter in effect and in each case as amended, and any
judicial or administrative interpretation thereof, including any judicial or
administrative order, consent decree or judgment, relating to the environment,
employee health and safety or Hazardous Materials, including, without
limitation, CERCLA; RCRA; the Federal Water Pollution Control Act, 33 U.S.C. (S)
1251 et seq.; the Toxic Substances Control Act, 15 U.S.C. (S) 2601  et seq.; the
     -- ----                                                       --- ----
Clean Air Act, 42 U.S.C. (S) 7401 et seq.; the Safe Drinking Water Act, 42
                                  -- ----
U.S.C. (S) 3803 et seq.; the Oil Pollution Act of 1990, 33 U.S.C. (S) 2701 et
                -- ----                                                    --
seq.; the Emergency Planning and the Community Right-to-Know Act of 1986, 42
----
U.S.C. (S) 11001 et seq.; the Hazardous Material Transportation Act, 49 U.S.C.
                 -- ----
(S) 1801 et seq. and the Occupational Safety and Health Act, 29 U.S.C. (S) 651
         -- ----
et seq.; and any state and local or foreign counter-parts or equivalents, in
-- ----
each case as amended from time to time.

                                      -5-
<PAGE>

     "ERISA" means the Employee Retirement Income Security Act of 1974 and the
      -----
regulations promulgated and rulings issued thereunder.  Section references to
ERISA are to ERISA, as in effect at the date of this Agreement, and to any
subsequent provisions of ERISA, amendatory thereof, supplemental thereto or
substituted therefor.

     "ERISA Affiliate" means any corporation or trade or business that is a
      ---------------
member of any group of organizations described in Section 414(b) or (c) of the
Code of which the Borrower is a member.

     "Eurodollar" when used in reference to any Loan or Borrowing, refers to
      ----------
whether such Loan, or the Loans comprising such Borrowing, are bearing interest
at a rate determined by reference to the Eurodollar Rate.

     "Eurodollar Rate" means, with respect to any Interest Period applicable to
      ---------------
any Eurodollar Loan, the rate of interest per annum, as determined by the Bank,
obtained by dividing (and then rounding to the nearest 1/16 of 1% or, if there
is no nearest 1/16 of 1%, then to the next higher 1/16 of 1%):

          (a)  the rate quoted by the Bank to leading banks in the interbank
eurodollar market as the rate at which the Bank is offering Dollar deposits in
an amount equal approximately to the Eurodollar Loan to which such Interest
Period shall apply for a period equal to such Interest Period, as quoted at
approximately 11:00 a.m. (New York City time) two Business Days prior to the
first day of such Interest Period, by

          (b)  a number equal to 1.00 minus the aggregate of the then stated
maximum rates during such Interest Period of all reserve requirements
(including, without limitation, marginal, emergency, supplemental and special
reserves), expressed as a decimal,  established by the Board and any other
banking authority to which the Bank and other major United States money center
banks are subject, in respect of eurocurrency funding (currently referred to as
"Eurocurrency liabilities" in Regulation D of the Board). Such reserve
requirements shall include, without limitation, those imposed under such
Regulation D. Eurodollar Loans shall be deemed to constitute Eurocurrency
liabilities and as such shall be deemed to be subject to such reserve
requirements without benefit of credits for proration, exceptions or offsets
which may be available from time to time to the Bank under such Regulation D.
The Eurodollar Rate shall be adjusted automatically on and as of the effective
date of any change in any such reserve requirement.

     "Event of Default" has the meaning assigned to such term in Section 7.01.
      ----------------

     "Excluded Taxes" means, with respect to the Bank or any other recipient of
      --------------
any payment to be made by or on account of any obligation of the Borrower
hereunder, (a) income or franchise taxes imposed on (or measured by) its net
income by the United States of America, or by the jurisdiction under the Laws of
which such recipient is organized or in which its principal office is located
or, in the case of Bank, in which its

                                      -6-
<PAGE>

applicable lending office is located; and (b) any branch profits taxes imposed
by the United States of America or any similar tax imposed by any other
jurisdiction in which the Borrower is located.

     "Facility" means the $25,000,000.00 364-day revolving line of credit
      --------
committed pursuant to this Agreement.

     "Federal Funds Rate" means, for any day, the weighted average of the rates
      ------------------
on overnight federal funds transactions with members of the Federal Reserve
System arranged by federal funds brokers, as published for such day (or if such
day is not a Business Day, for the next preceding Business Day) by the Federal
Reserve Bank of New York, or if such rate is not so published for any day which
is a Business Day, the average of quotations for such day on such transactions
received by the Bank from three federal funds brokers of recognized standing
selected by the Bank.

     "Foreign Pension Plan" means any plan, fund (including, without limitation,
      --------------------
any superannuation fund) or other similar program established or maintained
outside the United States of America by the Borrower or any one or more of its
Subsidiaries primarily for the benefit of employees of the Borrower or such
Subsidiaries residing outside the United States of America, which plan, fund or
other similar program provides, or results in, retirement income, a deferral of
income in contemplation of retirement or payments to be made upon termination of
employment, and which plan is not subject to ERISA or the Code.

     "GAAP" means generally accepted accounting principles in the United States
      ----
of America, as in effect from time to time, which shall include the official
interpretations thereof by the Financial Accounting Standards Board, applied in
a consistent manner.

     "Governmental Action" means any authorization, approval, order, decree,
      -------------------
ruling or other action by, or notice to or filing with, any Governmental
Authority.

     "Governmental Authority" means the government of the United States of
      ----------------------
America, any other nation or any political subdivision thereof, whether state or
local, and any agency, authority, bureau, instrumentality, regulatory body,
court, tribunal, central bank or other entity exercising executive, legislative,
judicial, taxing, regulatory or administrative powers or functions of or
pertaining to government.

     "Hazardous Materials" means (a) any petroleum or petroleum products,
      -------------------
radioactive materials, asbestos in any form that is friable, urea formaldehyde
foam insulation, transformers or other equipment that contain dielectric fluid
containing levels of poly-chlorinated biphenyls, and radon gas; (b) any
chemicals, materials or substances defined as or included in the definition of
"hazardous substances," "hazardous waste," "hazardous materials," "extremely
hazardous substances," "restricted hazardous waste," "toxic substances," "toxic
pollutants," "contaminants," or "pollutants," or words of similar import, under
any applicable Environmental Law; and (c) any other chemical,

                                      -7-
<PAGE>

material or substance, the Release of which is prohibited, limited or regulated
by any governmental authority.

     "Highest Lawful Rate" means the maximum rate of interest, if any, that at
      -------------------
any time or from time to time may be contracted for, taken, charged or received
on the Note or which may be owing to the Bank pursuant to this Agreement under
the laws applicable to the Bank and this transaction.

     "Indebtedness" of any Person, means (a) obligations created, issued or
      ------------
incurred by such Person for borrowed money (whether by loan, the issuance and
sale of debt securities or the sale of Property to another Person subject to an
understanding or agreement, contingent or otherwise, to repurchase such Property
from such Person); (b) obligations of such Person to pay the deferred purchase
or acquisition price of Property or services, other than trade accounts payable
(other than for borrowed money) arising, and accrued expenses incurred, in the
ordinary course of business; (c) Indebtedness of others secured by a Lien on the
Property of such Person, whether or not the respective indebtedness so secured
has been assumed by such Person; (d) obligations of such Person in respect of
letters of credit or similar instruments issued or accepted by banks and other
financial institutions for account of such Person; (e) Capital Lease Obligations
of such Person; and (f) any Contingent Obligation.

     "Indemnified Parties" means Bank, its Affiliates, and the directors,
      -------------------
officers, employees, attorneys and agents of each of the foregoing.

     "Indemnified Taxes" means all Taxes other than Excluded Taxes.
      -----------------

     "Index Debt" means the senior, unsecured, long-term indebtedness for
      ----------
borrowed money of the Borrower that is not guaranteed by any other Person or
subject to any credit enhancement.

     "Interest Election Request" means a request by the Borrower to convert or
      -------------------------
continue a Borrowing in accordance with Section 2.05.

     "Interest Payment Date" means (a) with respect to any ABR Loan, the first
      ---------------------
day of each month commencing on the first such day to occur after such ABR Loan
is made or any Eurodollar Loan is converted to an ABR Loan; and (b) with respect
to any Eurodollar Loan of which the Borrower has selected an Interest Period of
one, two or three months, the last day of such Interest Period.

     "Interest Period" means, with respect to any Eurodollar Loan requested by
      ---------------
the Borrower:

          (a)  initially, the period commencing on, as the case may be, the
Borrowing Date or Conversion Date with respect to such Eurodollar Loan and
ending one, two or three months thereafter, as selected by the Borrower in its
irrevocable notice

                                      -8-
<PAGE>

of borrowing as provided in Section 2.03 or its irrevocable notice of conversion
as provided in Section 2.05(b);

          (b)  thereafter, each period commencing on the last day of the
immediately preceding Interest Period applicable to such Eurodollar Loan and
ending one, two or three months thereafter, as selected by the Borrower in its
irrevocable notice of conversion as provided in Section 2.05(b);

provided, however, that all of the foregoing provisions relating to Interest
Periods are subject to the following:

               (i)   if any Interest Period pertaining to a Eurodollar Loan
would otherwise end on a day which is not a Business Day, such Interest Period
shall be extended to the next succeeding Business Day unless the result of such
extension would be to carry such Interest Period into another calendar month, in
which event such Interest Period shall end on the immediately preceding Business
Day;

               (ii)  if, with respect to any borrowing or the conversion of any
borrowing, the Borrower shall fail to give due notice as provided in Section
2.03 or 2.05(b), as the case may be, the Borrower shall be deemed to have
selected an Alternate Base Rate Loan for such borrowing or the borrowing shall
be automatically converted to an Alternate Base Rate Loan upon the expiration of
the Interest Period with respect thereto;

               (iii) any Interest Period pertaining to a Eurodollar Loan that
begins on the last Business Day of a calendar month (or on a day for which there
is no numerically corresponding day in the calendar month at the end of such
Interest Period) shall end on the last Business Day of a calendar month;

               (iv)  no Interest Period selected in respect of a Loan shall end
after the date on which such Loan shall be due and payable under Section
2.01(b); and

               (v)   the Borrower shall select Interest Periods so as not to
have more than five (5) different Interest Periods outstanding at any one time.

     "Investment" means, when used in connection with any Person, any investment
      ----------
by or of that Person, whether by means of purchase or other acquisition of stock
or other securities of any other Person or by means of a loan, advance creating
a debt, capital contribution, guaranty or other debt or equity participation or
interest in any other Person, including any partnership and joint venture
                              ---------
interests of such Person but excluding any Wholly-Owned Subsidiary of such
                             ---------
Person.  The amount of any Investment shall be the amount actually invested

(minus any return of capital with respect to such Investment which has actually
 -----
been received in cash or has been converted into cash), without adjustment for
subsequent increases or decreases in the value of such Investment.

                                      -9-
<PAGE>

     "Law" shall mean any law (including common law), constitution, statute,
      ---
treaty, convention, regulation, rule, ordinance, order, injunction, writ, decree
or award of any Governmental Authority.

     "Lien" means, with respect to any Property, any mortgage, lien, pledge,
      ----
charge, security interest or encumbrance of any kind in respect of such
Property.  For purposes of this Agreement, a Person shall be deemed to own
subject to a Lien any Property that it has acquired or holds subject to the
interest of a vendor or lessor under any conditional sale agreement, capital
lease or other title retention agreement (other than an operating lease)
relating to such Property.

     "Loan Documents" means this Agreement, each Borrowing Request, each
      --------------
Interest Election Request and each Note.

     "Loans" means advances under the Facility.
      -----

     "Material Adverse Effect" means a material adverse effect on (a) the
      -----------------------
Property, business, operations, financial condition, prospects, liabilities or
capitalization of the Borrower and its Subsidiaries taken as a whole, (b) the
ability of the Borrower to perform its obligations hereunder, (c) the validity
or enforceability of this Agreement, (d) the rights and remedies of the Bank
hereunder or (e) the timely payment of the principal of or interest on the Loans
or other amounts payable in connection therewith.

     "Maturity Date" means the earlier of (a) August 14, 2002; and (b) any
      -------------
earlier date the Note becomes due and payable as a result of acceleration or
otherwise.

     "Multiemployer Plan" means a multiemployer plan defined as such in Section
      ------------------
3(37) of ERISA to which contributions have been made by the Borrower or any
ERISA Affiliate and which is covered by Title IV of ERISA.

     "NPC" means Nevada Power Company, a Nevada corporation.
      ---

     "NPC Credit Agreement" means that certain Amended and Restated Credit
      --------------------
Agreement dated as of June 24, 1999, as amended through the date hereof
including the Amendment Agreement, dated as of August 1, 2001, among NPC, as
borrower, Mellon Bank, N.A. as administrative agent, First Union National Bank
and Wells Fargo Bank, N.A., as syndication agents, and the lender from time to
time party thereto.

     "NPC First Mortgage Bonds" means obligations issued from time to time
      ------------------------
under, and secured by, the NPC First Mortgage Indenture.

     "NPC First Mortgage Indenture" means the Indenture of Mortgage, dated as of
      ----------------------------
October 1, 1953, from NPC to Banker's Trust Company (successor to First
Interstate Bank of Nevada, N.A., formerly First National Bank of Nevada, Reno
Nevada), as

                                      -10-
<PAGE>

trustee, as modified, amended or supplemented at any time or from time to time
by supplemental indentures.

     "NPC General and Refunding Mortgage Bonds" means obligations issued from
      ----------------------------------------
time to time under, and secured by, the NPC General and Refunding Mortgage
Indenture.

     "NPC General and Refunding Mortgage Indenture" means the General and
      --------------------------------------------
Refunding Mortgage Indenture, dated as of May 1, 2001, between NPC and The Bank
of New York, as trustee, as the same may be amended, modified or supplemented
from time to time.

     "NPC Supplemental Credit Agreement" means that certain Credit Agreement
      ---------------------------------
dated as of August 1, 2001 among NPC, as borrower, Mellon Bank, N.A., as
administrative agent, BNP Paribas, First Union National Bank and Wells Fargo
Bank, N.A., as syndication agents, and the lenders from time to time party
thereto.

     "Note" has the meaning assigned to such term in Section 2.08.
      ----

     "Obligations" means all Indebtedness, obligations and liabilities of the
      -----------
Borrower to Bank from time to time arising under or in connection with or
related to or evidenced by or secured by this Agreement or any other Loan
Document, and all extensions, renewals or refinancings thereof, whether such
Indebtedness, obligations or liabilities are direct or indirect, otherwise
secured or unsecured, joint or several, absolute or contingent, due or to become
due, whether for payment or performance, now existing or hereafter arising.
Without limitation of the foregoing, such Indebtedness, obligations and
liabilities shall include the principal amount of all Loans, all interest, fees,
indemnities or expenses under or in connection with this Agreement or any other
Loan Document, and all extensions, renewals and refinancings thereof, whether or
not such Loans were made in compliance with the terms and conditions of this
Agreement or in excess of the obligation of the Bank to lend.  Obligations shall
remain obligations notwithstanding any assignment or transfer or any subsequent
assignment or transfer of any of the Obligations or any interest therein.

     "Other Taxes" means any and all present or future stamp or documentary
      -----------
taxes or any other excise or Property taxes, charges or similar levies arising
from any payment made hereunder or from the execution, delivery or enforcement
of, or otherwise with respect to, this Agreement.

     "Participant" has the meaning assigned to such term in Section 8.11(c).
      -----------

     "PBGC" means the Pension Benefit Guaranty Corporation or any entity
      ----
succeeding to any or all of its functions under ERISA.

     "Permitted Liens" has the meaning assigned to such term in Section 6.02.
      ---------------

                                      -11-
<PAGE>

     "Person" means any natural person, corporation, limited liability company,
      ------
trust, joint venture, association, company, partnership, Governmental Authority
or other entity.

     "Plan" means an employee benefit or other plan established or maintained by
      ----
the Borrower or any ERISA Affiliate and that is covered by Title IV of ERISA,
other than a Multiemployer Plan.

     "Preferred Securities" means any preferred securities issued by a financing
      --------------------
entity (i.e., partnership, trust, limited liability company, etc.) used
exclusively to raise capital for the Borrower having the following structural
characteristics: (a) the financing entity is capitalized by a nominal equity
investment from the Borrower and the remainder through preferred securities
issued by the financing entity, (b) the financing entity lends the proceeds from
the issuance of preferred securities to the Borrower in exchange for
subordinated debt securities (which debt securities are subordinated in all
respects to the Indebtedness of the Borrower, including the Indebtedness of the
Borrower under this Agreement, except for Indebtedness which by its terms is
expressly subordinated to or pari passu with such debt securities), (c) the
Borrower makes periodic interest payments (associated with the subordinated debt
securities) to the financing entity which, in turn, are used to make
corresponding payments to holders of the preferred securities of the financing
entity, (d) the subordinated debt securities issued by the Borrower and
corresponding preferred securities issued by the financing entity have a
maturity of at least thirty years, (e) interest payments on the subordinated
debt securities may be deferred at the Borrower's discretion for one or more
consecutive periods of up to five years, which would result in a corresponding
deferral of payments to holders of the preferred securities, plus accrual of
interest thereon, and (f) the subordinated debt securities and corresponding
preferred securities may not be redeemed for a period of five years from the
date of issuance other than as a result of a tax or other special event.

     "Principal Office" means the principal office of Bank located on the date
      ----------------
hereof at One Wall Street, New York, New York 10286.

     "Property" means any right or interest in or to property of any kind
      --------
whatsoever, whether real, personal or mixed and whether tangible or intangible.

     "Quarterly Dates" means the last day of March, June, September and December
      ---------------
in each year, the first of which shall be the first such day after the date
hereof; provided that if any such day is not a Business Day, then such Quarterly
Date shall be the next succeeding Business Day (unless such succeeding Business
Day falls in a subsequent calendar month, in which event such Quarterly Date
shall be the next preceding Business Day).

     "Release" means the disposing, discharging, injecting, spilling, pumping,
      -------
leaking, leaching, dumping, emitting, escaping, emptying, pouring or migrating,
into or upon any land or water or air, or otherwise entering into the
environment.

                                      -12-
<PAGE>

     "Reportable Event" means an event described in Section 4043(c) of ERISA
      ----------------
with respect to a Plan that is subject to Title IV of ERISA other than those
events as to which the 30-day notice period is waived under subsection .22, .23,
 .25, .27 or .28 of PBGC Regulation Section 4043 (provided that a failure to meet
the minimum funding standard of Section 412 of the Code or Section 302 of ERISA,
including, without limitation, the failure to make on or before its due date a
required installment under Section 412(m) of the Code or Section 302(e) of
ERISA, shall be a reportable event regardless of the issuance of any waivers in
accordance with Section 412(d) of the Code).

     "Responsible Officer" means the Treasurer, the Assistant Treasurer, the
      -------------------
Chief Financial Officer or the Controller of Borrower.

     "Revolving" means, when referred to a Loan or Borrowing, a Loan or
      ---------
Borrowing which may be repaid and reborrowed.

     "Shareholders' Equity" means, as of any date of determination, the amount,
      --------------------
which is shown as "shareholders' equity" (which shall include both common and
preferred equity) in the consolidated balance sheet of the Borrower at such
date.

     "Significant Subsidiary" has the meaning given to such term in Regulation
      ----------------------
S-X under the Securities Act of 1934, as amended.

     "Special Counsel" means Emmet, Marvin & Martin, LLP.
      ---------------

     "SPPC" means Sierra Pacific Power Company, a Nevada corporation.
      ----

     "SPPC Credit Agreement" means that certain Credit Agreement dated as of
      ---------------------
June 24, 1999, as amended through the date hereof, including the Amendment
Agreement dated as of August 1, 2001, among SPPC, as borrower, Mellon Bank,
N.A., as Administrative Agent, First Union National Bank and Wells Fargo Bank,
National Association, as syndication agents, and the lenders from time to time
party thereto.

     "SPPC First Mortgage Bonds" means obligations issued from time to time
      -------------------------
under, and secured by, the SPPC First Mortgage Indenture.

     "SPPC First Mortgage Indenture" means the Indenture of Mortgage, dated as
      -----------------------------
of December 1, 1940, from SPPC to State Street Bank and Trust Company (successor
to The New England Trust Company), as trustee, and Gerald R. Wheeler (successor
to Leo W. Huegle), as co-Trustee, as modified, amended or supplemented at any
time or from time to time by supplemental indentures.

     "SPPC General and Refunding Mortgage Bonds" means obligations issued from
      -----------------------------------------
time to time under, and secured by, the SPPC General and Refunding Mortgage
Indenture.

                                      -13-
<PAGE>

     "SPPC General and Refunding Mortgage Indenture" means the General and
      ---------------------------------------------
Refunding Mortgage Indenture, dated as of May 1, 2001, between SPPC and The Bank
of New York, as trustee, as the same may be amended, modified or supplemented
from time to time.

     "SPCC Supplemental Credit Agreement" means that certain Credit Agreement
      ----------------------------------
dated as of August 1, 2001 among SPPC, as borrower, Mellon Bank, N.A. as
administrative agent, BNP Paribas, First Union National Bank and Wells Fargo
Bank, N.A., as syndication agents, and the lenders from time to time party
thereto.

     "Subsidiary" shall mean, as to any Person, (i) any corporation more than
      ----------
50% of whose stock of any class or classes having by the terms thereof ordinary
voting power to elect a majority of the directors of such corporation
(irrespective of whether or not at the time stock of any class or classes of
such corporation shall have or might have voting power by reason of the
happening of any contingency) is at the time owned by such Person and/or one or
more Subsidiaries of such Person and (ii) any partnership, limited liability
company, association, joint venture or other entity in which such Person and/or
one or more Subsidiaries of such Person has more than a 50% equity interest at
the time.

     "Taxes" means any and all present or future taxes, levies, imposts, duties,
      -----
deductions, charges or withholdings imposed by any Governmental Authority.

     "Termination Date" means the earlier of (a) August 14, 2002; and (b) any
      ----------------
earlier date the Note becomes due and payable as a result of acceleration or
otherwise.

     "Type" when used in reference to any Loan or Borrowing, refers to whether
      ----
the rate of interest on such Loan, or on the Loans comprising such Borrowing, is
determined by reference to the Eurodollar Rate or the Alternate Base Rate.

     "Unfunded Current Liability" of any Plan, means the amount, if any, by
      --------------------------
which the value of the accumulated plan benefits under the Plan determined on a
plan termination basis in accordance with actuarial assumptions at such time
consistent with those prescribed by the PBGC for purposes of Section 4044 of
ERISA, exceeds the fair market value of all plan assets allocable to such
liabilities under Title IV of ERISA (excluding any accrued but unpaid
contributions).

     "Upfront Fee" means a non-refundable upfront fee in the amount of
      -----------
$150,000.00 payable to BNY in accordance with Section 4.01(j).

     "Wholly-Owned Subsidiary" shall mean, as to any Person, (i) any corporation
      -----------------------
100% of whose stock of any class or classes having by the terms thereof ordinary
voting power to elect a majority of the directors of such corporation
(irrespective of whether or not at the time stock of any class or classes of
such corporation shall have or might have voting power by reason of the
happening of any contingency) is at the time owned by such Person and/or one or
more Subsidiaries of such Person and (ii) any partnership,

                                      -14-
<PAGE>

limited liability company, association, joint venture or other entity in which
such Person and/or one or more Subsidiaries of such Person has a 100% equity
interest at the time.

     SECTION 1.02   CLASSIFICATION OF LOANS AND BORROWINGS.
                    ---------------------------------------

     For purposes of this Agreement, Loans or Borrowings may be classified and
referred to by Type (e.g., a "Eurodollar Borrowing"). All Borrowings under this
Facility shall be Revolving Borrowings.

     SECTION 1.03   TERMS GENERALLY.
                    ----------------

     The definitions of terms herein shall apply equally to the singular and
plural forms of the terms defined. Whenever the context may require, any pronoun
shall include the corresponding masculine, feminine and neuter forms. The words
"include", "includes" and "including" shall be deemed to be followed by the
phrase "without limitation". The word "will" shall be construed to have the same
meaning and effect as the word "shall". Unless the context requires otherwise
(a) any definition of or reference to any agreement, instrument or other
document herein shall be construed as referring to such agreement, instrument or
other document as from time to time amended, supplemented or otherwise modified
(subject to any restrictions on such amendments, supplements or modifications
set forth herein), (b) any reference herein to any Person shall be construed to
include such Person's successors and assigns, (c) the words "herein", "hereof"
and "hereunder", and words of similar import, shall be construed to refer to
this Agreement in its entirety and not to any particular provision hereof and
(d) all references herein to Articles, Sections, Exhibits and Schedules shall be
construed to refer to Articles and Sections of, and Exhibits and Schedules to,
this Agreement.

     SECTION 1.04   ACCOUNTING TERMS; GAAP.
                    -----------------------

     Except as otherwise expressly provided herein, all terms of an accounting
or financial nature shall be construed in accordance with GAAP.

                                  ARTICLE II

                                  THE CREDITS

     SECTION 2.01   THE COMMITMENT.
                    ---------------

     (a)  Subject to the terms and conditions set forth herein, the Bank agrees
to make advances to Borrower from time to time during the Commitment Period, not
to, at any time, exceed the aggregate principal amount of Twenty-Five Million
and 00/100 Dollars ($25,000,000.00), the proceeds of which shall be used for
general corporate purposes.

     (b)  Each Loan shall be due and payable on the Maturity Date.

                                      -15-
<PAGE>

     SECTION 2.02   LOANS AND BORROWINGS.
                    ---------------------

     (a)  Obligations of Bank.  Each Revolving Loan shall be made as part of a
          -------------------
Borrowing consisting of Loans of the same Type under the Facility made by the
Bank.

     (b)  Type of Loans.  Subject to Section 2.12, each Borrowing shall be
          -------------
comprised entirely of ABR Loans or Eurodollar Loans.  Bank may, at its option,
make any Eurodollar Loan by causing any domestic or foreign branch or Affiliate
of Bank to make such Loan; provided that any exercise of such option shall not
affect the obligation of the Borrower to repay such Loan in accordance with the
terms of this Agreement.

     (c)  Minimum Amounts; Limitation on Number of Borrowings.  Each Revolving
          ---------------------------------------------------
Borrowing (whether an ABR Borrowing or a Eurodollar Borrowing) shall be in an
aggregate amount equal to $2,000,000 or a multiple of $1,000,000 in excess
thereof, provided that an ABR Borrowing may be made in an aggregate amount that
is equal to the entire unused balance of the total Commitment of the Facility.
The Borrower may thereafter, upon irrevocable notice to the Bank in accordance
with Section 2.05(b), (i) elect, as of any Business Day, in the case of ABR
Loans, to convert any such ABR Loans or any part thereof, in an aggregate amount
equal to $2,000,000 or a multiple of $1,000,000 in excess thereof, into
Eurodollar Loans, and (ii) elect, as of the last day of the applicable Interest
Period, to continue any Eurodollar Loans having Interest Periods expiring on
such day or any part thereof in an aggregate amount of $2,000,000 or a multiple
of $1,000,000 in excess thereof; provided that, if at any time the aggregate
amount of Eurodollar Loans in respect of any Borrowing is reduced by payment,
prepayment or conversion of part thereof to be less than $2,000,000, such
Eurodollar Loans shall automatically convert into ABR Loans.  Borrowings of more
than one Type may be outstanding at the same time.

     (d)  Maximum Duration of Interest Periods.  Notwithstanding any other
          ------------------------------------
provision of this Agreement, the Borrower shall not be entitled to request, or
to elect to convert or continue, any Eurodollar Borrowing under the Facility if
the Interest Period requested with respect thereto would end after the Maturity
Date.

     SECTION 2.03   REQUESTS FOR REVOLVING BORROWINGS.
                    ----------------------------------

     To request a Revolving Borrowing under the Facility, the Borrower shall
notify the Bank of such request by telephone (a) in the case of a Eurodollar
Revolving Borrowing, not later than 11:00 A.M., New York City time, three
Business Days before the date of the proposed Borrowing, or (b) in the case of
an ABR Borrowing, not later than 11:00 A.M., New York City time, one Business
Day before the date of the proposed Borrowing.  Each such telephonic Borrowing
Request shall be irrevocable and shall be confirmed promptly by hand delivery or
telecopy to the Bank of a written Borrowing Request in the form attached hereto
as Exhibit B and signed by a Responsible Officer or the Chairman or President of
the Borrower.  Each such telephonic and written Borrowing Request shall specify
the following information in compliance with Section 2.02:

                                      -16-
<PAGE>

          (i)    the aggregate amount of the requested Borrowing;

          (ii)   the date of such Borrowing, which shall be a Business Day;

          (iii)  whether such Borrowing is to be an ABR Borrowing or a
Eurodollar Borrowing;

          (iv)   in the case of a Eurodollar Borrowing, the initial Interest
Period to be applicable thereto, which shall be a period contemplated by the
definition of the term "Interest Period"; and

          (v)    the location and number of the Borrower's account to which
funds are to be disbursed, which shall comply with the requirements of Section
2.04.

     If no election as to the Type of Revolving Borrowing is specified, then the
requested Revolving Borrowing shall be an ABR Borrowing.  If no Interest Period
is specified with respect to any Eurodollar Revolving Borrowing, then the
Borrower shall be deemed to have selected an Interest Period of one month's
duration.

     SECTION 2.04   FUNDING OF BORROWINGS.
                    ----------------------

     Subject to the satisfaction of the terms and conditions of this Agreement,
the Bank will make available the Borrowing requested to be made on the date
specified as the Borrowing Date in the Borrowing Request, in Dollars and in
immediately available funds at the Bank's Principal Office by crediting the
account of the Borrower at such office.

     SECTION 2.05   CONVERSIONS.
                    ------------

     (a)  Elections by the Borrower for Borrowings.  Each Borrowing initially
          ----------------------------------------
shall be of the Type specified in the applicable Borrowing Request and, in the
case of a Eurodollar Borrowing, shall have an initial Interest Period as
specified in such Borrowing Request.  Thereafter, the Borrower may elect to
convert such Borrowing to a different Type or to continue such Borrowing and, in
the case of a Eurodollar Borrowing, may elect Interest Periods therefor, all as
provided in this Section but subject to Section 2.02.  Once Loans have been made
pursuant to a Borrowing, the Borrower may elect to convert or continue different
portions of such Borrowing and the Loans comprising each such portion shall be
considered a separate Borrowing.

     (b)  Notice of Elections.  To make an election pursuant to this Section,
          -------------------
the Borrower shall notify the Bank of such election by telephone by the time
that a Borrowing Request would be required under Section 2.03 if the Borrower
were requesting a Revolving Borrowing of the Type resulting from such election
to be made on the effective date of such election.  Each such telephonic
Interest Election Request shall be irrevocable and shall be confirmed promptly
by hand delivery or telecopy to the

                                      -17-
<PAGE>

Bank of a written Interest Election Request in the form attached hereto as
Exhibit C and signed by a Responsible Officer or the Chairman or President of
the Borrower.

     (c)  Information in Interest Election Requests.  Each telephonic and
          -----------------------------------------
written Interest Election Request shall specify the following information in
compliance with Section 2.02:

          (i)    the Borrowing to which such Interest Election Request applies
and, if different options are being elected with respect to different portions
thereof, the portions thereof to be allocated to each resulting Borrowing (in
which case the information to be specified pursuant to clauses (iii) and (iv) of
this paragraph shall be specified for each resulting Borrowing);

          (ii)   the effective date of the election made pursuant to such
Interest Election Request, which shall be a Business Day;

          (iii)  whether the resulting Borrowing is to be an ABR Borrowing, or a
Eurodollar Borrowing; and

          (iv)   if the resulting Borrowing is a Eurodollar Borrowing, the
Interest Period to be applicable thereto after giving effect to such election,
which shall be a period contemplated by the definition of the term "Interest
Period".

     If any such Interest Election Request requests a Eurodollar Borrowing but
does not specify an Interest Period, then the Borrower shall be deemed to have
selected an Interest Period of one month's duration.

     (d)  Failure to Elect; Events of Default.  If the Borrower fails to deliver
          -----------------------------------
a timely Interest Election Request with respect to a Eurodollar Borrowing prior
to the end of the Interest Period applicable thereto, then, unless such
Borrowing is repaid as provided herein, at the end of such Interest Period such
Borrowing shall be converted to an ABR Borrowing.  Notwithstanding any contrary
provision hereof, if an Event of Default has occurred and is continuing and the
Bank so notifies the Borrower, then, so long as an Event of Default is
continuing (i) no outstanding Borrowing may be converted to or continued as a
Eurodollar Borrowing; and (ii) unless repaid, each Eurodollar Borrowing shall be
converted to an ABR Borrowing at the end of the Interest Period applicable
thereto.

     SECTION 2.06   TERMINATION OR REDUCTION OF COMMITMENT.
                    ---------------------------------------

     (a)  Scheduled Termination.  Unless previously terminated, the Facility
          ---------------------
shall terminate on the Maturity Date.

     (b)  Voluntary Termination or Reduction.  The Borrower shall have the right
          ----------------------------------
to reduce permanently the Commitment in whole at any time, or in part from time
to time,

                                      -18-
<PAGE>

without premium or penalty; provided that (i) each reduction of the Commitment
shall be in an amount that is $2,000,000 or greater, and (ii) the Borrower shall
not terminate or reduce the Commitment if, after giving effect to any concurrent
prepayment of the Loans in accordance with Section 2.09, the aggregate of all
Borrowings then outstanding would exceed the total Commitment.

