Exhibit 4.3
                                                                     -----------


                               (Face of Security)

         THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A
NOMINEE THEREOF. THIS SECURITY MAY NOT BE EXCHANGED IN WHOLE OR IN PART FOR A
SECURITY REGISTERED, AND NO TRANSFER OF THIS SECURITY IN WHOLE OR IN PART MAY BE
REGISTERED, IN THE NAME OF ANY PERSON OTHER THAN SUCH DEPOSITARY OR A NOMINEE
THEREOF, EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE.

         UNLESS THIS SECURITY IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO ISSUER OR ITS
AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY SECURITY
ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO
CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY A PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE
& CO., HAS AN INTEREST HEREIN.


<PAGE>

                      ALLEGHENY ENERGY SUPPLY COMPANY, LLC

                              7.80% NOTES DUE 2011

         CUSIP No. [__________]

         No. [__]                                                   $400,000,000

         Allegheny Energy Supply Company, LLC, a limited liability company duly
organized and existing under the laws of Delaware (herein called the "Company",
which term includes any successor Person under the Indenture hereinafter
referred to), for value received, hereby promises to pay to CEDE & CO., or
registered assigns, the principal sum of FOUR HUNDRED MILLION ($400,000,000)
Dollars (which principal amount may from time to time be increased or decreased
to such other principal amounts by adjustments made on the records of the
Trustee hereinafter referred to in accordance with the Indenture) on March 15,
2011, and to pay interest thereon from March 15, 2001 or from the most recent
Interest Payment Date to which interest has been paid or duly provided for,
semi-annually on March 15 and September 15 in each year commencing September 15,
2001 at the rate of 7.80% per annum, until the principal hereof is paid or made
available for payment.

         The interest so payable, and punctually paid or duly provided for, on
any Interest Payment Date will, as provided in such Indenture, be paid to the
Person in whose name this Security (or one or more Predecessor Securities) is
registered at the close of business on the Regular Record Date for such
interest, which shall be the September 1 or March 1 (whether or not a Business
Day), as the case may be, next preceding such Interest Payment Date. If any
Interest Payment Date falls on a day that is not a Business Day, it shall be
postponed to the following Business Day. Any such interest not so punctually
paid or duly provided for will forthwith cease to be payable to the Holder on
such Regular Record Date and may either be paid to the Person in whose name this
Security (or one or more Predecessor Securities) is registered at the close of
business on a Special Record Date for the payment of such Defaulted Interest to
be fixed by the Trustee, notice whereof shall be given to Holders of Securities
not less than 10 days prior to such Special Record Date, or be paid at any time
in any other lawful manner not inconsistent with the requirements of any
securities exchange on which the Securities may be listed, and upon such notice
as may be required by such exchange, all as more fully provided in said
Indenture. Payment of the principal of (and premium, if any) and interest on
this Security will be made at the office or agency of the Company maintained for
that purpose in The City of New York, New York, 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; PROVIDED, HOWEVER, that at the option of the
Company payment of interest may be made by check mailed to the address of the
Person entitled thereto as such address shall appear in the Security Register.

         If this Security is issued in the form of a Global Security, payments
of the principal of (and premium, if any) and interest on this Security shall be
made in


                                      -2-

<PAGE>

immediately available funds to the Depositary. If this Security is issued in
certificated form, payment of the principal of (and premium, if any) and
interest on this Security will be made at the corporate trust office of the
Trustee in The City of New York, New York, maintained for such purpose, and at
any other office or agency maintained by the Company for such purpose, 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; PROVIDED, HOWEVER, that at
the option of the Company payment of interest may be made by check mailed to the
address of the Person entitled thereto as such address shall appear in the
Security Register.

         Reference is hereby made to the further provisions of this Security set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

         Unless the certificate of authentication hereon has been executed by
the Trustee referred to on the reverse hereof by manual signature, this Security
shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.













                                      -3-
<PAGE>






                  IN WITNESS WHEREOF, the Company has caused this instrument to
be duly executed under its corporate seal.

