<PAGE>

                                                                     Exhibit 4.9

                                                                  EXECUTION COPY

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                                 U.S.$80,000,000

                    WORKING CAPITAL FACILITY CREDIT AGREEMENT

                                      among

            CONSTRUCTORA DE PROYECTOS HIDROELECTRICOS, S.A. DE C.V.,

                                  as Borrower,

         THE SEVERAL WORKING CAPITAL FACILITY LENDERS FROM TIME TO TIME
                                 PARTIES HERETO,

                                       and

                           WESTLB AG, NEW YORK BRANCH,

                as Working Capital Facility Administrative Agent

                          Dated as of October 19, 2007

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                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----
<S>                                                                         <C>
                                ARTICLE 1
                               DEFINITIONS

Section 1.1   Defined Terms .............................................     1
Section 1.2   Other Definitional Provisions .............................     4
Section 1.3   Rules of Construction .....................................     5

                                ARTICLE 2
                     AMOUNT AND TERMS OF COMMITMENTS

Section 2.1   Working Capital Facility Commitments ......................     5
Section 2.2   Procedure for Working Capital Facility Borrowings .........     5
Section 2.3   Repayment of Working Capital Loans ........................     7
Section 2.4   Optional Prepayments ......................................     7
Section 2.5   Conversion and Continuation Options .......................     7
Section 2.6   Interest Rates and Payment Dates ..........................     8
Section 2.7   Computation of Interest and Fees ..........................     9
Section 2.8   Inability to Determine Interest Rate ......................     9
Section 2.9   Pro Rata Treatment and Payments ...........................    10
Section 2.10  Fees. .....................................................    11
Section 2.11  Cancellation of Working Capital Facility Commitments ......    11

                                ARTICLE 3
                      REPRESENTATIONS AND WARRANTIES

Section 3.1   Representations and Warranties of the Borrower ............    12

                                ARTICLE 4
                           CONDITIONS PRECEDENT

Section 4.1   Conditions Precedent to the Initial Closing Date and the
                 Initial Working Capital Facility Borrowing .............    12
Section 4.2   Conditions Precedent to Each Working Capital Facility
                 Borrowing ..............................................    12

                                ARTICLE 5
                          AFFIRMATIVE COVENANTS

Section 5.1   Affirmative Covenants of the Borrower .....................    14

                                ARTICLE 6
                            NEGATIVE COVENANTS

Section 6.1   Negative Covenants of the Borrower ........................    14

                                ARTICLE 7
                          REPORTING OBLIGATIONS

Section 7.1   Reporting Obligations of the Borrower .....................    14
</TABLE>


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<TABLE>

<S>                                                                         <C>
                                ARTICLE 8
                            EVENTS OF DEFAULT

Section 8.1   Events of Default; Remedies. ..............................    14

                                ARTICLE 9
            THE WORKING CAPITAL FACILITY ADMINISTRATIVE AGENT

Section 9.1   Appointment ...............................................    15
Section 9.2   Delegation of Duties ......................................    15
Section 9.3   Exculpatory Provisions ....................................    16
Section 9.4   Reliance by Working Capital Facility Administrative
                 Agent ..................................................    16
Section 9.5   Notice of Default .........................................    16
Section 9.6   Non-Reliance on Working Capital Facility Administrative
                 Agent and Other Working Capital Facility Lenders .......    17
Section 9.7   Indemnification ...........................................    17
Section 9.8   Agent in Its Individual Capacity ..........................    18
Section 9.9   Successor Working Capital Facility Administrative Agent ...    18

                                ARTICLE 10
                              MISCELLANEOUS

Section 10.1  Incorporation of Miscellaneous Provisions by Reference ....    19
Section 10.2  Amendments and Waivers ....................................    19
Section 10.3  Notices ...................................................    20
Section 10.4  Survival of Representations and Warranties ................    20
Section 10.5  Successors and Assigns; Participations and Assignments ....    20
Section 10.6  Adjustments; Set off ......................................    23
Section 10.7  Counterparts ..............................................    24
Section 10.8  Severability ..............................................    24
Section 10.9  Integration ...............................................    24
Section 10.10 GOVERNING LAW, SUBMISSION TO JURISDICTION, ETC. ...........    24
</TABLE>