     (c)  Notice of Voluntary Termination or Reduction.  The Borrower shall
          --------------------------------------------
notify the Bank, in writing, of any election to terminate or reduce the
Commitment under the Facility in accordance with paragraph (b) of this Section
at least five (5) Business Days prior to the effective date of such termination
or reduction, specifying such election and the effective date thereof.  Each
notice delivered by the Borrower pursuant to this subsection shall be
irrevocable; provided that a notice of termination of the Commitment of a
Facility delivered by the Borrower may state that such notice is conditioned
upon the effectiveness of other credit facilities, in which case such notice may
be revoked by the Borrower (by notice to the Bank on or prior to the specified
effective date) if such condition is not satisfied.

     (d)  In General. Simultaneously with each reduction of the Commitment under
          ----------
this Section 2.06, the Borrower shall pay the Commitment Fee accrued on the
amount by which the Commitment has been reduced and prepay the amount, if any,
by which the unpaid principal balance of the Loans exceeds the Commitment as so
reduced.  If any prepayment is made under this Section 2.06 with respect to any
Eurodollar Loan, in whole or in part, prior to the last day of the applicable
Interest Period, the Borrower agrees that it shall indemnify the Bank in
accordance with Section 2.14. After giving effect to any partial prepayment with
respect to Eurodollar Loans which were made (whether as the result of a
borrowing or a conversion) on the same date and which had the same Interest
Period, the outstanding principal balance of such Eurodollar Loans shall not be
less than $2,000,000 or such amount plus a whole multiple of $1,000,000 in
excess thereof.

     SECTION 2.07   REPAYMENT OF LOANS.
                    -------------------

     (a)  Repayment. The Borrower hereby unconditionally promises to pay the
          ---------
Loans to the Bank.

     (b)  Manner of Payment. Prior to any repayment of any Borrowings hereunder,
          -----------------
the Borrower shall specify the Borrowing or Borrowings to be paid, the amount to
be paid and the date of payment, and shall notify the Bank by telephone
(confirmed by telecopy) of such selection not later than 12:00 noon, New York
City time, three Business Days before the scheduled date of such repayment;
provided that each repayment of Borrowings shall be applied to repay any
outstanding ABR Borrowings before any other Borrowings. If the Borrower fails to
make a timely selection of the Borrowing or Borrowings to be repaid, such
payment shall be applied, first, to pay any outstanding ABR Borrowings and,
second, to other Borrowings in the order of the remaining duration of their
respective Interest Periods (the Borrowing with the shortest

                                      -19-
<PAGE>

remaining Interest Period to be repaid first). Each payment of a Revolving
Borrowing shall be applied ratably to the Loans included in such Borrowing.

     SECTION 2.08   NOTE.
                    -----

     The Loans shall be evidenced by a promissory note of the Borrower,
substantially in the form of Exhibit A (as indorsed or otherwise modified from
time to time, including all replacements thereof, the "Note"), payable to the
                                                       ----
order of the Bank and representing the obligation of the Borrower to pay the
aggregate unpaid principal balance of all Loans, together with interest thereon
as prescribed in Section 2.11, on the Maturity Date. The Bank is authorized to
record (i) the date and amount of each Loan, (ii) its character as a Alternate
Base Rate Loan or a Eurodollar Loan, or a combination thereof, (iii) the
Interest Period and interest rate applicable to Eurodollar Loans and (iv) the
date and amount of each conversion of, and each payment or prepayment of
principal of, any Loan, on the schedule (and any continuations thereof) annexed
to and constituting a part of the Note. No failure to so record or any error in
so recording shall affect the obligation of the Borrower to repay the Loans,
together with interest as herein provided. The Note shall (a) be dated the
Effective Date, (b) be stated to mature on the Maturity Date and (c) bear
interest for the period from and including the date thereof on the unpaid
principal balance thereof from time to time outstanding at the applicable
interest rate per annum determined as provided in Section 2.11.  Interest on the
Note shall be payable as specified in Section 2.11.

     SECTION 2.09   PREPAYMENT.
                    -----------

     (a)  Optional Prepayments Right to Prepay Borrowings.  The Borrower shall
          -----------------------------------------------
have the right at any time and from time to time to prepay any Borrowing in
whole or in part, subject to the requirements of this Section.

     (b)  Notices, Etc.  The Borrower shall notify the Bank by telephone
          -------------
(confirmed by telecopy) of any optional prepayment hereunder (i) in the case of
prepayment of a Eurodollar Borrowing, not later than 12:00 noon, New York City
time, three Business Days before the date of prepayment, or (ii) in the case of
prepayment of an ABR Borrowing, not later than 12:00 noon, New York City time,
one Business Day before the date of prepayment.  Each such notice shall be
irrevocable and shall specify the loans to be prepaid, the prepayment date and
the principal amount of each Borrowing or portion thereof to be prepaid;
provided that, if a notice of prepayment is given in connection with a
conditional notice of termination of the Commitment as contemplated by Section
2.06(c), then such notice of prepayment may be revoked if such notice of
termination is revoked. Partial prepayments shall be in a principal amount of
$2,000,000 or such amount plus a whole multiple of $1,000,000 in excess thereof
or, if less, the outstanding principal balance of the Loans. After giving effect
to any partial prepayment with respect to Eurodollar Loans made on the same date
(whether as the result of a borrowing or a conversion) and which had the same
Interest Period, the outstanding principal balance of

                                      -20-
<PAGE>

such Eurodollar Loans made (whether as the result of a borrowing or a
conversion) shall equal $2,000,000 or such amount plus a whole multiple of
$1,000,000 in excess thereof.

     (c)   In General.  If any prepayment is made under this paragraph with
           ----------
respect to any Eurodollar Loans, in whole or in part, prior to the last day of
the applicable Interest Period, the Borrower agrees to indemnify the Bank in
accordance with Section 2.14.

     SECTION 2.10   FEES.
                    -----

     (a)   Commitment Fee.  The Borrower shall pay the Bank a commitment fee for
           --------------
the period from and including the Effective Date to and including the
Termination Date (the "Commitment Fee") computed at the per annum rate set forth
                       --------------
on the Pricing Table, payable on the average daily unused portion of the
Commitment, such fee to be paid quarterly in arrears on each Quarterly Date and
on the Termination Date. The facility fee shall be calculated on the basis of
the actual number of days elapsed in a year of 360 days.

     (b)   Payment of Fees.  All fees payable hereunder shall be paid on the
           ---------------
dates due, in immediately available funds, to the Bank.

     SECTION 2.11   INTEREST.
                    ---------

     (a)   ABR Loans.  The Loans comprising each ABR Revolving Borrowing shall
           ---------
bear interest at a rate per annum equal to the Alternate Base Rate plus the
Applicable Margin.

     (b)   Eurodollar Loans.  The Loans comprising each Eurodollar Borrowing
           ----------------
shall bear interest at a rate per annum equal to the Eurodollar Rate for the
Interest Period in effect for such Borrowing plus the Applicable Margin.

     (c)   Default Interest.  Notwithstanding the foregoing, if any principal of
           ----------------
or interest on any Loan or any fee or other amount payable by the Borrower
hereunder is not paid when due, whether at stated maturity, upon acceleration or
otherwise, such overdue amount shall bear interest, after as well as before
judgment, at a rate per annum equal to (i) in the case of overdue principal of
any Loan, 2% plus the rate otherwise applicable to such Loan as provided above
or (ii) in the case of any other amount, 2% plus the rate applicable to ABR
Loans as provided in paragraph (a) of this Section.

     (d)   Payment of Interest.  Accrued interest on each Loan shall be
           -------------------
payable in arrears on each Interest Payment Date for such Loan and upon
termination of the Commitment.

     (e)   Computation.  All interest hereunder shall be computed on the basis
           -----------
of a year of 360 days, except that interest computed by reference to the
Alternate Base Rate at

                                      -21-
<PAGE>

times when the Alternate Base Rate is based on the BNY Rate shall be computed on
the basis of a year of 365 days (or 366 days in a leap year), and in each case
shall be payable for the actual number of days elapsed (including the first day
but excluding the last day). The applicable Alternate Base Rate or Eurodollar
Rate shall be determined by the Bank, and such determination shall be
conclusive, absent manifest error. At no time shall the interest rate payable on
the Loans, together with the Commitment Fee, the Upfront Fee and all other fees
and other amounts payable hereunder, to the extent the same are construed to
constitute interest, exceed the Highest Lawful Rate. If interest payable to the
Bank on any date would exceed the maximum amount permitted by the Highest Lawful
Rate, such interest payment shall automatically be reduced to such maximum
permitted amount, and interest for any subsequent period, to the extent less
than the maximum amount permitted for such period by the Highest Lawful Rate,
shall be increased by the unpaid amount of such reduction. Any interest actually
received for any period in excess of such maximum allowable amount for such
period shall be deemed to have been applied as a prepayment of the Loans. The
Borrower acknowledges that the Alternate Base Rate is only one of the bases for
computing interest on loans made by the Bank, and by basing interest payable on
the Alternate Base Rate Loans on the Alternate Base Rate, the Bank has not
committed to charge, and the Borrower has not in any way bargained for, interest
based on a lower or the lowest rate at which the Bank may now or in the future
make loans to other borrowers.

     SECTION 2.12   ALTERNATE RATE OF INTEREST.
                    ---------------------------

     If prior to the commencement of any Interest Period for a Eurodollar
Borrowing:

     (a)   the Bank determines (which determination shall be conclusive, absent
manifest error) that adequate and reasonable means do not exist for ascertaining
the Eurodollar Rate for such Interest Period; or

     (b)   the Bank is advised that the Eurodollar Rate for such Interest Period
will not adequately and fairly reflect the cost to Bank of making or maintaining
the Loans included in such Borrowing for such Interest Period,

then the Bank shall give notice thereof to the Borrower and, until the Bank
notifies the Borrower that the circumstances giving rise to such notice no
longer exist, (i) any Interest Election Request that requests the conversion of
any Borrowing to, or continuation of any Borrowing as, a Eurodollar Borrowing
shall be ineffective, and (ii) if any Borrowing Request requests a Eurodollar
Revolving Borrowing, such Borrowing shall be made as an ABR Revolving Borrowing.

     SECTION 2.13   INCREASED COSTS.
                    ----------------

     (a)   Increased Costs Generally.  If any Change in Law shall:
           -------------------------

                                      -22-
<PAGE>

           (i)     impose, modify or deem applicable any reserve, special
deposit or similar requirement against assets of, deposits with or for the
account of, or credit extended by, Bank or the Bank's holding company (except
any such reserve requirement reflected in the Eurodollar Rate); or

           (ii)    impose on Bank or the Bank's holding company or the London
interbank market any other condition affecting this Agreement or Eurodollar
Loans made by Bank;

and the result of any of the foregoing shall be to increase the cost to Bank or
the Bank's holding company of making or maintaining any Eurodollar Loan (or of
maintaining its obligation to make any such Loan) or to reduce the amount of any
sum received or receivable by Bank hereunder (whether of principal, interest or
otherwise), then the Borrower will pay to Bank such additional amount or amounts
as will compensate Bank or the Bank's holding company, as the case may be, for
such additional costs incurred or reduction suffered.

     (b)   Capital Requirements.  If Bank determines that any Change in Law
           --------------------
regarding capital requirements has or would have the effect of reducing the rate
of return on Bank's capital or on the capital of the Bank's holding company as a
consequence of this Agreement or the Loans made by Bank to a level below that
which Bank or the Bank's holding company could have achieved but for such Change
in Law (taking into consideration Bank's policies and the policies of the Bank's
holding company with respect to capital adequacy), then from time to time the
Borrower will pay to Bank such additional amount or amounts as will compensate
Bank or the Bank's holding company for any such reduction suffered.

     (c)   Delay in Requests.  Failure or delay on the part of Bank to demand
           -----------------
compensation pursuant to this Section shall not constitute a waiver of Bank's
right to demand such compensation.

     SECTION 2.14   BREAK FUNDING PAYMENTS.
                    -----------------------

     In the event of (a) the payment of any principal of any Eurodollar Loan
other than on the last day of an Interest Period applicable thereto (including
as a result of an Event of Default), (b) the conversion of Eurodollar Loan other
than on the last day of the Interest Period applicable thereto, or (c) the
failure to borrow, convert, continue or prepay any Revolving Loan on the date
specified in any notice delivered pursuant hereto (regardless of whether such
notice is permitted to be revocable under Section 2.09(b) and is revoked in
accordance herewith), then, in any such event, the Borrower shall compensate
Bank for the loss, cost and expense attributable to such event. In the case of a
Eurodollar Loan, the loss to Bank attributable to any such event shall be deemed
to include an amount determined by Bank to be equal to the excess, if any, of
(i) the amount of interest that Bank would pay for a deposit equal to the
principal amount of such Loan for the period from the date of such payment,
conversion, failure or assignment to the last

                                      -23-
<PAGE>

day of the then current Interest Period for such Loan (or, in the case of a
failure to borrow, convert or continue, the duration of the Interest Period that
would have resulted from such borrowing, conversion or continuation) if the
interest rate payable on such deposit were equal to the Eurodollar Rate for such
Interest Period, over (ii) the amount of interest that Bank would earn on such
principal amount for such period if Bank were to invest such principal amount
for such period at the interest rate that would be bid by Bank (or an Affiliate
of Bank) for dollar deposits from other banks in the eurodollar market at the
commencement of such period. A certificate of Bank setting forth any amount or
amounts that Bank is entitled to receive pursuant to this Section shall be
delivered to the Borrower and shall be conclusive, absent manifest error. The
Borrower shall pay Bank the amount shown as due on any such certificate within
ten (10) days after receipt thereof.

     SECTION 2.15   TAXES.
                    ------

     (a)   Payments Free of Taxes.  Any and all payments by or on account of any
           ----------------------
obligation of the Borrower hereunder shall be made free and clear of and without
deduction for any Indemnified Taxes or Other Taxes; provided that if the
Borrower shall be required to deduct any Indemnified Taxes or Other Taxes from
such payments, then (i) the sum payable shall be increased as necessary so that
after making all required deductions (including deductions applicable to
additional sums payable under this Section) the Bank receives an amount equal to
the sum it would have received had no such deductions been made, (ii) the
Borrower shall make such deductions; and (iii) the Borrower shall pay the full
amount deducted to the relevant Governmental Authority in accordance with
applicable Law.

     (b)  Payment of Other Taxes by the Borrower.  In addition, the Borrower
          --------------------------------------
shall pay any other Taxes to the relevant Governmental Authority in accordance
with applicable Law.

     (c)  Indemnification by the Borrower.  The Borrower shall indemnify the
          -------------------------------
Bank, within ten (10) days after written demand therefor, for the full amount of
any Indemnified Taxes or Other Taxes (including Indemnified Taxes or Other Taxes
imposed or asserted on or attributable to amounts payable under this Section)
paid by the Bank, and any penalties, interest and reasonable expenses arising
therefrom or with respect thereto, whether or not such Indemnified Taxes or
Other Taxes were correctly or legally imposed or asserted by the relevant
Governmental Authority. A certificate as to the amount of such payment or
liability delivered to the Borrower by the Bank shall be conclusive, absent
manifest error.

     (d)  Evidence of Payments.  As soon as practicable after any payment of
          ---------------------
Indemnified Taxes or Other Taxes by the Borrower to a Governmental Authority,
the Borrower shall deliver to the Bank the original or a certified copy of a
receipt issued by such Governmental Authority evidencing such payment, a copy of
the return reporting such payment or other evidence of such payment reasonably
satisfactory to the Bank.

                                      -24-
<PAGE>

     SECTION 2.16   ILLEGALITY.
                    -----------

     Notwithstanding any other provision hereof, if any law, regulation, treaty
or directive, or any change therein or in the interpretation or application
thereof, shall make it unlawful for the Bank to make or maintain Eurodollar
Loans, as contemplated by this Agreement, (a) the commitment of the Bank to make
Eurodollar Loans or to convert Alternate Base Rate Loans to Eurodollar Loans
shall forthwith be suspended and (b) the Loans then outstanding as Eurodollar
Loans, if any, shall be converted automatically to Alternate Base Rate Loans on
the last day of the then current Interest Period applicable thereto or within
such earlier period as required by law. If the commitment of Bank with respect
to Eurodollar Loans is suspended pursuant to this paragraph and the Bank shall
notify the Borrower that it is once again legal for the Bank to make or maintain
Eurodollar Loans, the Bank's commitment to make or maintain Eurodollar Loans
shall be reinstated.

     SECTION 2.17   PAYMENTS GENERALLY.
                    -------------------

     (a)   Payments by the Borrower.  The Borrower shall make each payment
           ------------------------
required to be made by it hereunder (whether of principal, interest or fees, or
under Section 2.13, 2.14 or 2.15, or otherwise) prior to 1:00 PM, New York City
time, on the date when due, in immediately available funds, without set-off or
counterclaim. Any amounts received after such time on any such date shall be
deemed to have been received on the next succeeding Business Day for purposes of
calculating interest thereon. All such payments shall be made to the Bank at its
Principal Office and to such account at its Principal Office as the Bank shall
specify to the Borrower. If any payment hereunder shall be due on a day that is
not a Business Day, the date for payment shall be extended to the next
succeeding Business Day and, in the case of any payment accruing interest,
interest thereon shall be payable for the period of such extension. All payments
hereunder shall be made in Dollars.

                                  ARTICLE III
                        REPRESENTATIONS AND WARRANTIES

      The Borrower hereby represents and warrants to the Bank as follows:

     SECTION 3.01   CORPORATE STATUS.
                    -----------------

     The Borrower and each Significant Subsidiary of the Borrower is a
corporation, trust or limited liability company duly organized, validly existing
and in good standing under the Laws of its jurisdiction of organization. The
Borrower and each Significant Subsidiary of the Borrower has the corporate power
and authority to own its Property and to transact the business in which it is
engaged or presently proposes to engage. The Borrower and each Significant
Subsidiary of the Borrower is duly qualified to do business as a foreign
corporation, trust or limited liability company and is in good

                                      -25-
<PAGE>

standing in all jurisdictions in which the ownership of its properties or the
nature of its activities or both makes such qualification necessary or
advisable.

     SECTION 3.02   CORPORATE POWER AND AUTHORIZATION.
                    ----------------------------------

     The Borrower has the corporate power and authority to execute, deliver,
perform, and take all actions contemplated by, each of the Loan Documents to
which it is a party, and all such action has been duly and validly authorized by
all necessary corporate proceedings on its part. Without limiting the foregoing,
the Borrower has the corporate power and authority to borrow pursuant to the
Loan Documents to the fullest extent permitted hereby and thereby from time to
time, and has taken all necessary corporate action to authorize such borrowings.

     SECTION 3.03   EXECUTION AND BINDING EFFECT.
                    -----------------------------

     This Agreement and each of the other Loan Documents to which the Borrower
is a party and which is required to be delivered on or before the Effective Date
pursuant to Section 4.01 has been duly and validly executed and delivered by the
Borrower. This Agreement and each such other Loan Document constitutes, and when
executed and delivered by the Borrower will constitute, the legal, valid and
binding obligation of the Borrower, enforceable against the Borrower in
accordance with its terms, except as the enforceability hereof or thereof may be
limited by bankruptcy, insolvency or other similar laws of general application
affecting the enforcement of creditors' rights or by general principles of
equity limiting the availability of equitable remedies.

     SECTION 3.04   GOVERNMENTAL APPROVALS AND FILINGS.
                    -----------------------------------

     No Governmental Action is required for the due execution, delivery and
performance by the Borrower of this Agreement or any of the other Loan Documents
to which it is a party.

     SECTION 3.05   ABSENCE OF CONFLICTS.
                    ---------------------

     Neither the execution and delivery of any of the Loan Documents by the
Borrower, nor the consummation of the transactions herein or therein
contemplated by the Borrower, nor the performance of or the compliance with the
terms and conditions hereof or thereof by the Borrower, does or will:

     (a)   violate or conflict with any Law; or

     (b)   violate, conflict with or result in a breach of any term or condition
of, or constitute a default under, or result in (or give rise to any right,
    --                             --
contingent or otherwise, of any Person to cause) any termination, cancellation,
prepayment or acceleration of performance of, or result in the creation or
                                              --
imposition of (or give rise to any obligation, contingent or otherwise, to
create or impose) any Lien upon any of the Property of the

                                      -26-
<PAGE>

Borrower or any Subsidiary of the Borrower pursuant to, or otherwise result in
(or give rise to any right, contingent or otherwise, of any Person to cause) any
change in any right, power, privilege, duty or obligation of the Borrower or any
Subsidiary of the Borrower under or in connection with,

          (i)    the articles of incorporation or by-laws (or other constituent
documents) of the Borrower or any Subsidiary of the Borrower;

          (ii)   any agreement or instrument creating, evidencing or securing
any Indebtedness to which the Borrower or any Subsidiary of the Borrower is a
party or by which any of them or any of their respective properties (now owned
or hereafter acquired) may be subject or bound; or

          (iii)  any other material agreement or instrument to which the
Borrower or any Subsidiary of the Borrower is a party or by which any of them or
any of their respective properties (now owned or hereafter acquired) may be
subject or bound.

     SECTION 3.06   AUDITED FINANCIAL STATEMENTS.
                    -----------------------------

     The Borrower has heretofore furnished to the Bank consolidated balance
sheets of the Borrower, its consolidated Subsidiaries and NPC as of December 31,
2000 and the related consolidated statements of income, retained earnings and
changes in cash flows for the fiscal year then ended, as examined and reported
on by independent certified public accountants for the Borrower, who delivered
an unqualified opinion in respect thereof. Such financial statements (including
the notes thereto) present fairly the financial condition of the Borrower and
its consolidated Subsidiaries as of the end of each such fiscal year and the
results of their operations and their retained earnings and changes in cash
flows for the fiscal years then ended, all in conformity with GAAP.

     SECTION 3.07   INTERIM FINANCIAL STATEMENTS.
                    -----------------------------

     The Borrower has heretofore furnished to the Bank an interim consolidated
balance sheet of the Borrower and its consolidated Subsidiaries as of the end of
the fiscal quarter ending June 30, 2001, together with the related consolidated
statements of income, retained earnings and changes in cash flows for the
applicable fiscal period ending on such date. Such financial statements
(including the notes thereto) present fairly the financial condition of the
Borrower and its consolidated Subsidiaries as of the end of such fiscal quarter
and the results of their operations and their retained earnings and changes in
cash flows for the fiscal periods then ended, all in conformity with GAAP,
subject to normal and recurring year-end audit adjustments.

     SECTION 3.08   ABSENCE OF UNDISCLOSED LIABILITIES.
                    -----------------------------------

     Neither the Borrower nor any Subsidiary of the Borrower has any liability
or obligation of any nature whatever (whether absolute, accrued, contingent or
otherwise, whether or not due), forward or long-term commitment or unrealized or
anticipated losses from unfavorable commitments, except (a) as disclosed in the
financial statements referred to in Sections 3.06 and 3.07, and (b) liabilities,
obligations, commitments and losses incurred after June 30, 2001, in the
ordinary course of business and consistent with past practices.

     SECTION 3.09   ABSENCE OF MATERIAL ADVERSE CHANGE.
                    -----------------------------------

     Since June 30, 2001, there has been no material adverse change in the
business, operations, condition (financial or otherwise),

                                      -27-
<PAGE>

whether or not due), forward or long-term commitment or realized or anticipated
losses from unfavorable commitments, except (a) as disclosed in the financial
statements referred to in Sections 3.06 and 3.07, and (b) liabilities,
obligations, commitments and losses incurred after June 30, 2001, in the
ordinary course of business and consistent with past practices.

     SECTION 3.09   ABSENCE OF MATERIAL CHANGE
                    --------------------------

     Since June 30, 2001, there has been no material adverse change in the
business, operations, condition (financial or otherwise), or prospects of the
Borrower and its Subsidiaries taken as a whole.

     SECTION 3.10   ACCURATE AND COMPLETE DISCLOSURE.
                    ---------------------------------

     All information heretofore, contemporaneously or hereafter provided by or
on behalf of the Borrower to the Bank pursuant to or in connection with any Loan
Document or any transaction contemplated hereby or thereby is or will be (as the
case may be) true and accurate in all material respects on the date as of which
such information is dated (or, if not dated, when received by the Bank) and does
not or will not (as the case may be) omit to state any material fact necessary
to make such information not misleading at such time in light of the
circumstances in which it was provided. The Borrower has disclosed to the Bank
in writing every fact or circumstance which has, or which so far as the Borrower
can reasonably foresee is reasonably likely and is reasonably likely to have, a
Material Adverse Effect.

     SECTION 3.11   MARGIN REGULATIONS.
                    -------------------

     No part of the proceeds of any Loan hereunder will be used for the purpose
of buying or carrying any "margin stock", as such term is used in Regulation U
of the Board, as amended from time to time, or to extend credit to others for
the purpose of buying or carrying any "margin stock". Neither the Borrower nor
any Subsidiary of the Borrower is engaged in the business of extending credit to
others for the purpose of buying or carrying "margin stock". Neither the
Borrower nor any Subsidiary of the Borrower owns any "margin stock". Neither the
making of any Loan nor any use of proceeds of any such Loan will violate or
conflict with the provisions of Regulation T, U or X of the Board, as amended
from time to time.

     SECTION 3.12   LITIGATION.
                    -----------

     Except as set forth on Schedule 3.12 attached hereto, there is no pending
or (to the Borrower's knowledge after due inquiry) threatened action, suit,
proceeding or investigation (including any Environmental Claim) by or before any
Governmental Authority against or affecting the Borrower or any Subsidiary of
the Borrower which, if adversely decided, individually or in the aggregate,
would reasonably be expected to have a Material Adverse Effect.

                                      -28-
<PAGE>

     SECTION 3.13   ABSENCE OF EVENTS OF DEFAULT.
                    -----------------------------

     No event has occurred and is continuing and no condition exists which
constitutes a Default or an Event of Default.

     SECTION 3.14   ABSENCE OF OTHER CONFLICTS.
                    ---------------------------

     Neither the Borrower nor any Subsidiary of the Borrower is in violation of
or conflict with, or is subject to any contingent liability on account of any
violation of or conflict with:

     (a)   any Law (including ERISA, the Code, any applicable occupational
health, safety or welfare Law or any applicable Environmental Law);

     (b)   its articles of incorporation or by-laws (or other constituent
documents); or

     (c)   any agreement or instrument to which it is party or by which it or
any of its properties (now owned or hereafter acquired) may be subject or bound;

except for matters which, individually or in the aggregate, would not reasonably
be expected to have a Material Adverse Effect.

     SECTION 3.15   INSURANCE.
                    ----------

     The Borrower and each Subsidiary of the Borrower maintains with financially
sound and reputable insurers insurance with respect to its properties and
business and against at least such liabilities, casualties and contingencies and
in at least such types and amounts as is customary in the case of corporations
engaged in the same or a similar business or having similar properties similarly
situated.

     SECTION 3.16   TITLE TO PROPERTY; NO LIENS.
                    ----------------------------

     The Borrower and each Subsidiary of the Borrower has good and marketable
title in fee simple to all real Property owned or purported to be owned by it
and good title to all other Property of whatever nature owned or purported to be
owned by it, including but not limited to all Property reflected in the most
recent audited balance sheet referred to in Section 3.06 or submitted pursuant
to Section 5.01(b), as the case may be (except as sold or otherwise disposed of
in the ordinary course of business after the date of such balance sheet). Except
for (i) Liens consisting of zoning or planning restrictions, easements, permits
and other restrictions or limitations on the use of real Property or
irregularities in title thereto which do not materially detract from the value
of, or impair the use of, such Property by the Borrower or any Subsidiary of the
Borrower in the operation of its business, (ii) Liens for current Taxes not yet
due and delinquent and (iii) Liens permitted by Section 6.02, no Property owned
by the Borrower or any Subsidiary of the Borrower is subject to any Lien.

                                      -29-
<PAGE>

     SECTION 3.17   TAXES.
                    ------

     All tax and information returns required to be filed by or on behalf of the
Borrower or any Subsidiary of the Borrower have been properly prepared, executed
and filed. All Taxes upon the Borrower or any Subsidiary of the Borrower or upon
any of their respective Properties, incomes, sales or franchises which are due
and payable have been paid, other than those not yet delinquent and payable
without premium or penalty, and except for those being diligently contested in
good faith by appropriate proceedings, and in each case adequate reserves and
provisions for Taxes have been made on the books of the Borrower and each
Subsidiary of the Borrower. The reserves and provisions for Taxes on the books
of the Borrower and each Subsidiary of the Borrower are adequate for all open
years and for its current fiscal period. Neither the Borrower nor any Subsidiary
of the Borrower knows of any proposed additional assessment or basis for any
material assessment for additional Taxes (whether or not reserved against).

     SECTION 3.18   BORROWER NOT AN INVESTMENT COMPANY OR A REGISTERED PUBLIC
                    ---------------------------------------------------------
UTILITY HOLDING COMPANY.
------------------------

     The Borrower is not an "investment company" or a company controlled by an
"investment company" within the meaning of the Investment Company Act of 1940.
The Borrower is not a "holding company" within the meaning of the Public Utility
Holding Company Act of 1935 which is subject to registration.

     SECTION 3.19   ENVIRONMENTAL MATTERS.
                    ----------------------

     (a)   The Borrower and each of its Subsidiaries have complied with and are
in compliance with, all applicable Environmental Laws and the requirements of
any permits issued under such Environmental Laws. Except as set forth on
Schedule 3.19 attached hereto, there are no pending or threatened Environmental
Claims against the Borrower or any of its Subsidiaries (including any such claim
arising out of the ownership, lease or operation by the Borrower or any of its
Subsidiaries of any real Property no longer owned, leased or operated by the
Borrower or any of its Subsidiaries) or any real Property owned, leased or
operated by the Borrower or any of its Subsidiaries. Except as set forth on
Schedule 3.19 attached hereto, there are no facts, circumstances, conditions or
occurrences with respect to the business or operations of the Borrower or any of
its Subsidiaries, or any real Property owned, leased or operated by the Borrower
or any of its Subsidiaries (including any real Property formerly owned, leased
or operated by the Borrower or any of its Subsidiaries but no longer owned,
leased or operated by the Borrower or any of its Subsidiaries) or any Property
adjoining or adjacent to any such real Property that could be expected (i) to
form the basis of an Environmental Claim against the Borrower or any of its
Subsidiaries or any real Property owned, leased or operated by the Borrower or
any of its Subsidiaries or (ii) to cause any real Property owned, leased or
operated by the Borrower or any of its Subsidiaries to be subject to any
restrictions on the ownership, occupancy or transferability of such real
Property by the Borrower or any of its Subsidiaries under any applicable
Environmental Law.

                                      -30-
<PAGE>

     (b)  Hazardous Materials have not at any time been generated, used, treated
or stored on, or transported to or from, any real Property owned, leased or
operated by the Borrower or any of its Subsidiaries where such generation, use,
treatment or storage has violated or could be expected to violate any
Environmental Law. Hazardous Materials have not at any time been Released on or
from any real Property owned, leased or operated by Borrower or any of its
Subsidiaries where such Release has violated or would be expected to violate any
applicable Environmental Law.

     (c)  Notwithstanding anything to the contrary in this Section, the
representations made in this Section shall not be untrue unless the effect of
all violations, claims, restrictions, failures and noncompliances of the types
described in this Section would reasonably be expected to, individually or in
the aggregate, have a Material Adverse Effect on the Borrower.

     SECTION 3.20   ERISA.
                    ------

     (a)  Each Plan (and each related trust, insurance contract or fund) is in
substantial compliance with its terms and with all applicable Laws, including
without limitation ERISA and the Code; each Plan (and each related trust, if
any) which is intended to be qualified under Section 401(a) of the Code has
received a determination letter from the Internal Revenue Service to the effect
that it meets the requirements of Sections 401(a) and 501(a) of the Code; no
Reportable Event has occurred; no Multiemployer Plan is insolvent or in
reorganization; no Plan has an Unfunded Current Liability; no Plan which is
subject to Section 412 of the Code or Section 302 of ERISA has an accumulated
funding deficiency within the meaning of such sections of the Code or ERISA or
has applied for or received a waiver of an accumulated funding deficiency or an
extension of any amortization period within the meaning of Section 412 of the
Code or Section 303 or 304 of ERISA; all contributions required to be made with
respect to a Plan have been timely made; neither the Borrower nor any Subsidiary
of the Borrower nor any ERISA Affiliate has incurred any material liability
(including any indirect, contingent or secondary liability) to or on account of
a Plan pursuant to Section 409, 502(i), 502(l), 515, 4062, 4063, 4064, 4069,
4201, 4204 or 4212 of ERISA or Section 401(a)(29), 4971 or 4975 of the Code or
expects to incur any such liability under any of the foregoing sections with
respect to any Plan; no condition exists which presents a material risk to the
Borrower or any Subsidiary of the Borrower or any ERISA Affiliate of incurring a
liability to or on account of a Plan pursuant to the foregoing provisions of
ERISA and the Code; no proceedings have been instituted to terminate or appoint
a trustee to administer any Plan; no action, suit, proceeding, hearing, audit or
investigation with respect to the administration, operation or the investment of
assets of any Plan (other than routine claims for benefits) is pending, expected
or threatened; using actuarial assumptions and computation methods consistent
with Part 1 of subtitle E of Title IV of ERISA, the aggregate liabilities of the
Borrower and its Subsidiaries and its ERISA Affiliates to all Multiemployer
Plans in the event of a complete withdrawal therefrom, as of the close of the
most recent fiscal year of each such Plan ended prior to the date of the

                                      -31-
<PAGE>

most recent Borrowing, would not have a Material Adverse Effect; each group
health plan (as defined in Section 607(1) of ERISA or Section 4980B(g)(2) of the
Code) which covers or has covered employees or former employees of the Borrower,
any Subsidiary of the Borrower, or any ERISA Affiliate has at all times been
operated in compliance with the provisions of Part 6 of subtitle B of Title I of
ERISA and Section 4980B of the Code; no Lien imposed under the Code or ERISA on
the assets of the Borrower or any Subsidiary of the Borrower or any ERISA
Affiliate exists or is likely to arise on account of any Plan; and the Borrower
and its Subsidiaries may cease contributions to or terminate any Plan maintained
by any of them without incurring any material liability.

