<PAGE>

                                                                     EXHIBIT 4.2

THIS GLOBAL NOTE IS HELD BY THE DEPOSITARY (AS DEFINED IN THE OFFICERS'
CERTIFICATE UNDER THE INDENTURE GOVERNING THIS NOTE) OR ITS NOMINEE IN CUSTODY
FOR THE BENEFIT OF THE BENEFICIAL OWNERS HEREOF, AND IS NOT TRANSFERABLE TO ANY
PERSON UNDER ANY CIRCUMSTANCES EXCEPT THAT (I) THE TRUSTEE MAY MAKE SUCH
NOTATIONS HEREON AS MAY BE REQUIRED PURSUANT TO ARTICLE II OF THE INDENTURE,
(II) THIS GLOBAL NOTE MAY BE EXCHANGED IN WHOLE BUT NOT IN PART PURSUANT TO
SECTION 3 OF THE OFFICERS' CERTIFICATE UNDER THE INDENTURE, (III) THIS GLOBAL
NOTE MAY BE DELIVERED TO THE TRUSTEE FOR CANCELLATION PURSUANT TO SECTION 2.11
OF THE INDENTURE AND (IV) THIS GLOBAL NOTE MAY BE TRANSFERRED TO A SUCCESSOR
DEPOSITARY WITH THE PRIOR WRITTEN CONSENT OF THE COMPANY OR ANY SUCCESSOR
THERETO.

UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITARY,
TO THE COMPANY OR ANY SUCCESSOR THERETO OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITARY (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO
SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITARY), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY
OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE &
CO., HAS AN INTEREST HEREIN.

THE NOTES EVIDENCED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF
1933, AS AMENDED (THE "SECURITIES ACT"), OR OTHER SECURITIES LAWS. NEITHER THIS
NOTE NOR ANY INTEREST OR PARTICIPATION HEREIN MAY BE REOFFERED, SOLD, ASSIGNED,
TRANSFERRED, PLEDGED, ENCUMBERED OR OTHERWISE DISPOSED OF IN THE ABSENCE OF SUCH
REGISTRATION OR UNLESS THE TRANSACTION IS EXEMPT FROM, OR NOT SUBJECT TO, THE
REGISTRATION REQUIREMENTS OF THE SECURITIES ACT. THE HOLDER OF THIS NOTE BY ITS
ACCEPTANCE HEREOF (1) REPRESENTS THAT (A) IT IS A "QUALIFIED INSTITUTIONAL
BUYER" (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) OR (B) IT IS NOT A
U.S. PERSON AND IS ACQUIRING ITS NOTE IN AN "OFFSHORE TRANSACTION" PURSUANT TO
RULE 904 OF REGULATION S UNDER THE SECURITIES ACT, (2) AGREES THAT IT WILL NOT
PRIOR TO (X) THE DATE WHICH IS TWO YEARS (OR SUCH SHORTER PERIOD OF TIME AS
PERMITTED BY RULE 144(k) UNDER THE SECURITIES ACT OR ANY SUCCESSOR PROVISION
THEREUNDER) AFTER THE LATER OF THE ORIGINAL ISSUE DATE HEREOF (OR OF ANY
PREDECESSOR OF THIS NOTE) OR THE LAST DAY ON WHICH THE COMPANY OR ANY AFFILIATE
OF THE COMPANY WAS THE OWNER OF THIS NOTE (OR ANY PREDECESSOR OF THIS NOTE) AND
(Y) SUCH LATER DATE, IF ANY, AS MAY BE REQUIRED BY APPLICABLE LAW (THE "RESALE
RESTRICTION TERMINATION DATE"), OFFER, SELL OR OTHERWISE TRANSFER THIS NOTE
EXCEPT (A) TO THE COMPANY, (B) PURSUANT TO A REGISTRATION STATEMENT WHICH HAS
BEEN DECLARED EFFECTIVE UNDER THE SECURITIES ACT, (C) FOR SO LONG AS THE NOTES
ARE ELIGIBLE FOR RESALE PURSUANT TO RULE 144A, TO A PERSON IT REASONABLY
BELIEVES IS A "QUALIFIED INSTITUTIONAL BUYER" AS DEFINED IN RULE 144A UNDER THE
SECURITIES ACT THAT PURCHASES FOR ITS OWN ACCOUNT OR FOR THE ACCOUNT OF A
QUALIFIED INSTITUTIONAL BUYER TO WHOM NOTICE IS GIVEN THAT THE TRANSFER IS BEING
MADE IN RELIANCE ON RULE 144A