         Dated:

                                   ALLEGHENY ENERGY SUPPLY COMPANY, LLC



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



         Attest:



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





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

                                   BANK ONE TRUST COMPANY, N.A.,
                                                                 AS TRUSTEE

                                   By:
                                      -------------------------------------
                                   AUTHORIZED OFFICER




                                       -4-
<PAGE>


                              (Reverse of Security)

         This Security is one of a duly authorized issue of Securities of the
Company designated as its 7.80% Notes due 2011 (herein called the "Securities"),
issued under an Indenture, dated as of March 15, 2001 (herein called the
"Indenture"), between the Company and Bank One Trust Company, N.A., as Trustee
(herein called the "Trustee", which term includes any successor trustee under
the Indenture). The Securities will be unlimited in aggregate principal amount.
The Securities will initially be issued in an aggregate principal amount of
$400,000,000. The Company may, without the consent of the Holders, create and
issue additional Securities (the "Additional Securities") ranking equally with
the Securities and otherwise similar in all respects so that the Additional
Securities shall be consolidated and form a single series with the Securities.
The Company may not issue Additional Securities if an Event of Default shall
occur and be continuing with respect to the Securities. Reference is hereby made
to the Indenture and all indentures supplemental thereto for a statement of the
respective rights, limitations of rights, duties and immunities thereunder of
the Company, the Trustee and the Holders of the Securities and of the terms upon
which the Securities are, and are to be, authenticated and delivered.

         The Securities are subject to redemption upon not less than 30 nor more
than 60 days' notice by mail, at any time, as a whole or in part, at the
election of the Company, at a Redemption Price equal to the greater of (a) 100%
of the principal amount of the Securities to be redeemed, plus accrued interest
to the Redemption Date, or (b) as determined by the Quotation Agent, the sum of
the present values of the remaining scheduled payments of principal and interest
on the Securities to be redeemed (not including any portion of payments of
interest accrued as of the Redemption Date), discounted to the Redemption Date
on a semi-annual basis at the Adjusted Treasury Rate plus 35 basis points, plus
accrued interest to the Redemption Date.

         The Redemption Price will be calculated assuming a 360-day year
consisting of twelve 30-day months.

         "Adjusted Treasury Rate" means, with respect to any Redemption Date,
the rate per annum equal to the semi-annual equivalent yield to maturity of the
Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue
(expressed as a percentage of its principal amount) equal to the Comparable
Treasury Price for that Redemption Date.

         "Comparable Treasury Issue" means the United States Treasury security
selected by the Quotation Agent as having a maturity comparable to the remaining
term of the Securities that would be used, at the time of the selection and in
accordance with customary financial practice, in pricing new issues of corporate
debt securities of comparable maturity to the remaining term of the Securities.


                                      -5-
<PAGE>

         "Comparable Treasury Price" means, with respect to any Redemption Date:
(a) the average of the Reference Treasury Dealer Quotations for the Redemption
Date, after excluding the highest and lowest of the Reference Treasury Dealer
Quotations, or (b) if the Trustee obtains fewer than three Reference Treasury
Dealer Quotations, the average of all Reference Treasury Dealer Quotations so
received.

         "Quotation Agent" means the Reference  Treasury Dealer appointed by the
Company.

         "Reference Treasury Dealer" means (a) each of Salomon Smith Barney
Inc., Banc of America Securities LLC, Chase Securities Inc., Mellon Financial
Markets, LLC and SunTrust Equitable Securities Corporation and their respective
successors, unless any of them ceases to be a primary U.S. Government securities
dealer in New York City (a "Primary Treasury Dealer"), in which case the Company
shall substitute another Primary Treasury Dealer; and (b) any other Primary
Treasury Dealer selected by the Company.

         "Reference Treasury Dealer Quotations" means, with respect to each
Reference Treasury Dealer and any Redemption Date, the average, as determined by
the Trustee, of the bid and asked prices for the Comparable Treasury Issue
(expressed in each case as a percentage of its principal amount) quoted in
writing to the Trustee by that Reference Treasury Dealer at 5:00 p.m., New York
City time, on the third business day preceding that Redemption Date.