     (b)  Each Foreign Pension Plan, if any, has been maintained in substantial
compliance with its terms and with the requirements of any and all applicable
Laws, statutes, rules, regulations and orders and has been maintained, where
required, in good standing with applicable regulatory authorities. All
contributions required to be made with respect to a Foreign Pension Plan have
been timely made. Neither the Borrower nor any of its Subsidiaries has incurred
any obligation in connection with the termination of or withdrawal from any
Foreign Pension Plan. The present value of the accrued benefit liabilities
(whether or not vested) under each Foreign Pension Plan, determined as of the
end of the Borrower's most recently ended fiscal year on the basis of actuarial
assumptions, each of which is reasonable, did not exceed the current value of
the assets of such Foreign Pension Plan allocable to such benefit liabilities.

     SECTION 3.21   PARI PASSU STATUS.
                    ------------------

     The claims and rights of the Bank against the Borrower hereunder are not
subordinated to, and rank at least pari passu with, the claims and rights of
other holders of its unsecured indebtedness except to the extent otherwise
provided by Law (including without limitation the Bankruptcy Code and the
provisions of 31 U.S.C. (S)3713).

                                  ARTICLE IV
                                  CONDITIONS

     SECTION 4.01   EFFECTIVE DATE.
                    ---------------

     This Agreement and the other Loan Documents shall become effective as
against the Bank on the first date on which all of the following conditions
shall be satisfied or waived:

     (a)  Agreement; Note.  The Bank shall have received an executed counterpart
          ---------------
of this Agreement for Bank, duly executed by the Borrower, and the Note.

     (b)  Corporate Proceedings.  The Bank shall have received certificates by
          ---------------------
the Secretary or Assistant Secretary of the Borrower dated as of the Effective
Date as to (i) true copies of the articles of incorporation and by-laws (or
other constituent documents) of the Borrower as in effect on such date (which,
in the case of articles of

                                      -32-
<PAGE>

incorporation or other constituent documents filed or required to be filed with
the Secretary of State or other Governmental Authority in its jurisdiction of
incorporation, shall be certified to be true, correct and complete by such
Secretary of State or other Governmental Authority not more than 30 days before
the date hereof), (ii) true copies of all corporate action taken by the Borrower
relative to this Agreement and the other Loan Documents, and (iii) the
incumbency and signatures of the respective officers of the Borrower executing
this Agreement and the other Loan Documents to which the Borrower is a party,
together with satisfactory evidence of the incumbency of such Secretary or
Assistant Secretary. The Bank shall have received, certificates from the
Secretary of State of Nevada (or other applicable Governmental Authority) dated
not more than 30 days before the Effective Date showing the good standing of the
Borrower in Nevada and in each state in which the Borrower does business.

     (c)  Legal Opinion of Counsel to the Borrower.  The Bank shall have
          ----------------------------------------
received, an opinion addressed to the Bank, dated Effective Date, of Choate,
Hall & Stewart and of Woodburn and Wedge as to issues under the laws of the
State of Nevada, as to such matters as may be requested by the Bank and in form
and substance satisfactory to the Bank.

     (d)  Financial Statements.  The Bank shall have received a true and correct
          --------------------
copy of the (i) audited consolidated financial statements, including balance
sheets, income statements and cash flow statements, for the Borrower, NPC, SPPC
and their respective consolidated Subsidiaries for the year ended December 31,
2000, and (ii) unaudited interim consolidated financial statements, including a
balance sheet, income statement and statement of cash flows, for the Borrower,
NPC, SPPC and their respective consolidated Subsidiaries for the six month
period ended June 30, 2001.

     (e)  No Material Adverse Effect.  Nothing shall have occurred (and the Bank
          --------------------------
shall have not become aware of any facts or conditions not previously known)
which Bank shall determine has, had, or could reasonably be expected to have, a
Material Adverse Effect. The Bank shall have received a certificate of a
Responsible Officer of the Borrower, dated the Effective Date, to the effect
that, as of the Effective Date, there has been no Material Adverse Effect since
June 30, 2001.

     (f)  No Injunctions.  There shall not exist any judgment, order, injunction
          --------------
or other restraint issued or filed or a hearing seeking injunctive relief or
other restraint pending or notified prohibiting or imposing materially adverse
conditions upon the transactions contemplated hereby or otherwise referred to
herein.

     (g)  Litigation, Proceedings and Investigations. There shall be no actions,
          ------------------------------------------
arbitrations, suits, investigations or proceedings pending or threatened with
respect to this Agreement or which the Bank shall determine could reasonably be
expected to have a Material Adverse Effect.

                                      -33-
<PAGE>

     (h)  No Violation of Existing Agreements.  Neither the Borrower nor any
          -----------------------------------
Subsidiary of the Borrower is in violation of any material agreement or
instrument to which it is party or by which it or any of its properties (now
owned or hereafter acquired) may be subject or bound.

     (i)  Officers' Certificates. The Bank shall have received, with an executed
          ----------------------
counterpart, certificates from such officers of the Borrower as to such matters
as the Bank may request.

     (j)  Fees, Expenses, etc.  All fees and other items required to be paid to
          -------------------
Bank on or before the Effective Date (including, but not limited to, the Upfront
Fee) shall have been paid or received.

     (k)  Section 4.02 Conditions.
          -----------------------

          (i)   Each of the representations and warranties made by the Borrower
herein and in each other Loan Document shall be true and correct in all material
respects on and as of the Effective Date as if made on and as of such date, both
before and after giving effect to the Loans requested to be made on such date.

          (ii)  No Default or Event of Default shall have occurred and be
continuing on the Effective Date.

     (l)  Additional Matters.  The Bank shall have received, with copies or
          ------------------
executed counterparts, such other certificates, opinions, documents and
instruments as the Bank may reasonably request.  All corporate and other
proceedings, and all documents, instruments and other matters in connection with
the transactions contemplated by this Agreement and the other Loan Documents
shall be satisfactory in form and substance to the Bank and its Special Counsel.

     SECTION 4.02   CONDITIONS TO ALL LOANS.
                    ------------------------

     The obligation of Bank to make, convert or continue any Loan on the
occasion of any Borrowing is subject to satisfaction of the conditions precedent
set forth in Section 4.01 and satisfaction of the following further conditions
precedent:

     (a)  Notice.  The Borrower shall have executed and delivered to the Bank a
          ------
Borrowing Request or Interest Election Request for such Borrowing in accordance
with Section 2.03 or 2.05, as the case may be.

     (b)  Representations and Warranties.  Each of the representations and
          ------------------------------
warranties made by the Borrower herein and in each other Loan Document shall be
true and correct in all material respects on and as of such date as if made on
and as of such date, both before and after giving effect to the making,
conversion or continuation of Loans requested to be made, converted or continued
on such date.

                                      -34-
<PAGE>

     (c)  No Defaults. No Default or Event of Default shall have occurred and be
          -----------
continuing on such date or after giving effect to the making, conversion or
continuation of Loans requested to be made, converted or continued on such date.

     (d)  No Violations of Law, etc.  Neither the making, conversion nor
          -------------------------
continuation nor use of the Loans shall cause Bank to violate or be in conflict
with any Law.

     (e)  No Material Adverse Change.  There shall not have occurred, or be
          --------------------------
threatened, any other event, act or condition which would reasonably be expected
to have a Material  Adverse Effect.

     (f)  Documentation and Proceedings. All corporate and legal proceedings and
          -----------------------------
all documents and papers relating to the Borrower in connection with the
transactions contemplated by this Agreement shall be satisfactory in form and
substance to the Bank and the Bank shall have received all information and
copies of all documents, including records of corporate proceedings, which the
Bank may reasonably have requested in connection therewith, such documents where
appropriate to be certified by proper corporate or governmental authorities.

     Each request by the Borrower for any Loan or conversion or continuation
thereof shall constitute a representation and warranty by the Borrower that the
conditions set forth in this Section 4.02 have been satisfied as of the date of
such request. Failure of the Bank to receive notice from the Borrower to the
contrary before such Loan is made shall constitute a further representation and
warranty by the Borrower that the conditions referred to in this Section 4.02
have been satisfied as of the date such Loan is made.

                                   ARTICLE V
                             AFFIRMATIVE COVENANTS

     The Borrower hereby covenants to the Bank:

     SECTION 5.01   BASIC REPORTING REQUIREMENTS.
                    -----------------------------

     (a)  Annual Audit Reports.  As soon as practicable, and in any event within
          --------------------
90 days after the close of each fiscal year of the Borrower, the Borrower shall
furnish to the Bank, consolidated statements of income, retained earnings and
cash flows of the Borrower and its consolidated Subsidiaries for such fiscal
year and a consolidated balance sheet of the Borrower and its consolidated
Subsidiaries as of the close of such fiscal year, and notes to each, all in
reasonable detail, setting forth in comparative form the corresponding figures
for the preceding fiscal year.  Such financial statements shall be accompanied
by an opinion of independent certified public accountants of recognized national
standing selected by the Borrower, which opinion shall not be subject to any
qualification as to scope of audit or as to any other matter which the Bank
determines is adverse.  Such opinion in any event shall contain a written
statement of such accountants

                                      -35-
<PAGE>

substantially to the effect that (i) such accountants examined such financial
statements in accordance with generally accepted auditing standards and
accordingly made such tests of accounting records and such other auditing
procedures as such accountants considered necessary in the circumstances and
(ii) in the opinion of such accountants such financial statements present fairly
the financial position of the Borrower and its consolidated Subsidiaries as of
the end of such fiscal year and the results of their operations and their
retained earnings and cash flows for such fiscal year, in conformity with GAAP.

     (b)  Quarterly Consolidated Reports.  As soon as practicable, and in any
          ------------------------------
event within 45 days after the close of each of the first three fiscal quarters
of each fiscal year of the Borrower, the Borrower shall furnish to the Bank,
unaudited consolidated statements of income, retained earnings and cash flows of
the Borrower and its consolidated Subsidiaries for the period from the beginning
of such fiscal year to the end of such fiscal quarter and an unaudited
consolidated balance sheet of the Borrower and its consolidated Subsidiaries as
of the close of such fiscal quarter, and notes to each, all in reasonable
detail, setting forth in comparative form the corresponding figures for the same
periods or as of the same date during the preceding fiscal year (except for the
consolidated balance sheet, which shall set forth in comparative form the
corresponding balance sheet as of the prior fiscal year end).  Such financial
statements shall be certified by a Responsible Officer of the Borrower as
presenting fairly the financial position of the Borrower and its consolidated
Subsidiaries as of the end of such fiscal quarter and the results of their
operations and their retained earnings and changes in cash flows for such fiscal
year, in conformity with GAAP, subject to normal and recurring year-end audit
adjustments.

     (c)  Compliance Certificates.  The Borrower shall deliver to the Bank, a
          -----------------------
Compliance Certificate, duly completed and signed by a Responsible Officer of
the Borrower concurrently with the delivery of the financial statements referred
to in subsections (a) and (b) of this Section 5.01.

     (d)  Certain Other Reports and Information.  Promptly upon their becoming
          -------------------------------------
available to the Borrower, the Borrower shall deliver to the Bank, a copy of (i)
all regular or special reports, registration statements and amendments to the
foregoing which the Borrower or any Subsidiary of the Borrower shall file with
the Securities and Exchange Commission (or any successor thereto) or any
securities exchange, and (ii) all reports, proxy statements, financial
statements and other information distributed by the Borrower to its
stockbrokers, bondholders or the financial community generally.

     (e)  Further Information.  The Borrower shall promptly furnish to the Bank,
          -------------------
such other information and in such form as the Bank or Bank may reasonably
request from time to time.

     (f)  Notice of Certain Events.  Promptly (and, in the case of clause (i)
          ------------------------
below, no later than two Business Days) upon becoming aware of any of the
following, the Borrower shall give the Bank notice thereof, together with a
written statement of a

                                      -36-
<PAGE>

Responsible Officer of the Borrower setting forth the details thereof and any
action with respect thereto taken or proposed to be taken by the Borrower:

          (i)    Any Default or Event of Default.

          (ii)   The occurrence or existence of any event or condition
(including (A) the violation or alleged violation of any Environmental Law by
the Borrower or any Subsidiary of the Borrower or the assertion of any
Environmental Claim against the Borrower or any Subsidiary of the Borrower, (B)
the commencement of any other action, suit, proceeding or investigation by or
before any Governmental Authority against or affecting the Borrower or any
Subsidiary of the Borrower, or (C) the violation, breach or default or alleged
violation, breach or default by the Borrower or any Subsidiary of the Borrower
or any other Person under any agreement or instrument material to the business,
operations, condition (financial or otherwise) or prospects of the Borrower and
its Subsidiaries taken as a whole) which event or condition, either individually
or in the aggregate, has, or would reasonably be expected to have, a Material
Adverse Effect.

          (iii)  Any change in the Index Debt rating.

     (g)  Visitation; Verification.  The Borrower shall permit such Persons as
          ------------------------
the Bank or Bank may designate from time to time to visit and inspect any of the
properties of the Borrower and of any Subsidiary, to examine their respective
books and records and take copies and extracts therefrom and to discuss their
respective affairs with their respective officers, employees and independent
accountants at such times and as often as the Bank or Bank may reasonably
request; provided, however, that the Borrower reserves the right to restrict
access to any of its generating facilities in accordance with reasonably adopted
practices relating to safety and security.  The Borrower hereby authorizes such
officers, employees and independent accountants to discuss with the Bank or Bank
the affairs of the Borrower and its Subsidiaries.

     (h)  ERISA.  Within thirty (30) days after the Borrower knows that any of
          -----
the events or conditions specified below with respect to any Plan or
Multiemployer Plan has occurred or exists, a statement signed by a Responsible
Officer of the Borrower setting forth details respecting such event or condition
and the action, if any, that the Borrower or its ERISA Affiliate proposes to
take with respect thereto (and a copy of any report or notice required to be
filed with or given to PBGC by the Borrower or an ERISA Affiliate with respect
to such event or condition):

          (i)    any Reportable Event and any request for a waiver under Section
412(d) of the Code for any Plan;

          (ii)   the distribution under Section 4041 of ERISA of a notice of
intent to terminate any Plan or any action taken by the Borrower or an ERISA
Affiliate to terminate any Plan, in each case with respect to which there are
insufficient assets to pay benefits as they become due;

                                      -37-
<PAGE>

          (iii)  the institution by PBGC of proceedings under Section 4042 of
ERISA for the termination of, or the appointment of a trustee to administer, any
Plan, or the receipt by the Borrower or any ERISA Affiliate of a notice from a
Multiemployer Plan that such action has been taken by PBGC with respect to such
Multiemployer Plan;

          (iv)   the complete or partial withdrawal from a Multiemployer Plan by
the Borrower or any ERISA Affiliate that results in liability under Section 4201
or 4204 of ERISA (including the obligation to satisfy secondary liability as a
result of a purchaser default) or the receipt by the Borrower or any ERISA
Affiliate of notice from a Multiemployer Plan that it is in reorganization or
insolvency pursuant to Section 4241 or 4245 of ERISA or that it intends to
terminate or has terminated under Section 4041A of ERISA; and

          (v)    the adoption of an amendment to any Plan that, pursuant to
Section 401(a)(29) of the Code or Section 307 of ERISA, would result in the loss
of tax-exempt status of the trust of which such Plan is a part if the Borrower
or an ERISA Affiliate fails to timely provide security to the Plan in accordance
with the provisions of said Sections.

     (i)  Satisfaction of Certain Reporting Requirements.   Notwithstanding any
          ----------------------------------------------
other provision of this Section 5.01, the Borrower shall be deemed to have
satisfied its obligations pursuant to Sections 5.01(a) and (b) if and to the
extent that it shall have provided to the Bank, pursuant to Section 5.01(d),
copies of its periodic reports (on Form 10-K or 10-Q, as the case may be) as
required to be filed with the Securities and Exchange Commission (or any
successor thereto) pursuant to the Securities and Exchange Act of 1934, as
amended (or any successor statute of similar import), for the annual and
quarterly periods described in such Sections.

     SECTION 5.02   INSURANCE.
                    ----------

     The Borrower shall, and shall cause each of its Subsidiaries to, maintain
with financially sound and reputable insurers insurance with respect to its
properties and business and against such liabilities, casualties and
contingencies and of such types and in such amounts as is customary in the case
of corporations engaged in the same or similar businesses or having similar
properties similarly situated and as is satisfactory from time to time to the
Bank in its reasonable discretion.

     SECTION 5.03   PAYMENT OF TAXES AND OTHER POTENTIAL CHARGES AND PRIORITY
                    ---------------------------------------------------------
CLAIMS.
-------

     The Borrower shall, and shall cause each of its Subsidiaries to, pay or
discharge:

     (a)  on or prior to the date on which penalties or Liens attach thereto,
all Taxes imposed upon it or any of its properties;

                                      -38-
<PAGE>

     (b)  on or prior to the date when due, all lawful claims of materialmen,
mechanics, carriers, warehousemen, landlords and other like Persons which, if
unpaid, might result in the creation of a Lien upon any such Property; and

     (c)  on or prior to the date when due, all other lawful claims which, if
unpaid, might result in the creation of a Lien upon any such Property or which,
if unpaid, might give rise to a claim entitled to priority over general
creditors of the Borrower or such Subsidiary in a case under the Bankruptcy
Code;

provided, that, unless and until foreclosure, distraint, levy, sale or similar
proceedings shall have been commenced, the Borrower or such Subsidiary need not
pay or discharge any such Tax, assessment, charge or claim so long as (x) the
validity thereof is contested in good faith and by appropriate proceedings
diligently conducted, and (y) such reserves or other appropriate provisions as
may be required by GAAP shall have been made therefor.

     SECTION 5.04   PRESERVATION OF CORPORATE STATUS AND FRANCHISES.
                    ------------------------------------------------

     The Borrower shall, and shall cause each of its Significant Subsidiaries
to, maintain its status as a corporation, trust or limited liability company
duly organized, validly existing and in good standing under the Laws of its
jurisdiction of organization, and to be duly qualified to do business as a
foreign corporation, trust or limited liability company and in good standing in
all jurisdictions in which the ownership of its properties or the nature of its
business or both make such qualification necessary or advisable; provided,
however, that nothing in this Section 5.04 shall prevent the withdrawal by the
Borrower or any of its Subsidiaries of its qualification as a foreign
corporation in any jurisdiction where such withdrawal could not have a Material
Adverse Effect. The Borrower shall, and shall cause each of its Subsidiaries to,
do or cause to be done, all things necessary to preserve and keep in full force
and effect its material rights, franchises, licenses and patents.

     SECTION 5.05   GOVERNMENTAL APPROVALS AND FILINGS.
                    -----------------------------------

     The Borrower shall keep and maintain in full force and effect all
Governmental Actions necessary or advisable in connection with execution and
delivery of any Loan Document, consummation of the transactions herein or
therein contemplated, performance of or compliance with the terms and conditions
hereof or thereof or to ensure the legality, validity, binding effect or
enforceability hereof or thereof.

     SECTION 5.06   MAINTENANCE OF PROPERTIES.
                    --------------------------

     The Borrower shall, and shall cause each of its Significant Subsidiaries
to, maintain or cause to be maintained in good repair, working order and
condition the properties now or hereafter owned, leased or otherwise possessed
by it and shall make or

                                      -39-
<PAGE>

cause to be made all needful and proper repairs, renewals, replacements and
improvements thereto so that the business carried on in connection therewith may
be properly and advantageously conducted at all times.

     SECTION 5.07   AVOIDANCE OF OTHER CONFLICTS.
                    -----------------------------

     The Borrower shall not, and shall not permit any of its Subsidiaries to,
violate or conflict with, be in violation of or in conflict with, or be or
remain subject to any liability (contingent or otherwise) on account of any
violation or conflict with

     (a)  any Law;

     (b)  its articles of incorporation or by-laws; or

     (c)  any agreement or instrument to which it is party or by which any of
them or any of their respective Subsidiaries is a party or by which any of them
or any of their respective properties (now owned or hereafter acquired) may be
subject or bound, except for matters which would not reasonably be expected,
either individually or in the aggregate, to have a Material Adverse Effect.

     SECTION 5.08   FINANCIAL ACCOUNTING PRACTICES.
                    -------------------------------

     The Borrower shall, and shall cause each of its Subsidiaries to, make and
keep books, records and accounts which, in reasonable detail, accurately and
fairly reflect its transactions and dispositions of its assets and maintain a
system of internal accounting controls sufficient to provide reasonable
assurances that (a) transactions are executed in accordance with management's
general or specific authorization, (b) transactions are recorded as necessary
(i) to permit preparation of financial statements in conformity with GAAP and
(ii) to maintain accountability for assets, (c) access to assets is permitted
only in accordance with management's general or specific authorization and (d)
the recorded accountability for assets is compared with the existing assets at
reasonable intervals and appropriate action is taken with respect to any
differences.

     SECTION 5.09   USE OF PROCEEDS.
                    ----------------

     The Borrower shall apply the proceeds of all Loans hereunder only for
general corporate purposes of the Borrower. The Borrower shall not use the
proceeds of any Loans hereunder directly or indirectly for any unlawful purpose,
in any manner inconsistent with Section 3.11, or inconsistent with any other
provision of any Loan Document.

                                      -40-
<PAGE>

     SECTION 5.10   END OF FISCAL PERIODS.
                    ----------------------

     The Borrower shall cause (a) each of its, and each of its Subsidiary's,
fiscal years to end on December 31 and (b) each of its, and each of its
Subsidiary's, fiscal quarters to end on March 31, June 30, September 30 and
December 31.

                                  ARTICLE VI
                              NEGATIVE COVENANTS

     The Borrower hereby covenants to the Bank as follows:

     SECTION 6.01   INDEBTEDNESS.
                    -------------

     The Borrower shall not at any time create, incur, assume or suffer to exist
any Indebtedness (including, but not limited to, any Contingent Obligations of
Borrower) or agree, become or remain liable (contingently or otherwise) for any
Indebtedness in excess of Six Hundred Seventy-Five Million and 00/100 Dollars
($675,000,000.00), in the aggregate. For purposes of this Section, the term
"Indebtedness" shall be deemed to include the Revolving Loans.

     SECTION 6.02   LIENS.
                    ------

     The Borrower shall not, and shall not permit any of its Subsidiaries to, at
any time create, incur, assume or suffer to exist any Lien on any of its
Property (now owned or hereafter acquired), or agree, become or remain liable
(contingently or otherwise) to do any of the foregoing, except for the following
("Permitted Liens"):
  ---------------

     (a)   Liens existing on the date hereof and securing obligations existing
on the date hereof, other than Indebtedness to be refinanced;

     (b)   Liens securing obligations of NPC issued under and pursuant to the
terms and conditions of the NPC First Mortgage Indenture;

     (c)   Liens securing obligations of SPPC issued under and pursuant to the
terms and conditions of the SPPC First Mortgage Indenture;

     (d)   Liens on NPC First Mortgage Bonds issued as collateral for pollution
control revenue bonds issued for the benefit of NPC or its Subsidiaries (and
related rights and interests) to secure obligations of NPC or such Subsidiaries
for the benefit of the holders of such bonds, provided that such bonds are not
secured by any other assets or Properties of NPC or its Subsidiaries;

     (e)   Liens on SPPC First Mortgage Bonds issued as collateral for pollution
control or gas or water facility revenue bonds issued for the benefit of SPPC or
its Subsidiaries (and related rights and interests) to secure obligations of
SPPC or such

                                      -41-
<PAGE>

Subsidiaries for the benefit of the holders of such bonds, provided that such
bonds are not secured by any other assets or Properties of SPPC or its
Subsidiaries;

     (f)   Liens on SPPC First Mortgage Bonds issued as collateral for medium-
term notes issued pursuant to the Collateral Trust Indenture, dated as of June
1, 1992, between SPPC and Bankers Trust Company, as Trustee;

     (g)   Liens securing obligations of NPC issued under and pursuant to the
terms and conditions of the NPC General and Refunding Mortgage Indenture;

     (h)   Liens securing obligations of SPPC issued under and pursuant to the
terms and conditions of the SPPC General and Refunding Mortgage Indenture;

     (i)   Liens on "transition property" arising pursuant to Section 843 of the
California Public Utility Code for the benefit of holders of rate reduction
bonds issued pursuant to a valid financing order of the California Public
Utilities Commission;

     (j)   Liens arising from taxes, assessments, charges or claims described in
Section 5.03 that are not yet due or that remain payable without penalty or to
the extent permitted to remain unpaid under the proviso to such Section 5.03;

     (k)   Deposits or pledges of cash or securities in the ordinary course of
business to secure (i) worker's compensation, unemployment insurance or other
social security obligations, (ii) performance of bids, tenders, trade contracts
(other than for payment of money) or leases, (iii) stay, surety or appeal bonds,
or (iv) other obligations of a like nature incurred in the ordinary course of
business;

     (l)   Zoning restrictions, easements, minor restrictions on the use of real
Property, minor irregularities in title thereto and other minor Liens that do
not secure the payment of money or the performance of an obligation and that do
not in the aggregate materially detract from the value of an asset to, or
materially impair its use in the business of, the Borrower or such Subsidiary;
and

     (m)   Liens on Property securing all or part of the purchase price thereof
and Liens (whether or not assumed) existing in Property at the time of purchase
thereof, provided that: (i) such Lien is created before or substantially
simultaneously with the purchase of such Property by the Borrower or such
Subsidiary, (ii) such Lien is confined solely to the Property so purchased,
improvements thereto and proceeds thereof, (iii) the aggregate amount secured by
such Liens on any particular Property at the time purchased by the Borrower or
such Subsidiary, as the case may be, shall not exceed the lesser of the purchase
price of such Property and the fair market value of such Property at the time of
purchase thereof by the Borrower or such Subsidiary, and (iv) the aggregate
amount secured by all Liens described in this Section 6.02(k) shall not at any
time exceed $150,000,000.

                                      -42-
<PAGE>

     "Permitted Liens" shall in no event include any Lien imposed by, or
required to be granted pursuant to, ERISA or any Environmental Law.

     SECTION 6.03   MERGERS.
                    --------

     The Borrower shall not, and shall not permit any of its Subsidiaries to,
(a) merge with or into or consolidate with any other Person, (b) liquidate,
wind-up, dissolve or divide, or (c) agree, become or remain liable (contingently
or otherwise) to do any of the foregoing, except:

          (i)     A Person may merge with or into or consolidate with any
Subsidiary of the Borrower, provided that (x) the surviving Person shall be a
Subsidiary of the Borrower, (y) no Default or Event of Default shall have
occurred and be continuing or shall exist at such time or after giving effect to
such transaction and (z) the Borrower shall deliver to the Bank (A) a
certificate, in a form reasonably satisfactory to the Bank, certifying that no
Default or Event of Default exists or will result from such merger; and (B) pro
forma financial statements in support of such certification; and

          (ii)    A Person may merge with or into or consolidate with the
Borrower, provided that (x) the Borrower shall be the surviving Person, (y) no
Default or Event of Default shall have occurred and be continuing or shall exist
at such time or after giving effect to such transaction and (z) the Borrower
shall deliver to the Bank (A) a certificate, in a form reasonably satisfactory
to the Bank, certifying that no Default or Event of Default exists or will
result from such merger; and (B) pro forma financial statements in support of
such certification.

     SECTION 6.04   DISPOSITIONS OF PROPERTIES.
                    ---------------------------

     The Borrower shall not, and shall not permit any of its Subsidiaries to,
sell, convey, assign, lease, sale-leaseback, transfer, abandon or otherwise
dispose of, voluntarily or involuntarily (collectively, "Dispose"), any of its
                                                         -------
Properties, or agree, become or remain liable contingently or otherwise to do
any of the foregoing, except that, so long as no Default or Event of Default
shall have occurred and be continuing or shall exist at such time or after
giving effect to such transaction, the Borrower and its Subsidiaries may Dispose
of Property (a) in transactions in the ordinary course of business consistent
with past practice, (b) that is obsolete, (c) comprising accounts receivable
transferred by NPC or SPPC to one or more commercial paper conduits, special
purpose subsidiaries or similar entities; provided that (i) the aggregate face
                                          --------
amount of such accounts receivable, when added to the aggregate face amount of
all other accounts receivable Disposed of in reliance on this clause (c), does
not exceed $250,000,000, and (ii) the net cash proceeds from the Disposition of
such accounts receivable, (A) when added to the net cash proceeds of all other
Dispositions of accounts receivable by such entity made in reliance on this
clause (c), are not less than 80% of the aggregate face amount of all accounts
receivable Disposed of by such entity in reliance on this clause (c) and (B) at
the time of such Disposition, do not exceed the sum of (I) the

                                      -43-
<PAGE>

balance of NPC's and SPPC's aggregate deferred energy accrual accounts at such
time and (II) NPC's and SPPC's aggregate deferred energy costs actually incurred
but not yet reflected in NPC's and SPPC's respective deferred energy accrual
accounts, in each case as set forth in NPC's and SPPC's books and records;
provided, further, that each Disposition made by NPC or SPPC in reliance on this
clause (c) shall constitute a representation and warranty of the Borrower, made
at the time of such Disposition, that the conditions set forth in clauses (i)
and (ii) above are satisfied at such time; and (d) in transactions other than as
provided in Section 6.04 (a), (b) and (c) provided that the aggregate book value
of all Property Disposed of pursuant to this Section 6.04(d) from and after the
date hereof shall not exceed $120,000,000.

     SECTION 6.05   INVESTMENTS AND ACQUISITIONS.
                    -----------------------------

     Prior to the making of any Investment or the consummation of any
Acquisition by the Borrower or any of its Subsidiaries, the amount or purchase
price of which, as the case may be, when aggregated with the amounts and
purchase prices of other Investments and Acquisitions made by the Borrower and
its Subsidiaries, would exceed $70,000,000 in the aggregate at any time, the
Borrower shall deliver to the Bank (i) a certificate, in a form reasonably
satisfactory to the Bank, certifying that no Default or Event of Default exists
or will result from such Acquisition and (ii) pro forma financial statements in
support of such certification.

     SECTION 6.06   DIVIDENDS AND STOCK REPURCHASES.
                    --------------------------------

     The Borrower shall not declare or pay any dividend on its capital stock
(except for (i) dividends in the form of capital stock; and (ii) dividends
declared prior to the date of this Agreement), or redeem or repurchase any of
its capital stock if a Default or Event of Default shall have occurred and be
continuing or shall exist at such time or after giving effect to such
transaction.

     SECTION 6.07   TRANSACTIONS WITH AFFILIATES.
                    -----------------------------

     The Borrower shall not enter into any transaction of any kind with any
Person that Controls the Borrower or is controlled by the Borrower or is under
common control with the Borrower other than (a) salary, bonus, employee stock
option and other compensation arrangements with directors or officers in the
ordinary course of business, (b) transactions that are fully disclosed to the
board of directors (or executive committee thereof) of the Borrower and
expressly authorized by a resolution of the board of directors (or executive
committee) of the Borrower which is approved by a majority of the directors (or
executive committee) not having an interest in the transaction, (c) transactions
between or among the Borrower and its Wholly-Owned Subsidiaries, and (d)
transactions on overall terms at least as favorable to the Borrower as would be
the case in an arm's-length transaction between unrelated parties of equal
bargaining power.

                                      -44-
<PAGE>

     SECTION 6.08   EQUAL AND RATABLE LIEN.
                    -----------------------

     If, notwithstanding the prohibition contained in Section 6.02, the Borrower
or any of its Subsidiaries shall create, assume or permit to exist any Lien upon
any of its Property, other than those permitted by the provisions of Section
6.02, it will make or cause to be made effective provision whereby the
Borrowings will be secured equally and ratably with any and all other
obligations thereby secured, such security to be pursuant to agreements
reasonably satisfactory to the Bank and, in any such case, the Borrowings shall
have the benefit, to the fullest extent that, and with such priority as, the
Bank may be entitled under applicable law, of an equitable Lien on such
Property. Such violation of Section 6.02 will constitute an Event of Default,
whether or not provision is made for an equal and ratable Lien pursuant to this
Section.

     SECTION 6.09   RESTRICTIVE AGREEMENTS.
                    -----------------------

     Except as otherwise permitted under Article VI hereunder, and except for
agreements referenced in or permitted by or covenants contained within Article
VI of the SPPC Credit Agreement and Article VI of the NPC Credit Agreement, the
Borrower will not, and will not permit any of its Subsidiaries to, directly or
indirectly, enter into, incur or permit to exist any agreement or other
instrument that (a) creates, incurs or permits to exist any Lien upon any of its
Property or assets, or (b) prohibits, restricts or imposes any conditions upon
the ability of any Subsidiary to pay dividends or other distributions with
respect to any shares of its capital stock or to make or repay loans or advances
to the Borrower or any other Subsidiary or to guarantee Indebtedness of the
Borrower or any other Subsidiary.

     SECTION 6.10   DEBT TO CAPITALIZATION RATIO.
                    ----------------------------

     Until satisfaction in full of all the obligations of the Borrower under
this Agreement and termination of the Commitment of the Bank hereunder, the
Borrower will not permit the ratio of Consolidated Indebtedness to Consolidated
Total Capitalization to exceed 0.65 to 1.00 as of the end of any fiscal quarter
of any fiscal year.

                                  ARTICLE VII
                                   DEFAULTS

     SECTION 7.01   EVENTS OF DEFAULT.
                    ------------------

     An "Event of Default" shall mean the occurrence or existence of one or more
of the following events or conditions (for any reason, whether voluntary,
involuntary or effected or required by Law):

     (a)   The Borrower shall fail to pay when due principal of any Loan.

                                      -45-
<PAGE>

     (b)   The Borrower shall fail to pay when due interest on any Loan, any
fees, indemnity or expenses, or any other amount due hereunder or under any
other Loan Document and such failure shall have continued for a period of three
(3) Business Days.