<PAGE>

INSIDE THE UNITED STATES, (D) PURSUANT TO OFFERS AND SALES THAT OCCUR OUTSIDE
THE UNITED STATES, AND, DURING THE "40-DAY DISTRIBUTION COMPLIANCE PERIOD," ONLY
TO NON-U.S. PERSONS, ALL WITHIN THE MEANING OF REGULATION S UNDER THE SECURITIES
ACT OR (E) PURSUANT TO ANY OTHER AVAILABLE EXEMPTION FROM THE REGISTRATION
REQUIREMENTS OF THE SECURITIES ACT AND (3) AGREES THAT IT WILL GIVE TO EACH
PERSON TO WHOM THIS NOTE IS TRANSFERRED A NOTICE SUBSTANTIALLY TO THE EFFECT OF
THIS LEGEND; PROVIDED THAT THE COMPANY, THE TRUSTEE AND THE REGISTRAR SHALL HAVE
THE RIGHT PRIOR TO ANY SUCH OFFER, SALE OR TRANSFER (I) PURSUANT TO CLAUSE (E)
TO REQUIRE THE DELIVERY OF AN OPINION OF COUNSEL, CERTIFICATION AND/ OR OTHER
INFORMATION SATISFACTORY TO EACH OF THEM, AND (II) IN EACH OF THE FOREGOING
CASES, TO REQUIRE THAT A CERTIFICATION OF TRANSFER IN THE FORM APPEARING ON THE
OTHER SIDE OF THIS NOTE IS COMPLETED AND DELIVERED BY THIS TRANSFEROR TO THE
TRUSTEE. THIS LEGEND SHALL BE REMOVED UPON THE REQUEST OF THE HOLDER AFTER THE
RESALE RESTRICTION TERMINATION DATE. AS USED HEREIN, THE TERMS "OFFSHORE
TRANSACTION," "UNITED STATES" AND "U.S. PERSON" HAVE THE MEANINGS GIVEN TO THEM
BY REGULATION S UNDER THE SECURITIES ACT.

                            SIERRA PACIFIC RESOURCES
                          6 3/4% Senior Notes due 2017

<TABLE>
<S>                                <C>                         <C>
Original Interest Accrual Date:    August 12, 2005             Redeemable: Yes [X] No [ ]
Stated Maturity:                   August 15, 2017             Redemption Date: See Below
Interest Rate:                     6 3/4%                      Redemption Price: See Below
Interest Payment Dates:            February 15 andAugust 15
Record Dates:                      February 1 and August 1
</TABLE>

                 The Security is not a Discount Security within
                 the meaning of the within-mentioned Indenture.

                                                             CUSIP No. 826428AM6

                          6 3/4% Senior Notes due 2017

No. R-1                                                             $225,000,000

promises to pay to Cede & Co. or registered assigns, the principal sum of
$225,000,000 on August 15, 2017.

      1.    Interest. Sierra Pacific Resources, a Nevada corporation (the
"Company"), promises to pay interest on the principal amount of this Senior Note
at 6 3/4% per annum, from August 12, 2005 until maturity and shall pay the
Liquidated Damages payable pursuant to Section 2.5 of the Registration Rights
Agreement referred to below. The Company shall pay interest and Liquidated
Damages, if any, semi-annually in arrears on February 15 and August 15 of each
year, or if any such day is not a Business Day, on the next succeeding Business
Day (each an "Interest Payment Date"). Interest on the Senior Notes shall accrue
from the most

