<PAGE>   1
                                                                Exhibit 10.22(a)


                           ASSIGNMENT AND REASSIGNMENT
                              OF PROJECT AGREEMENTS
                                      (BA3)


                            Dated as of July 20, 2000


                                     between

                                PPL MONTANA, LLC,
                                   as Assignor



                                       and

                                MONTANA OL4 LLC,
                                   as Assignee


                           COLSTRIP GENERATING UNIT 3
                          AND RELATED COMMON FACILITIES
<PAGE>   2
                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                            PAGE


<S>                <C>                                                      <C>
SECTION 1.         DEFINITIONS...........................................     2

SECTION 2.         ASSIGNMENT OF PROJECT AGREEMENTS TO OWNER LESSOR......     3

     Section 2.1      Transfer/Assignment of Ownership Agreement 3-4.....     3

     Section 2.2      Assignment of Common Facilities Agreement..........     3

     Section 2.3      Assignment of Vote Sharing Agreement...............     3

     Section 2.4      Assumption by the Owner Lessor.....................     4

SECTION 3.         TRANSFER/REASSIGNMENT OF PROJECT AGREEMENTS TO PPL
                   MONTANA ..............................................     4

     Section 3.1      Transfer/Reassignment of Ownership Agreement 3-4...     4

     Section 3.2      Reassignment of Common Facilities Agreement........     4

     Section 3.3      Reassignment of Vote Sharing Agreement.............     5

     Section 3.4      Assumption by PPL Montana..........................     5

SECTION 4.         PROJECT COMMITTEE MEMBER..............................     5

SECTION 5.         AMENDMENT OF PROJECT AGREEMENTS.......................     5

SECTION 6.         SECURITY FOR OWNER LESSOR'S OBLIGATION UNDER LESSOR
                   NOTE .................................................     6

SECTION 7.         MISCELLANEOUS.........................................     6

     Section 7.1      Amendments and Waivers.............................     6

     Section 7.2      Notices............................................     6

     Section 7.3      Survival...........................................     7

     Section 7.4      Successors and Assigns.............................     8

     Section 7.5      Governing Law......................................     8

     Section 7.6      Severability.......................................     8

     Section 7.7      Counterparts.......................................     8

     Section 7.8      Headings...........................................     8

     Section 7.9      Further Assurances.................................     8

     Section 7.10     Effectiveness of Colstrip Agreements Reassignment..     8

     Section 7.11     Limitation of Liability............................     8

     Section 7.12     Measuring Life.....................................     9
</TABLE>



                                       -i-
<PAGE>   3
                           ASSIGNMENT AND REASSIGNMENT
                              OF PROJECT AGREEMENTS
                                      (BA3)



         This ASSIGNMENT AND REASSIGNMENT OF PROJECT AGREEMENTS (BA3), dated as
of July 20, 2000 (this "Agreement"), is entered into between PPL MONTANA, LLC, a
Delaware limited liability company ("PPL Montana") and MONTANA OL4 LLC, a
Delaware limited liability company (the "Owner Lessor").

         WHEREAS, the rights and obligations as tenants-in-common of the
co-owners of Units 3 and 4 and the Common Facilities 3-4 are governed by the
Ownership Agreement 3-4; and the rights and obligations as tenants-in-common of
the co-owners of the Common Facilities 1-2-3-4 are governed by the Common
Facilities Agreement;

         WHEREAS, in connection with the purchase by PPL Montana of Unit 3 from
Montana Power Company ("MPC"), PPL Montana and MPC entered into a Project
Committee Vote Sharing Agreement, entered into as of December 17, 1999 (the
"Vote Sharing Agreement") in accordance with which PPL Montana, as "Owner" of
Unit 3, and MPC, as "Project User" of Unit 4, agreed to share the right to
direct the vote of one member of the Project Committee created pursuant to
Section 17 of the Ownership Agreement 3-4 (such vote of such member of the
Project Committee shared by PPL Montana and MPC pursuant to the Vote Sharing
Agreement hereinafter called the "Shared Vote");

         WHEREAS, simultaneously herewith, PPL Montana has conveyed to the Owner
Lessor the Undivided Interest pursuant to the Bill of Sale, and has leased to
the Owner Lessor the Ground Interest pursuant to the Site Lease and Sublease;