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SCHEDULES:

1    Commitments

EXHIBITS:

A    Form of Assignment and Assumption

B    Form of Interest Rate Notice

C    Form of Working Capital Facility Notice of Borrowing

D    Form of Disbursement LC


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<PAGE>

     WORKING CAPITAL FACILITY CREDIT AGREEMENT (this "Agreement"), dated as of
October 19, 2007, among CONSTRUCTORA DE PROYECTOS HIDROELECTRICOS, S.A. DE C.V.,
a sociedad anonima de capital variable organized under the laws of Mexico (the
"Borrower"), the several banks and other financial institutions or entities from
time to time parties to this Agreement (the "Working Capital Facility Lenders"),
and WESTLB AG, NEW YORK BRANCH, as working capital facility administrative agent
(the "Working Capital Facility Administrative Agent").

     The parties hereto hereby agree as follows:

                                    ARTICLE 1
                                   DEFINITIONS

     Section 1.1 Defined Terms. As used in this Agreement, the terms listed in
this Section 1.1 shall have the respective meanings set forth in this Section
1.1.:

     "Agreement": as defined in the preamble hereto.

     "Applicable Margin": means, on any date of determination, for an ABR Loan:
1.00% per annum, or for a Eurodollar Loan: 0.75% per annum.

     "Approved Fund": as defined in Section 10.5(b).

     "Assignee": as defined in Section 10.5(b).

     "Assignment": an Assignment and Assumption, substantially in the form of
Exhibit A.

     "Availability Period": with respect to the Working Capital Loans, the
period from the Signing Date until the earliest of (i) the date that is thirty
(30) days after the Signing Date in the event that the Initial Closing Date
shall not have occurred by such date, (ii) full utilization of the amounts
available under the aggregate Working Capital Facility Commitments, and (iii)
the Loan Maturity Date.

     "Benefitted Lender": as defined in Section 10.6(a).

     "Borrower": as defined in the preamble hereto.

     "Borrowing Date": any Business Day specified by the Borrower as a date on
which the Borrower requests the Working Capital Facility Lenders to make Working
Capital Loans hereunder.

     "Cost Certificate": a certificate, in substantially the form of Schedule I
to Exhibit C hereto, duly executed and delivered by the Borrower's Financial
Representative to the Working Capital Facility Administrative Agent and the
Independent Engineer pursuant to Section 4.02(a) of the Common Agreement and
Section 2.2(b) of this Agreement in connection with each Working Capital
Facility Borrowing.


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<PAGE>

     "Critical Event" has the meaning assigned to Evento Critico in the Public
Works Contract.

     "Critical Event Date" has the meaning assigned to Fecha de Evento Critico
in the Public Works Contract.

     "Disbursement LC Provider": an Acceptable LC Provider (or any other
financial institution acceptable to the Working Capital Facility Administrative
Agent in its sole discretion) issuing or, if applicable, confirming any
Disbursement LC.

     "Disbursement LCs": means, collectively, the standby letters of credit,
each in substantially the form of Exhibit D to this Agreement (or otherwise in
form and substance acceptable to the Working Capital Facility Administrative
Agent), issued or confirmed by the Disbursement LC Providers in favor of the
Working Capital Facility Administrative Agent.

     "Funding Office": the office of the Working Capital Facility Administrative
Agent set forth on its signature page to the Common Agreement or such other
office as may be specified from time to time by the Working Capital Facility
Administrative Agent as its funding office by written notice to the Borrower and
the Working Capital Facility Lenders.

     "Interest Payment Date": (a) as to any ABR Loan, the last day of each
calendar month to occur while such ABR Loan is outstanding and the final
maturity date of such ABR Loan, (b) as to any Eurodollar Loan having an Interest
Period of one month, the last day of such Interest Period and (c) as to any
Working Capital Loan (other than any Working Capital Loan that is an ABR Loan),
the date of any repayment or prepayment made in respect thereof.