                                       2
<PAGE>

recent date to which interest has been paid or, if no interest has been paid,
from the Original Interest Accrual Date specified above; provided that if there
is no existing Default in the payment of interest, and if this Senior Note is
authenticated between a record date referred to on the face hereof and the next
succeeding Interest Payment Date, interest shall accrue from such next
succeeding Interest Payment Date, except in the case of the original issuance of
Senior Notes, in which case interest shall accrue from the Original Interest
Accrual Date specified above; provided, further, that the first Interest Payment
Date shall be February 15, 2006. The Company shall pay interest (including
postpetition interest in any proceeding under the Bankruptcy Law) on overdue
principal and premium, if any, from time to time on demand at a rate that is 1%
per annum in excess of the rate then in effect on the Senior Notes; it shall pay
interest (including post-petition interest in any proceeding under the
Bankruptcy Law) on overdue installments of interest and Liquidated Damages, if
any, (without regard to any applicable grace periods) from time to time on
demand at the same rate to the extent lawful. Interest shall be computed on the
basis of a 360-day year of twelve 30-day months.

      2.    Method of Payment. The Company shall pay interest on the Senior
Notes (except Defaulted Interest) and Liquidated Damages to the Persons who are
registered Holders of Senior Notes at the close of business on the February 1
and August 1 next preceding the Interest Payment Date, even if such Senior Notes
are canceled after such record date and on or before such Interest Payment Date,
except as provided in Section 2.12 of the Indenture with respect to Defaulted
Interest. The Senior Notes shall be payable as to principal, premium and
Liquidated Damages, if any, and interest at the office or agency of the Company
maintained for such purpose within the City and State of New York, or, at the
option of the Company, payment of interest and Liquidated Damages may be made by
check mailed to the Holders of Senior Notes at their addresses set forth in the
register of Holders, and provided that payment by wire transfer of immediately
available funds shall be required with respect to principal of, and interest,
premium and Liquidated Damages on, all Global Notes and all other Senior Notes
the Holders of which shall have provided wire transfer instructions to the
Company or the Paying Agent. Such payment shall be in such coin or currency of
the United States of America as at the time of payment is legal tender for
payment of public and private debts.

      3.    Paying Agent and Security Registrar. Initially, The Bank of New
York, the Trustee under the Indenture, shall act as Paying Agent and Security
Registrar. The Company may change any Paying Agent or Security Registrar without
notice to any Holder of Senior Notes. The Company or any of its Subsidiaries may
act in any such capacity.

      4.    Indenture. This Senior Note is one of a duly authorized issue of
Securities of the Company, issued and issuable in one or more series under the
Indenture, dated as of May 1, 2000 (such Indenture as originally executed and
delivered and as supplemented or amended from time to time thereafter, together
with any constituent instruments establishing the terms of particular
Securities, being herein called the "Indenture"), between the Company and The
Bank of New York, Trustee (herein called the "Trustee," which term includes any
successor Trustee under the Indenture), to which Indenture and all indentures
supplemental thereto reference is hereby made for a description of the
respective rights, limitations of rights, duties and immunities of the Company,
the Trustee and the Holders of the Securities thereunder and of the terms and
conditions upon which the Securities are, and are to be, authenticated and
delivered and secured. The acceptance of this Senior Note shall be deemed to
constitute the consent and agreement by

                                       3
<PAGE>

the Holder hereof to all of the terms and provisions of the Indenture. This
Senior Note is one of the series designated above. The terms of the Senior Notes
include those stated in the Indenture, the Officers' Certificate dated August
12, 2005 (the "Officers' Certificate") and those made part of the Indenture by
reference to the Trust Indenture Act. The Senior Notes are subject to all such
terms, and Holders of Senior Notes are referred to the Indenture and such Act
for a statement of such terms. To the extent any provision of this Senior Note
conflicts with the express provisions of the Indenture or the Officers'
Certificate, the provisions of the Indenture and the Officers' Certificate shall
govern and be controlling. The Senior Notes are general obligations of the
Company initially limited to $225,000,000 aggregate principal amount in the case
of Senior Notes issued on the Issue Date.