         WHEREAS, the Owner Lessor will lease to PPL Montana the Undivided
Interest pursuant to the Facility Lease, and will sublease to PPL Montana the
Ground Interest pursuant to the Site Lease and Sublease, in each case for the
Facility Lease Term;

         WHEREAS, pursuant to this Agreement and the terms hereof, (i) PPL
Montana will assign to the Owner Lessor the Owner Lessor's Percentage of all of
PPL Montana's right, title and interest as "Owner" under the Ownership Agreement
3-4 and (ii) the Owner Lessor will reassign all of Owner Lessor's right, title,
and interest under the Ownership Agreement 3-4 assigned to it by PPL Montana
hereunder back to PPL Montana for a term equal to the Facility Lease Term
(unless earlier terminated pursuant to the terms of this Agreement);

         WHEREAS, pursuant to this Agreement and the terms hereof, (i) PPL
Montana will assign to the Owner Lessor all of PPL Montana's right, title and
interest as "Owner" under the Common Facilities Agreement with respect to
Colstrip Unit 3, and (ii) the Owner Lessor will reassign all of Owner Lessor's
right, title, and interest under the Common Facilities Agreement
<PAGE>   4
assigned to it by PPL Montana hereunder back to PPL Montana for a term equal to
the Facility Lease Term (unless earlier terminated pursuant to the terms of this
Agreement);

         WHEREAS, pursuant to this Agreement and the terms hereof, (i) PPL
Montana will assign to the Owner Lessor all of PPL Montana's right, title and
interest under the Vote Sharing Agreement, and (ii) the Owner Lessor will
reassign all of Owner Lessor's right, title, and interest under the Vote Sharing
Agreement assigned to it by PPL Montana hereunder back to PPL Montana for a term
equal to the Facility Lease Term (unless earlier terminated pursuant to the
terms of this Agreement); and

         WHEREAS, the parties to this Agreement desire to clarify the Owner
Lessor's and PPL Montana's rights and obligations relating to the Undivided
Interest under the Project Agreements.

         NOW, THEREFORE, in consideration of the foregoing premises, the mutual
agreements herein contained, and other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereto
agree as follows:

SECTION 1. DEFINITIONS

         Unless the context hereof shall otherwise require, capitalized terms
used, including those in the recitals, and not otherwise defined herein shall
have the respective meanings set forth in Appendix A to the Participation
Agreement (BA3), dated as of July 13, 2000, among PPL Montana, the Owner Lessor,
the Owner Participant referred to therein, Wilmington Trust Company, in the
capacities referred to therein, and The Chase Manhattan Bank, in the capacities
referred to therein. The general provisions of such Appendix A shall apply to
the terms used in this Agreement and specifically defined herein.

         As used in this Agreement, the following terms shall have the
respective meanings assigned thereto as follows:

         "Costs" shall have the meaning specified in Section 5 of the Common
Facilities Agreement.

         "Costs of Operation" shall have the meaning ascribed to such term in
the Ownership Agreement 3-4.

         "Lessor Possession Date" shall mean the earlier to occur of (a) the
expiration of the Facility Lease Term, and (b) the date on which PPL Montana
shall lose possession of the Undivided Interest pursuant to Section 13 (unless
it shall have purchased the Undivided Interest), 14 or 17 of the Facility Lease.

         "Net Generating Capability" shall have the meaning ascribed to such
term in the Ownership Agreement 3-4.

         "Owner" shall mean the owner of the Undivided Interest pursuant to the
Ownership Agreement 3-4.


                                       2
<PAGE>   5
         "Project Agreements" shall mean the Ownership Agreement 3-4, the Vote
Sharing Agreement and the Common Facilities Agreement.

         "Project User" shall have the meaning specified in Section 1 of the
Ownership Agreement 3-4.

         "Unit 4 Loss" shall mean the date of the decommissioning or permanent
taking out of service of Unit 4.

SECTION 2. ASSIGNMENT OF PROJECT AGREEMENTS TO OWNER LESSOR

         Section 2.1 Transfer/Assignment of Ownership Agreement 3-4.