     "Interest Period": as to any Eurodollar Loan, (a) initially, the period
commencing on the borrowing or conversion date, as the case may be, with respect
to such Eurodollar Loan and ending one month thereafter, as set forth by the
Borrower in its Working Capital Facility Notice of Borrowing or notice of
conversion, as the case may be, given with respect thereto; and (b) thereafter,
each period commencing on the last day of the next preceding Interest Period
applicable to such Eurodollar Loan and ending one month thereafter, as set forth
by the Borrower by irrevocable notice to the Working Capital Facility
Administrative Agent not later than 11:00 A.M., New York City time, on the date
that is three Business Days prior to the last day of the then current Interest
Period with respect thereto; provided that, all of the foregoing provisions
relating to Interest Periods are subject to the following:

          (i) if any Interest Period would otherwise end on a day that 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) the Borrower may not select an Interest Period that would extend
     beyond the Loan Maturity Date;

          (iii) any Interest Period 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


                                        2

<PAGE>

     month at the end of such Interest Period) shall end on the last Business
     Day of a calendar month; and

          (iv) the Borrower shall select Interest Periods so as not to require a
     payment or prepayment of any Eurodollar Loan during an Interest Period for
     such Eurodollar Loan.

     "Interest Rate Notice": as defined in Section 2.2(c).

     "Monthly Payment Date": the earlier of (i) the date of any Working Capital
Facility Borrowing in each calendar month and (ii), if no Working Capital
Facility Borrowing has occurred in a calendar month, the last Business Day of
such calendar month.

     "Participant": as defined in Section 10.5(c).

     "Permissible Critical Event Delay" means any delay in achieving any
Critical Event (other than the Provisional Acceptance of the First Unit or the
Project Completion) on the date set forth therefor on the Construction Schedule
(a) that is excused pursuant to Section 13.3(b) of the Public Works Contract,
provided that (i) such delay does not equal or exceed sixty (60) days in the
aggregate and (ii) all documented financial costs incurred by the Borrower as a
result of such delay are being paid by CFE to the Borrower when due in
accordance with the Public Works Contract (or CFE has recognized in a writing
executed after the occurrence of the relevant act or omission of CFE (which
writing is in form and substance satisfactory to the Working Capital Facility
Administrative Agent) its obligation to pay such amounts not later than on the
Loan Maturity Date), (b) that is excused pursuant to Section 13.3(a) of the
Public Works Contract as the result of Governmental Force Majeure, provided that
such delay does not equal or exceed sixty (60) days in the aggregate, (c) that
is excused pursuant to Section 13.3(a) of the Public Works Contract as the
result of an Event of Force Majeure which does not continue for more than one
hundred eighty (180) consecutive days or two hundred seventy (270) cumulative
days, (d) that is excused pursuant to a written waiver validly executed and
delivered by CFE, a copy of which (certified as true, correct and complete by
the Borrower) shall have been provided to the Working Capital Facility
Administrative Agent or (e) that is attributable to any other reason (other than
a Commission PWC Event of Default or an Event of Force Majeure), provided that
(i) such delay does not equal or exceed thirty (30) days and (ii) the Working
Capital Facility Administrative Agent is satisfied that all amounts payable to
CFE under the Public Works Contract during the period of such delay will be made
pursuant to the Public Works Contract and the Performance Guarantee, and, in
each of (a), (b), (c) and (d), provided CFE shall provided a written
acknowledgement to the Borrower, a copy of which (certified as true, correct and
complete by the Borrower) shall have been provided to the Working Capital
Facility Administrative Agent, that the delay is excusable under Section
13.3(a), 13.3(b) of the Public Works Contract or such waiver, as applicable;
provided that after giving effect to any such delay under (a), (b), (c), (d) and
(e) above the representations and warranties set forth in subsection 5.01(dd) of
the Common Agreement are true and correct.

     "Register": as defined in Section 10.5(b).