     (c)   Any representation or warranty made or deemed made by the Borrower in
or pursuant to or in connection with any Loan Document, or any statement made by
the Borrower in any financial statement, certificate, report, exhibit or
document furnished by the Borrower to the Bank pursuant to or in connection with
any Loan Document, shall prove to have been false or misleading in any material
respect as of the time when made or deemed made (including by omission of
material information necessary to make such representation, warranty or
statement not misleading).

     (d)   The Borrower shall default in the performance or observance of any
covenant contained in Article VI or any of the covenants contained in Sections
5.01(f)(i) or 5.09 or 5.10.

     (e)   The Borrower shall default in the performance or observance of any
other covenant, agreement or duty under this Agreement or any other Loan
Document and (i) in the case of a default under Section 5.01 (other than as
referred to in subsection (f)(i) thereof) such default shall have continued for
a period of ten (10) Business Days and (ii) in the case of any other default
such default shall have continued for a period of thirty (30) days after notice
from the Bank to the Borrower.

     (f)   The Borrower or any Subsidiary of the Borrower shall (i) fail to make
any payment (x) on account of any Indebtedness under the NPC Credit Agreement or
the SPPC Credit Agreement, (y) on account of any Indebtedness aggregating
$10,000,000 or more in principal amount or (z) aggregating $10,000,000 or more
on any Indebtedness, or any interest or premium thereon, in each case, when due
(whether by scheduled maturity, required prepayment, acceleration, demand or
otherwise), and, in each case, such failure shall have continued beyond any
applicable grace period specified in any agreement or instrument relating to
such Indebtedness, or (ii) fail to perform or observe any other term, covenant
or condition on its part to be performed or observed under any agreement or
instrument relating to any Indebtedness when required to be performed or
observed, and such failure shall have continued beyond any applicable grace
period specified in any agreement or instrument relating to such Indebtedness,
if the effect of such failure to perform or observe is to accelerate, or to
permit the acceleration of, the maturity of such Indebtedness, the unpaid
principal amount of which then aggregates $10,000,000.

     (g)   One or more final judgments or orders for the payment of money shall
have been entered against the Borrower or any Subsidiary of the Borrower, which
judgments or orders exceed $10,000,000 in the aggregate, and such judgments or
orders shall have remained undischarged and unstayed for a period of thirty
consecutive days.

                                      -46-
<PAGE>

     (h)   One or more writs or warrants of attachment, garnishment, execution,
distraint or similar process exceeding in value the aggregate amount of
$10,000,000 shall have been issued against the Borrower or any Subsidiary of the
Borrower or any of their respective properties and shall have remained
undischarged and unstayed for a period of thirty consecutive days.

     (i)   Any Governmental Action now or hereafter made by or with any
Governmental Authority in connection with any Loan Document is not obtained or
shall have ceased to be in full force and effect or shall have been modified or
amended or shall have been held to be illegal or invalid, and the Bank shall
have determined (which determination shall be conclusive provided it is reached
in good faith) that the consequence of any of the foregoing events would
reasonably be expected to have, individually or in the aggregate, a Material
Adverse Effect.

     (j)   Any Loan Document or any material term or provision thereof shall
have ceased to be in full force and effect, or the Borrower or any Governmental
Authority with jurisdiction over the Borrower shall, or shall purport to,
terminate, repudiate, declare voidable or void or otherwise contest, any Loan
Document or any material term or provision thereof or any obligation or
liability of the Borrower thereunder.

     (k)   An event or condition specified in Section 5.01(h) hereof shall occur
or exist with respect to any Plan or Multiemployer Plan or any Lien arises
pursuant to ERISA and, as a result of such event or condition or Liens, together
with all other such events or conditions or Liens, the Borrower or any ERISA
Affiliate shall incur or shall be reasonably likely to incur a liability to a
Plan, a Multiemployer Plan or PBGC or suffer an encumbrance to exist in favor of
any thereof (or any combination of the foregoing) which would constitute a
Material Adverse Effect.

     (l)   The Borrower or any Subsidiary of the Borrower shall have violated
any Environmental Law or become subject to any Environmental Claim and, in
either case, the Bank shall have determined (which determination shall be
conclusive provided it is reached in good faith) that such event would
reasonably be expected, either individually or in the aggregate, to have a
Material Adverse Effect.

     (m)   A proceeding shall have been instituted in respect of the Borrower or
any Subsidiary of the Borrower:

           (i)    seeking to have an order for relief entered in respect of such
Person, or seeking a declaration or entailing a finding that such Person is
insolvent or a similar declaration or finding, or seeking dissolution, winding-
up, charter revocation or forfeiture, liquidation, reorganization, arrangement,
adjustment, composition or other similar relief with respect to such Person, its
assets or its debts under any Law relating to bankruptcy, insolvency, relief of
debtors or protection of creditors, termination of legal entities or any other
similar Law now or hereafter in effect, or

                                      -47-
<PAGE>

           (ii)   seeking appointment of a receiver, trustee, liquidator,
assignee, sequestrator or other custodian for such Person or for all or any
substantial part of its Property, and such proceeding shall result in the entry,
making or grant of any such order for relief, declaration, finding, relief or
appointment, or such proceeding shall remain undismissed and unstayed for a
period of thirty consecutive days.

     (n)   The Borrower or any Subsidiary of the Borrower shall become
insolvent; shall fail to pay, become unable to pay, or state that it is or will
be unable to pay, its debts as they become due; shall voluntarily suspend
transaction of its business; shall make a general assignment for the benefit of
creditors; shall institute (or fail to controvert in a timely and appropriate
manner) a proceeding described in Section 7.01(m)(i), or (whether or not any
such proceeding has been instituted) shall consent to or acquiesce in any such
order for relief, declaration, finding or relief described therein; shall
institute (or fail to controvert in a timely and appropriate manner) a
proceeding described in Section 7.01(m)(ii), or (whether or not any such
proceeding has been instituted) shall consent to or acquiesce in any such
appointment or to the taking of possession by any such custodian of all or any
substantial part of its Property; shall dissolve, wind-up, revoke or forfeit its
charter (or other constituent documents) or liquidate itself or any substantial
part of its Property; or shall take any action in furtherance of any of the
foregoing.

     (o)   A Change in Control shall occur.

     (p)   The Borrower shall fail to maintain ongoing utility segment-
identifiable assets (exclusive of cash and marketable securities) and operating
income relating to the generation, transmission and/or distribution of
electricity or gas in a proportion not less than 80% of total assets (exclusive
of cash and marketable securities) and operating income.

     SECTION 7.02   CONSEQUENCES OF AN EVENT OF DEFAULT.
                    ------------------------------------

     (a)   If an Event of Default specified in subsections (a) through (l), (o)
or (p) of Section 7.01 shall occur and, be continuing or shall exist, then, in
addition to all other rights and remedies which the Bank may have hereunder or
under any other Loan Document, at law, in equity or otherwise, Bank shall be
under no further obligation to make Loans hereunder, and the Bank may, by notice
to the Borrower, from time to time do any or all of the following:

           (i)    Declare the Commitment terminated, whereupon the Commitment
will terminate and any fees hereunder shall be immediately due and payable
without presentment, demand, protest or further notice of any kind, all of which
are hereby waived, and an action therefor shall immediately accrue.

           (ii)   Declare the unpaid principal amount of the Loans, interest
accrued thereon and all other obligations to be immediately due and payable
without presentment,

                                      -48-
<PAGE>

demand, protest or further notice of any kind, all of which are hereby waived,
and an action therefor shall immediately accrue.

     (b)   If an Event of Default specified in subsection (m) or (n) of Section
7.01 shall occur or exist, then, in addition to all other rights and remedies
which the Bank may have hereunder or under any other Loan Document, at law, in
equity or otherwise, the Commitment shall automatically terminate and the Bank
shall be under no further obligation to make Loans, and the unpaid principal
amount of the Loans, interest accrued thereon and all other obligations shall
become immediately due and payable without presentment, demand, protest or
notice of any kind, all of which are hereby waived, and an action therefor shall
immediately accrue.

                                 ARTICLE VIII
                                 MISCELLANEOUS

     SECTION 8.01   AMENDMENTS AND WAIVERS.
                    -----------------------

     Neither this Agreement nor any other Loan Document may be amended, modified
or supplemented except in accordance with the provisions of this Section 8.01.
The Bank and the Borrower may from time to time amend, modify or supplement the
provisions of this Agreement or any other Loan Document for the purpose of
amending, adding to or waiving any provision, or changing in any manner the
rights and duties of the Borrower, or Bank. Any such amendment, modification or
supplement made by the Borrower and the Bank in accordance with the provisions
of this Section 8.01 shall be binding upon the Borrower and the Bank.

     SECTION 8.02   NO IMPLIED WAIVER; CUMULATIVE REMEDIES.
                    --------------------------------------

     No course of dealing and no delay or failure of the Bank in exercising any
right, power or privilege under this Agreement or any other Loan Document shall
affect any other or future exercise thereof or the exercise of any other right,
power or privilege; nor shall any single or partial exercise of any such right,
power or privilege or any abandonment or discontinuance of steps to enforce such
a right, power or privilege preclude any further exercise thereof or of any
other right, power or privilege. The rights and remedies of the Bank under this
Agreement and any other Loan Document are cumulative and not exclusive of any
rights or remedies which the Bank would otherwise have hereunder or thereunder,
at law, in equity or otherwise.

     SECTION 8.03   NOTICES.
                    --------

     (a)   Except to the extent otherwise expressly permitted hereunder or
thereunder, all notices, requests, demands, directions and other communications
(collectively, "notices") under this Agreement or any other Loan Document shall
                -------
be in writing (including telecopied communication) and shall be sent by first-
class mail, or by nationally-recognized overnight courier, or by telecopier
(with confirmation in writing

                                      -49-
<PAGE>

mailed first-class or sent by such an overnight courier), or by personal
delivery. All notices shall be sent to the applicable party at the address
stated on the signature pages hereof or in accordance with the last unrevoked
written direction from such party to the other parties hereto in all cases with
postage or other charges prepaid. Any such properly given notice shall be
effective on the earliest to occur of receipt, telephone confirmation of receipt
of telecopy communication, one Business Day after delivery to a nationally-
recognized overnight courier, or three Business Days after deposit in the mail.

     (b)   A copy of any notice to the Borrower or any other party to a Loan
Document shall simultaneously be sent to Bank.

     (c)   The Bank may rely on any notice (whether or not such notice is made
in a manner permitted or required by this Agreement or any other Loan Document)
purportedly made by or on behalf of the Borrower, and the Bank shall not have
any duty to verify the identity or authority of any Person giving such notice.

     SECTION 8.04   EXPENSES; TAXES; INDEMNITY.
                    ---------------------------

     (a)   The Borrower agrees to pay or cause to be paid and to save the Bank
harmless against liability for the payment of all reasonable out-of-pocket costs
and expenses (including but not limited to reasonable fees and expenses of
counsel) incurred by the Bank from time to time arising from or relating to (i)
the negotiation, syndication, preparation, execution, delivery, administration
and performance of this Agreement and the other Loan Documents, (ii) any
amendments, modifications, supplements, waivers or consents to this Agreement or
any other Loan Document (whether or not ultimately entered into or granted), and
(iii) the enforcement or preservation of rights under this Agreement or any
other Loan Document (including but not limited to any such costs or expenses
arising from or relating to (A) collection or enforcement of an outstanding Loan
or any other amount owing hereunder or thereunder by the Bank, and (B) any
litigation, proceeding, dispute, work-out, restructuring or rescheduling related
in any way to this Agreement or the Loan Documents).

     (b)   The Borrower hereby agrees to pay all stamp, document, transfer,
recording, filing, registration, search, sales and excise fees and taxes and all
similar impositions now or hereafter determined by the Bank to be payable in
connection with this Agreement or any other Loan Documents or any other
documents, instruments or transactions pursuant to or in connection herewith or
therewith (which determination shall be conclusive provided it is reached in
good faith), and the Borrower agrees to save the Bank harmless from and against
any and all present or future claims, liabilities or losses with respect to or
resulting from any omission to pay or delay in paying any such fees, taxes or
impositions.

     (c)   The Borrower hereby agrees to reimburse and indemnify each of the
Indemnified Parties from and against any and all losses, liabilities, claims,
damages, expenses, obligations, penalties, actions, judgments, suits, costs or
disbursements of any

                                      -50-
<PAGE>

kind or nature whatsoever (including, without limitation, the reasonable fees
and disbursements of counsel for such Indemnified Party in connection with any
investigative, administrative or judicial proceeding commenced or threatened,
whether or not such Indemnified Party shall be designated a party thereto) that
may at any time be imposed on, asserted against or incurred by such Indemnified
Party as a result of, or arising out of, or in any way related to or by reason
of, this Agreement or any other Loan Document, any transaction from time to time
contemplated hereby or thereby, or any transaction financed in whole or in part
or directly or indirectly with the proceeds of any Loan (and without in any way
limiting the generality of the foregoing, including any violation or breach of
any Environmental Law or any other Law by the Borrower or any Subsidiary of the
Borrower; any Environmental Claim arising out of the management, use, control,
ownership or operation of Property by any of such Persons, including all on-site
and off-site activities involving Hazardous Materials; or any exercise by the
Bank of any of its rights or remedies under this Agreement or any other Loan
Document); but excluding any such losses, liabilities, claims, damages,
expenses, obligations, penalties, actions, judgments, suits, costs or
disbursements resulting solely from the gross negligence or willful misconduct
of such Indemnified Party, as finally determined by a court of competent
jurisdiction. If and to the extent that the foregoing obligations of the
Borrower under this subsection (c), or any other indemnification obligation of
the Borrower hereunder or under any other Loan Document, are unenforceable for
any reason, the Borrower hereby agrees to make the maximum contribution to the
payment and satisfaction of such obligations which is permissible under
applicable Law.

     SECTION 8.05   SEVERABILITY.
                    -------------

     The provisions of this Agreement are intended to be severable. If any
provision of this Agreement shall be held invalid or unenforceable in whole or
in part in any jurisdiction such provision shall, as to such jurisdiction, be
ineffective to the extent of such invalidity or unenforceability without in any
manner affecting the validity or enforceability thereof in any other
jurisdiction or the remaining provisions hereof in any jurisdiction.

     SECTION 8.06   PRIOR UNDERSTANDINGS.
                    ---------------------

     This Agreement, the other Loan Documents and any commitment letter
regarding the Facility between Bank, and the Borrower, as such agreements shall
be amended from time to time, supersede all prior and contemporaneous
understandings and agreements, whether written or oral, among the parties hereto
relating to the transactions provided for herein and therein.

     SECTION 8.07   DURATION; SURVIVAL.
                    -------------------

     All representations and warranties of the Borrower contained herein or in
any other Loan Document or made in connection herewith or therewith shall
survive the making, and shall not be waived by the execution and delivery, of
this Agreement or any

                                      -51-
<PAGE>

other Loan Document, any investigation by or knowledge of the Bank, the making
of any Loan, or any other event or condition whatever. All covenants and
agreements of the Borrower contained herein or in any other Loan Document shall
continue in full force and effect from and after the date hereof so long as the
Borrower may borrow hereunder and until payment in full of all Obligations.
Without limitation, all obligations of the Borrower hereunder or under any other
Loan Document to make payments to or indemnify the Bank shall survive the
payment in full of all other Obligations, termination of the Borrower's right to
borrow hereunder, and all other events and conditions whatever.

     SECTION 8.08   COUNTERPARTS.
                    -------------

     This Agreement may be executed in any number of counterparts and by the
different parties hereto on separate counterparts each of which, when so
executed, shall be deemed an original, but all such counterparts shall
constitute but one and the same instrument.

     SECTION 8.09   LIMITATION ON PAYMENTS.
                    -----------------------

     The parties hereto intend to conform to all applicable Laws in effect from
time to time limiting the maximum rate of interest that may be charged or
collected. Accordingly, notwithstanding any other provision hereof or of any
other Loan Document, the Borrower shall not be required to make any payment to
the Bank, and Bank shall refund any payment made by the Borrower, to the extent
that such requirement or such failure to refund would violate or conflict with
nonwaivable provisions of applicable Laws limiting the maximum amount of
interest which may be charged or collected by Bank.

     SECTION 8.10   SET-OFF.
                    --------

     The Borrower hereby agrees that, to the fullest extent permitted by Law, if
any Obligation of the Borrower shall be due and payable (by acceleration or
otherwise), Bank shall have the right, without notice to the Borrower, to set-
off against and to appropriate and apply to such Obligation any indebtedness,
liability or obligation of any nature owing to the Borrower by Bank, including
but not limited to all deposits (whether time or demand, general or special,
provisionally credited or finally credited, whether or not evidenced by a
certificate of deposit) now or hereafter maintained by the Borrower with Bank.
Such right shall be absolute and unconditional in all circumstances and, without
limitation shall exist whether or not Bank or any other Person shall have given
notice or made a demand to the Borrower or any other Person, whether such
indebtedness, obligation or liability owed to the Borrower is contingent,
absolute, matured or unmatured (it being agreed that Bank may deem such
indebtedness, obligation or liability to be then due and payable at the time of
such setoff), and regardless of the existence or adequacy of any collateral,
guaranty or any other security, right or remedy available to Bank or any other
Person. The Borrower hereby agrees that, to the fullest extent

                                      -52-
<PAGE>

permitted by Law, any branch, subsidiary or affiliate of Bank shall have the
same rights of set-off as the Bank as provided in this Section (regardless of
whether such branch, subsidiary or affiliate would otherwise be deemed in
privity with or a direct creditor of the Borrower). The rights provided by this
Section are in addition to all other rights of set-off and banker's lien and all
other rights and remedies which Bank (or any such branch, subsidiary or
affiliate) may otherwise have under this Agreement, any other Loan Document, at
law or in equity, or otherwise, and nothing in this Agreement or any other Loan
Document shall be deemed a waiver or prohibition of or restriction on the rights
of set-off or bankers' lien of any such Person.

     SECTION 8.11   SUCCESSORS AND ASSIGNS; ASSIGNMENTS; PARTICIPATIONS.
                    ----------------------------------------------------

     (a)   Successors and Assigns.  This Agreement shall be binding upon and
           ----------------------
inure to the benefit of the Borrower, the Bank, all future holders of the Note,
and their respective successors and assigns, except that the Borrower may not
assign or transfer any of its rights hereunder or interests herein without the
prior written consent of Bank, and any purported assignment without such consent
shall be void.

     (b)   Assignments.  The Bank may assign to one or more assignees that are
           -----------
financial institutions all or a portion of its rights and obligations under this
Agreement (including all or a portion of its Commitment and the Loans at the
time owing to it); provided, however, any assignment to a financial institution
that is not an Affiliate of the Bank shall be made only with the consent (which
in each case shall not be unreasonably withheld) of the Borrower (so long as no
Default or Event of Default shall have occurred and be continuing) and the Bank.
From and after the effective date of such assignment, the assignee thereunder
shall be a party hereto and, to the extent of the interest assigned, have the
rights and obligations of the Bank under the Loan Documents and the Bank shall,
to the extent of the interest so assigned, be released from its obligations
under the Loan Documents (and, in the case of an assignment covering all of the
Bank's rights and obligations under the Loan Documents, the Bank shall cease to
be a party hereto but shall continue to be entitled to the benefits of Sections
2.12, 2.13, 2.14, 2.15, 2.16 and 8.04). In the event that any assignee will be a
foreign lender, the Bank or such foreign lender shall furnish to the Borrower,
prior to and as a condition of such assignments, such forms as are required by
the Code to confirm that the Borrower is not subject to any withholding tax
obligation.

     (c)   Participations.  (i)  The Bank may sell participations to one or more
           --------------
banks or other entities (each such bank or other entity being called a
"Participant") in all or a portion of the Bank's rights and obligations under
------------
the Loan Documents (including all or a portion of its Revolving Commitment and
the Loans owing to it). Subject to subsection (ii) below, the Borrower agrees
that each Participant shall be entitled to the benefits of Sections 2.12, 2.13,
2.14, 2.15, 2.16 and 8.04 to the same extent as if it were the Bank and had
acquired its interest by assignment pursuant to Section 8.11(b).

                                      -53-
<PAGE>

           (ii)   A Participant shall not be entitled to receive any greater
payment under Sections 2.12, 2.13, 2.14, 2.15 and 8.04 than the Bank would have
been entitled to receive with respect to the participation sold to such
Participant, unless the sale of the participation to such Participant is made
with the Borrower's prior written consent.

     (d)   Assignments to Federal Reserve Bank.  Bank may at any time assign all
           -----------------------------------
or any portion of its rights under this Agreement, including without limitation
any Loans owing to it, and any Note held by it, to a Federal Reserve Bank. No
such assignment shall relieve the transferor Lender from its obligations
hereunder.

     SECTION 8.12   GOVERNING LAW; CONSENT TO JURISDICTION.
                    ---------------------------------------

     (a)   This Agreement shall be governed by, and construed in accordance
with, the laws of the State of New York.

     (b)   The Borrower irrevocably submits to the jurisdiction of any New York
State or Federal court sitting in New York County over any suit, action,
counterclaim or proceeding arising out of or relating to the Loan Documents, and
whether sounding in contract, tort or otherwise. The Borrower irrevocably
waives, to the fullest extent enforceable by law, any objection which it may now
or hereafter have to the laying of the venue of any such suit, action,
counterclaim or proceeding and any claim that any such suit, action,
counterclaim or proceeding brought in such a court has been brought in an
inconvenient forum. The Borrower agrees that a final judgment in any such suit,
action, counterclaim or proceeding brought in such a court shall be conclusive
and binding upon the Borrower.

     SECTION 8.13   SERVICE OF PROCESS.
                    -------------------

          Process may be served in any suit, action, counterclaim or proceeding
by mailing copies thereof by certified mail, postage prepaid, return receipt
requested, to the address of the Borrower set forth next to its signature block
or to any other address of which the Borrower shall have given written notice to
the Bank. The Borrower hereby agrees that such service (a) shall be deemed in
every respect effective service of process upon it in any such suit, action,
counterclaim or proceeding, and (b) shall to the fullest extent enforceable by
law, be taken and held to be valid personal service upon and personal delivery
to it.

     SECTION 8.14   NO LIMITATION ON SERVICE OR SUIT.
                    --------------------------------

          Nothing in the Loan Documents shall affect the right of the Bank to
serve process in any manner permitted by law or limit the right of the Bank to
bring proceedings against the Borrower in the courts of any jurisdiction or
jurisdictions.

                                      -54-
<PAGE>

     SECTION 8.15   WAIVER OF TRIAL BY JURY.
                    ------------------------

          THE BANK AND THE BORROWER EACH HEREBY KNOWINGLY, VOLUNTARILY AND
INTENTIONALLY WAIVES ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY
LITIGATION ARISING OUT OF, UNDER OR IN CONNECTION WITH THE LOAN DOCUMENTS AND
THE TRANSACTIONS CONTEMPLATED THEREIN, WHETHER SOUNDING IN CONTRACT, TORT OR
OTHERWISE. FURTHER THE BORROWER HEREBY CERTIFIES THAT NO REPRESENTATIVE OF THE
BANK, OR COUNSEL TO THE BANK, HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT THE
BANK WOULD NOT, IN THE EVENT OF SUCH LITIGATION, SEEK TO ENFORCE THIS PROVISION.
THE BORROWER ACKNOWLEDGES THAT THE BANK HAS BEEN INDUCED TO ENTER INTO THE LOAN
DOCUMENTS BY, INTER ALIA, THE PROVISIONS OF THIS SECTION.
              ----- ----

     SECTION 8.16   NO CONSEQUENTIAL DAMAGES.
                    -------------------------

          Neither party hereto shall under any circumstances be liable to the
other for any consequential, indirect or punitive damages arising out of the
Loan Documents and each party hereto hereby waives any right it may have to seek
any such damages against the other.

                          [Signature Page To Follow]

                                      -55-
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed and delivered as of the day and year first above written.

Address                                 SIERRA PACIFIC RESOURCES
-------
Sierra Pacific Resources
6100 Neil Road
P.O. Box 30150                          By:   ______________________________
Reno, Nevada 89520                      Name:
Attn: Richard K. Atkinson               Title:
Telecopier: (775) 834-5462
Telephone: (775) 834-5640

Address                                 THE BANK OF NEW YORK
-------
The Bank of New York
One Wall Street
New York, New York  10286               By: ________________________________
Attn: Steven Kalachman                  Name: Steven Kalachman
Telecopier: (212) 635-7923              Title: Vice President
Telephone: (212) 635-7881

                                      -56-
<PAGE>

                                 PRICING TABLE

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------------
  Borrower's Senior        Applicable Margin          Applicable Margin         Applicable Commitment
   Unsecured Debt         Alternate Base Rate             Eurodollar                     Fee
      Ratings                    Loans                      Loans
   (S&P/Moody's)
--------------------------------------------------------------------------------------------------------
<S>                       <C>                         <C>                       <C>
      Level 1                      0%                       1.50%                       0.30%
      -------
 Ratings equal to or
     greater than
      BBB-/Baa3

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

      Level 2                     0.50%                     2.00%                       0.40%
      -------
 Ratings by S&P is
 less than BBB- or
 Ratings by Moody's
 is less than Baa3
--------------------------------------------------------------------------------------------------------

      Level 3                     1.00%                     2.50%                       0.50%
      -------
 Ratings by S&P is
 less than BBB- and
 Ratings by Moody's
 is less than Baa3.

--------------------------------------------------------------------------------------------------------
</TABLE>

     Notwithstanding the foregoing, for purposes of determining the pricing on
the initial Loan made to the Borrower under this Agreement, the Borrower's
Status shall be deemed to be Level 1 Status.

     The applicable Level shall be based on the long-term senior unsecured, non-
credit-enhanced indebtedness rating of Standard & Poor's and Moody's Investors
Service for the Borrower.

     "Moody's Rating" means, at any time, the credit rating issued by Moody's
Investors Services, Inc. and then in effect with respect to the Borrower's
senior unsecured long-term debt securities without third-party credit
enhancement.

     "S&P Rating" means, at any time, the credit rating issued by Standard and
Poor's Rating Services, a division of The McGraw Hill Companies, Inc., and then
in effect with respect to the Borrower's senior unsecured long-term debt
securities without third-party credit enhancement.

     "Status" means Level 1 Status, Level 2 Status, or Level 3 Status.
<PAGE>

     The Applicable Margin and Commitment Fee shall be determined in accordance
with the foregoing table based on the Borrower's Status as determined from its
then-current Moody's and S&P Ratings.  The credit rating in effect on any date
for the purposes of this Pricing Table is that in effect at the close of
business on such date.  If at any time the Borrower has no Moody's Rating or no
S&P Rating, Level 3 Status shall exist.

                                      -2-
<PAGE>

                                 SCHEDULE 3.12

                              LIST OF LITIGATION

     With respect to pending or threatened actions, suits, proceedings or
investigations (including any Environmental Claim) by or before any Governmental
Authority against or affecting the Borrower or any Subsidiary of the Borrower,
reference is made to descriptions thereof contained in the Borrower's reports
heretofore filed with the Securities and Exchange Commission pursuant to the
Securities and Exchange Act of 1934, as amended, which descriptions are
incorporated herein by reference.
<PAGE>

                                 SCHEDULE 3.19

                             ENVIRONMENTAL MATTERS

     With respect to pending or threatened Environmental Claims against the
Borrower or any of its Subsidiaries, reference is made to descriptions thereof
contained in the Borrower's reports heretofore filed with the Securities and
Exchange Commission pursuant to the Securities and Exchange Act of 1934, as
amended, which descriptions are incorporated herein by reference.
<PAGE>

                                   EXHIBIT A

                                    Form of
                                   --------

                                REVOLVING NOTE
                                --------------

$25,000,000.00                                                   August __, 2001
                                                              New York, New York

     FOR VALUE RECEIVED, the undersigned, SIERRA PACIFIC RESOURCES, a Nevada
corporation (the "Borrower"), hereby promises to pay to the order of THE BANK OF
NEW YORK (the "Bank"), the principal amount of $25,000,000.00, or such lesser
unpaid principal amount as shall be outstanding hereunder, in the amounts, and
at the times set forth in the 364-Day Credit Agreement, dated as of August __,
2001, between the Borrower and the Bank (as the same may be amended,
supplemented or otherwise modified from time to time, the "Credit Agreement"),
and to pay interest thereon from the date of each such Loan on the principal
balance of each such Loan from time to time outstanding, at the rate or rates
and at the times set forth in the Credit Agreement, in each case at the office
of the Bank located at One Wall Street, New York, New York, or at such other
place as the Bank may specify from time to time, in lawful money of the United
States in immediately available funds.

     Capitalized terms used herein which are not otherwise defined herein shall
have the respective meanings ascribed thereto in the Credit Agreement.

     The Loans evidenced by this Revolving Note are prepayable in the amounts,
and under the circumstances, and their maturity is subject to acceleration upon
the terms set forth in the Credit Agreement. This Revolving Note is the "Note"
under, and as such term is defined in, the Credit Agreement, and is subject to,
and should be construed in accordance with, the provisions thereof.

     The Bank is hereby authorized to record on the schedule annexed hereto, and
any continuation sheets which the Bank may attach hereto, (i) the date and
amount of each Loan made by the Bank to the Borrower, (ii) its character as an
Alternate Base Rate Loan or a Eurodollar Loan, or combination thereof, (iii) the
Interest Period and interest rate applicable to Eurodollar Loans, and (iv) the
date and amount of each conversion of, and each payment or prepayment of
principal of, any such Loan. No failure to so record or any error in so
recording shall affect the obligation of the Borrower to repay the Loans,
together with interest thereon, as provided in the Credit Agreement, and the
outstanding principal balance of the Loans made by the Bank as set forth in such
schedule shall be presumed to be correct absent manifest error.

     Except as specifically otherwise provided in the Credit Agreement, the
Borrower hereby waives presentment, demand, notice of dishonor, protest, notice
of protest and all
<PAGE>

other demands, protests and notices in connection with the execution, delivery,
performance, collection and enforcement of this Revolving Note.

     This Revolving Note may be amended only by an instrument in writing
executed pursuant to the provisions of Section 8.01 of the Credit Agreement.

     THIS REVOLVING NOTE SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN
ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

                              SIERRA PACIFIC RESOURCES

                              By: _________________________________
                                  Name: ___________________________
                                  Title: __________________________

                                      -2-
<PAGE>

                          SCHEDULE TO REVOLVING NOTE
                          --------------------------

<TABLE>
<CAPTION>
                                                                         Interest
                                                                         Rate on
                                                                         Eurodollar
                                                     Amount of           Borrowings
              Type of                                principal           (without         Interest
              Borrowing                              converted,          regard to        Period for
              (ABR or             Amount of          paid or             Applicable       Eurodollar       Notation
Date          Eurodollar)         Borrowing          prepaid             Margin)          Borrowings       Made By
----          -----------         ---------          ----------          -------          ----------       --------
<S>           <C>                 <C>                <C>                 <C>              <C>              <C>
</TABLE>

                                      -3-
<PAGE>

                                  EXHIBIT B
                               Borrowing Request
                               -----------------

                                                             __________ __, 200_

The Bank of New York
One Wall Street
New York, New York 10286
Attention:

     Reference is made to that certain 364-Day Credit Agreement, dated as of
August __, 2001, between SIERRA PACIFIC RESOURCES, a Nevada corporation (the
"Borrower"), and THE BANK OF NEW YORK (the "Bank") (as the same may be amended,
supplemented or otherwise modified from time to time, the "Credit Agreement").
Capitalized terms used herein that are defined in the Credit Agreement shall
have the meanings therein defined.

     1.   Pursuant to Section 2.03 of the Credit Agreement, the Borrower hereby
gives notice of the Borrower's intention to borrow Loans in an aggregate
principal amount of $_______ on _________ __, 200_ (the "Borrowing Date"), which
borrowings shall consist of the following Advances:

  Type of Borrowing                                 Initial Interest Period
  (Alternate Base Rate Loan or                      for Eurodollar Borrowings
                                                    -------------------------
  Eurodollar Loan, or combination   Amount
  thereof)                          ------
  --------
  ________________                  $____________   ________________

     2.   The proceeds of the Loans requested in Section 1 should be disbursed
in accordance with the annexed Wire Transfer Instructions.

     3.   The amount of the requested Loan(s) does not exceed the amount of the
Commitment.

     4.   The Borrower hereby certifies that on the date hereof and on the
Borrowing Date set forth above, and after giving effect to the Loans requested
hereby, (i) no Event of Default has or shall have occurred and be continuing;
and (ii) the representations and warranties contained in the Loan Documents are
and shall be true and correct, except to the extent such representations and
warranties specifically relate to an earlier date, in which case such
representations and warranties shall have been true and correct on and as of
such earlier date.

                          [Signature Page To Follow]
<PAGE>

     IN WITNESS WHEREOF, the Borrower has duly executed this Borrowing Request
as of the date and year first written above.

                                   SIERRA PACIFIC RESOURCES

                                   By: ______________________________
                                       Name:  _______________________
                                       Title: _______________________

                                      -2-
<PAGE>

                                   EXHIBIT C

                           Interest Election Request
                           -------------------------

                                                    _____________ __, 200_

The Bank of New York
One Wall Street
New York, New York 10286
Attention: _____________________
           Agency Function Administration

     Reference is made to that certain 364-Day Credit Agreement, dated as of
August __, 2001, between SIERRA PACIFIC RESOURCES, a Nevada corporation (the
"Borrower"), and THE BANK OF NEW YORK (as the same may be amended, supplemented
or otherwise modified from time to time, the "Credit Agreement"). Capitalized
terms used herein that are defined in the Credit Agreement shall have the
meanings therein defined.

     1.   Pursuant to Section 2.05 of the Credit Agreement, the Borrower hereby
gives notice of its request to convert Borrowings comprising Revolving Loans as
set forth below:

          (a)     on ____ __, 200_, to convert $_______ in principal amount of
presently outstanding Eurodollar Borrowings having an Interest Period that
expires on ____ __, 200_ to ABR Borrowings.