                  (a) PPL Montana as seller of the Undivided Interest conveyed
(and for avoidance of doubt hereby assigns) to the Owner Lessor the Owner
Lessor's Percentage of all of PPL Montana's right, title, and interest in, to
and under (i) the Ownership Agreement 3-4 as "Owner" of a 30% undivided interest
in Colstrip Unit 3 and (ii) the Rights Sharing Agreement. It is expressly
recognized that this assignment does not include any of PPL Montana's right,
title and interest under the Ownership Agreement 3-4 as "Operator" of Colstrip
Units 3 and 4. The assignment effected by this Section 2.1(a) shall terminate
only (i) upon early termination of the Facility Lease pursuant to and in
accordance with Section 10 thereof, or (ii) if PPL Montana purchases the
Undivided Interest upon the early termination of the Facility Lease pursuant to
and in accordance with Section 13 thereof.

                  (b) The parties hereto agree that, in consequence of the
assignment effected by Section 2.1(a) and the reassignment effected by Section
3.1(a), from and after the Lessor Possession Date, the Owner Lessor shall have
the Owner Lessor's Percentage of all right, title and interest of PPL Montana in
and to, and under the Ownership Agreement 3-4 and the Rights Sharing Agreement

         Section 2.2 Assignment of Common Facilities Agreement. PPL Montana
hereby assigns to the Owner Lessor the Owner Lessor's Percentage of PPL
Montana's right, title, and interest in, to and under the Common Facilities
Agreement as "Owner" of a 30% undivided interest in Colstrip Unit 3. It is
expressly recognized that this assignment does not include any of PPL Montana's
right, title and interest under the Common Facilities Agreement as "Common
Facilities Operator" or as "Owner" of an undivided interest in Colstrip Units 1
and 2. The assignment effected by this Section 2.2 shall terminate only (i) upon
early termination of the Facility Lease pursuant to and in accordance with
Section 10 thereof, or (ii) if PPL Montana purchases the Undivided Interest upon
the early termination of the Facility Lease pursuant to and in accordance with
Section 13 thereof.

         Section 2.3 Assignment of Vote Sharing Agreement. PPL Montana hereby
assigns to the Owner Lessor all of PPL Montana's right, title, and interest in,
to and under the Vote Sharing Agreement. The assignment effected by this Section
2.3 shall terminate only (i) upon the early termination of the Facility Lease
pursuant to and in accordance with Section 10 thereof, or (ii) if PPL Montana
purchases the Undivided Interest upon the early termination of the Facility
Lease pursuant to and in accordance with Section 13 thereof.



                                       3
<PAGE>   6
         Section 2.4 Assumption by the Owner Lessor.

                  (a) Subject to paragraph (b) of this Section 2.4, the Owner
Lessor hereby assumes and agrees to perform, effective as of the Lessor
Possession Date, the Owner Lessor's Percentage of all of the duties and
obligations of PPL Montana as "Owner" of the 30% undivided interest in Colstrip
Unit 3 under the Ownership Agreement 3-4, the Rights Sharing Agreement and the
Common Facilities Agreement and all of the duties and obligations of PPL Montana
under the Vote Sharing Agreement.

                  (b) Notwithstanding anything to the contrary hereinabove set
forth, the Owner Lessor shall not be liable (i) prior to the Lessor Possession
Date, for any Costs of Operation of Unit 3 or any part thereof, any Costs
relating to the Common Facilities or any part thereof, or any other costs or
expense in connection with the operation, maintenance or improvement of Colstrip
Unit 3 or any part thereof, or for the performance of any of the duties and
obligations of PPL Montana under the Vote Sharing Agreement, or (ii) after the
Lessor Possession Date but prior to any Unit 4 Loss, for any Costs relating to
the Common Facilities in excess of Owner Lessor's Percentage of 15% of the
amount of the Costs allocated to the Project Users pursuant to the Common
Facilities Agreement, (iii) after the later of the Lessor Possession Date and
any Unit 4 Loss, for any Costs relating to the Common Facilities in excess of
the Owner Lessor's Percentage of 30% of the amount of the Costs allocated to the
Project Users pursuant to the Common Facilities Agreement.

SECTION 3. TRANSFER/REASSIGNMENT OF PROJECT AGREEMENTS TO PPL MONTANA

         Section 3.1 Transfer/Reassignment of Ownership Agreement 3-4.