      5.    Optional Redemption.

            (a) Except as set forth in clause (b) of this Section 5, the Company
shall not have the option to redeem the Senior Notes pursuant to this Section 5
prior to August 15, 2010. Thereafter, the Company shall have the option to
redeem the Senior Notes, in whole or in part, upon not less than 30, nor more
than 60 days' notice, at the redemption prices (expressed as percentages of
principal amount) set forth below plus accrued and unpaid interest and
Liquidated Damages, if any, to the applicable redemption date, if redeemed
during the twelve-month period beginning on August 15 of the years indicated
below:

<TABLE>
<CAPTION>
YEAR                                                                 Percentage
----                                                                 ----------
<S>                                                                  <C>
2010............................................................      103.375%
2011............................................................      102.250%
2012............................................................      101.125%
2013 and thereafter.............................................      100.000%
</TABLE>

            (b) Equity Claw-back. Notwithstanding the provisions of clause (a)
of this Section 5, at any time or from time to time on or prior to August 15,
2008, the Company may on any one or more occasions redeem up to 35% of the
aggregate principal amount of Senior Notes at a redemption price equal to
106.75% of the principal amount thereof, plus accrued and unpaid interest, if
any, and Liquidated Damages thereon, if any, to the Redemption Date, with the
net cash proceeds of any public or private offering of its Equity Interests
(other than Disqualified Stock); provided that (1) at least 65% of the aggregate
principal amount of Senior Notes remain outstanding immediately after the
occurrence of such redemption (excluding Senior Notes held by the Company and
its Subsidiaries); and (2) that each such redemption shall occur within 120 days
of the date of the closing of such offering.

      6.    Notice of Optional Redemption. Notice of optional redemption shall
be mailed at least 30 days but not more than 60 days before the Redemption Date
to each Holder whose Senior Notes are to be redeemed at its registered address.
Senior Notes in denominations larger than $1,000 may be redeemed in part but
only in whole multiples of $1,000, unless all of the Senior Notes held by a
Holder are to be redeemed. On and after the redemption date, interest and
Liquidated Damages, if any, cease to accrue on Senior Notes or portions thereof
called for redemption.

                                       4
<PAGE>

      7.    Mandatory Redemption.

            (a) Other than in connection with Section 8 below or in connection
with a redemption at the option of the Holders of the Senior Notes pursuant to
Sections 10(iii) and 10(iv) of the Officers' Certificate, the Company shall not
be required to make mandatory redemption, purchase or sinking fund payments with
respect to the Senior Notes.

      8.    Redemption at the Option of Holders. Upon the occurrence of any of
the following Triggering Events: (a) failure for 30 days to pay when due
interest on, or Liquidated Damages with respect to, the Senior Notes; (b)
failure to pay when due the principal of, or premium, if any, on the Senior
Notes; (c) failure by the Company or any of its Restricted Subsidiaries to
comply with the provisions described in Sections 18(A), 18(C) or 18(L) of the
Officers' Certificate; (d) failure by the Company or any of its Restricted
Subsidiaries for 30 days after notice to comply with the provisions described in
Section 10 (iii) or (iv) of the Officers' Certificate; (e) failure by the
Company or any of its Restricted Subsidiaries for 60 days after notice to comply
with any of the other agreements in the Officers' Certificate or the Senior
Notes; (f) default under any mortgage, indenture or instrument under which there
may be issued or by which there may be secured or evidenced any Indebtedness for
money borrowed by the Company whether such Indebtedness or guarantee now exists,
or is created after the original issue date of the Senior Notes, if that default
(i) is caused by a failure to pay principal of, or interest or premium, if any,
on such Indebtedness prior to the expiration of the grace period provided in
such Indebtedness on the date of such default (a "Payment Default") or (ii)
results in the acceleration of such Indebtedness prior to its express maturity,
and, in each case, the principal amount of any such Indebtedness, together with
the principal amount of any other such Indebtedness under which there has been a
Payment Default or the maturity of which has been so accelerated, aggregates
$25.0 million or more; (g) failure by the Company or any of its Subsidiaries to
pay final judgments aggregating in excess of $50.0 million, which judgments are
not paid, discharged or stayed for a period of 60 days; or (h) certain events of
bankruptcy or insolvency, with respect to the Company or any of its Significant
Subsidiaries or any group of Restricted Subsidiaries that, taken as a group,
would constitute a Significant Subsidiary, the Holders of at least 25% in
principal amount of the Senior Notes then Outstanding may deliver a notice to
the Company requiring the Company to redeem the Senior Notes immediately at a
Redemption Price equal to 100% of the aggregate principal amount of the Senior
Notes plus accrued and unpaid interest, if any, on the Senior Notes to the
Redemption Date. The Holders of a majority in aggregate principal amount of the
Senior Notes then Outstanding by notice to the Company and the Trustee may on
behalf of the Holders of all of the Senior Notes waive any existing Triggering
Event and its consequences except a continuing Triggering Event related to the
payment of interest on, or the principal of, the Senior Notes. In the case of
any Triggering Event by reason of any willful action or inaction taken or not
taken by or on behalf of the Company with the intention of avoiding payment of
the premium that the Company would have had to pay if the Company then had
elected to redeem the Senior Notes pursuant to the provisions of Section 9(i) of
the Officers' Certificate or, prior to August 15, 2008, pursuant to the
provisions of Section 9(ii) of the Officers' Certificate relating to redemption
at the option of the Company, an equivalent premium equal to the premium payable
under Section 9(i) or, prior to August 15, 2008, Section 9(ii), whichever is
greater, shall also become and be immediately due and payable to the extent
permitted by law upon the redemption of the Senior Notes at the option of the
Holders thereof.