          (b)     on ____ __, 200_, to continue $_______ in principal amount of
presently outstanding Eurodollar Borrowings having an Interest Period that
expires on ____ __, 200_ as new Eurodollar Borrowings that have an Interest
Period of __ months;

          (c)     on ____ __, 200_, to convert $_______ in principal amount of
presently outstanding ABR Borrowings to Eurodollar Borrowings that have an
Interest Period of __ months.

     2.   The Borrower hereby certifies that on the date hereof and on the dates
set forth above, and after giving effect to the Loans requested hereby, (i) no
Event of Default has or shall have occurred and be continuing; and (ii) the
representations and warranties contained in the Loan Documents are and shall be
true and correct, except to the extent such representations and warranties
specifically relate to an earlier date, in which case such representations and
warranties shall have been true and correct on and as of such earlier date.
<PAGE>

     IN WITNESS WHEREOF, the Borrower has duly executed this Interest Election
Request as of the date and year first written above.

                                   SIERRA PACIFIC RESOURCES, a Nevada
                                   Corporation

                                   By: ___________________________________
                                   Name: _________________________________
                                   Title: ________________________________

                                      -2-

<PAGE>

                                   EXHIBIT D

                            Compliance Certificate
                            ----------------------

     I, ______________, do hereby certify that I am the _______ of SIERRA
PACIFIC RESOURCES, a Nevada corporation (the "Borrower"), and that, as such, I
                                              --------
am duly authorized to execute and deliver this Compliance Certificate on the
Borrower's behalf pursuant to Section 5.01(c) of the Credit Agreement, dated as
of August __, 2001, between the Company and THE BANK OF NEW YORK, (the "Bank")
                                                                        ----
(as the same may be amended, supplemented or otherwise modified from time to
time, the "Credit Agreement"). Capitalized terms used herein that are defined
           ----------------
in the Credit Agreement shall have the meanings therein defined.

     I hereby certify that:

          1. To the best of my knowledge, all financial statements delivered
herewith have been prepared in accordance with GAAP. There have been no changes
in GAAP or in the application thereof since the date of the Financial Statements
[, except as follows:]/1/

          2. Consolidated Indebtedness is $__________ and Consolidated Total
Capitalization is $________. Accordingly, Consolidated Indebtedness is ____% of
Consolidated Total Capitalization. [Consolidated Indebtedness must be less than
65% of Consolidated Total Capitalization.]

          3. There exists no Default or Event of Default under the Credit
Agreement.

     IN WITNESS WHEREOF, I have executed this Compliance Certificate on this ___
day of ________, 200_.

_______________________
/1/       Specify all such changes, and the effect of each such change on the
financial statements accompanying this Compliance Certificate.<PAGE>

                                                                    Exhibit 10.2

                                  $25,000,000

                                CREDIT AGREEMENT

                                  dated as of

                               September 10, 2001

                                     among

                            SIERRA PACIFIC RESOURCES

                                  as Borrower

                                      and

                    WELLS FARGO BANK, NATIONAL ASSOCIATION,

                                    as Bank,
<PAGE>

          CREDIT AGREEMENT, dated as of September 10, 2001, Between SIERRA
PACIFIC RESOURCES, a Nevada corporation, ("Borrower") and WELLS FARGO BANK,
NATIONAL ASSSOCIATION ("Bank").

                              W I T N E S S E T H:
                              - - - - - - - - - -

          WHEREAS, the Borrower has requested, and Bank has agreed to make
available, the credit facility described below upon the terms and conditions
contained herein.

          NOW, THEREFORE, in consideration of the premises and of the mutual
covenants herein contained and intending to be legally bound hereby, the parties
hereto agree as follows:

                                   ARTICLE I
                           DEFINITIONS; CONSTRUCTION

          SECTION 1.01 DEFINED TERMS.
                       -------------

          As used in this Agreement, the following terms have the following
meanings:

          "ABR", when used in reference to any Loan or Borrowing, refers to
           ---
whether such Loan, or the Loans comprising such Borrowing, are bearing interest
at a rate determined by reference to the Alternate Base Rate.

          "Acquisition" means any transaction, or any series of related
           -----------
transactions, consummated after the Effective Date, by which the Borrower and/or
any of its Subsidiaries directly or indirectly (a) acquires any ongoing business
or all or substantially all of the assets of any Person engaged in any ongoing
business, whether through purchase of assets, merger or otherwise, (b) acquires
control of securities of a Person engaged in an ongoing business representing
more than 50% of the ordinary voting power for the election of directors or
other governing position if the business affairs of such Person are managed by a
board of directors or other governing body or (c) acquires control of more than
50% of the ownership interest in any partnership, joint venture, limited
liability company, business trust or other Person engaged in an ongoing business
that is not managed by a board of directors or other governing body.

          "Adjusted LIBO Rate" means, with respect to any Eurodollar Revolving
           ------------------
Borrowing for any Interest Period, an interest rate per annum (rounded upwards,
if necessary, to the nearest 1/100 of 1%) equal to (a) the LIBO Rate for such
Interest Period multiplied by (b) the Statutory Reserve Rate.

          "Affiliate" means, any Person that directly or indirectly Controls, or
           ---------
is under common Control with, or is Controlled by, another Person, provided
that, in any event, any Person that owns directly or indirectly securities
having 20% or more of the voting power for the election of directors or other
governing body of a corporation or 20% or more of the partnership or other
ownership interests of any other Person (other than as a limited partner of such
other Person) will be deemed to Control such corporation or other Person.

          "Alternate Base Rate" means, for any day, a rate per annum equal to
           -------------------
the greater of (a) the Prime Rate in effect on such day and (b) the Federal
Funds Effective Rate in effect on such day plus 1/2 of 1%. Any change in the
Alternate Base Rate due to a change in the Prime Rate or the Federal Funds
Effective Rate shall be effective from and including the effective date of such
change in the Prime Rate or the Federal Funds Effective Rate, respectively.

                                       2
<PAGE>

          "Applicable Rate" means, for any day, with respect to the facility
           ---------------
fees payable hereunder, with respect to any Eurodollar Revolving Loan or with
respect to any usage fees payable hereunder, as the case may be, the applicable
rate per annum set forth below under the caption "Facility Fee",  "Eurodollar
Spread" or "Usage Fee", as the case may be, based on the ratings by S&P and
Moody's, respectively, applicable on such day to the Index Debt:

<TABLE>
<CAPTION>
            Public Senior
           Unsecured Debt
               Ratings                                           Base Rate               LIBOR
             S&P/Moody's                 Facility Fee             Spread                 Margin
             -----------                 ------------             ------                 ------
     <S>                                 <C>                      <C>                    <C>
     Ratings greater than A-/A3            .1500%                   0.00%                 .3500%
     Ratings equal to A-/A3                .1500%                   0.00%                 .4000%
     Ratings equal to BBB+/Baa1            .2000%                   0.00%                 .5500%
     Ratings equal to BBB/Baa2            .22500%                   0.00%                 .7750%
     Ratings equal to BBB-/Baa3            .2500%                   0.00%                1.2500%
     Ratings less than BBB-/Baa3           .3750%                 0.6250%                 .6250%
</TABLE>

For purposes of the foregoing, (i) if either Moody's or S&P shall not have in
effect a rating for the Index Debt (other than by reason of the circumstances
referred to in the last sentence of this definition), then such rating agency
shall be deemed to have established a rating in its lowest rating category, (ii)
if the ratings established or deemed to have been established by Moody's and S&P
for the Index Debt shall be changed (other than as a result of a change in the
rating system of Moody's or S&P), such change shall be effective as of two
Business Days after it is first announced by the applicable rating agency and
(iii) if the rating assigned by Moody's and the rating assigned by S&P shall
differ (a) by one level (e.g., Moody's rating of A3 and S&P rating of BBB+),
then the higher rating level shall apply (i.e., A3) and (b) by more than one
level (e.g., Moody's rating of A3 and S&P rating of BBB-), then the rating level
above the lower rating level shall apply (i.e., BBB/Baa2).  Each change in the
Applicable Rate shall apply during the period commencing two Business Days after
the effective date of such change and ending on the date immediately preceding
the effective date of the next such change.  If the rating system of Moody's or
S&P shall change, or if either such rating agency shall cease to be in the
business of rating corporate debt obligations, the Borrower and Bank shall
negotiate in good faith to amend this definition to reflect such changed rating
system or the unavailability of ratings from such rating agency and, pending the
effectiveness of any such amendment, the Applicable Rate shall be determined by
reference to the rating most recently in effect prior to such change or
cessation.

          "Bankruptcy Code" means Title 11 of the United States Code entitled
           ---------------
"Bankruptcy," as now or hereafter in effect or any successor thereto.

          "Board" means the Board of Governors of the Federal Reserve System of
           -----
the United States of America.

          "Borrower" means Sierra Pacific Resources, a Nevada corporation.
           --------

                                       3
<PAGE>

          "Borrowing" means advances under the Facility, made, converted or
           ---------
continued on the same date and, in the case of Eurodollar Loans, as to which a
single Interest Period is in effect.

          "Borrowing Request" means a request by the Borrower for a Borrowing
           -----------------
made in accordance with Section 2.03.

          "Business Day" means any day that is not a Saturday, Sunday or other
           ------------
day on which commercial banks in Nevada are authorized or required by Law to
remain closed; provided that, when used in connection with a Eurodollar Loan,
the term "Business Day" shall also exclude any day on which banks are not open
for dealings in dollar deposits in the London interbank market.

          "Capital Lease Obligations" of any Person means all obligations of
           -------------------------
such Person to pay rent or other amounts under a lease of (or other agreement
conveying the right to use) Property to the extent such obligations are required
to be classified and accounted for as a capital lease on a balance sheet of such
Person under GAAP (including Statement of Financial Accounting Standards No. 13
of the Financial Accounting Standards Board), and, for purposes of this
Agreement, the amount of such obligations shall be the capitalized amount
thereof, determined in accordance with GAAP (including such Statement No. 13).

          "Change in Control" means (a) the acquisition of ownership, directly
           -----------------
or indirectly, beneficially or of record, by any Person or group (within the
meaning of the Securities Exchange Act of 1934 and the rules of the Securities
and Exchange Commission thereunder as in effect on the date hereof) of shares
representing more than 20% of the aggregate ordinary voting power represented by
the issued and outstanding capital stock of the Borrower; (b) for any period of
12 consecutive calendar months, a majority of the Board of Directors of  the
Borrower shall no longer be composed of individuals (i) who were members of said
Board on the first day of such period, (ii) whose election or nomination to said
Board was approved by individuals referred to in clause (i) above constituting
at the time of such election or nomination at least a majority of said Board or
(iii) whose election or nomination to said Board was approved by individuals
referred to in clauses (i) and (ii) above constituting at the time of such
election or nomination at least a majority of said Board; (c) the failure of the
Borrower to own, legally and beneficially, 100% of the aggregate ordinary voting
power represented by the issued and outstanding capital stock of either NPC or
SPPC; or (d) any reduction in Borrower's ownership, either legal or beneficial,
of a Significant Subsidiary.

          "Change in Law" means (a) the adoption of any Law after the date of
           -------------
this Agreement, (b) any change in any Law or in the interpretation or
application thereof by any Governmental Authority after the date of this
Agreement or (c) compliance by Bank (or, for purposes of Section 2.13(b), by any
lending office of Bank or by Bank's Parent, if any) with any request, guideline
or directive (whether or not having the force of Law) of any Governmental
Authority made or issued after the date of this Agreement.

          "Code" means the Internal Revenue Code of 1986 and the regulations
           ----
promulgated and rulings issued thereunder.  Section references to the Code are
to the Code, as in effect at the date of this Agreement and any subsequent
provisions of the Code, amendatory thereof, supplemental thereto or substituted
therefor.

          "Commitment" means, the Commitment of Bank under the Facility.
           ----------

          "Control" of a Person (including, with its correlative meanings,
           -------
"Controlled by" and "under common Control with") means possession, directly or
indirectly, of the power to direct or cause the

                                       4
<PAGE>

direction of management or policies (whether through ownership of securities or
partnership or other ownership interests, by contract or otherwise) of such
Person.

          "Default" means any event, act or condition, which upon notice, lapse
           -------
of time or both would, unless cured or waived, become an Event of Default.

          "Default Interest" has the meaning assigned to such term in Section
           ----------------
2.11(c).

          "Dollars" or "$" refers to freely transferable lawful money of the
           -------      -
United States of America.

          "Effective Date" means the date on which the conditions specified in
           --------------
Section 4.01 are satisfied (or waived in accordance with Section 8.01).

          "Environmental Claims" means any and all administrative, regulatory or
           --------------------
judicial actions, suits, demands, demand letters, directives, claims, liens,
notices of non-compliance or violation, investigations or proceedings relating
in any way to any Environmental Law or any permit issued, or any approval given,
under any such Environmental Law (hereafter, "Claims"), including, without
                                              ------
limitation, (a) any and all Claims by governmental or regulatory authorities for
enforcement, cleanup, removal, response, remedial or other actions or damages
pursuant to any applicable Environmental Law, and (b) any and all Claims by any
third party seeking damages, contribution, indemnification, cost recovery,
compensation or injunctive relief in connection with alleged injury or threat of
injury to health, safety or the environment due to the presence of Hazardous
Materials.

          "Environmental Law" means any Federal, state, foreign or local
           -----------------
statute, Law, rule, regulation, ordinance, code, guideline, written policy and
rule of common law now or hereafter in effect and in each case as amended, and
any judicial or administrative interpretation thereof, including any judicial or
administrative order, consent decree or judgment, relating to the environment,
employee health and safety or Hazardous Materials, including, without
limitation, CERCLA; RCRA; the Federal Water Pollution Control Act, 33 U.S.C. (S)
1251 et seq.; the Toxic Substances Control Act, 15 U.S.C. (S) 2601  et seq.; the
     -- ----                                                       --- ----
Clean Air Act, 42 U.S.C. (S) 7401 et seq.; the Safe Drinking Water Act, 42
                                  -- ----
U.S.C. (S) 3803 et seq.; the Oil Pollution Act of 1990, 33 U.S.C. (S) 2701 et
                -- ----                                                    --
seq.; the Emergency Planning and the Community Right-to-Know Act of 1986, 42
----
U.S.C. (S) 11001 et seq.; the Hazardous Material Transportation Act, 49 U.S.C.
                 -- ----
(S) 1801 et seq. and the Occupational Safety and Health Act, 29 U.S.C. (S) 651
         -- ----
et seq. ; and any state and local or foreign counter-parts or equivalents, in
-- ----
each case as amended from time to time.

          "ERISA" means the Employee Retirement Income Security Act of 1974 and
           -----
the regulations promulgated and rulings issued thereunder.  Section references
to ERISA are to ERISA, as in effect at the date of this Agreement, and to any
subsequent provisions of ERISA, amendatory thereof, supplemental thereto or
substituted therefor.

          "ERISA Affiliate" means any corporation or trade or business that is a
           ---------------
member of any group of organizations described in Section 414(b) or (c) of the
Code of which the Borrower is a member.

          "Eurodollar", when used in reference to any Loan or Borrowing, refers
           ----------
to whether such Loan, or the Loans comprising such Borrowing, are bearing
interest at a rate determined by reference to the Adjusted LIBO Rate.

          "Event of Default" has the meaning assigned to such term in Section
           ----------------
7.01.

                                       5
<PAGE>

          "Excluded Taxes" means, with respect to the Bank or any other
           --------------
recipient of any payment to be made by or on account of any obligation of the
Borrower hereunder, (a) income or franchise taxes imposed on (or measured by)
its net income by the United States of America, or by the jurisdiction under the
Laws of which such recipient is organized or in which its principal office is
located or, in the case of Bank, in which its applicable lending office is
located, and (b) any branch profits taxes imposed by the United States of
America or any similar tax imposed by any other jurisdiction in which the
Borrower is located.

          "Facility" means the $25,000,000.00 revolving line of credit committed
           --------
pursuant to this Agreement.

          "Federal Funds Effective Rate" means, for any day, the weighted
           ----------------------------
average (rounded upwards, if necessary, to the next 1/100 of 1%) of the rates on
overnight Federal funds transactions with members of the Federal Reserve System
arranged by Federal funds brokers, as published on the next succeeding Business
Day by the Federal Reserve Bank of New York, or, if such rate is not so
published for any day that is a Business Day, the average (rounded upwards, if
necessary, to the next 1/100 of 1%) of the quotations for such day for such
transactions received by the Bank from three Federal funds brokers of recognized
standing selected by it.

          "Final Fee Payment Date" has the meaning assigned to such term in
           ----------------------
Section 2.10(a).

          "Foreign Pension Plan" means any plan, fund (including, without
           --------------------
limitation, any superannuation fund) or other similar program established or
maintained outside the United States of America by the Borrower or any one or
more of its Subsidiaries primarily for the benefit of employees of the Borrower
or such Subsidiaries residing outside the United States of America, which plan,
fund or other similar program provides, or results in, retirement income, a
deferral of income in contemplation of retirement or payments to be made upon
termination of employment, and which plan is not subject to ERISA or the Code.

          "GAAP" means generally accepted accounting principles in the United
           ----
States of America applied in a consistent manner.

          "Governmental Action" means any authorization, approval, order,
           -------------------
decree, ruling or other action by, or notice to or filing with, any Governmental
Authority.

          "Governmental Authority" means the government of the United States of
           ----------------------
America, any other nation or any political subdivision thereof, whether state or
local, and any agency, authority, bureau, instrumentality, regulatory body,
court, tribunal, central bank or other entity exercising executive, legislative,
judicial, taxing, regulatory or administrative powers or functions of or
pertaining to government.

          "Hazardous Materials" means (a) any petroleum or petroleum products,
           -------------------
radioactive materials, asbestos in any form that is friable, urea formaldehyde
foam insulation, transformers or other equipment that contain dielectric fluid
containing levels of poly-chlorinated biphenyls, and radon gas; (b) any
chemicals, materials or substances defined as or included in the definition of
"hazardous substances," "hazardous waste," "hazardous materials," "extremely
hazardous substances," "restricted hazardous waste," "toxic substances," "toxic
pollutants," "contaminants," or "pollutants," or words of similar import, under
any applicable Environmental Law; and (c) any other chemical, material or
substance, the Release of which is prohibited, limited or regulated by any
governmental authority.

                                       6
<PAGE>

          "Indebtedness" of any Person means, (a) obligations created, issued or
           ------------
incurred by such Person for borrowed money (whether by loan, the issuance and
sale of debt securities or the sale of Property to another Person subject to an
understanding or agreement, contingent or otherwise, to repurchase such Property
from such Person); (b) obligations of such Person to pay the deferred purchase
or acquisition price of Property or services, other than trade accounts payable
(other than for borrowed money) arising, and accrued expenses incurred, in the
ordinary course of business; (c) Indebtedness of others secured by a Lien on the
Property of such Person, whether or not the respective indebtedness so secured
has been assumed by such Person; (d) obligations of such Person in respect of
letters of credit or similar instruments issued or accepted by banks and other
financial institutions for account of such Person; (e) Capital Lease Obligations
of such Person; and (f) any guarantee or other arrangement by which such Person
guarantees or is otherwise liable for the Indebtedness of others; provided,
                                                                  --------
however, that "Indebtedness" shall not include Secured Nonrecourse Obligations.
-------

          "Indemnified Parties" means Bank, its Affiliates, and the directors,
           -------------------
officers, employees, attorneys and agents of each of the foregoing.

          "Indemnified Taxes" means all Taxes other than Excluded Taxes.
           -----------------

          "Index Debt" means the senior, unsecured, long-term indebtedness for
           ----------
borrowed money of the Borrower that is not guaranteed by any other Person or
subject to any credit enhancement.

          "Interest Election Request" means a request by the Borrower to convert
           -------------------------
or continue a Borrowing in accordance with Section 2.05.

          "Interest Payment Date" means (a) with respect to any ABR Loan, each
           ---------------------
Quarterly Date, and (b) with respect to any Eurodollar Loan, the last day of the
Interest Period applicable to the Borrowing of which such Loan is a part and, in
the case of a Eurodollar Borrowing with an Interest Period of more than three
months' duration, each day prior to the last day of such Interest Period that
occurs at intervals of three months' duration after the first day of such
Interest Period.

          "Interest Period" means, with respect to any Eurodollar Borrowing, the
           ---------------
period commencing on the date of such Borrowing and ending on the numerically
corresponding day in the calendar month that is one, two, three or six months
thereafter, as the Borrower may elect; provided, that (a) if any Interest Period
would end on a day other than a Business Day, such Interest Period shall be
extended to the next succeeding Business Day unless such next succeeding
Business Day would fall in the next calendar month, in which case such Interest
Period shall end on the next preceding Business Day and (b) any Interest Period
that commences on the last Business Day of a calendar month (or on a day for
which there is no numerically corresponding day in the last calendar month of
such Interest Period) shall end on the last Business Day of the last calendar
month of such Interest Period.  For purposes hereof, the date of a Borrowing
initially shall be the date on which such Borrowing is made and, thereafter
shall be the effective date of the most recent conversion or continuation of
such Borrowing.

          "Investment" means, when used in connection with any Person, any
           ----------
investment by or of that Person, whether by means of purchase or other
acquisition of stock or other securities of any other Person or by means of a
loan, advance creating a debt, capital contribution, guaranty or other debt or
equity participation or interest in any other Person, including any partnership
                                                      ---------
and joint venture interests of such Person but excluding any Wholly-Owned
                                               ---------
Subsidiary of such Person.  The amount of any Investment shall be the amount
actually invested (minus any return of capital with respect to such Investment
                   -----
which has actually been received in cash or has been converted into cash),
without adjustment for subsequent increases or decreases in the value of such
Investment.

                                       7
<PAGE>

          "Law" shall mean any law (including common law), constitution,
           ---
statute, treaty, convention, regulation, rule, ordinance, order, injunction,
writ, decree or award of any Governmental Authority.

          "LIBO Rate" means, with respect to any Eurodollar Borrowing for any
           ---------
Interest Period, the average of the offered rates for Dollar deposits for the
applicable Interest Period which appear on the Telerate Page 3750, British
Bankers Association Interest Settlement Rates, with maturities comparable to the
Interest Period to be applicable to such Eurodollar Loan, determined as of 10:00
A.M. (Las Vegas, Nevada time) on the date which is two Business Days prior to
the commencement of such Interest Period.

          "Lien" means, with respect to any Property, any mortgage, lien,
           ----
pledge, charge, security interest or encumbrance of any kind in respect of such
Property.  For purposes of this Agreement, a Person shall be deemed to own
subject to a Lien any Property that it has acquired or holds subject to the
interest of a vendor or lessor under any conditional sale agreement, capital
lease or other title retention agreement (other than an operating lease)
relating to such Property.

          "Loan Documents" means this Agreement, each Borrowing Request, each
           --------------
Interest Election Request and each Note.

          "Loans" means advances under the Facility.
           -----

          "Material Adverse Effect" means a material adverse effect on (a) the
           -----------------------
Property, business, operations, financial condition, prospects, liabilities or
capitalization of the Borrower and its Subsidiaries taken as a whole, (b) the
ability of the Borrower to perform its obligations hereunder, (c) the validity
or enforceability of this Agreement, (d) the rights and remedies of the Bank
hereunder or (e) the timely payment of the principal of or interest on the Loans
or other amounts payable in connection therewith.

          "Maturity Date" means the earlier of November 30, 2001, or the date of
           -------------
closing of a syndication of the Facility.

          "Moody's" means Moody's Investors Service, Inc.; provided that if such
           -------
corporation (or its successors and assigns) shall for any reason no longer
perform the functions of a securities rating agency, "Moody's" shall be deemed
to refer to any other nationally recognized securities rating agency approved
for purposes hereof by Bank and the Borrower.

          "Multiemployer Plan" means a multiemployer plan defined as such in
           ------------------
Section 3(37) of ERISA to which contributions have been made by the Borrower or
any ERISA Affiliate and which is covered by Title IV of ERISA.

          "NPC" means Nevada Power Company, a Nevada corporation.
           ---

          "NPC Credit Agreement" means that certain Amended and Restated Credit
           --------------------
Agreement dated as of June 24, 1999, as amended through the date hereof
including the Amendment Agreement dated as of August 1, 2001, among NPC, as
borrower, Mellon Bank, N.A. as administrative agent, First Union National Bank
and Wells Fargo Bank, N.A., as syndication agents, and the lenders from time to
time party thereto.

          "NPC First Mortgage Bonds" means obligations issued from time to time
           ------------------------
under, and secured by, the NPC First Mortgage Indenture.

                                       8
<PAGE>

          "NPC First Mortgage Indenture" means the Indenture of Mortgage, dated
           ----------------------------
as of October 1, 1953, from NPC to Banker's Trust Company (successor to First
Interstate Bank of Nevada, N.A., formerly First National Bank of Nevada, Reno
Nevada), as trustee, as modified, amended or supplemented at any time or from
time to time by supplemental indentures.

          "NPC General and Refunding Mortgage Bonds" means obligations issued
           ----------------------------------------
from time to time under, and secured by, the NPC General and Refunding Mortgage
Indenture.

          "NPC General and Refunding Mortgage Indenture" means the General and
           --------------------------------------------
Refunding Mortgage Indenture, dated as of May 1, 2001, between NPC and The Bank
of New York, as trustee, as the same may be amended, modified or supplemented
from time to time.

          "NPC Supplemental Credit Agreement" means that certain Credit
           ---------------------------------
Agreement dated as of August 1, 2001, among NPC, as Borrower, Mellon Bank, N.A.,
as administrative agent, BNP Paribas, First Union National Bank and Wells Fargo
Bank, N.A., as syndication agents, and the lenders from time to time party
thereto.

          "Note" means the promissory note, a form of which is attached hereto
           ----
as Exhibit "A."

          "Obligations" means all Indebtedness, obligations and liabilities of
           -----------
the Borrower to Bank from time to time arising under or in connection with or
related to or evidenced by or secured by this Agreement or any other Loan
Document, and all extensions, renewals or refinancings thereof, whether such
Indebtedness, obligations or liabilities are direct or indirect, otherwise
secured or unsecured, joint or several, absolute or contingent, due or to become
due, whether for payment or performance, now existing or hereafter arising.
Without limitation of the foregoing, such Indebtedness, obligations and
liabilities shall include the principal amount of all Loans, all interest, fees,
indemnities or expenses under or in connection with this Agreement or any other
Loan Document, and all extensions, renewals and refinancings thereof, whether or
not such Loans were made in compliance with the terms and conditions of this
Agreement or in excess of the obligation of Bank to lend.  Obligations shall
remain obligations notwithstanding any assignment or transfer or any subsequent
assignment or transfer of any of the Obligations or any interest therein.

          "Other Taxes" means any and all present or future stamp or documentary
           -----------
taxes or any other excise or Property taxes, charges or similar levies arising
from any payment made hereunder or from the execution, delivery or enforcement
of, or otherwise with respect to, this Agreement.

          "Parent" means any Person that controls a Lender.
           ------

          "PBGC" means the Pension Benefit Guaranty Corporation or any entity
           ----
succeeding to any or all of its functions under ERISA.

          "Permitted Liens" has the meaning assigned to such term in Section
           ---------------
6.02.

          "Person" means any natural person, corporation, limited liability
           ------
company, trust, joint venture, association, company, partnership, Governmental
Authority or other entity.

          "Plan" means an employee benefit or other plan established or
           ----
maintained by the Borrower or any ERISA Affiliate and that is covered by Title
IV of ERISA, other than a Multiemployer Plan.

                                       9
<PAGE>

          "Prime Rate" means the rate of interest per annum publicly announced
           ----------
from time to time by Bank as its prime rate, the Prime Rate to change when and
as such prime rate changes.  The Prime Rate is a reference rate and does not
necessarily represent the lowest or best rate actually charged to any customer.
Bank may make commercial loans or other loans at rates of interest at, above or
below the Prime Rate.

          "Principal Office" means the principal office of Bank located on the
           ----------------
date hereof at Las Vegas Regional Commercial Banking Office, 3800 Howard Hughes
Parkway, Las Vegas, Nevada.

          "Property" means any right or interest in or to property of any kind
           --------
whatsoever, whether real, personal or mixed and whether tangible or intangible.

          "Quarterly Dates" means the last day of March, June, September and
           ---------------
December in each year, the first of which shall be the first such day after the
date hereof; provided that if any such day is not a Business Day, then such
Quarterly Date shall be the next succeeding Business Day (unless such succeeding
Business Day falls in a subsequent calendar month, in which event such Quarterly
Date shall be the next preceding Business Day).

          "Related Parties" means, with respect to any specified Person, such
           ---------------
Person's Affiliates and the respective directors, officers, employees, agents
and advisors of such Person and such Person's Affiliates.

          "Release" means the disposing, discharging, injecting, spilling,
           -------
pumping, leaking, leaching, dumping, emitting, escaping, emptying, pouring or
migrating, into or upon any land or water or air, or otherwise entering into the
environment.

          "Reportable Event" means an event described in Section 4043(c) of
           ----------------
ERISA with respect to a Plan that is subject to Title IV of ERISA other than
those events as to which the 30-day notice period is waived under subsection
 .22, .23, .25, .27 or .28 of PBGC Regulation Section 4043 (provided that a
failure to meet the minimum funding standard of Section 412 of the Code or
Section 302 of ERISA, including, without limitation, the failure to make on or
before its due date a required installment under Section 412(m) of the Code or
Section 302(e) of ERISA, shall be a reportable event regardless of the issuance
of any waivers in accordance with Section 412(d) of the Code).

          "Responsible Officer" means the Treasurer, the Assistant Treasurer,
           -------------------
the Chief Financial Officer or the Controller of Borrower.

          "Revolving" means, when referred to a Loan or Borrowing, a Loan or
           ---------
Borrowing, which may be repaid and reborrowed.

          "Secured Nonrecourse Obligations" means and includes (a) secured
           -------------------------------
obligations of the Borrower taken on a consolidated basis where recourse of the
payee of such obligations is expressly limited to an assigned lease or loan
receivable and the Property related thereto and (b) liabilities of the Borrower
taken on a consolidated basis to manufacturers of leased equipment where such
liabilities are payable solely out of revenues derived from the leasing or sale
of such equipment.

          "Shareholders' Equity" means, as of any date of determination, the
           --------------------
amount, which is shown as "shareholders' equity" (which shall include both
common and preferred equity) in the consolidated balance sheet of the Borrower
at such date.

                                       10
<PAGE>

          "Significant Subsidiary" has the meaning given to such term in
           ----------------------
Regulation S-X under the Securities Act of 1934, as amended.

          "SPPC" means Sierra Pacific Power Company, a Nevada corporation.
           ----

          "SPPC Credit Agreement" means that certain Credit Agreement dated as
           ---------------------
of June 24, 1999, as amended through the date hereof, including the Amendment
Agreement dated as of August 1, 2001, among SPPC, as borrower, Mellon Bank,
N.A., as Administrative Agent, First Union National Bank and Wells Fargo Bank,
National Association, as syndication agents, and the lenders from time to time
party thereto.

          "SPPC First Mortgage Bonds" means obligations issued from time to time
           -------------------------
under, and secured by, the SPPC First Mortgage Indenture.

          "SPPC First Mortgage Indenture" means the Indenture of Mortgage, dated
           -----------------------------
as of December 1, 1940, from SPPC to State Street Bank and Trust Company
(successor to The New England Trust Company), as trustee, and Gerald R. Wheeler
(successor to Leo W. Huegle), as co-Trustee, as modified, amended or
supplemented at any time or from time to time by supplemental indentures.

          "SPPC General and Refunding Mortgage Bonds" means obligations issued
           -----------------------------------------
from time to time under, and secured by, the SPPC General and Refunding Mortgage
Indenture.

          "SPPC General and Refunding Mortgage Indenture" means the General and
           ---------------------------------------------
Refunding Mortgage Indenture, dated as of May 1, 2001, between SPPC and The Bank
of New York, as trustee, as the same may be amended, modified or supplemented
from time to time.

          "SPPC Supplemental Credit Agreement" means that certain Credit
           ----------------------------------
Agreement dated as of August 1, 2001, among SPPC, as borrower, Mellon Bank, N.A.
as administrative agent, BNP Paribas, First Union National Bank and Wells Fargo
Bank N.A., as syndication agents, and the lenders from time to time party
thereto.

          "S&P" means Standard & Poor's Ratings Group, a division of The McGraw
           ---
Hill Companies, Inc., and its successor and assigns; provided that if such
corporation (or its successors and assigns) shall for any reason no longer
perform the functions of a securities rating agency, "S&P" shall be deemed to
refer to any other nationally recognized securities rating agency approved for
purposes hereof by the Bank and the Borrower.

          "Statutory Reserve Rate" means a fraction (expressed as a decimal),
           ----------------------
the numerator of which is the number one and the denominator of which is the
number one minus the aggregate of the maximum reserve percentages (including any
marginal, special, emergency or supplemental reserves) expressed as a decimal
established by the Board to which the Bank is subject for eurocurrency funding
(currently referred to as "Eurocurrency liabilities" in Regulation D of the
Board).  Such reserve percentages shall include those imposed pursuant to such
Regulation D. Eurodollar Loans shall be deemed to constitute eurocurrency
funding and to be subject to such statutory reserve rates without benefit of or
credit for proration, exemptions or offsets that may be available from time to
time to Bank under such Regulation D or any comparable regulation.  The
Statutory Reserve Rate shall be adjusted automatically on and as of the
effective date of any change in any reserve percentage.

          "Subsidiary" shall mean, as to any Person, (i) any corporation more
           ----------
than 50% of whose stock of any class or classes having by the terms thereof
ordinary voting power to elect a majority of the directors

                                       11
<PAGE>

of such corporation (irrespective of whether or not at the time stock of any
class or classes of such corporation shall have or might have voting power by
reason of the happening of any contingency) is at the time owned by such Person
and/or one or more Subsidiaries of such Person and (ii) any partnership, limited
liability company, association, joint venture or other entity in which such
Person and/or one or more Subsidiaries of such Person has more than a 50% equity
interest at the time.