                  (a) The Owner Lessor as lessor of the Undivided Interest is
conveying (and for avoidance of doubt hereby reassigns) to PPL Montana all of
the Owner Lessor's right, title, and interest in, to and under (i) the Ownership
Agreement 3-4 as a "Project User" of the Undivided Interest being leased to PPL
Montana pursuant to the Facility Lease and (ii) the Rights Sharing Agreement.
The reassignment effected by this Section 3.1(a) shall terminate only (x) on the
later to occur of the stated expiration of the Facility Lease Term or any
Renewal Lease Term elected by PPL Montana in accordance with Section 15 of the
Facility Lease, (y) upon the earlier termination of the Facility Lease pursuant
to and in accordance with Section 10, 13 or 14 of the Facility Lease, or (z)
upon the earlier termination of the Facility Lease pursuant to and in accordance
with Section 17.1(b) of the Facility Lease in consequence of a Lease Event of
Default thereunder.

                  (b) The parties hereto agree that, in consequence of the
transfer/assignment effected by Section 3.1(a), from and after the date of this
Agreement until the reassignment shall have terminated pursuant to Section
3.1(a), PPL Montana shall, inter alia, have all right, title and interest of the
Owner Lessor as a "Project User" in, to and under the Ownership Agreement 3-4
and the Rights Sharing Agreement.

         Section 3.2 Reassignment of Common Facilities Agreement. The Owner
Lessor hereby reassigns all of Owner Lessor's right, title, and interest in, to
and under the Common Facilities


                                       4
<PAGE>   7
Agreement assigned to it by PPL Montana pursuant to Section 2.2 back to PPL
Montana. The reassignment effected by this Section 3.2 shall terminate only (i)
on the later to occur of the stated expiration of the Facility Lease Term or any
Renewal Lease Term elected by PPL Montana in accordance with Section 15 of the
Facility Lease, (ii) upon the earlier termination of the Facility Lease pursuant
to and in accordance with Section 10, 13 or 14 of the Facility Lease, or (iii)
upon the earlier termination of the Facility Lease pursuant to and in accordance
with Section 17.1(b) of the Facility Lease in consequence of a Lease Event of
Default thereunder.

         Section 3.3 Reassignment of Vote Sharing Agreement. The Owner Lessor
hereby reassigns all of the Owner Lessor's right, title, and interest under the
Vote Sharing Agreement assigned to it by PPL Montana pursuant to Section 2.3
back to PPL Montana. The reassignment effected by this Section 3.3 shall
terminate only (i) on the later to occur of the stated expiration of the
Facility Lease Term or any Renewal Lease Term elected by PPL Montana in
accordance with Section 15 of the Facility Lease, (ii) upon the earlier
termination of the Facility Lease pursuant to and in accordance with Section 10,
13 or 14 of the Facility Lease, or (iii) upon the earlier termination of the
Facility Lease pursuant to and in accordance with Section 17.1(b) of the
Facility Lease in consequence of a Lease Event of Default thereunder.

         Section 3.4 Assumption by PPL Montana. PPL Montana hereby assumes and
agrees to perform, effective as of the date of this Agreement, all of the duties
and obligations of the Owner Lessor relating to the Unit 3 Interest under the
Ownership Agreement 3-4, the Rights Sharing Agreement and the Common Facilities
Agreement arising or relating to the period prior to the Lessor Possession Date
with respect to such Unit Interest, and all of the duties and obligations of the
Owner Lessor under the Voting Sharing Agreement arising or relating to the
period prior to the Lessor Possession Date. The parties hereto agree that, in
consequence of the reassignment effected by this Section 3, PPL Montana shall,
from and after the date hereof to the Lessor Possession Date, perform all of the
duties and obligations of the Owner Lessor under the Vote Sharing Agreement and
be liable for all costs relating to the operation and maintenance of and
improvement to Colstrip Unit 3 attributable to the Undivided Interest or the
Ground Interest.

SECTION 4. PROJECT COMMITTEE MEMBER.

         The Owner Lessor and PPL Montana agree that, assuming that the
Ownership Agreement 3-4 has not been amended to allow each "Project User" to
appoint a member to the Project Committee, the right under the Vote Sharing
Agreement to jointly with MPC and its successor and assigns appoint one member
to the Project Committee (and to direct such member) shall be voted in
accordance with the Omnibus Voting Agreement.

SECTION 5. AMENDMENT OF PROJECT AGREEMENTS.

         PPL Montana agrees that it will not, without the prior written consent
of the Owner Lessor, consent to any amendment, modification or supplement to the
Project Agreements that could reasonably be expected to have a material adverse
effect on the rights of the Owner Lessor or, so long as the Lien of the Lease
Indenture shall not have been terminated or discharged, the Lease Indenture
Trustee, or the value of the Undivided Interest, unless such modification or
supplement is required by Applicable Law or is necessary to operate or maintain
the Colstrip Project in compliance with Applicable Law.