                                       5
<PAGE>

      9.    Denominations, Transfer, Exchange. The Senior Notes are in
registered form without coupons in denominations of $1,000 and integral
multiples of $1,000. The transfer of Senior Notes may be registered and Senior
Notes may be exchanged as provided in the Indenture and the Officers'
Certificate. The Security Registrar and the Trustee may require a Holder of
Senior Notes, among other things, to furnish appropriate endorsements and
transfer documents and the Company may require a Holder of Senior Notes to pay
any taxes and fees required by law or permitted by the Indenture. The Company
need not exchange or register the transfer of any Senior Note or portion of a
Senior Note selected for redemption, except for the unredeemed portion of any
Senior Note being redeemed in part. Also, the Company need not exchange or
register the transfer of any Senior Notes for a period of 15 days before a
selection of Senior Notes to be redeemed or during the period between a record
date and the corresponding Interest Payment Date.

      10.   Persons Deemed Owners. The registered Holder of a Senior Note may be
treated as its owner for all purposes.

      11.   Amendment, Supplement and Waiver. The Indenture permits, with
certain exceptions as therein provided, the Trustee to enter into one or more
supplemental indentures for the purpose of adding any provisions to, or changing
in any manner or eliminating any of the provisions of, the Indenture with the
consent of the Holders of not less than a majority in aggregate principal amount
of the Securities of all series then Outstanding under the Indenture, considered
as one class; provided, however, that if there shall be Securities of more than
one series Outstanding under the Indenture and if a proposed supplemental
indenture shall directly affect the rights of the Holders of Securities of one
or more, but less than all, of such series, then the consent only of the Holders
of a majority in aggregate principal amount of the Outstanding Securities of all
series so directly affected, considered as one class, shall be required; and
provided, further, that if the Securities of any series shall have been issued
in more than one Tranche and if the proposed supplemental indenture shall
directly affect the rights of the Holders of Securities of one or more, but less
than all, of such Tranches, then the consent only of the Holders of a majority
in aggregate principal amount of the Outstanding Securities of all Tranches so
directly affected, considered as one class, shall be required; and provided,
further, that the Indenture permits the Trustee to enter into one or more
supplemental indentures for limited purposes without the consent of any Holders
of Securities. The Indenture also contains provisions permitting the Holders of
a majority in principal amount of the Securities then Outstanding, on behalf of
the Holders of all Securities, to waive compliance by the Company with certain
provisions of the Indenture and certain past defaults under the Indenture and
their consequences. Any such consent or waiver by the Holder of this Senior Note
shall be conclusive and binding upon such Holder and upon all future Holders of
this Senior Note and of any Senior Note issued upon the registration of transfer
hereof or in exchange therefor or in lieu hereof, whether or not notation of
such consent or waiver is made upon this Senior Note.

      12.   Events of Default. If an Event of Default shall occur and be
continuing, the principal of this Senior Note may be declared due and payable in
the manner and with the effect provided in the Indenture.