          "Taxes" means any and all present or future taxes, levies, imposts,
           -----
duties, deductions, charges or withholdings imposed by any Governmental
Authority.

          "Total Indebtedness" means, as of any date of determination, the sum
           ------------------
of all Indebtedness of the Borrower and its consolidated Subsidiaries as of such
date.

          "Type", when used in reference to any Loan or Borrowing, refers to
           ----
whether the rate of interest on such Loan, or on the Loans comprising such
Borrowing, is determined by reference to the Adjusted LIBO Rate or the Alternate
Base Rate.

          "Unfunded Current Liability" of any Plan means the amount, if any, by
           --------------------------
which the value of the accumulated plan benefits under the Plan determined on a
plan termination basis in accordance with actuarial assumptions at such time
consistent with those prescribed by the PBGC for purposes of Section 4044 of
ERISA, exceeds the fair market value of all plan assets allocable to such
liabilities under Title IV of ERISA (excluding any accrued but unpaid
contributions).

          "Wholly-Owned Subsidiary" shall mean, as to any Person, (i) any
           -----------------------
corporation 100% of whose stock of any class or classes having by the terms
thereof ordinary voting power to elect a majority of the directors of such
corporation (irrespective of whether or not at the time stock of any class or
classes of such corporation shall have or might have voting power by reason of
the happening of any contingency) is at the time owned by such Person and/or one
or more Subsidiaries of such Person and (ii) any partnership, limited liability
company, association, joint venture or other entity in which such Person and/or
one or more Subsidiaries of such Person has a 100% equity interest at the time.

     SECTION 1.02.  CLASSIFICATION OF LOANS AND BORROWINGS.
                    --------------------------------------

          For purposes of this Agreement, Loans or Borrowings may be classified
and referred to by Type (e.g., a "Eurodollar Borrowing").  All Borrowings under
this Facility shall be Revolving Borrowings.

     SECTION 1.03  TERMS GENERALLY.
                   ---------------

     The definitions of terms herein shall apply equally to the singular and
plural forms of the terms defined.  Whenever the context may require, any
pronoun shall include the corresponding masculine, feminine and neuter forms.
The words "include", "includes" and "including" shall be deemed to be followed
by the phrase "without limitation". The word "will" shall be construed to have
the same meaning and effect as the word "shall".  Unless the context requires
otherwise (a) any definition of or reference to any agreement, instrument or
other document herein shall be construed as referring to such agreement,
instrument or other document as from time to time amended, supplemented or
otherwise modified (subject to any restrictions on such amendments, supplements
or modifications set forth herein), (b) any reference herein to any Person shall
be construed to include such Person's successors and assigns, (c) the words
"herein", "hereof" and "hereunder", and words of similar import, shall be
construed to refer to this Agreement in its entirety and not to any particular
provision hereof and (d) all references herein to Articles, Sections, Exhibits
and Schedules shall be construed to refer to Articles and Sections of, and
Exhibits and Schedules to, this Agreement.

                                       12
<PAGE>

     SECTION 1.04  ACCOUNTING TERMS; GAAP.
                   ----------------------

     Except as otherwise expressly provided herein, all terms of an accounting
or financial nature shall be construed in accordance with GAAP, as in effect
from time to time.

                                  ARTICLE II
                                  THE CREDITS

     SECTION 2.01  THE COMMITMENT.
                   --------------

     (a) Subject to the terms and conditions set forth herein, Bank agrees to
make advances to Borrower from time to time up to and including the Maturity
Date, not to, at any time, exceed the aggregate principal amount of Twenty-Five
Million Dollars ($25,000,000.00) the proceeds of which shall be used for general
corporate purposes.

     SECTION 2.02  LOANS AND BORROWINGS.
                   --------------------

     (a) Obligations of Bank.  Each Revolving Loan shall be made as part of a
         -------------------
Borrowing consisting of Loans of the same Type under the Facility made by the
Bank.

     (b) Type of Loans.  Subject to Section 2.12, each Borrowing shall be
         -------------
comprised entirely of ABR Loans or Eurodollar Loans.  Bank may, at its option,
make any Eurodollar Loan by causing any domestic or foreign branch or Affiliate
of Bank to make such Loan; provided that any exercise of such option shall not
affect the obligation of the Borrower to repay such Loan in accordance with the
terms of this Agreement.

     (c) Minimum Amounts; Limitation on Number of Borrowings.  Each Revolving
         ---------------------------------------------------
Borrowing (whether an ABR Borrowing or a Eurodollar Borrowing) shall be in an
aggregate amount equal to $2,000,000 or a multiple of $1,000,000 in excess
thereof, provided that an ABR Borrowing may be made in an aggregate amount that
is equal to the entire unused balance of the total Commitment of the Facility.
The Borrower may thereafter, upon irrevocable notice to the Bank in accordance
with Section 2.05(b), (i) elect, as of any Business Day, in the case of ABR
Loans, to convert any such ABR Loans or any part thereof, in an aggregate amount
equal to $2,000,000 or a multiple of $1,000,000 in excess thereof, into
Eurodollar Loans, and (ii) elect, as of the last day of the applicable Interest
Period, to continue any Eurodollar Loans having Interest Periods expiring on
such day or any part thereof in an aggregate amount of $2,000,000 or a multiple
of $1,000,000 in excess thereof; provided that, if at any time the aggregate
amount of Eurodollar Loans in respect of any Borrowing is reduced by payment,
prepayment or conversion of part thereof to be less than $2,000,000, such
Eurodollar Loans shall automatically convert into ABR Loans.

     (d) Maximum Duration of Interest Periods.  Notwithstanding any other
         ------------------------------------
provision of this Agreement, the Borrower shall not be entitled to request, or
to elect to convert or continue, any Eurodollar Borrowing under the Facility if
the Interest Period requested with respect thereto would end after the Maturity
Date.

     SECTION 2.03  REQUESTS FOR REVOLVING BORROWINGS.
                   ---------------------------------

                                       13
<PAGE>

     To request a Revolving Borrowing under the Facility, the Borrower shall
notify the Bank of such request by telephone (a) in the case of a Eurodollar
Revolving Borrowing, not later than 12:00 noon, Las Vegas, Nevada time, three
Business Days before the date of the proposed Borrowing, or (b) in the case of
an ABR Borrowing, not later than 12:00 noon, Las Vegas, Nevada time, one
Business Day before the date of the proposed Borrowing.  Each such telephonic
Borrowing Request shall be irrevocable and shall be confirmed promptly by hand
delivery or telecopy to the Bank of a written Borrowing Request in the form
attached hereto as Exhibit B and signed by the Borrower.  Each such telephonic
and written Borrowing Request shall specify the following information in
compliance with Section 2.02:

         (i)   the aggregate amount of the requested Borrowing;

         (ii)  the date of such Borrowing, which shall be a Business Day;

         (iii) whether such Borrowing is to be an ABR Borrowing or a
     Eurodollar Borrowing;

         (iv)  in the case of a Eurodollar Borrowing, the initial Interest
     Period to be applicable thereto, which shall be a period contemplated by
     the definition of the term "Interest Period"; and

         (v)   the location and number of the Borrower's account to which funds
     are to be disbursed, which shall comply with the requirements of Section
     2.04.

If no election as to the Type of Revolving Borrowing is specified, then the
requested Revolving Borrowing shall be an ABR Borrowing.  If no Interest Period
is specified with respect to any Eurodollar Revolving Borrowing, then the
Borrower shall be deemed to have selected an Interest Period of one month's
duration.  Promptly following receipt of a Borrowing Request in accordance with
this Section, the Bank shall advise of the details thereof and of the amount of
Bank's Loan to be made as part of the requested Borrowing.

     SECTION 2.04  FUNDING OF BORROWINGS.
                   ---------------------

     Funding by Bank.  No later than 12:00 noon, Las Vegas, Nevada time, on the
     ---------------
date specified in each Borrowing Request, Bank will make available the Borrowing
requested to be made on such date, in Dollars and in immediately available funds
at the account of the Bank most recently designated by it for such purpose by
notice to the Bank.  The Bank will make such Loans available to the Borrower by
promptly crediting the amounts so received, in like funds, to an account of the
Borrower maintained with Bank or as designated by the Borrower in the applicable
Borrowing Request.

     SECTION 2.05  INTEREST ELECTIONS.
                   ------------------

     (a) Elections by the Borrower for Borrowings.  Each Borrowing initially
         ----------------------------------------
shall be of the Type specified in the applicable Borrowing Request and, in the
case of a Eurodollar Borrowing, shall have an initial Interest Period as
specified in such Borrowing Request.  Thereafter, the Borrower may elect to
convert such Borrowing to a different Type or to continue such Borrowing and, in
the case of a Eurodollar Borrowing, may elect Interest Periods therefor, all as
provided in this Section but subject to Section 2.02.  Once Loans have been made
pursuant to a Borrowing, the Borrower may elect to convert or continue different
portions of such Borrowing,.

     (b) Notice of Elections.  To make an election pursuant to this Section, the
         -------------------
Borrower shall notify the Bank of such election by telephone by the time that a
Borrowing Request would be required under Section 2.03 if the Borrower were
requesting a Revolving Borrowing of the Type resulting from

                                       14
<PAGE>

such election to be made on the effective date of such election. Each such
telephonic Interest Election Request shall be irrevocable and shall be confirmed
promptly by hand delivery or telecopy to the Bank of a written Interest Election
Request in a form approved by the Bank and signed by the Borrower.

     (c) Information in Interest Election Requests.  Each telephonic and written
         -----------------------------------------
Interest Election Request shall specify the following information in compliance
with Section 2.02:

         (i)   the Borrowing to which such Interest Election Request applies
     and, if different options are being elected with respect to different
     portions thereof, the portions thereof to be allocated to each resulting
     Borrowing (in which case the information to be specified pursuant to
     clauses (iii) and (iv) of this paragraph shall be specified for each
     resulting Borrowing);

         (ii)  the effective date of the election made pursuant to such Interest
     Election Request, which shall be a Business Day;

         (iii) whether the resulting Borrowing is to be an ABR Borrowing, or a
     Eurodollar Borrowing; and

         (iv)  if the resulting Borrowing is a Eurodollar Borrowing, the
     Interest Period to be applicable thereto after giving effect to such
     election, which shall be a period contemplated by the definition of the
     term "Interest Period".

     If any such Interest Election Request requests a Eurodollar Borrowing but
does not specify an Interest Period, then the Borrower shall be deemed to have
selected an Interest Period of one month's duration.

     (d) [Intentionally Omitted]
          ----------------------

     (e) Failure to Elect; Events of Default.  If the Borrower fails to deliver
         -----------------------------------
a timely Interest Election Request with respect to a Eurodollar Borrowing prior
to the end of the Interest Period applicable thereto, then, unless such
Borrowing is repaid as provided herein, at the end of such Interest Period such
Borrowing shall be converted to an ABR Borrowing.  Notwithstanding any contrary
provision hereof, if an Event of Default has occurred and is continuing and the
Bank so notifies the Borrower, then, so long as an Event of Default is
continuing (i) no outstanding Borrowing may be converted to or continued as a
Eurodollar Borrowing and (ii) unless repaid, each Eurodollar Borrowing shall be
converted to an ABR Borrowing at the end of the Interest Period applicable
thereto.

     SECTION 2.06  TERMINATION, REDUCTION AND EXTENSION OF COMMITMENT.
                   --------------------------------------------------

     (a) Scheduled Termination.  Unless previously terminated, the Facility
         ---------------------
shall terminate on the Maturity Date.

     (b) Voluntary Termination or Reduction.  The Borrower may at any time prior
         ----------------------------------
to the Maturity Date termination, or from time to time reduce, the Commitment;
provided that (i) each reduction of the Commitment shall be in an amount that is
$2,000,000 or greater, and (ii) the Borrower shall not terminate or reduce the
Commitment if, after giving effect to any concurrent prepayment of the Loans in
accordance with Section 2.09, the aggregate of all  Borrowings then outstanding
would exceed the total Commitment.

                                       15
<PAGE>

     (c) Notice of Voluntary Termination or Reduction.  The Borrower shall
         --------------------------------------------
notify the Bank of any election to terminate or reduce the Commitment under the
Facility in accordance with paragraph (b) of this Section at least three
Business Days prior to the effective date of such termination or reduction,
specifying such election and the effective date thereof.  Each notice delivered
by the Borrower pursuant to this subsection shall be irrevocable; provided that
a notice of termination of the Commitment of a Facility delivered by the
Borrower may state that such notice is conditioned upon the effectiveness of
other credit facilities, in which case such notice may be revoked by the
Borrower (by notice to the Bank on or prior to the specified effective date) if
such condition is not satisfied.

     SECTION 2.07  REPAYMENT OF LOANS; EVIDENCE OF DEBT.
                   ------------------------------------

     (a) Repayment. The Borrower hereby unconditionally promises to pay the
         ---------
Loans to the Bank.

     (b) Manner of Payment.  Prior to any repayment or prepayment of any
         -----------------
Borrowings hereunder, the Borrower shall select the Borrowing or Borrowings to
be paid and shall notify the Bank by telephone (confirmed by telecopy) of such
selection not later than 12:00 noon, Las Vegas, Nevada time, three Business Days
before the scheduled date of such repayment or prepayment; provided that each
repayment or prepayment of Borrowings shall be applied to repay or prepay any
outstanding ABR Borrowings before any other Borrowings. If the Borrower fails to
make a timely selection of the Borrowing or Borrowings to be repaid or prepaid,
such payment shall be applied, first, to pay any outstanding ABR Borrowings and,
second, to other Borrowings in the order of the remaining duration of their
respective Interest Periods (the Borrowing with the shortest remaining Interest
Period to be repaid first).  Each payment of a Revolving Borrowing shall be
applied ratably to the Loans included in such Borrowing.

     (c) Maintenance of Loan Accounts by Bank.  Bank shall maintain in
         ------------------------------------
accordance with its usual practice an account or accounts evidencing the
indebtedness of the Borrower to Bank resulting from each Loan made by Bank,
including the amounts of principal and interest payable and paid to Bank from
time to time hereunder.

     (d) [Intentionally Omitted]
          ----------------------

     (e) Effect of Entries.  The entries made in the accounts maintained
         -----------------
pursuant to paragraph (c) of this Section shall be prima facie evidence of the
existence and amounts of the obligations recorded therein; provided that the
failure of the Bank to maintain such accounts or any error therein shall not in
any manner affect the obligation of the Borrower to repay the Loans in
accordance with the terms of this Agreement.

     SECTION 2.08  [Intentionally Omitted]

     SECTION 2.09  PREPAYMENT.
                   ----------

     (a) Optional Prepayments Right to Prepay Borrowings.  The Borrower shall
         -----------------------------------------------
have the right at any time and from time to time to prepay any Borrowing in
whole or in part, subject to the requirements of this Section.

     (b) Notices, Etc.  The Borrower shall notify the Bank by telephone
         -------------
(confirmed by telecopy) of any optional prepayment hereunder (i) in the case of
prepayment of a Eurodollar Borrowing, not later than 12:00 noon, Las Vegas,
Nevada time, three Business Days before the date of prepayment, or (ii) in

                                       16
<PAGE>

the case of prepayment of an ABR Borrowing, not later than 12:00 noon, Las
Vegas, Nevada time, one Business Day before the date of prepayment. Each such
notice shall be irrevocable and shall specify the prepayment date and the
principal amount of each Borrowing or portion thereof to be prepaid; provided
that, if a notice of prepayment is given in connection with a conditional notice
of termination of the Commitment as contemplated by Section 2.06(c), then such
notice of prepayment may be revoked if such notice of termination is revoked in
accordance with Section 2.06(c).

     SECTION 2.10  FEES.
                   ----

     (a) Facility Fee.  The Borrower shall pay the Bank a facility fee for the
         ------------
period from and including the Effective Date to the Maturity Date (the "Final
Fee Payment Date") computed at a rate per annum equal to the Applicable Rate on
Bank's daily average Commitment, such fee to be paid quarterly in arrears on
each Quarterly Date and on the Final Fee Payment Date. The facility fee shall be
calculated on the basis of the actual number of days elapsed in a year of 360
days.

     (b) Payment of Fees.  All fees payable hereunder shall be paid on the dates
         ---------------
due, in immediately available funds, to the Bank.

     SECTION 2.11  INTEREST.
                   --------

     (a) ABR Loans.  The Loans comprising each ABR Revolving Borrowing shall
         ---------
bear interest at a rate per annum equal to the Alternate Base Rate.

     (b) Eurodollar Loans.  The Loans comprising each Eurodollar Borrowing shall
         ----------------
bear interest at a rate per annum equal to the Adjusted LIBO Rate for the
Interest Period in effect for such Borrowing plus the Applicable Rate.

     (c) Default Interest.  Notwithstanding the foregoing, if any principal of
         ----------------
or interest on any Loan or any fee or other amount payable by the Borrower
hereunder is not paid when due, whether at stated maturity, upon acceleration or
otherwise, such overdue amount shall bear interest, after as well as before
judgment, at a rate per annum equal to (i) in the case of overdue principal of
any Loan, 2% plus the rate otherwise applicable to such Loan as provided above
or (ii) in the case of any other amount, 2% plus the rate applicable to ABR
Loans as provided in paragraph (a) of this Section.

     (d) Payment of Interest.  Accrued interest on each Loan shall be payable in
         -------------------
arrears on each Interest Payment Date for such Loan and upon termination of the
Commitment.

     (e) Computation.  All interest hereunder shall be computed on the basis of
         -----------
a year of 360 days, except that interest computed by reference to the Alternate
Base Rate at times when the Alternate Base Rate is based on the Prime Rate shall
be computed on the basis of a year of 365 days (or 366 days in a leap year), and
in each case shall be payable for the actual number of days elapsed (including
the first day but excluding the last day).  The applicable Alternate Base Rate,
Adjusted LIBO Rate or LIBO Rate shall be determined by the Bank, and such
determination shall be conclusive, absent manifest error.

     SECTION 2.12  ALTERNATE RATE OF INTEREST.
                   --------------------------

     If prior to the commencement of any Interest Period for a Eurodollar
Borrowing:

                                       17
<PAGE>

     (a) the Bank determines (which determination shall be conclusive, absent
manifest error) that adequate and reasonable means do not exist for ascertaining
the Adjusted LIBO Rate or the LIBO Rate, as applicable, for such Interest
Period; or

     (b) the Bank is advised that the Adjusted LIBO Rate or the LIBO Rate, as
applicable, for such Interest Period will not adequately and fairly reflect the
cost to Bank of making or maintaining the Loans included in such Borrowing for
such Interest Period.

     Then the Bank shall give notice thereof to the Borrower and, until the Bank
notifies the Borrower that the circumstances giving rise to such notice no
longer exist, (i) any Interest Election Request that requests the conversion of
any Borrowing to, or continuation of any Borrowing as, a Eurodollar Borrowing
shall be ineffective, and (ii) if any Borrowing Request requests a Eurodollar
Revolving Borrowing, such Borrowing shall be made as an ABR Revolving Borrowing.

     SECTION 2.13  INCREASED COSTS.
                   ---------------

     (a) Increased Costs Generally.  If any Change in Law shall:
         -------------------------

         (i)  impose, modify or deem applicable any reserve, special deposit or
     similar requirement against assets of, deposits with or for the account of,
     or credit extended by, Bank or its Parent (except any such reserve
     requirement reflected in the Adjusted LIBO Rate); or

         (ii) impose on Bank or its Parent or the London interbank market any
     other condition affecting this Agreement or Eurodollar Loans made by Bank;

and the result of any of the foregoing shall be to increase the cost to Bank or
its Parent of making or maintaining any Eurodollar Loan (or of maintaining its
obligation to make any such Loan) or to reduce the amount of any sum received or
receivable by Bank hereunder (whether of principal, interest or otherwise), then
the Borrower will pay to Bank such additional amount or amounts as will
compensate Bank or its Parent, as the case may be, for such additional costs
incurred or reduction suffered.

     (b) Capital Requirements.  If Bank determines that any Change in Law
         --------------------
regarding capital requirements has or would have the effect of reducing the rate
of return on Bank's capital or on the capital of its Parent as a consequence of
this Agreement or the Loans made by Bank to a level below that which Bank or its
Parent could have achieved but for such Change in Law (taking into consideration
Bank's policies and the policies of its Parent with respect to capital
adequacy), then from time to time the Borrower will pay to Bank such additional
amount or amounts as will compensate Bank or its Parent for any such reduction
suffered.

     (c) [Intentionally Omitted]
         -----------------------

     (d) Delay in Requests.  Failure or delay on the part of Bank to demand
         -----------------
compensation pursuant to this Section shall not constitute a waiver of Bank's
right to demand such compensation.

     SECTION 2.14  BREAK FUNDING PAYMENTS.
                   ----------------------

     In the event of (a) the payment of any principal of any Eurodollar Loan
other than on the last day of an Interest Period applicable thereto (including
as a result of an Event of Default), (b) the conversion of Eurodollar Loan other
than on the last day of the Interest Period applicable thereto, or (c) the
failure to borrow, convert, continue or prepay any Revolving Loan on the date
specified in any notice delivered

                                       18
<PAGE>

pursuant hereto (regardless of whether such notice is permitted to be revocable
under Section 2.09(b) and is revoked in accordance herewith), then, in any such
event, the Borrower shall compensate Bank for the loss, cost and expense
attributable to such event. In the case of a Eurodollar Loan, the loss to Bank
attributable to any such event shall be deemed to include an amount determined
by Bank to be equal to the excess, if any, of (i) the amount of interest that
Bank would pay for a deposit equal to the principal amount of such Loan for the
period from the date of such payment, conversion, failure or assignment to the
last day of the then current Interest Period for such Loan (or, in the case of a
failure to borrow, convert or continue, the duration of the Interest Period that
would have resulted from such borrowing, conversion or continuation) if the
interest rate payable on such deposit were equal to the Adjusted LIBO Rate for
such Interest Period, over (ii) the amount of interest that Bank would earn on
such principal amount for such period if Bank were to invest such principal
amount for such period at the interest rate that would be bid by Bank (or an
Affiliate of Bank) for dollar deposits from other banks in the eurodollar market
at the commencement of such period. A certificate of Bank setting forth any
amount or amounts that Bank is entitled to receive pursuant to this Section
shall be delivered to the Borrower and shall be conclusive, absent manifest
error. The Borrower shall pay Bank the amount shown as due on any such
certificate within 10 days after receipt thereof.

     SECTION 2.15  TAXES.
                   -----

     (a) Payments Free of Taxes.  Any and all payments by or on account of any
         ----------------------
obligation of the Borrower hereunder shall be made free and clear of and without
deduction for any Indemnified Taxes or Other Taxes; provided that if the
Borrower shall be required to deduct any Indemnified Taxes or Other Taxes from
such payments, then (i) the sum payable shall be increased as necessary so that
after making all required deductions (including deductions applicable to
additional sums payable under this Section) the Bank receives an amount equal to
the sum it would have received had no such deductions been made, (ii) the
Borrower shall make such deductions and (iii) the Borrower shall pay the full
amount deducted to the relevant Governmental Authority in accordance with
applicable Law.

     (b) Payment of Other Taxes by the Borrower. In addition, the Borrower shall
         --------------------------------------
pay any other Taxes to the relevant Governmental Authority in accordance with
applicable Law.

     (c) Indemnification by the Borrower.  The Borrower shall indemnify the
         -------------------------------
Bank,  within 10 days after written demand therefor, for the full amount of any
Indemnified Taxes or Other Taxes (including Indemnified Taxes or Other Taxes
imposed or asserted on or attributable to amounts payable under this Section)
paid by the Bank, and any penalties, interest and reasonable expenses arising
therefrom or with respect thereto, whether or not such Indemnified Taxes or
Other Taxes were correctly or legally imposed or asserted by the relevant
Governmental Authority. A certificate as to the amount of such payment or
liability delivered to the Borrower by the Bank shall be conclusive, absent
manifest error.

     (d) Evidence of Payments.  As soon as practicable after any payment of
         ---------------------
Indemnified Taxes or Other Taxes by the Borrower to a Governmental Authority,
the Borrower shall deliver to the Bank the original or a certified copy of a
receipt issued by such Governmental Authority evidencing such payment, a copy of
the return reporting such payment or other evidence of such payment reasonably
satisfactory to the Bank.

     SECTION 2.16  PAYMENTS GENERALLY.
                   ------------------

          Payments by the Borrower.  The Borrower shall make each payment
          ------------------------
required to be made by it hereunder (whether of principal, interest or fees, or
under Section 2.13, 2.14 or 2.15, or otherwise)

                                       19
<PAGE>

prior to 1:00 PM, Las Vegas, Nevada time, on the date when due, in immediately
available funds, without set-off or counterclaim. Any amounts received after
such time on any such date shall be deemed to have been received on the next
succeeding Business Day for purposes of calculating interest thereon. All such
payments shall be made to the Bank at its Principal Office and to such account
at its Principal Office as the Bank shall specify to the Borrower. If any
payment hereunder shall be due on a day that is not a Business Day, the date for
payment shall be extended to the next succeeding Business Day and, in the case
of any payment accruing interest, interest thereon shall be payable for the
period of such extension. All payments hereunder shall be made in Dollars.

                                  ARTICLE III
                        REPRESENTATIONS AND WARRANTIES

     The Borrower hereby represents and warrants to the Bank as follows:

     SECTION 3.01  CORPORATE STATUS.
                   ----------------

     The Borrower and each Significant Subsidiary of the Borrower is a
corporation, trust or limited liability company duly organized, validly existing
and in good standing under the Laws of its jurisdiction of organization.  The
Borrower and each Significant Subsidiary of the Borrower has the corporate power
and authority to own its Property and to transact the business in which it is
engaged or presently proposes to engage.  The Borrower and each Significant
Subsidiary of the Borrower is duly qualified to do business as a foreign
corporation, trust or limited liability company and is in good standing in all
jurisdictions in which the ownership of its properties or the nature of its
activities or both makes such qualification necessary or advisable.

     SECTION 3.02  CORPORATE POWER AND AUTHORIZATION.
                   ---------------------------------

     The Borrower has the corporate power and authority to execute, deliver,
perform, and take all actions contemplated by, each of the Loan Documents to
which it is a party, and all such action has been duly and validly authorized by
all necessary corporate proceedings on its part.  Without limiting the
foregoing, the Borrower has the corporate power and authority to borrow pursuant
to the Loan Documents to the fullest extent permitted hereby and thereby from
time to time, and has taken all necessary corporate action to authorize such
borrowings.

     SECTION 3.03  EXECUTION AND BINDING EFFECT.
                   ----------------------------

     This Agreement and each of the other Loan Documents to which the Borrower
is a party and which is required to be delivered on or before the Effective Date
pursuant to Section 4.01 has been duly and validly executed and delivered by the
Borrower. This Agreement and each such other Loan Document constitutes, and when
executed and delivered by the Borrower will constitute, the legal, valid and
binding obligation of the Borrower, enforceable against the Borrower in
accordance with its terms, except as the enforceability hereof or thereof may be
limited by bankruptcy, insolvency or other similar laws of general application
affecting the enforcement of creditors' rights or by general principles of
equity limiting the availability of equitable remedies.

     SECTION 3.04  GOVERNMENTAL APPROVALS AND FILINGS.
                   ----------------------------------

     No Governmental Action is required for the due execution, delivery and
performance by the Borrower of this Agreement or any of the other Loan Documents
to which it is a party.

                                       20
<PAGE>

     SECTION 3.05  ABSENCE OF CONFLICTS.
                   --------------------

     Neither the execution and delivery of any of the Loan Documents by the
Borrower, nor the consummation of the transactions herein or therein
contemplated by the Borrower, nor the performance of or the compliance with the
terms and conditions hereof or thereof by the Borrower, does or will:

     (a)  violate or conflict with any Law; or

     (b)  violate, conflict with or result in a breach of any term or condition
of, or constitute a default under, or result in (or give rise to any right,
    --                             --
contingent or otherwise, of any Person to cause) any termination, cancellation,
prepayment or acceleration of performance of, or result in the creation or
                                              --
imposition of (or give rise to any obligation, contingent or otherwise, to
create or impose) any Lien upon any of the Property of the Borrower or any
Subsidiary of the Borrower pursuant to, or otherwise result in (or give rise to
                                        --
any right, contingent or otherwise, of any Person to cause) any change in any
right, power, privilege, duty or obligation of the Borrower or any Subsidiary of
the Borrower under or in connection with,

          (i)   the articles of incorporation or by-laws (or other constituent
     documents) of the Borrower or any Subsidiary of the Borrower;

          (ii)  any agreement or instrument creating, evidencing or securing any
     Indebtedness to which the Borrower or any Subsidiary of the Borrower is a
     party or by which any of them or any of their respective properties (now
     owned or hereafter acquired) may be subject or bound; or

          (iii) any other material agreement or instrument to which the
     Borrower or any Subsidiary of the Borrower is a party or by which any of
     them or any of their respective properties (now owned or hereafter
     acquired) may be subject or bound.

     SECTION 3.06  AUDITED FINANCIAL STATEMENTS.
                   ----------------------------

     The Borrower has heretofore furnished to the Bank consolidated balance
sheets of the Borrower and its consolidated Subsidiaries as of December 31,
2000, and the related consolidated statements of income, retained earnings and
changes in cash flows for the fiscal year then ended, as examined and reported
on by independent certified public accountants for the Borrower, who delivered
an unqualified opinion in respect thereof.  Such financial statements (including
the notes thereto) present fairly the financial condition of the Borrower and
its consolidated Subsidiaries as of the end of each such fiscal year and the
results of their operations and their retained earnings and changes in cash
flows for the fiscal year then ended, all in conformity with GAAP.

     SECTION 3.07  INTERIM FINANCIAL STATEMENTS.
                   ----------------------------

     The Borrower has heretofore furnished to the Bank an interim consolidated
balance sheet of the Borrower and its consolidated Subsidiaries as of the end of
the fiscal quarter ending June 30, 2001, together with the related consolidated
statements of income, retained earnings and changes in cash flows for the
applicable fiscal period ending on such date.  Such financial statements
(including the notes thereto) present fairly the financial condition of the
Borrower and its consolidated Subsidiaries as of the end of such fiscal quarter
and the results of their operations and their retained earnings and changes in
cash flows for the fiscal periods then ended, all in conformity with GAAP,
subject to normal and recurring year-end audit adjustments.

                                       21
<PAGE>

     SECTION 3.08  ABSENCE OF UNDISCLOSED LIABILITIES.
                   ----------------------------------

     Neither the Borrower nor any Subsidiary of the Borrower has any liability
or obligation of any nature whatever (whether absolute, accrued, contingent or
otherwise, whether or not due), forward or long-term commitment or unrealized or
anticipated losses from unfavorable commitments, except (a) as disclosed in the
financial statements referred to in Sections 3.06 and 3.07, and (b) liabilities,
obligations, commitments and losses incurred after June 30, 2001, in the
ordinary course of business and consistent with past practices.

     SECTION 3.09  ABSENCE OF MATERIAL ADVERSE CHANGE.
                   ----------------------------------

     Since June 30, 2001, there has been no material adverse change in the
business, operations, condition (financial or otherwise), or prospects of the
Borrower and its Subsidiaries taken as a whole.

     SECTION 3.10  ACCURATE AND COMPLETE DISCLOSURE.
                   --------------------------------

     All information heretofore, contemporaneously or hereafter provided by or
on behalf of the Borrower to the Bank pursuant to or in connection with any Loan
Document or any transaction contemplated hereby or thereby is or will be (as the
case may be) true and accurate in all material respects on the date as of which
such information is dated (or, if not dated, when received by the Bank) and does
not or will not (as the case may be) omit to state any material fact necessary
to make such information not misleading at such time in light of the
circumstances in which it was provided.  The Borrower has disclosed to the Bank
in writing every fact or circumstance which has, or which so far as the Borrower
can reasonably foresee is reasonably likely and is reasonably likely to have, a
Material Adverse Effect.

     SECTION 3.11  MARGIN REGULATIONS.
                   ------------------

     No part of the proceeds of any Loan hereunder will be used for the purpose
of buying or carrying any "margin stock", as such term is used in Regulation U
of the Board, as amended from time to time, or to extend credit to others for
the purpose of buying or carrying any "margin stock".  Neither the Borrower nor
any Subsidiary of the Borrower is engaged in the business of extending credit to
others for the purpose of buying or carrying "margin stock".  Neither the
Borrower nor any Subsidiary of the Borrower owns any "margin stock".  Neither
the making of any Loan nor any use of proceeds of any such Loan will violate or
conflict with the provisions of Regulation T, U or X of the Board, as amended
from time to time.

     SECTION 3.12  LITIGATION.
                   ----------

     There is no pending or (to the Borrower's knowledge after due inquiry)
threatened action, suit, proceeding or investigation (including any
Environmental Claim) by or before any Governmental Authority against or
affecting the Borrower or any Subsidiary of the Borrower which, if adversely
decided, individually or in the aggregate, would reasonably be expected to have
a Material Adverse Effect, except for matters described in the financial
statements referred to in Section 3.06 or matters previously disclosed to the
Bank.

     SECTION 3.13  ABSENCE OF EVENTS OF DEFAULT.
                   ----------------------------

                                       22
<PAGE>

     No event has occurred and is continuing and no condition exists which
constitutes a Default or an Event of Default.

     SECTION 3.14  ABSENCE OF OTHER CONFLICTS.
                   --------------------------

     Neither the Borrower nor any Significant Subsidiary of the Borrower is in
violation of or conflict with, or is subject to any contingent liability on
account of any violation of or conflict with:

     (a) any Law (including ERISA, the Code, any applicable occupational health,
safety or welfare Law or any applicable Environmental Law);

     (b) its articles of incorporation or by-laws (or other constituent
documents); or

     (c) any agreement or instrument to which it is party or by which it or any
of its properties (now owned or hereafter acquired) may be subject or bound;

except for matters which, individually or in the aggregate, would not reasonably
be expected to have a Material Adverse Effect.