                                       5
<PAGE>   8
SECTION 6. SECURITY FOR OWNER LESSOR'S OBLIGATION UNDER LESSOR NOTE

         In order to secure the Lessor Note, the Owner Lessor will, pursuant to
the Lease Indenture, grant a Lien to the Lease Indenture Trustee in and to all
of the Owner Lessor's right, title and interest in, to and under this Agreement.
PPL Montana hereby consents to such assignment and creation of such Lien and
acknowledges receipt of copies of the Lease Indenture, it being understood that
such consent shall not affect any requirement or the absence of any requirement
for any consent under any other circumstances. Unless and until the Owner Lessor
shall have received written notice from the Lease Indenture Trustee that the
Lien of the Lease Indenture has been fully released, the Lease Indenture Trustee
under the Lease Indenture shall have the rights of the Owner Lessor under this
Agreement to the extent set forth in, and subject in each case to, the
exceptions set forth in, the Lease Indenture.

SECTION 7. MISCELLANEOUS

         Section 7.1 Amendments and Waivers. No term, covenant, agreement or
condition of this Agreement may be terminated, amended or compliance therewith
waived (either generally or in a particular instance, retroactively or
prospectively) except by an instrument or instruments in writing executed by
each party hereto.

         Section 7.2 Notices. Unless otherwise expressly specified or permitted
by the terms hereof, all communications and notices provided for herein shall be
in writing or by a telecommunications device capable of creating a written
record, and any such notice shall become effective (a) upon personal delivery
thereof, including by overnight mail or courier service, (b) in the case of
notice by United States mail, certified or registered, postage prepaid, return
receipt requested, upon receipt thereof, or (c) in the case of notice by such a
telecommunications device, upon transmission thereof, provided such transmission
is promptly confirmed by either of the methods set forth in clauses (a) or (b)
above, in each case addressed to each party hereto at its address set forth
below or, in the case of any such party hereto, at such other address as such
party may from time to time designate by written notice to the other parties
hereto:

If to PPL Montana:

                  303 North Broadway, Suite 400
                  Billings, MT  59101
                  Telephone No.: (406) 869-5100
                  Facsimile No.: (406) 869-5149
                  Attention: Vice President and General Counsel





                                       6
<PAGE>   9
If to the Owner Lessor:

                  Montana OL4 LLC
                  c/o Wilmington Trust Company
                  Rodney Square North
                  1100 North Market Street
                  Wilmington, Delaware 19890-0001
                  Telephone No.: (302) 651-1000
                  Facsimile No.: (302) 651-8882
                  Attention: Corporate Trust Administration

         with a copy to:

                  Montana OP4 LLC
                  c/o Bell Atlantic Credit Corporation
                  245 Park Avenue, 40th Floor
                  New York, New York 10167
                  Telephone No.: (212) 557-4799
                  Facsimile No.: (212) 557-4569
                  Attention: Asset Administrator

         and to the Lease Indenture Trustee:

                  c/o The Chase Manhattan Bank
                  Capital Markets Fiduciary Services
                  450 West 33rd Street, 15th Floor
                  New York, New York 10001-2697
                  Telephone No.: (212) 946-7557
                  Facsimile No.: (212) 946-8177/8
                  Attention: Annette M. Marsula

         If to the Pass Through Trustee:

                  c/o The Chase Manhattan Bank
                  Capital Markets Fiduciary Services
                  450 West 33rd Street, 15th Floor
                  New York, New York 10001-2697
                  Telephone No.: (212) 946-7557
                  Facsimile No.: (212) 946-8177/8

         A copy of all notices provided for herein shall be sent by the party
giving such notice to each of the other parties hereto.

         Section 7.3 Survival. Except as expressly set forth herein, the
warranties and covenants made by each party hereto shall not survive the
expiration or termination of this Agreement.



                                       7
<PAGE>   10
         Section 7.4 Successors and Assigns.

                  (a) This Agreement shall be binding upon and shall inure to
the benefit of, and shall be enforceable by, the parties hereto and their
respective successors and permitted assigns as permitted by and in accordance
with the terms hereof.