      13.   No Recourse Against Others. No directors, officer, employee,
incorporator or stockholder of the Company or any Subsidiary, as such, will have
any liability for any

                                       6
<PAGE>

obligations of the Company or any Subsidiary Guarantor under the Senior Notes,
the Indenture, any Subsidiary Guarantees, or for any claim based on, in respect
of, or by reason of, such obligations or their creation. Each holder of Senior
Notes by accepting a Senior Note waives and releases all such liability. The
waiver and release are part of the consideration for issuance of the Senior
Notes. The waiver may not be effective to waive liabilities under the federal
securities laws.

      14.   Authentication. Unless the certificate of authentication hereon has
been executed by the Trustee or an Authenticating Agent by manual signature,
this Senior Note shall not be entitled to any benefit under the Indenture or be
valid or obligatory for any purpose.

      15.   Transfer and Exchange.

            (a) As provided in the Indenture and subject to certain limitations
therein set forth, the transfer of this Senior Note is registrable in the
Security Register, upon surrender of this Senior Note for registration of
transfer at the Corporate Trust Office of The Bank of New York in New York, New
York or such other office or agency as may be designated by the Company from
time to time, duly endorsed by, or accompanied by a written instrument of
transfer in form satisfactory to the Company and the Security Registrar duly
executed by, the Holder hereof or his attorney duly authorized in writing, and
thereupon one or more new Senior Notes of this series of authorized
denominations and of like tenor and aggregate principal amount, will be issued
to the designated transferee or transferees.

            (b) No service charge shall be made for any such registration of
transfer or exchange, but the Company may require payment of a sum sufficient to
cover any tax or other governmental charge payable in connection therewith.

            (c) Prior to due presentment of this Senior Note for registration of
transfer, the Company, the Trustee and any agent of the Company or the Trustee
may treat the Person in whose name this Senior Note is registered as the
absolute owner hereof for all purposes, whether or not this Senior Note be
overdue, and neither the Company, the Trustee nor any such agent shall be
affected by notice to the contrary.

      16.   Governing Law. The Senior Notes shall be governed by and construed
in accordance with the laws of the State of New York.

      17.   Definition of "Business Day" and Other Terms. As used herein,
"Business Day" shall mean any day, other than Saturday or Sunday, on which
commercial banks are open for business, including dealings in deposits in U.S.
dollars, in New York. All other terms used in this Senior Note which are defined
in the Indenture or the Officers' Certificate shall have the meanings assigned
to them in the Indenture or the Officers' Certificate, as applicable, unless
otherwise indicated.

      18.   Abbreviations. Customary abbreviations may be used in the name of a
Holder of Senior Notes or an assignee, such as: TEN COM (= tenants in common),
TEN ENT (= tenants by the entireties), JT TEN joint tenants with right of
survivorship and not as tenants in common), CUST (= Custodian), and U/G/M/A (=
Uniform Gifts to Minors Act).

                                       7
<PAGE>

      19. Additional Rights of Holders of Restricted Global Notes and Restricted
Definitive Notes. In addition to the rights provided to Holders of Senior Notes
under the Indenture, Holders of Restricted Global Notes and Restricted
Definitive Notes shall have all the rights set forth in the Registration Rights
Agreement dated as of August 12, 2005 between Sierra Pacific Resources and the
parties named on the signature pages thereof (the "Registration Rights
Agreement").

      20. CUSIP Numbers. Pursuant to a recommendation promulgated by the
Committee on Uniform Security Identification Procedures, the Company has caused
CUSIP numbers to be printed on the Senior Notes and the Trustee may use CUSIP
numbers in notices of redemption as a convenience to Holders of Senior Notes. No
representation is made as to the accuracy of such numbers either as printed on
the Senior Notes or as contained in any notice of redemption and reliance may be
placed only on the other identification numbers placed thereon.

      The Company shall furnish to any Holder of Senior Notes upon written
request and without charge a copy of the Indenture and/or the Registration
Rights Agreement. Requests may be made to:

                            Sierra Pacific Resources
                                 P.O. Box 30150
                                 6100 Neil Road
                               Reno, Nevada 89520
                         Attention: Corporate Treasurer

                                       8
<PAGE>

      IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed.