         In the event of redemption of this Security in part only, a new
Security or Securities of this series and of like tenor for the unredeemed
portion hereof will be issued in the name of the Holder hereof upon the
cancellation hereof.

         The Securities do not have the benefit of any sinking fund obligations.

         In the event of a deposit or withdrawal of an interest in this Security
(including upon an exchange, transfer, redemption or repurchase of this Security
in part only) effected in accordance with the Applicable Procedures, the
Security Registrar, upon receipt of notice of such event from the Depositary's
custodian for this Security, shall make an adjustment on its records to reflect
an increase or decrease of the Outstanding principal amount of this Security
resulting from such deposit or withdrawal, as the case may be.

         If an Event of Default shall occur and be continuing, the principal of
all the Securities may be declared due and payable in the manner and with the
effect provided in the Indenture.

         The Indenture contains provisions for defeasance at any time of (i) the
entire indebtedness of this Security, or (ii) certain restrictive covenants and
Events of Default with respect to this Security, in each case upon compliance
with certain conditions set forth therein.

         Unless the context otherwise requires, the Original Securities (as
defined in the Indenture) and the Exchange Securities (as defined in the
Indenture) shall constitute one

                                      -6-
<PAGE>

series for all purposes under the Indenture, including without limitation,
amendments, waivers and redemptions.

         The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders of the Securities under the Indenture at
any time by the Company and the Trustee with the consent of the Holders of 50%
in aggregate principal amount of the Securities at the time Outstanding. The
Indenture also contains provisions permitting the Holders of specified
percentages in aggregate principal amount of the Securities at the time
Outstanding, on behalf of the Holders of all the 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 Security shall be conclusive and binding upon such Holder
and upon all future Holders of this Security and of any Security issued upon the
registration of transfer hereof or in exchange herefor or in lieu hereof,
whether or not notation of such consent or waiver is made upon this Security.

         As provided in and subject to the provisions of the Indenture, the
Holder of this Security shall not have the right to institute any proceeding
with respect to the Indenture or for the appointment of a receiver or trustee or
for any other remedy thereunder, unless such Holder shall have previously given
the Trustee written notice of a continuing Event of Default, the Holders of not
less than 25% in principal amount of the Outstanding Securities shall have made
written request to the Trustee to institute proceedings in respect of such Event
of Default as Trustee and offered the Trustee reasonable indemnity, and the
Trustee shall not have received from the Holders of a majority in principal
amount of Outstanding Securities a direction inconsistent with such request, and
shall have failed to institute any such proceeding, for 60 days after receipt of
such notice, request and offer of indemnity. The foregoing shall not apply to
any suit instituted by the Holder of this Security for the enforcement of any
payment of principal hereof or any premium or interest hereon on or after the
respective due dates expressed herein.

         No reference herein to the Indenture and no provision of this Security
or of the Indenture shall alter or impair the obligation of the Company, which
is absolute and unconditional, to pay the principal of (and premium, if any) and
interest on this Security at the times, place and rate, and in the coin or
currency, herein prescribed.

         As provided in the Indenture and subject to certain limitations therein
set forth, the transfer of this Security is registrable in the Security
Register, upon surrender of this Security for registration of transfer at the
office or agency of the Company in The City of New York, New York, 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
Securities, of authorized denominations and for the same aggregate principal
amount, will be issued to the designated transferee or transferees.

                                      -7-
<PAGE>


         The Securities are issuable only in registered form without coupons in
denominations of $1,000 and any integral multiple thereof. As provided in the
Indenture and subject to certain limitations therein set forth, Securities are
exchangeable for a like aggregate principal amount of Securities of a different
authorized denomination, as requested by the Holder surrendering the same.

         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.

         Prior to due presentment of this Security 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 Security is registered as the owner hereof for all
purposes, whether or not this Security be overdue, and neither the Company, the
Trustee nor any such agent shall be affected by notice to the contrary.

         Interest on this Security shall be computed on the basis of a 360-day
year of twelve 30-day months.

         All terms used in this Security which are defined in the Indenture
shall have the meanings assigned to them in the Indenture.






                                      -8-