                  (b) Except as expressly provided herein or in any other
Operative Document, PPL Montana may not assign or transfer any of its interests
herein without the consent of the Owner Lessor.

         Section 7.5 Governing Law. This Agreement shall be in all respects
governed by and construed in accordance with the laws of the State of New York,
including all matters of construction, validity and performance (without giving
effect to the conflicts of laws provision thereof, other than New York General
Obligations Law Section 5-1401), except to the extent the laws of the State of
Montana are mandatorily applicable under the laws of the State of Montana.

         Section 7.6 Severability. If any provision hereof shall be invalid,
illegal or unenforceable under Applicable Law, the validity, legality and
enforceability of the remaining provisions hereof shall not be affected or
impaired thereby.

         Section 7.7 Counterparts. This Agreement may be executed in any number
of counterparts, each executed counterpart constituting an original but all
together only one instrument.

         Section 7.8 Headings. The headings of the sections and table of
contents of this Agreement are inserted for purposes of convenience only and
shall not be construed to affect the meaning or construction of any of the
provisions hereof.

         Section 7.9 Further Assurances. Each party hereto will promptly and
duly execute and deliver such further documents to make such further assurances
for and take such further action reasonably requested by any party to whom such
first party is obligated, all as may be reasonably necessary to carry out more
effectively the intent and purpose of this Agreement.

         Section 7.10 Effectiveness of Colstrip Agreements Reassignment. This
Agreement has been dated as of the date first above written for convenience
only. This Agreement shall become effective on July 20, 2000, the date of
execution and delivery by each of PPL Montana and the Owner Lessor.

         Section 7.11 Limitation of Liability. It is expressly understood and
agreed by the parties hereto that (a) this Agreement is executed and delivered
by Wilmington Trust Company ("Wilmington"), not individually or personally but
solely as Lessor Manager under the LLC Agreement, in the exercise of the powers
and authority conferred and vested in it pursuant thereto, (b) each of the
representations, undertakings and agreements herein made on the part of the
Owner Lessor is made and intended not as personal representations, undertakings
and agreements by Wilmington but is made and intended for the purpose for
binding only the Owner Lessor, (c) nothing herein contained shall be construed
as creating any liability on Wilmington individually or personally, to perform
any covenant either expressed or implied contained herein, all such liability,
if any, being expressly waived by the parties hereto or by any Person claiming


                                       8
<PAGE>   11
by, through or under the parties hereto and (d) under no circumstances shall
Wilmington, be personally liable for the payment of any indebtedness or expenses
of the Owner Lessor or be liable for the breach or failure of any obligation,
representation, warranty or covenant made or undertaken by the Owner Lessor
under this Agreement.

         Section 7.12 Measuring Life. If and to the extent that any of the
rights and privileges granted under this Agreement, would, in the absence of the
limitation imposed by this sentence, be invalid or unenforceable as being in
violation of the rule against perpetuities or any other rule or law relating to
the vesting of interests in property or the suspension of the power of
alienation of property, then it is agreed that notwithstanding any other
provision of this Agreement, such options, rights and privileges, subject to the
respective conditions hereof governing the exercise of such options, rights and
privileges, will be exercisable only during (a) the longer of (i) a period which
will end twenty-one (21) years after the death of the last survivor of the
descendants living on the date of the execution of this Agreement, of the
following Presidents of the United States: Franklin D. Roosevelt, Harry S.
Truman, Dwight D. Eisenhower, John F. Kennedy, Lyndon B. Johnson, Richard M.
Nixon, Gerald R. Ford, James E. Carter, Ronald W. Reagan, George H.W. Bush and
William J. Clinton or (ii) the period provided under the Uniform Statutory Rule
Against Perpetuities or (b) the specific applicable period of time expressed in
this Agreement, whichever of (a) and (b) is shorter.






                                       9
<PAGE>   12
         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed by their respective officers thereunto duly authorized.




                                  PPL MONTANA, LLC


                                  By:  /s/ Paul A. Farr
                                     -------------------------------------------
                                     Name:  Paul A. Farr
                                     Title: Vice President


                                  MONTANA OL4 LLC


                                  By: Wilmington Trust Company,
                                      not in its individual capacity, but solely
                                      as Lessor Manager


                                      By:  /s/ James P. Lawler
                                         ---------------------------------------
                                         Name:  James P. Lawler
                                         Title: Vice President