     SECTION 3.15  INSURANCE.
                   ---------

     The Borrower and each Subsidiary of the Borrower maintains with financially
sound and reputable insurers insurance with respect to its properties and
business and against at least such liabilities, casualties and contingencies and
in at least such types and amounts as is customary in the case of corporations
engaged in the same or a similar business or having similar properties similarly
situated.

     SECTION 3.16  TITLE TO PROPERTY; NO LIENS.
                   ---------------------------

     The Borrower and each Subsidiary of the Borrower has good and marketable
title in fee simple to all real Property owned or purported to be owned by it
and good title to all other Property of whatever nature owned or purported to be
owned by it, including but not limited to all Property reflected in the most
recent audited balance sheet referred to in Section 3.06 or the balance sheet
referred to in Section 3.07, as the case may be (except as sold or otherwise
disposed of in the ordinary course of business after the date of such balance
sheet).  Except for (i) Liens reflected in the audited balance sheet referred to
in Section 3.06 or the balance sheet referred to in Section 3.07, as the case
may be, (ii) Liens consisting of zoning or planning restrictions, easements,
permits and other restrictions or limitations on the use of real Property or
irregularities in title thereto which do not materially detract from the value
of, or impair the use of, such Property by the Borrower or any Subsidiary of the
Borrower in the operation of its business, (iii) Liens for current Taxes not yet
due and delinquent and (iv) Liens permitted by Section 6.02, no Property owned
by the Borrower or any Subsidiary of the Borrower is subject to any Lien.

     SECTION 3.17  TAXES.
                   -----

     All tax and information returns required to be filed by or on behalf of the
Borrower or any Subsidiary of the Borrower have been properly prepared, executed
and filed.  All Taxes upon the Borrower or any Subsidiary of the Borrower or
upon any of their respective Properties, incomes, sales or franchises which are
due and payable have been paid, other than those not yet delinquent and payable
without premium or penalty, and except for those being diligently contested in
good faith by appropriate proceedings, and in each case adequate reserves and
provisions for Taxes have been made on the books of the Borrower and each
Subsidiary of the Borrower.  The reserves and provisions for Taxes on the

                                       23
<PAGE>

books of the Borrower and each Subsidiary of the Borrower are adequate for all
open years and for its current fiscal period. Neither the Borrower nor any
Subsidiary of the Borrower knows of any proposed additional assessment or basis
for any material assessment for additional Taxes (whether or not reserved
against).

     SECTION 3.18  BORROWER NOT AN INVESTMENT COMPANY NOR A REGISTERED PUBLIC
                   ----------------------------------------------------------
UTILITY HOLDING COMPANY.
-----------------------

     The Borrower is not an "investment company" or a company controlled by an
"investment company" within the meaning of the Investment Company Act of 1940.
The Borrower is a "holding company" within the meaning of the Public Utility
Holding Company Act of 1935, as amended (the "1935 Act"), but pursuant to
Section 3 (a)(1) of the 1935 Act, is exempt from all provisions of the 1935 Act
except Section 9 (a) (2) thereof.

     SECTION 3.19  ENVIRONMENTAL MATTERS.
                   ---------------------

     (a) The Borrower and each of its Subsidiaries have complied with and are in
compliance with, all applicable Environmental Laws and the requirements of any
permits issued under such Environmental Laws.  Except as disclosed to Bank,
there are no pending or threatened Environmental Claims against the Borrower or
any of its Subsidiaries (including any such claim arising out of the ownership,
lease or operation by the Borrower or any of its Subsidiaries of any real
Property no longer owned, leased or operated by the Borrower or any of its
Subsidiaries) or any real Property owned, leased or operated by the Borrower or
any of its Subsidiaries.  Except as disclosed to Bank, there are no facts,
circumstances, conditions or occurrences with respect to the business or
operations of the Borrower or any of its Subsidiaries, or any real Property
owned, leased or operated by the Borrower or any of its Subsidiaries (including
any real Property formerly owned, leased or operated by the Borrower or any of
its Subsidiaries but no longer owned, leased or operated by the Borrower or any
of its Subsidiaries) or any Property adjoining or adjacent to any such real
Property that could be expected (i) to form the basis of an Environmental Claim
against the Borrower or any of its Subsidiaries or any real Property owned,
leased or operated by the Borrower or any of its Subsidiaries or (ii) to cause
any real Property owned, leased or operated by the Borrower or any of its
Subsidiaries to be subject to any restrictions on the ownership, occupancy or
transferability of such real Property by the Borrower or any of its Subsidiaries
under any applicable Environmental Law.

     (b) Hazardous Materials have not at any time been generated, used, treated
or stored on, or transported to or from, any real Property owned, leased or
operated by the Borrower or any of its Subsidiaries where such generation, use,
treatment or storage has violated or could be expected to violate any
Environmental Law.  Hazardous Materials have not at any time been Released on or
from any real Property owned, leased or operated by Borrower or any of its
Subsidiaries where such Release has violated or would be expected to violate any
applicable Environmental Law.

     (c) Notwithstanding anything to the contrary in this Section, the
representations made in this Section shall not be untrue unless the effect of
all violations, claims, restrictions, failures and noncompliances of the types
described in this Section would reasonably be expected to, individually or in
the aggregate, have a Material Adverse Effect on the Borrower.

     SECTION 3.20  ERISA.
                   -----

     (a) Each Plan (and each related trust, insurance contract or fund) is in
substantial compliance with its terms and with all applicable Laws, including
without limitation ERISA and the

                                       24
<PAGE>

Code; each Plan (and each related trust, if any) which is intended to be
qualified under Section 401(a) of the Code has received a determination letter
from the Internal Revenue Service to the effect that it meets the requirements
of Sections 401(a) and 501(a) of the Code; no Reportable Event has occurred; no
Multiemployer Plan is insolvent or in reorganization; no Plan has an Unfunded
Current Liability; no Plan which is subject to Section 412 of the Code or
Section 302 of ERISA has an accumulated funding deficiency within the meaning of
such sections of the Code or ERISA or has applied for or received a waiver of an
accumulated funding deficiency or an extension of any amortization period within
the meaning of Section 412 of the Code or Section 303 or 304 of ERISA; all
contributions required to be made with respect to a Plan have been timely made;
neither the Borrower nor any Subsidiary of the Borrower nor any ERISA Affiliate
has incurred any material liability (including any indirect, contingent or
secondary liability) to or on account of a Plan pursuant to Section 409, 502(i),
502(l), 515, 4062, 4063, 4064, 4069, 4201, 4204 or 4212 of ERISA or Section
401(a)(29), 4971 or 4975 of the Code or expects to incur any such liability
under any of the foregoing sections with respect to any Plan; no condition
exists which presents a material risk to the Borrower or any Subsidiary of the
Borrower or any ERISA Affiliate of incurring a liability to or on account of a
Plan pursuant to the foregoing provisions of ERISA and the Code; no proceedings
have been instituted to terminate or appoint a trustee to administer any Plan;
no action, suit, proceeding, hearing, audit or investigation with respect to the
administration, operation or the investment of assets of any Plan (other than
routine claims for benefits) is pending, expected or threatened; using actuarial
assumptions and computation methods consistent with Part 1 of subtitle E of
Title IV of ERISA, the aggregate liabilities of the Borrower and its
Subsidiaries and its ERISA Affiliates to all Multiemployer Plans in the event of
a complete withdrawal therefrom, as of the close of the most recent fiscal year
of each such Plan ended prior to the date of the most recent Borrowing, would
not have a Material Adverse Effect; each group health plan (as defined in
Section 607(1) of ERISA or Section 4980B(g)(2) of the Code) which covers or has
covered employees or former employees of the Borrower, any Subsidiary of the
Borrower, or any ERISA Affiliate has at all times been operated in compliance
with the provisions of Part 6 of subtitle B of Title I of ERISA and Section
4980B of the Code; no Lien imposed under the Code or ERISA on the assets of the
Borrower or any Subsidiary of the Borrower or any ERISA Affiliate exists or is
likely to arise on account of any Plan; and the Borrower and its Subsidiaries
may cease contributions to or terminate any Plan maintained by any of them
without incurring any material liability.

     (b) Each Foreign Pension Plan, if any, has been maintained in substantial
compliance with its terms and with the requirements of any and all applicable
Laws, statutes, rules, regulations and orders and has been maintained, where
required, in good standing with applicable regulatory authorities.  All
contributions required to be made with respect to a Foreign Pension Plan have
been timely made.  Neither the Borrower nor any of its Subsidiaries has incurred
any obligation in connection with the termination of or withdrawal from any
Foreign Pension Plan.  The present value of the accrued benefit liabilities
(whether or not vested) under each Foreign Pension Plan, determined as of the
end of the Borrower's most recently ended Fiscal Year on the basis of actuarial
assumptions, each of which is reasonable, did not exceed the current value of
the assets of such Foreign Pension Plan allocable to such benefit liabilities.

     SECTION 3.21 PARI PASSU STATUS.
                  -----------------

     The claims and rights of the Bank against the Borrower hereunder are not
subordinated to, and rank at least pari passu with, the claims and rights of
other holders of its unsecured indebtedness except to the extent otherwise
provided by Law (including without limitation the Bankruptcy Code and the
provisions of 31 U.S.C. (S)3713).

                                       25
<PAGE>

                                  ARTICLE IV
                                  CONDITIONS

     SECTION 4.01  EFFECTIVE DATE.
                   --------------

     This Agreement and the other Loan Documents shall become effective as
against the Bank on the first date on which all of the following conditions
shall be satisfied or waived:

     (a) Agreement; Note.  The Bank shall have received an executed counterpart
         ---------------
of this Agreement for Bank, duly executed by the Borrower, and the Note.

     (b) Corporate Proceedings.  The Bank shall have received certificates by
         ---------------------
the Secretary or Assistant Secretary of the Borrower dated as of the Effective
Date as to (i) true copies of the articles of incorporation and by-laws (or
other constituent documents) of the Borrower as in effect on such date (which,
in the case of articles of incorporation or other constituent documents filed or
required to be filed with the Secretary of State or other Governmental Authority
in its jurisdiction of incorporation, shall be certified to be true, correct and
complete by such Secretary of State or other Governmental Authority not more
than 30 days before the date hereof), (ii) true copies of all corporate action
taken by the Borrower relative to this Agreement and the other Loan Documents,
and (iii) the incumbency and signatures of the respective officers of the
Borrower executing this Agreement and the other Loan Documents to which the
Borrower is a party, together with satisfactory evidence of the incumbency of
such Secretary or Assistant Secretary.  The Bank shall have received,
certificates from the Secretary of State of Nevada (or other applicable
Governmental Authority) dated not more than 30 days before the Effective Date
showing the good standing of the Borrower in Nevada and in each state in which
the Borrower does business.

     (c) Legal Opinion of Counsel to the Borrower.  The Bank shall have
         ----------------------------------------
received, an opinion addressed to the Bank, dated Effective Date, of Choate,
Hall & Stewart, and an opinion of Woodburn and Wedge as to issues under the laws
of the State of Nevada, as to such matters as may be requested by the Bank and
in form and substance satisfactory to the Bank.

     (d) Financial Statements.  The Bank shall have received a true and correct
         --------------------
copy of the (i) audited consolidated financial statements, including balance
sheets, income statements and cash flow statements, for the Borrower, NPC, SPPC
and their respective consolidated Subsidiaries for the year ended December 31,
2000, and (ii) unaudited interim consolidated financial statements, including a
balance sheet, income statement and statement of cash flows, for the Borrower,
NPC, SPPC and their respective consolidated Subsidiaries for the three month
period ended June 30, 2001.

     (e) No Material Adverse Effect.  Nothing shall have occurred (and the Bank
         --------------------------
shall have not become aware of any facts or conditions not previously known)
which Bank shall determine has, had, or could reasonably be expected to have, a
Material Adverse Effect. The Bank shall have received a certificate of a
Responsible Officer of the Borrower, dated the Effective Date, to the effect
that, as of the Effective Date, there has been no Material Adverse Effect since
June 30, 2001.

     (f) No Injunctions.  There shall not exist any judgment, order, injunction
         --------------
or other restraint issued or filed or a hearing seeking injunctive relief or
other restraint pending or notified prohibiting or imposing materially adverse
conditions upon the transactions contemplated hereby or otherwise referred to
herein.

                                       26
<PAGE>

     (g) Litigation, Proceedings and Investigations.  There shall be no actions,
         ------------------------------------------
arbitrations, suits, investigations or proceedings pending or threatened with
respect to this Agreement or which the Bank shall determine could reasonably be
expected to have a Material Adverse Effect.

     (h) No Violation of Existing Agreements.  Neither the Borrower nor any
         -----------------------------------
Subsidiary of the Borrower is in violation of any material agreement or
instrument to which it is party or by which it or any of its properties (now
owned or hereafter acquired) may be subject or bound;

     (i)  [Intentionally Omitted]
          -----------------------

     (j) Ratings.  The Bank shall have received a certificate of a Responsible
         -------
Officer of the Borrower, dated the Effective Date, setting forth the then
current ratings of the Index Debt.

     (k) Officers' Certificates.  The Bank shall have received, with an executed
         ----------------------
counterpart, certificates from such officers of the Borrower as to such matters
as the Bank may request.

     (l) Fees, Expenses, etc.  All fees and other items required to be paid to
         -------------------
Bank on or before the Effective Date (including all fees referenced in fee
letters and offer letters) shall have been paid or received.

     (m) Section 4.02 Conditions.
         -----------------------

         (i)  Each of the representations and warranties made by the Borrower
     herein and in each other Loan Document shall be true and correct in all
     material respects on and as of the Effective Date as if made on and as of
     such date, both before and after giving effect to the Loans requested to be
     made on such date.

         (ii) No Default or Event of Default shall have occurred and be
     continuing on the Effective Date.

     (n) Additional Matters.  The Bank shall have received, with copies or
         ------------------
executed counterparts, such other certificates, opinions, documents and
instruments as the Bank may have requested.  All corporate and other
proceedings, and all documents, instruments and other matters in connection with
the transactions contemplated by this Agreement and the other Loan Documents
shall be satisfactory in form and substance to the Bank.

     SECTION 4.02  CONDITIONS TO ALL LOANS.
                   -----------------------

     The obligation of Bank to make, convert or continue any Loan on the
occasion of any Borrowing is subject to satisfaction of the conditions precedent
set forth in Section 4.01 and satisfaction of the following further conditions
precedent:

     (a) Notice.  The Borrower shall have executed and delivered to the Bank a
         ------
Borrowing Request or Interest Election Request for such Borrowing in accordance
with Section 2.03 or 2.05, as the case may be.

     (b) Representations and Warranties.  Each of the representations and
         ------------------------------
warranties made by the Borrower herein and in each other Loan Document shall be
true and correct in all material respects on and as of such date as if made on
and as of such date, both before and after giving effect to the making,
conversion or continuation of Loans requested to be made, converted or continued
on such date.

                                       27
<PAGE>

     (c) No Defaults.  No Default or Event of Default shall have occurred and be
         -----------
continuing on such date or after giving effect to the making, conversion or
continuation of Loans requested to be made, converted or continued on such date.

     (d) No Violations of Law, etc.  Neither the making, conversion nor
         -------------------------
continuation nor use of the Loans shall cause Bank to violate or be in conflict
with any Law.

     (e) No Material Adverse Change.  There shall not have occurred, or be
         --------------------------
threatened, any other event, act or condition which would reasonably be expected
to have a Material  Adverse Effect.

     Each request by the Borrower for any Loan or conversion or continuation
thereof shall constitute a representation and warranty by the Borrower that the
conditions set forth in this Section 4.02 have been satisfied as of the date of
such request.  Failure of the Bank to receive notice from the Borrower to the
contrary before such Loan is made shall constitute a further representation and
warranty by the Borrower that the conditions referred to in this Section 4.02
have been satisfied as of the date such Loan is made.

                                   ARTICLE V
                             AFFIRMATIVE COVENANTS

     The Borrower hereby covenants to the Bank:

     SECTION 5.01  BASIC REPORTING REQUIREMENTS.
                   ----------------------------

     (a) Annual Audit Reports.  As soon as practicable, and in any event within
         --------------------
90 days after the close of each fiscal year of the Borrower, the Borrower shall
furnish to the Bank, consolidated statements of income, retained earnings and
cash flows of the Borrower and its consolidated Subsidiaries for such fiscal
year and a consolidated balance sheet of the Borrower and its consolidated
Subsidiaries as of the close of such fiscal year, and notes to each, all in
reasonable detail, setting forth in comparative form the corresponding figures
for the preceding fiscal year.  Such financial statements shall be accompanied
by an opinion of independent certified public accountants of recognized national
standing selected by the Borrower, which opinion shall not be subject to any
qualification as to scope of audit or as to any other matter which the Bank
determines is adverse.  Such opinion in any event shall contain a written
statement of such accountants substantially to the effect that (i) such
accountants examined such financial statements in accordance with generally
accepted auditing standards and accordingly made such tests of accounting
records and such other auditing procedures as such accountants considered
necessary in the circumstances and (ii) in the opinion of such accountants such
financial statements present fairly the financial position of the Borrower and
its consolidated Subsidiaries as of the end of such fiscal year and the results
of their operations and their retained earnings and cash flows for such fiscal
year, in conformity with GAAP.

     (b) Quarterly Consolidated Reports.  As soon as practicable, and in any
         ------------------------------
event within 45 days after the close of each of the first three fiscal quarters
of each fiscal year of the Borrower, the Borrower shall furnish to the Bank,
unaudited consolidated statements of income, retained earnings and cash flows of
the Borrower and its consolidated Subsidiaries for the period from the beginning
of such fiscal year to the end of such fiscal quarter and an unaudited
consolidated balance sheet of the Borrower and its consolidated Subsidiaries as
of the close of such fiscal quarter, and notes to each, all in reasonable
detail, setting forth in comparative form the corresponding figures for the same
periods or as of the same date during the preceding fiscal year (except for the
consolidated balance sheet, which shall set forth in

                                       28
<PAGE>

comparative form the corresponding balance sheet as of the prior fiscal year
end). Such financial statements shall be certified by a Responsible Officer of
the Borrower as presenting fairly the financial position of the Borrower and its
consolidated Subsidiaries as of the end of such fiscal quarter and the results
of their operations and their retained earnings and changes in cash flows for
such fiscal year, in conformity with GAAP, subject to normal and recurring year-
end audit adjustments.

     (c) Quarterly Compliance Certificates.  The Borrower shall deliver to the
         ---------------------------------
Bank, a quarterly compliance certificate in form and detail acceptable to Bank,
duly completed and signed by a Responsible Officer of the Borrower concurrently
with the delivery of the financial statements referred to in subsections (a) and
(b) of this Section 5.01.

     (d) Certain Other Reports and Information.  Promptly upon their becoming
         -------------------------------------
available to the Borrower, the Borrower shall deliver to the Bank, a copy of (i)
all regular or special reports, registration statements and amendments to the
foregoing which the Borrower or any Subsidiary of the Borrower shall file with
the Securities and Exchange Commission (or any successor thereto) or any
securities exchange, and (ii) all reports, proxy statements, financial
statements and other information distributed by the Borrower to its
stockbrokers, bondholders or the financial community generally.

     (e) Further Information.  The Borrower shall promptly furnish to the Bank,
         -------------------
such other information and in such form as the Bank or Bank may reasonably
request from time to time.

     (f) Notice of Certain Events.  Promptly (and, in the case of clause (i)
         ------------------------
below, no later than two Business Days) upon becoming aware of any of the
following, the Borrower shall give the Bank notice thereof, together with a
written statement of a Responsible Officer of the Borrower setting forth the
details thereof and any action with respect thereto taken or proposed to be
taken by the Borrower:

         (i)  Any Default or Event of Default.

         (ii) The occurrence or existence of any event or condition (including
     (A) the violation or alleged violation of any Environmental Law by the
     Borrower or any Subsidiary of the Borrower or the assertion of any
     Environmental Claim against the Borrower or any Subsidiary of the Borrower,
     (B) the commencement of any other action, suit, proceeding or investigation
     by or before any Governmental Authority against or affecting the Borrower
     or any Subsidiary of the Borrower, or (C) the violation, breach or default
     or alleged violation, breach or default by the Borrower or any Subsidiary
     of the Borrower or any other Person under any agreement or instrument
     material to the business, operations, condition (financial or otherwise) or
     prospects of the Borrower and its Subsidiaries taken as a whole) which
     event or condition, either individually or in the aggregate, has, or would
     reasonably be expected to have, a Material Adverse Effect.

         (iii) Any change in the Index Debt rating.

     (g) Visitation; Verification.  The Borrower shall permit such Persons as
         ------------------------
the Bank or Bank may designate from time to time to visit and inspect any of the
properties of the Borrower and of any Subsidiary, to examine their respective
books and records and take copies and extracts therefrom and to discuss their
respective affairs with their respective officers, employees and independent
accountants at such times and as often as the Bank or Bank may reasonably
request; provided, however, that the Borrower reserves the right to restrict
         --------
access to any of its generating facilities in accordance with reasonably adopted
practices relating to safety and security.  The Borrower hereby authorizes such

                                       29
<PAGE>

officers, employees and independent accountants to discuss with the Bank or Bank
the affairs of the Borrower and its Subsidiaries.

     (h) ERISA.  Within 30 days after the Borrower knows that any of the events
         -----
or conditions specified below with respect to any Plan or Multiemployer Plan has
occurred or exists, a statement signed by a Responsible Officer of the Borrower
setting forth details respecting such event or condition and the action, if any,
that the Borrower or its ERISA Affiliate proposes to take with respect thereto
(and a copy of any report or notice required to be filed with or given to PBGC
by the Borrower or an ERISA Affiliate with respect to such event or condition):

         (i)   any Reportable Event and any request for a waiver under Section
     412(d) of the Code for any Plan;

         (ii)  the distribution under Section 4041 of ERISA of a notice of
     intent to terminate any Plan or any action taken by the Borrower or an
     ERISA Affiliate to terminate any Plan, in each case with respect to which
     there are insufficient assets to pay benefits as they become due;

         (iii) the institution by PBGC of proceedings under Section 4042 of
     ERISA for the termination of, or the appointment of a trustee to
     administer, any Plan, or the receipt by the Borrower or any ERISA Affiliate
     of a notice from a Multiemployer Plan that such action has been taken by
     PBGC with respect to such Multiemployer Plan;

         (iv)  the complete or partial withdrawal from a Multiemployer Plan by
     the Borrower or any ERISA Affiliate that results in liability under Section
     4201 or 4204 of ERISA (including the obligation to satisfy secondary
     liability as a result of a purchaser default) or the receipt by the
     Borrower or any ERISA Affiliate of notice from a Multiemployer Plan that it
     is in reorganization or insolvency pursuant to Section 4241 or 4245 of
     ERISA or that it intends to terminate or has terminated under Section 4041A
     of ERISA; and

         (v)   the adoption of an amendment to any Plan that, pursuant to
     Section 401(a)(29) of the Code or Section 307 of ERISA, would result in the
     loss of tax-exempt status of the trust of which such Plan is a part if the
     Borrower or an ERISA Affiliate fails to timely provide security to the Plan
     in accordance with the provisions of said Sections.

     (i) Satisfaction of Certain Reporting Requirements.   Notwithstanding any
         ----------------------------------------------
other provision of this Section 5.01, the Borrower shall be deemed to have
satisfied its obligations pursuant to Sections 5.01(a) and (b) if and to the
extent that it shall have provided to the Bank, pursuant to Section 5.01(d),
copies of its periodic reports (on Form 10-K or 10-Q, as the case may be) as
required to be filed with the Securities and Exchange Commission (or any
successor thereto) pursuant to the Securities and Exchange Act of 1934, as
amended (or any successor statute of similar import), for the annual and
quarterly periods described in such Sections.

     SECTION 5.02  INSURANCE.
                   ---------

     The Borrower shall, and shall cause each of its Subsidiaries to, maintain
with financially sound and reputable insurers insurance with respect to its
properties and business and against such liabilities, casualties and
contingencies and of such types and in such amounts as is customary in the case
of corporations engaged in the same or similar businesses or having similar
properties similarly situated and as is satisfactory from time to time to the
Bank in its reasonable discretion.

                                       30
<PAGE>

     SECTION 5.03  PAYMENT OF TAXES AND OTHER POTENTIAL CHARGES AND PRIORITY
                   ---------------------------------------------------------
CLAIMS.
------

     The Borrower shall, and shall cause each of its Subsidiaries to, pay or
discharge

     (a) on or prior to the date on which penalties or Liens attach thereto, all
Taxes imposed upon it or any of its properties;

     (b) on or prior to the date when due, all lawful claims of materialmen,
mechanics, carriers, warehousemen, landlords and other like Persons which, if
unpaid, might result in the creation of a Lien upon any such Property; and

     (c) on or prior to the date when due, all other lawful claims which, if
unpaid, might result in the creation of a Lien upon any such Property or which,
if unpaid, might give rise to a claim entitled to priority over general
creditors of the Borrower or such Subsidiary in a case under the Bankruptcy
Code;

provided, that, unless and until foreclosure, distraint, levy, sale or similar
--------
proceedings shall have been commenced, the Borrower or such Subsidiary need not
pay or discharge any such Tax, assessment, charge or claim so long as (x) the
validity thereof is contested in good faith and by appropriate proceedings
diligently conducted, and (y) such reserves or other appropriate provisions as
may be required by GAAP shall have been made therefor.

     SECTION 5.04  PRESERVATION OF CORPORATE STATUS AND FRANCHISES.
                   -----------------------------------------------

     The Borrower shall, and shall cause each of its Significant Subsidiaries
to, maintain its status as a corporation, trust or limited liability company
duly organized, validly existing and in good standing under the Laws of its
jurisdiction of organization, and to be duly qualified to do business as a
foreign corporation, trust or limited liability company and in good standing in
all jurisdictions in which the ownership of its properties or the nature of its
business or both make such qualification necessary or advisable; provided,
                                                                 --------
however, that nothing in this Section 5.04 shall prevent the withdrawal by the
-------
Borrower or any of its Subsidiaries of its qualification as a foreign
corporation in any jurisdiction where such withdrawal could not have a Material
Adverse Effect .  The Borrower shall, and shall cause each of its Subsidiaries
to, do or cause to be done, all things necessary to preserve and keep in full
force and effect its material rights, franchises, licenses and patents.

     SECTION 5.05  GOVERNMENTAL APPROVALS AND FILINGS.
                   ----------------------------------

     The Borrower shall keep and maintain in full force and effect all
Governmental Actions necessary or advisable in connection with execution and
delivery of any Loan Document, consummation of the transactions herein or
therein contemplated, performance of or compliance with the terms and conditions
hereof or thereof or to ensure the legality, validity, binding effect or
enforceability hereof or thereof.

     SECTION 5.06  MAINTENANCE OF PROPERTIES.
                   -------------------------

     The Borrower shall, and shall cause each of its Subsidiaries to, maintain
or cause to be maintained in good repair, working order and condition the
properties now or hereafter owned, leased or otherwise possessed by it and shall
make or cause to be made all needful and proper repairs, renewals, replacements
and improvements thereto so that the business carried on in connection therewith
may be properly and advantageously conducted at all times.

                                       31
<PAGE>

     SECTION 5.07  AVOIDANCE OF OTHER CONFLICTS.
                   ----------------------------

     The Borrower shall not, and shall not permit any of its Subsidiaries to,
violate or conflict with, be in violation of or in conflict with, or be or
remain subject to any liability (contingent or otherwise) on account of any
violation or conflict with

     (a)  any Law;

     (b)  its articles of incorporation or by-laws; or

     (c)  any agreement or instrument to which it is party or by which any of
them or any of their respective Significant Subsidiaries is a party or by which
any of them or any of their respective properties (now owned or hereafter
acquired) may be subject or bound, except for matters which would not reasonably
be expected, either individually or in the aggregate, to have a Material Adverse
Effect.

     SECTION 5.08  FINANCIAL ACCOUNTING PRACTICES.
                   ------------------------------

     The Borrower shall, and shall cause each of its Significant Subsidiaries
to, make and keep books, records and accounts which, in reasonable detail,
accurately and fairly reflect its transactions and dispositions of its assets
and maintain a system of internal accounting controls sufficient to provide
reasonable assurances that (a) transactions are executed in accordance with
management's general or specific authorization, (b) transactions are recorded as
necessary (i) to permit preparation of financial statements in conformity with
GAAP and (ii) to maintain accountability for assets, (c) access to assets is
permitted only in accordance with management's general or specific authorization
and (d) the recorded accountability for assets is compared with the existing
assets at reasonable intervals and appropriate action is taken with respect to
any differences.

     SECTION 5.09  USE OF PROCEEDS.
                   ---------------

     The Borrower shall apply the proceeds of all Loans hereunder only for
working capital and general corporate purposes of the Borrower, including
commercial paper backup.  The Borrower shall not use the proceeds of any Loans
hereunder directly or indirectly for any unlawful purpose, in any manner
inconsistent with Section 3.11, or inconsistent with any other provision of any
Loan Document.

     SECTION 5.10  END OF FISCAL PERIODS.
                   ---------------------

     The Borrower shall cause (a) each of its, and each of its Subsidiary's,
fiscal years to end on December 31 and (b) each of its, and each of its
Subsidiary's, fiscal quarters to end on March 31, June 30, September 30 and
December 31.

                                   ARTICLE VI
                               NEGATIVE COVENANTS

     The Borrower hereby covenants to the Bank as follows:

     SECTION 6.01  FINANCIAL CONDITION AND DEBT RATING.  At all times during the
                   -----------------------------------
term of this Agreement, the Borrower's public unsecured debt shall be rated by
each of Moody's and S&P at not less than the minimum rating considered by each
such rating agency as "investment grade"; provided,

                                       32
<PAGE>

however, that if such debt rating from either Moody's or S&P shall be reduced to
a rating considered by such rating agency to be below "investment grade", such
downgrade shall not constitute an Event of Default under this Agreement unless
and until such time as the rating has remained below "investment grade" for more
than 15 days from the date of such downgrade.

     SECTION 6.02  LIENS.
                   -----

     The Borrower shall not, and shall not permit any of its Subsidiaries to, at
any time create, incur, assume or suffer to exist any Lien on any of its
Property (now owned or hereafter acquired), or agree, become or remain liable
(contingently or otherwise) to do any of the foregoing, except for the following
("Permitted Liens"):
  ---------------

     (a) Liens existing on the date hereof and securing obligations existing on
the date hereof, other than Indebtedness to be refinanced;

     (b) Liens securing obligations of NPC issued under and pursuant to the
terms and conditions of the NPC First Mortgage Indenture;

     (c) Liens securing obligations of SPPC issued under and pursuant to the
terms and conditions of the SPPC First Mortgage Indenture;

     (d) Liens on NPC First Mortgage Bonds issued as collateral for pollution
control revenue bonds issued for the benefit of NPC or its Subsidiaries (and
related rights and interests) to secure obligations of NPC or such Subsidiaries
for the benefit of the holders of such bonds, provided that such bonds are not
secured by any other assets or Properties of NPC or its Subsidiaries;

     (e) Liens on SPPC First Mortgage Bonds issued as collateral for pollution
control or gas or water facility revenue bonds issued for the benefit of SPPC or
its Subsidiaries (and related rights and interests) to secure obligations of
SPPC or such Subsidiaries for the benefit of the holders of such bonds, provided
that such bonds are not secured by any other assets or Properties of SPPC or its
Subsidiaries;

     (f) Liens on SPPC First Mortgage Bonds issued as collateral for medium-term
notes issued pursuant to the Collateral Trust Indenture, dated as of June 1,
1992, between SPPC and Bankers Trust Company, as Trustee;

     (g) Liens securing obligations of NPC issued under and pursuant to the
terms and conditions of the NPC General and Refunding Mortgage Indenture;

     (h) Liens securing obligations of SPPC issued under and pursuant to the
terms and conditions of the SPPC General and Refunding Mortgage Indenture;

     (i) Liens on "transition property" arising pursuant to Section 843 of the
California Public Utility Code for the benefit of holders of rate reduction
bonds issued pursuant to a valid financing order of the California Public
Utilities Commission;

     (j) Liens arising from taxes, assessments, charges or claims described in
Section 5.03 that are not yet due or that remain payable without penalty or to
the extent permitted to remain unpaid under the proviso to such Section 5.03;

                                       33
<PAGE>

     (k)  Deposits or pledges of cash or securities in the ordinary course of
business to secure (i) worker's compensation, unemployment insurance or other
social security obligations, (ii) performance of bids, tenders, trade contracts
(other than for payment of money) or leases, (iii) stay, surety or appeal bonds,
or (iv) other obligations of a like nature incurred in the ordinary course of
business;

     (l)  Zoning restrictions, easements, minor restrictions on the use of real
Property, minor irregularities in title thereto and other minor Liens that do
not secure the payment of money or the performance of an obligation and that do
not in the aggregate materially detract from the value of an asset to, or
materially impair its use in the business of, the Borrower or such Subsidiary;
and

     (m)  Liens on Property securing all or part of the purchase price thereof
and Liens (whether or not assumed) existing in Property at the time of purchase
thereof, provided that: (i) such Lien is created before or substantially
simultaneously with the purchase of such Property by the Borrower or such
Subsidiary, (ii) such Lien is confined solely to the Property so purchased,
improvements thereto and proceeds thereof, (iii) the aggregate amount secured by
such Liens on any particular Property at the time purchased by the Borrower or
such Subsidiary, as the case may be, shall not exceed the lesser of the purchase
price of such Property and the fair market value of such Property at the time of
purchase thereof by the Borrower or such Subsidiary, and (iv) the aggregate
amount secured by all Liens described in this Section 6.02(k) shall not at any
time exceed $150,000,000.

     "Permitted Liens" shall in no event include any Lien imposed by, or
required to be granted pursuant to, ERISA or any Environmental Law.