                                         SIERRA PACIFIC RESOURCES

                                         By: _____________________________
                                             William D. Rogers
                                             Corporate Treasurer

                          CERTIFICATE OF AUTHENTICATION

            This is one of the Securities of the series designated therein
referred to in the within-mentioned Indenture.

Dated: August ____, 2005

                                         THE BANK OF NEW YORK, as Trustee

                                         By: ________________________________
                                             Authorized Signatory

<PAGE>

            SCHEDULE OF EXCHANGES OF INTERESTS IN THE GLOBAL NOTE ***

      The following exchanges of a part of this Global Note for an interest in
another Global Note or for a Definitive Note, or exchanges of a part of another
Global Note or Definitive Note for an interest in this Global Note, have been
made:

<TABLE>
<CAPTION>
                                                   PRINCIPAL
               AMOUNT OF         AMOUNT OF      AMOUNT OF THIS     SIGNATURE OF
              DECREASE IN       INCREASE IN       GLOBAL NOTE       AUTHORIZED
               PRINCIPAL         PRINCIPAL      FOLLOWING SUCH     SIGNATORY OF
 DATE OF    AMOUNT OF THIS    AMOUNT OF THIS     DECREASE (OR     TRUSTEE OR NOTE
EXCHANGE      GLOBAL NOTE       GLOBAL NOTE        INCREASE)         CUSTODIAN
--------    --------------    --------------    --------------    ---------------
<S>         <C>               <C>               <C>               <C>

</TABLE>

----------------
*** This should be included only if the Note is issued in global form.

<PAGE>

                                 ASSIGNMENT FORM

   To assign this Senior Note, fill in the form below: (I) or (we) assign and
                          transfer this Senior Note to

________________________________________________________________________________
                  (Insert assignee's soc. sec. or tax I.D. no.)

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________
              (Print or type assignee's name, address and zip code)

and irrevocably appoint ________________________________________________________
to transfer this Senior Note on the books of the Company. The agent may
substitute another to act for him.

Date:
Your Signature: ________________________________________________________________
             (Sign exactly as your name appears on the face of this Senior Note)

                               SIGNATURE GUARANTEE

________________________________________________________________________________

                                            Signatures must be guaranteed by an
                                            "eligible guarantor institution"
                                            meeting the requirements of the
                                            Security Registrar, which
                                            requirements include membership or
                                            participation in the Security
                                            Transfer Agent Medallion Program
                                            ("STAMP") or such other "signature
                                            guarantee program" as may be
                                            determined by the Security Registrar
                                            in addition to, or in substitution
                                            for, STAMP, all in accordance with
                                            the Securities Exchange Act of 1934,
                                            as amended.

<PAGE>

                       OPTION OF HOLDER TO ELECT PURCHASE

      If you want to elect to have this Senior Note purchased by the Company
pursuant to Section 10(iii) (Offer to Purchase upon Change of Control) or 10(iv)
(Offer to Purchase Upon Application of Excess Proceeds) of the Officers'
Certificate, check the box below:

      [ ] Section 10(iii) (Offer to Purchase     [ ] Section 10(iv) (Offer to
           upon Change of Control)                    Purchase Upon Application
                                                      of Excess Proceeds)

      If you want to elect to have only part of the Senior Note purchased by the
Company pursuant to Section 10(iii) (Offer to Purchase upon Change of Control)
or 10(iv) (Offer to Purchase Upon Application of Excess Proceeds) of the
Indenture, state the amount you elect to have purchased:

      $________________________

Date:

Your Signature:_________________________________________________________________
              (Sign exactly as your name appears on the face of the Senior Note)

Tax Identification No.: ________________________________________________________

                               SIGNATURE GUARANTEE

________________________________________________________________________________

                                            Signatures must be guaranteed by an
                                            "eligible guarantor institution"
                                            meeting the requirements of the
                                            Security Registrar, which
                                            requirements include membership or
                                            participation in the Security
                                            Transfer Agent Medallion Program
                                            ("STAMP") or such other "signature
                                            guarantee program" as may be
                                            determined by the Security Registrar
                                            in addition to, or in substitution
                                            for, STAMP, all in accordance with
                                            the Securities Exchange Act of 1934,
                                            as amended.