     SECTION 6.03  MERGERS.
                   -------

     The Borrower shall not, and shall not permit any of its Subsidiaries to,
(a) merge with or into or consolidate with any other Person, (b) liquidate,
wind-up, dissolve or divide, or (c) agree, become or remain liable (contingently
or otherwise) to do any of the foregoing, except:

     (i)  A Person may merge with or into or consolidate with any Subsidiary of
the Borrower, provided that (x) the surviving Person shall be a Subsidiary of
the Borrower, (y) no Default or Event of Default shall have occurred and be
continuing or shall exist at such time or after giving effect to such
transaction and (z) the Borrower shall deliver to the Bank (A) a certificate, in
a form reasonably satisfactory to the Bank, certifying that no Default or Event
of Default exists or will result from such merger and (B) pro forma financial
statements in support of such certification; and

     (ii) A Person may merge with or into or consolidate with the Borrower,
provided that (x) the Borrower shall be the surviving Person, (y) no Default or
Event of Default shall have occurred and be continuing or shall exist at such
time or after giving effect to such transaction and (z) the Borrower shall
deliver to the Bank (A) a certificate, in a form reasonably satisfactory to the
Bank, certifying that no Default or Event of Default exists or will result from
such merger and (B) pro forma financial statements in support of such
certification.

     SECTION 6.04  DISPOSITIONS OF PROPERTIES.
                   --------------------------

     The Borrower shall not, and shall not permit any of its Subsidiaries to,
sell, convey, assign, lease, sale-leaseback, transfer, abandon or otherwise
dispose of, voluntarily or involuntarily (collectively, "Dispose"), any of its
Properties, or agree, become or remain liable contingently or otherwise to do
any of the foregoing, except that, so long as no Default or Event of Default
shall have occurred and be continuing or shall exist at such time or after
giving effect to such transaction, the Borrower and its

                                       34
<PAGE>

Subsidiaries may Dispose of Property (a) in transactions in the ordinary course
of business, (b) that is obsolete, (c) comprising accounts receivable
transferred by NPC or SPPC to one or more commercial paper conduits, special
purpose subsidiaries or similar entities; provided that (i) the aggregate face
amount of such accounts receivable, when added to the aggregate face amount of
all other accounts receivable Disposed of in reliance on this clause (c), does
not exceed $250,000,000 and (ii) the net cash proceeds from the Disposition of
such accounts receivable, (A) when added to the net cash proceeds of all other
Dispositions of accounts receivable by such entity made in reliance on this
clause (c), are not less than 80% of the aggregate face amount of all accounts
receivable Disposed of by such entity in reliance on this clause (c) and (B) at
the time of such Disposition, do not exceed the sum of (I) the balance of NPC's
and SPPC's aggregate deferred energy accrual accounts at such time and (II)
NPC's and SPPC's aggregate deferred energy costs actually incurred but not yet
reflected in NPC's and SPPC's respective deferred energy accrual accounts, in
each case as set forth in NPC's and SPPC's books and records; provided, further,
that each Disposition made by NPC or SPPC in reliance on this clause (c) shall
constitute a representation and warranty of the Borrower, made at the time of
such Disposition, that the conditions set forth in clauses (i) and (ii) above
are satisfied at such time; and (d) in transactions other than as provided in
Section 6.04 (a), (b), (c), and (d) provided that the aggregate book value of
all Property Disposed of pursuant to this Section 6.04 (e) from and after the
date hereof shall not exceed $120,000,000.

     SECTION 6.05  INVESTMENTS AND ACQUISITIONS.
                   ----------------------------

     Prior to the making of any Investment or the consummation of any
Acquisition by the Borrower or any of its Subsidiaries, the amount or purchase
price of which, as the case may be, when aggregated with the amounts and
purchase prices of other Investments and Acquisitions made by the Borrower and
its Subsidiaries, would exceed $70,000,000 in the aggregate at any time, the
Borrower shall deliver to the Bank (i) a certificate, in a form reasonably
satisfactory to the Bank, certifying that no Default or Event of Default exists
or will result from such Acquisition and (ii) pro forma financial statements in
support of such certification.

     SECTION 6.06  DIVIDENDS AND STOCK REPURCHASES.
                   -------------------------------

     The Borrower shall not declare or pay any dividend on its capital stock
(except for dividends in the form of capital stock), or redeem or repurchase any
of its capital stock, if a Default or Event of Default shall have occurred and
be continuing or shall exist at such time or after giving effect to such
transaction.

     SECTION 6.07  TRANSACTIONS WITH AFFILIATES.
                   ----------------------------

     The Borrower shall not enter into any transaction of any kind with any
Person that Controls the Borrower or is controlled by the Borrower or is under
common control with the Borrower other than (a) salary, bonus, employee stock
option and other compensation arrangements with directors or officers in the
ordinary course of business, (b) transactions that are fully disclosed to the
board of directors (or executive committee thereof) of the Borrower and
expressly authorized by a resolution of the board of directors (or executive
committee) of the Borrower which is approved by a majority of the directors (or
executive committee) not having an interest in the transaction, (c) transactions
between or among the Borrower and its Wholly-Owned Subsidiaries, and (d)
transactions on overall terms at least as favorable to the Borrower as

                                       35
<PAGE>

would be the case in an arm's-length transaction between unrelated parties of
equal bargaining power.

     SECTION 6.08  EQUAL AND RATABLE LIEN.
                   ----------------------

     If, notwithstanding the prohibition contained in Section 6.02, the Borrower
or any of its Subsidiaries shall create, assume or permit to exist any Lien upon
any of its Property, other than those permitted by the provisions of Section
6.02, it will make or cause to be made effective provision whereby the
Borrowings will be secured equally and ratably with any and all other
obligations thereby secured, such security to be pursuant to agreements
reasonably satisfactory to the Bank and, in any such case, the Borrowings shall
have the benefit, to the fullest extent that, and with such priority as, the
Bank may be entitled under applicable law, of an equitable Lien on such
Property.  Such violation of Section 6.02 will constitute an Event of Default,
whether or not provision is made for an equal and ratable Lien pursuant to this
Section.

     SECTION 6.09  RESTRICTIVE AGREEMENTS.
                   ----------------------

     Except as otherwise permitted under Article VI hereunder, and except for
agreements referenced in or permitted by or covenants contained within Article
VI of the SPPC Credit Agreement and Article VI of the NPC Credit Agreement, the
Borrower will not, and will not permit any of its Subsidiaries to, directly or
indirectly, enter into, incur or permit to exist any agreement or other
instrument that creates, incurs or permits to exist any Lien upon any of its
Property or assets, or (b) prohibits, restricts or imposes any conditions upon
the ability of any Subsidiary to pay dividends or other distributions with
respect to any shares of its capital stock or to make or repay loans or advances
to the Borrower or any other Subsidiary or to guarantee Indebtedness of the
Borrower or any other Subsidiary.

                                  ARTICLE VII
                                   DEFAULTS

     SECTION 7.01  EVENTS OF DEFAULT.
                   -----------------

     An "Event of Default" shall mean the occurrence or existence of one or more
         ----------------
of the following events or conditions (for any reason, whether voluntary,
involuntary or effected or required by Law):

     (a) The Borrower shall fail to pay when due principal of any Loan.

     (b) The Borrower shall fail to pay when due interest on any Loan, any fees,
indemnity or expenses, or any other amount due hereunder or under any other Loan
Document and such failure shall have continued for a period of three (3)
Business Days.

     (c) Any representation or warranty made or deemed made by the Borrower in
or pursuant to or in connection with any Loan Document, or any statement made by
the Borrower in any financial statement, certificate, report, exhibit or
document furnished by the Borrower to the Bank pursuant to or in connection with
any Loan Document, shall prove to have been false or misleading in any material
respect as of the time when made or deemed made (including by omission of
material information necessary to make such representation, warranty or
statement not misleading).

                                       36
<PAGE>

     (d) The Borrower shall default in the performance or observance of any
covenant contained in Article VI or any of the covenants contained in Sections
5.01(f)(i) or 5.09 or 5.10.

     (e) The Borrower shall default in the performance or observance of any
other covenant, agreement or duty under this Agreement or any other Loan
Document and (i) in the case of a default under Section 5.01 (other than as
referred to in subsection (f)(i) thereof) such default shall have continued for
a period of ten Business Days and (ii) in the case of any other default such
default shall have continued for a period of 30 days after notice from the Bank
to the Borrower.

     (f) The Borrower or any Subsidiary of the Borrower shall (i) fail to make
any payment (x) on account of any Indebtedness under the NPC Credit Agreement or
the SPPC Credit Agreement, (y) on account of any Indebtedness aggregating
$10,000,000 or more in principal amount or (z) aggregating $10,000,000 or more
on any Indebtedness, or any interest or premium thereon, in each case, when due
(whether by scheduled maturity, required prepayment, acceleration, demand or
otherwise), and, in each case, such failure shall have continued beyond any
applicable grace period specified in any agreement or instrument relating to
such Indebtedness, or (ii) fail to perform or observe any other term, covenant
or condition on its part to be performed or observed under any agreement or
instrument relating to any Indebtedness when required to be performed or
observed, and such failure shall have continued beyond any applicable grace
period specified in any agreement or instrument relating to such Indebtedness,
if the effect of such failure to perform or observe is to accelerate, or to
permit the acceleration of, the maturity of such Indebtedness, the unpaid
principal amount of which then aggregates $10,000,000.

     (g) One or more final judgments or orders for the payment of money shall
have been entered against the Borrower or any Subsidiary of the Borrower, which
judgments or orders exceed $10,000,000 in the aggregate, and such judgments or
orders shall have remained undischarged and unstayed for a period of thirty
consecutive days.

     (h) One or more writs or warrants of attachment, garnishment, execution,
distraint or similar process exceeding in value the aggregate amount of
$10,000,000 shall have been issued against the Borrower or any Subsidiary of the
Borrower or any of their respective properties and shall have remained
undischarged and unstayed for a period of thirty consecutive days.

     (i) Any Governmental Action now or hereafter made by or with any
Governmental Authority in connection with any Loan Document is not obtained or
shall have ceased to be in full force and effect or shall have been modified or
amended or shall have been held to be illegal or invalid, and the Bank shall
have determined (which determination shall be conclusive provided it is reached
in good faith) that the consequence of any of the foregoing events would
reasonably be expected to have, individually or in the aggregate, a Material
Adverse Effect.

     (j) Any Loan Document or any material term or provision thereof shall have
ceased to be in full force and effect, or the Borrower or any Governmental
Authority with jurisdiction over the Borrower shall, or shall purport to,
terminate, repudiate, declare voidable or void or otherwise contest, any Loan
Document or any material term or provision thereof or any obligation or
liability of the Borrower thereunder.

     (k) An event or condition specified in Section 5.01(h) hereof shall occur
or exist with respect to any Plan or Multiemployer Plan or any Lien arises
pursuant to ERISA and, as a result of such event or condition or Liens, together
with all other such events or conditions or Liens, the Borrower or any ERISA
Affiliate shall incur or shall be reasonably likely to incur a liability to a
Plan, a

                                       37
<PAGE>

Multiemployer Plan or PBGC or suffer an encumbrance to exist in favor of any
thereof (or any combination of the foregoing) which would constitute a Material
Adverse Effect.

     (l) The Borrower or any Subsidiary of the Borrower shall have violated any
Environmental Law or become subject to any Environmental Claim and, in either
case, the Bank shall have determined (which determination shall be conclusive
provided it is reached in good faith) that such event would reasonably be
expected, either individually or in the aggregate, to have a Material Adverse
Effect.

     (m) A proceeding shall have been instituted in respect of the Borrower or
any Subsidiary of the Borrower:

         (i)  seeking to have an order for relief entered in respect of such
     Person, or seeking a declaration or entailing a finding that such Person is
     insolvent or a similar declaration or finding, or seeking dissolution,
     winding-up, charter revocation or forfeiture, liquidation, reorganization,
     arrangement, adjustment, composition or other similar relief with respect
     to such Person, its assets or its debts under any Law relating to
     bankruptcy, insolvency, relief of debtors or protection of creditors,
     termination of legal entities or any other similar Law now or hereafter in
     effect, or

         (ii) seeking appointment of a receiver, trustee, liquidator, assignee,
     sequestrator or other custodian for such Person or for all or any
     substantial part of its Property, and such proceeding shall result in the
     entry, making or grant of any such order for relief, declaration, finding,
     relief or appointment, or such proceeding shall remain undismissed and
     unstayed for a period of thirty consecutive days.

     (n) The Borrower or any Subsidiary of the Borrower shall become insolvent;
shall fail to pay, become unable to pay, or state that it is or will be unable
to pay, its debts as they become due; shall voluntarily suspend transaction of
its business; shall make a general assignment for the benefit of creditors;
shall institute (or fail to controvert in a timely and appropriate manner) a
proceeding described in Section 7.01(m)(i), or (whether or not any such
proceeding has been instituted) shall consent to or acquiesce in any such order
for relief, declaration, finding or relief described therein; shall institute
(or fail to controvert in a timely and appropriate manner) a proceeding
described in Section 7.01(m)(ii), or (whether or not any such proceeding has
been instituted) shall consent to or acquiesce in any such appointment or to the
taking of possession by any such custodian of all or any substantial part of its
Property; shall dissolve, wind-up, revoke or forfeit its charter (or other
constituent documents) or liquidate itself or any substantial part of its
Property; or shall take any action in furtherance of any of the foregoing.

     (o) A Change in Control shall occur.

     (p) NPC or SPPC shall cease to maintain a first mortgage bond rating of at
least Baa3 by Moody's and BBB- by S&P.

     (q) The Borrower shall fail to maintain ongoing utility segment-
identifiable assets (exclusive of cash and marketable securities) and operating
income relating to the generation or transmission and/or distribution of
electricity or gas in a proportion not less than 80% of total assets (exclusive
of cash and marketable securities) and operating income.

     SECTION 7.02  CONSEQUENCES OF AN EVENT OF DEFAULT.
                   -----------------------------------

                                       38
<PAGE>

     (a)      If an Event of Default specified in subsections (a) through (l),
(o), (p) or (q) of Section 7.01 shall occur and, be continuing or shall exist,
then, in addition to all other rights and remedies which the Bank may have
hereunder or under any other Loan Document, at law, in equity or otherwise, Bank
shall be under no further obligation to make Loans hereunder, and the Bank may,
, by notice to the Borrower, from time to time do any or all of the following:

              (i)  Declare the Commitment terminated, whereupon the Commitment
     will terminate and any fees hereunder shall be immediately due and payable
     without presentment, demand, protest or further notice of any kind, all of
     which are hereby waived, and an action therefor shall immediately accrue.

              (ii) Declare the unpaid principal amount of the Loans, interest
     accrued thereon and all other obligations to be immediately due and payable
     without presentment, demand, protest or further notice of any kind, all of
     which are hereby waived, and an action therefor shall immediately accrue.

     (b)      If an Event of Default specified in subsection (m) or (n) of
Section 7.01 shall occur or exist, then, in addition to all other rights and
remedies which the Bank may have hereunder or under any other Loan Document, at
law, in equity or otherwise, the Commitment shall automatically terminate and
the Bank shall be under no further obligation to make Loans, and the unpaid
principal amount of the Loans, interest accrued thereon and all other
obligations shall become immediately due and payable without presentment,
demand, protest or notice of any kind, all of which are hereby waived, and an
action therefor shall immediately accrue.

                                 ARTICLE VIII
                                 MISCELLANEOUS

     SECTION 8.01  AMENDMENTS AND WAIVERS.
                   ----------------------

     Neither this Agreement nor any other Loan Document may be amended, modified
or supplemented except in accordance with the provisions of this Section 8.01.
The Bank and the Borrower may from time to time amend, modify or supplement the
provisions of this Agreement or any other Loan Document for the purpose of
amending, adding to or waiving any provision, or changing in any manner the
rights and duties of the Borrower, or Bank.  Any such amendment, modification or
supplement made by the Borrower and the Bank in accordance with the provisions
of this Section 8.01 shall be binding upon the Borrower and the Bank

     SECTION 8.02  NO IMPLIED WAIVER; CUMULATIVE REMEDIES.
                   --------------------------------------

     No course of dealing and no delay or failure of the Bank in exercising any
right, power or privilege under this Agreement or any other Loan Document shall
affect any other or future exercise thereof or the exercise of any other right,
power or privilege; nor shall any single or partial exercise of any such right,
power or privilege or any abandonment or discontinuance of steps to enforce such
a right, power or privilege preclude any further exercise thereof or of any
other right, power or privilege.  The rights and remedies of the Bank under this
Agreement and any other Loan Document are cumulative and not exclusive of any
rights or remedies which the Bank would otherwise have hereunder or thereunder,
at law, in equity or otherwise.

     SECTION 8.03  NOTICES.
                   -------

                                       39
<PAGE>

     (a)  Except to the extent otherwise expressly permitted hereunder or
thereunder, all notices, requests, demands, directions and other communications
(collectively "notices") under this Agreement or any other Loan Document shall
be in writing (including telecopied communication) and shall be sent by first-
class mail, or by nationally-recognized overnight courier, or by telecopier
(with confirmation in writing mailed first-class or sent by such an overnight
courier), or by personal delivery. All notices shall be sent to the applicable
party at the address stated on the signature pages hereof or in accordance with
the last unrevoked written direction from such party to the other parties hereto
in all cases with postage or other charges prepaid. Any such properly given
notice shall be effective on the earliest to occur of receipt, telephone
confirmation of receipt of telecopy communication, one Business Day after
delivery to a nationally-recognized overnight courier, or three Business Days
after deposit in the mail.

     (b)  A copy of any notice to the Borrower or any other party to a Loan
Document shall simultaneously be sent to Bank.

     (c)  The Bank may rely on any notice (whether or not such notice is made in
a manner permitted or required by this Agreement or any other Loan Document)
purportedly made by or on behalf of the Borrower, and the Bank shall not have
any duty to verify the identity or authority of any Person giving such notice.

     SECTION 8.04   EXPENSES; TAXES; INDEMNITY.
                    --------------------------

     (a)  The Borrower agrees to pay or cause to be paid and to save the Bank
harmless against liability for the payment of all reasonable out-of-pocket costs
and expenses (including but not limited to reasonable fees and expenses of
counsel) incurred by the Bank from time to time arising from or relating to (i)
in the case of the Bank, the negotiation, syndication, preparation, execution,
delivery, administration and performance of this Agreement and the other Loan
Documents, (ii)  in the case of the Bank, any amendments, modifications,
supplements, waivers or consents to this Agreement or any other Loan Document
(whether or not ultimately entered into or granted), and (iii) in the case of
the Bank, the enforcement or preservation of rights under this Agreement or any
other Loan Document (including but not limited to any such costs or expenses
arising from or relating to (A) collection or enforcement of an outstanding Loan
or any other amount owing hereunder or thereunder by the Bank, and (B) any
litigation, proceeding, dispute, work-out, restructuring or rescheduling related
in any way to this Agreement or the Loan Documents).

     (b)  The Borrower hereby agrees to pay all stamp, document, transfer,
recording, filing, registration, search, sales and excise fees and taxes and all
similar impositions now or hereafter determined by the Bank to be payable in
connection with this Agreement or any other Loan Documents or any other
documents, instruments or transactions pursuant to or in connection herewith or
therewith (which determination shall be conclusive provided it is reached in
good faith), and the Borrower agrees to save the Bank harmless from and against
any and all present or future claims, liabilities or losses with respect to or
resulting from any omission to pay or delay in paying any such fees, taxes or
impositions.

     (c)  The Borrower hereby agrees to reimburse and indemnify each of the
Indemnified Parties from and against any and all losses, liabilities, claims,
damages, expenses, obligations, penalties, actions, judgments, suits, costs or
disbursements of any kind or nature whatsoever (including, without limitation,
the reasonable fees and disbursements of counsel for such Indemnified Party in
connection with any investigative, administrative or judicial proceeding
commenced or threatened, whether or not such Indemnified Party shall be
designated a party thereto) that may at any time be imposed on, asserted against
or incurred by such Indemnified Party as a result of, or arising out of, or in
any way related to or

                                       40
<PAGE>

by reason of, this Agreement or any other Loan Document, any transaction from
time to time contemplated hereby or thereby, or any transaction financed in
whole or in part or directly or indirectly with the proceeds of any Loan (and
without in any way limiting the generality of the foregoing, including any
violation or breach of any Environmental Law or any other Law by the Borrower or
any Subsidiary of the Borrower; any Environmental Claim arising out of the
management, use, control, ownership or operation of Property by any of such
Persons, including all on-site and off-site activities involving Hazardous
Materials; or any exercise by the Bank of any of its rights or remedies under
this Agreement or any other Loan Document); but excluding any such losses,
liabilities, claims, damages, expenses, obligations, penalties, actions,
judgments, suits, costs or disbursements resulting solely from the gross
negligence or willful misconduct of such Indemnified Party, as finally
determined by a court of competent jurisdiction. If and to the extent that the
foregoing obligations of the Borrower under this subsection (c), or any other
indemnification obligation of the Borrower hereunder or under any other Loan
Document, are unenforceable for any reason, the Borrower hereby agrees to make
the maximum contribution to the payment and satisfaction of such obligations
which is permissible under applicable Law.

     SECTION 8.05   SEVERABILITY.
                    ------------

     The provisions of this Agreement are intended to be severable. If any
provision of this Agreement shall be held invalid or unenforceable in whole or
in part in any jurisdiction such provision shall, as to such jurisdiction, be
ineffective to the extent of such invalidity or unenforceability without in any
manner affecting the validity or enforceability thereof in any other
jurisdiction or the remaining provisions hereof in any jurisdiction.

     SECTION 8.06   PRIOR UNDERSTANDINGS.
                    --------------------

     This Agreement, the other Loan Documents and any commitment letter
regarding the Facility between Bank, and the Borrower, as such agreements shall
be amended from time to time, supersede all prior and contemporaneous
understandings and agreements, whether written or oral, among the parties hereto
relating to the transactions provided for herein and therein.

     SECTION 8.07   DURATION; SURVIVAL.
                    ------------------

     All representations and warranties of the Borrower contained herein or in
any other Loan Document or made in connection herewith or therewith shall
survive the making, and shall not be waived by the execution and delivery, of
this Agreement or any other Loan Document, any investigation by or knowledge of
the Bank, the making of any Loan, or any other event or condition whatever. All
covenants and agreements of the Borrower contained herein or in any other Loan
Document shall continue in full force and effect from and after the date hereof
so long as the Borrower may borrow hereunder and until payment in full of all
Obligations. Without limitation, all obligations of the Borrower hereunder or
under any other Loan Document to make payments to or indemnify the Bank shall
survive the payment in full of all other Obligations, termination of the
Borrower's right to borrow hereunder, and all other events and conditions
whatever.

     SECTION 8.08   COUNTERPARTS.
                    ------------

     This Agreement may be executed in any number of counterparts and by the
different parties hereto on separate counterparts each of which, when so
executed, shall be deemed an original, but all such counterparts shall
constitute but one and the same instrument.

                                       41
<PAGE>

     SECTION 8.09   LIMITATION ON PAYMENTS.
                    ----------------------

     The parties hereto intend to conform to all applicable Laws in effect from
time to time limiting the maximum rate of interest that may be charged or
collected. Accordingly, notwithstanding any other provision hereof or of any
other Loan Document, the Borrower shall not be required to make any payment to
the Bank, and Bank shall refund any payment made by the Borrower, to the extent
that such requirement or such failure to refund would violate or conflict with
nonwaivable provisions of applicable Laws limiting the maximum amount of
interest which may be charged or collected by Bank.

     SECTION 8.10   SET-OFF.
                    -------

     The Borrower hereby agrees that, to the fullest extent permitted by Law, if
any Obligation of the Borrower shall be due and payable (by acceleration or
otherwise), Bank shall have the right, without notice to the Borrower, to set-
off against and to appropriate and apply to such Obligation any indebtedness,
liability or obligation of any nature owing to the Borrower by Bank, including
but not limited to all deposits (whether time or demand, general or special,
provisionally credited or finally credited, whether or not evidenced by a
certificate of deposit) now or hereafter maintained by the Borrower with Bank.
Such right shall be absolute and unconditional in all circumstances and, without
limitation shall exist whether or not Bank or any other Person shall have given
notice or made a demand to the Borrower or any other Person, whether such
indebtedness, obligation or liability owed to the Borrower is contingent,
absolute, matured or unmatured (it being agreed that Bank may deem such
indebtedness, obligation or liability to be then due and payable at the time of
such setoff), and regardless of the existence or adequacy of any collateral,
guaranty or any other security, right or remedy available to Bank or any other
Person. The Borrower hereby agrees that, to the fullest extent permitted by Law,
any branch, subsidiary or affiliate of Bank shall have the same rights of set-
off as the Bank as provided in this Section (regardless of whether such branch,
subsidiary or affiliate would otherwise be deemed in privity with or a direct
creditor of the Borrower). The rights provided by this Section are in addition
to all other rights of set-off and banker's lien and all other rights and
remedies which Bank (or any such branch, subsidiary or affiliate) may otherwise
have under this Agreement, any other Loan Document, at law or in equity, or
otherwise, and nothing in this Agreement or any other Loan Document shall be
deemed a waiver or prohibition of or restriction on the rights of set-off or
bankers' lien of any such Person.

     SECTION 8.11   [INTENTIONALLY OMITTED]
                    -----------------------

     SECTION 8.12   SUCCESSORS AND ASSIGNS; ASSIGNMENTS.
                    -----------------------------------

     (a)  Successors and Assigns. This Agreement shall be binding upon and inure
          ----------------------
to the benefit of the Borrower, the Bank, all future holders of the Note, and
their respective successors and assigns, except that the Borrower may not assign
or transfer any of its rights hereunder or interests herein without the prior
written consent of Bank, and any purported assignment without such consent shall
be void.

     (b)  [Intentionally Omitted].
          -----------------------

     (c)  Assignments. Bank may, in the ordinary course of its commercial
          -----------
banking business and in accordance with applicable Law, at any time assign all
or a portion of its rights and obligations under this Agreement and the other
Loan Documents (including, without limitation, all or any portion of its
Commitment and Loans owing to it and any Note held by it) to any Affiliate of
Bank or to one or more additional commercial banks or other Persons (each a
"Purchasing Lender"); provided, that
------------------    --------

                                       42
<PAGE>

          (i)   any such assignment to a Purchasing Lender which is not an
     affiliate of Bank shall be made only with the consent (which in each case
     shall not be unreasonably withheld) of the Borrower (so long as no Default
     or Event of Default shall have occurred and be continuing) and the Bank;

          (ii)  if Bank makes such an assignment of less than all of its then
     remaining rights and obligations under this Agreement and the other Loan
     Documents, the Bank shall retain, after such assignment, a minimum
     principal amount of $10,000,000 of the Commitment and Loans then
     outstanding, and such assignment, shall be in a minimum principal amount of
     $10,000,000 of the Commitment and Loans then outstanding;

     (d)  Financial and Other Information.  The Borrower authorizes the Bank to
          -------------------------------
disclose to any Purchasing Lender (each, a "transferee") and any prospective
                                            ----------
transferee any and all financial and other information in such Person's
possession concerning the Borrower and its Subsidiaries and Affiliates which has
been or may be delivered to such Person by or on behalf of the Borrower in
connection with this Agreement or any other Loan Document or such Person's
credit evaluation of the Borrower and its Subsidiaries and Affiliates.

     (e)  Assignments to Federal Reserve Bank.  Bank may at any time assign all
          -----------------------------------
or any portion of its rights under this Agreement, including without limitation
any Loans owing to it, and any Note held by it, to a Federal Reserve Bank.  No
such assignment shall relieve the transferor Lender from its obligations
hereunder.

     SECTION 8.13   GOVERNING LAW; SUBMISSION TO JURISDICTION WAIVER OF JURY
                    --------------------------------------------------------
TRIAL; LIMITATION OF LIABILITY.
------------------------------

     (a)  Governing Law. THIS AGREEMENT AND ALL OTHER LOAN DOCUMENTS (EXCEPT TO
          -------------
THE EXTENT, IF ANY, OTHERWISE EXPRESSLY STATED IN SUCH OTHER LOAN DOCUMENTS)
SHALL BE GOVERNED BY, AND CONSTRUED AND ENFORCED IN ACCORDANCE WITH, THE LAWS OF
THE STATE OF NEVADA, WITHOUT REGARD TO CHOICE OF LAW PRINCIPLES.

     (b)  Certain Waivers. EACH PARTY TO THIS AGREEMENT HEREBY IRREVOCABLY AND
          ---------------
UNCONDITIONALLY:

          (i)  AGREES THAT ANY ACTION, SUIT OR PROCEEDING BY ANY PERSON ARISING
     FROM OR RELATING TO THIS AGREEMENT OR ANY OTHER LOAN DOCUMENT OR ANY
     STATEMENT, COURSE OF CONDUCT, ACT, OMISSION, OR EVENT OCCURRING IN
     CONNECTION HEREWITH OR THEREWITH (COLLECTIVELY, "RELATED LITIGATION") MAY
                                                      ------------------
     BE BROUGHT IN ANY STATE OR FEDERAL COURT OF COMPETENT JURISDICTION SITTING
     IN LAS VEGAS, NEVADA AND SUBMITS TO THE JURISDICTION OF SUCH COURTS (AND,
     TO THE FULLEST EXTENT PERMITTED BY LAW, THE BORROWER AGREES THAT IT WILL
     NOT BRING ANY RELATED LITIGATION IN ANY OTHER FORUM, BUT NOTHING HEREIN
     SHALL AFFECT THE RIGHT OF THE BANK TO BRING ANY ACTION, SUIT OR PROCEEDING
     IN ANY OTHER FORUM IN WHICH THE BORROWER OR ANY OF ITS ASSETS MAY BE
     LOCATED OR IN WHICH THE BORROWER MAY BE DOING BUSINESS OR THE RIGHT OF THE
     BORROWER TO ASSERT ANY DEFENSE OR COUNTERCLAIM TO ANY ACTION BROUGHT BY THE
     BANK IN ANY FORUM);

                                       43
<PAGE>

          (ii)   WAIVES ANY OBJECTION WHICH IT MAY HAVE AT ANY TIME TO THE
     LAYING OF VENUE OF ANY RELATED LITIGATION BROUGHT IN ANY SUCH COURT, WAIVES
     ANY CLAIM THAT ANY SUCH RELATED LITIGATION HAS BEEN BROUGHT IN AN
     INCONVENIENT FORUM, AND WAIVES ANY RIGHT TO OBJECT, WITH RESPECT TO ANY
     RELATED LITIGATION BROUGHT IN ANY SUCH COURT, THAT SUCH COURT DOES NOT HAVE
     JURISDICTION OVER IT;

          (iii)  CONSENTS AND AGREES TO SERVICE OF ANY SUMMONS, COMPLAINT OR
     OTHER LEGAL PROCESS IN ANY RELATED LITIGATION BY REGISTERED OR CERTIFIED
     U.S. MAIL, POSTAGE PREPAID, TO IT AT THE ADDRESS FOR NOTICES DESCRIBED IN
     SECTION 8.03, AND CONSENTS AND AGREES THAT SUCH SERVICE SHALL CONSTITUTE IN
     EVERY RESPECT VALID AND EFFECTIVE SERVICE (BUT NOTHING HEREIN SHALL AFFECT
     THE VALIDITY OR EFFECTIVENESS OF PROCESS SERVED IN ANY OTHER MANNER
     PERMITTED BY LAW); AND

          (iv)   WAIVES THE RIGHT TO TRIAL BY JURY IN ANY RELATED LITIGATION.

     (c)  Limitation of Liability. TO THE FULLEST EXTENT PERMITTED BY LAW, NO
          -----------------------
CLAIM MAY BE MADE BY ANY PARTY TO THIS AGREEMENT AGAINST ANY OTHER PARTY TO THIS
AGREEMENT OR ANY AFFILIATE, DIRECTOR, OFFICER, EMPLOYEE, ATTORNEY OR AGENT OF
ANY OF THEM FOR ANY SPECIAL, INCIDENTAL, INDIRECT, CONSEQUENTIAL OR PUNITIVE
DAMAGES IN RESPECT OF ANY CLAIM ARISING FROM OR RELATING TO THIS AGREEMENT OR
ANY OTHER LOAN DOCUMENT OR ANY STATEMENT, COURSE OF CONDUCT, ACT, OMISSION, OR
EVENT OCCURRING IN CONNECTION HEREWITH OR THEREWITH (WHETHER FOR BREACH OF
CONTRACT, TORT OR ANY OTHER THEORY OF LIABILITY).  EACH PARTY TO THIS AGREEMENT
HEREBY WAIVES, RELEASES AND AGREES NOT TO SUE UPON ANY CLAIM FOR ANY SUCH
DAMAGES, WHETHER SUCH CLAIM PRESENTLY EXISTS OR ARISES HEREAFTER AND WHETHER OR

NOT SUCH CLAIM IS KNOWN OR SUSPECTED TO EXIST IN ITS FAVOR.

                  [Balance of page intentionally left blank]

                                       44
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed and delivered as of the day and year first above written.

SIERRA PACIFIC RESOURCES                  Address
                                          -------
By: _______________________________
Name:                                     Sierra Pacific Resources
Title                                     6100 Neil Road
                                          P.O. Box 30150
                                          Reno, Nevada 89520
                                          Attn: Richard K. Atkinson
                                          Telecopier: 775-834-5462
                                          Telephone: 775-834-5640

WELLS FARGO BANK,                         Address
NATIONAL ASSOCIATION                      -------

By: _______________________________       Wells Fargo Bank
Name:  Steven Dastrup                     Las Vegas Regional Commercial
Title: Vice-President                     Banking Office
                                          3800 Howard Hughes Parkway
                                          Las Vegas, NV 89109
                                          Attn: Steven Dastrup
                                          Telecopier: ________________
                                          Telephone: ________________

                                       45

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