     "United States": the United States of America.


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<PAGE>

     "Working Capital Facility Administrative Decision": means (i) the
determination of Eurodollar Base Rate and ABR from time to time and (ii) any of
the other routine and administrative decisions, actions, authorizations,
directions, approvals, determinations, waivers and consents that (a) do not
relate to a Default or Event of Default (except to the limited extent set forth
in the proviso in Section 9.5) and could not reasonably be expected to result in
a Default or Event of Default, (b) could not have a Material Adverse Effect on
the interests of any Secured Party and (c) do not constitute Fundamental
Decisions or require the instruction or direction of the Working Capital
Facility Administrative Agent by any Working Capital Facility Lender or Working
Capital Facility Lenders or their approval or consent pursuant to the Common
Agreement, the Intercreditor Agreement or the Working Capital Facility Credit
Agreement.

     "Working Capital Facility Commitment": as to any Working Capital Facility
Lender, the obligation of such Working Capital Facility Lender to make a Working
Capital Loan to the Borrower in a principal amount not to exceed the amount set
forth under the heading "Commitment" opposite such Working Capital Facility
Lender's name on Schedule 1 or in the Assignment pursuant to which such Working
Capital Facility Lender became a party hereto, as the same may be changed from
time to time pursuant to the terms hereof. The original aggregate amount of the
Working Capital Facility Commitments is eighty million U.S. Dollars
($80,000,000).

     "Working Capital Facility Lenders": as defined in the preamble hereto;
provided, that unless the context otherwise requires, each reference herein to
the Working Capital Facility Lenders shall be deemed to include any Conduit
Lender.

     "Working Capital Facility Notice of Borrowing" means the notice and related
Cost Certificate, in substantially the form of Exhibit C hereto, duly executed
and delivered by the Borrower's Financial Representative to the Working Capital
Facility Administrative Agent and the Independent Engineer pursuant to Section
4.02(a) of the Common Agreement and Section 2.2(b) of this Agreement in
connection with each Working Capital Facility Borrowing. Each Working Capital
Facility Notice of Borrowing shall specify the amount of the requested Working
Capital Facility Borrowing.

     "Working Capital Facility Percentage": in respect of any Working Capital
Facility Lender, the percentage set forth next to such Lender's name under the
column entitled "Percentage" on Schedule 1 (as reduced or increased by later
Assignments) or in the Assignment pursuant to which such Lender became a Working
Capital Facility Lender.

     "Working Capital Loan": any loan made by any Working Capital Facility
Lender pursuant to this Agreement.

     Section 1.2 Other Definitional Provisions. (a) All capitalized terms used
and not defined herein shall have the respective meanings assigned thereto in
the Common Agreement.

          (b) The meanings given to terms defined herein shall be equally
applicable to both the singular and plural forms of such terms.


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<PAGE>


     Section 1.3 Rules of Construction. The rules of construction set forth in
Section 1.03 of the Common Agreement shall apply as if it were fully set out
herein; provided, that, the words "hereof," "herein," and "hereunder" and words
of similar import when used in this Agreement shall refer to this Agreement as a
whole and not to any particular provision of this Agreement, and section,
subsection, schedule and exhibit references are to this Agreement unless
otherwise specified.

                                    ARTICLE 2
                         AMOUNT AND TERMS OF COMMITMENTS

     Section 2.1 Working Capital Facility Commitments.

          (a) Subject to the terms and conditions hereof, each Working Capital
Facility Lender severally agrees to make revolving credit loans ("Working
Capital Loans") to the Borrower from time to time during the Availability Period
in an aggregate principal amount at any one time outstanding which does not
exceed the amount of such Working Capital Facility Lender's Working Capital
Facility Commitment. During the Availability Period the Borrower may use the
Working Capital Facility Commitments by borrowing, prepaying the Working Capital
Loans in whole or in part, and reborrowing, all in accordance with the terms and
conditions hereof. The Working Capital Facility Commitments shall terminate in
their entirety upon the expiration of the Availability Period.

          (b) The failure of any Working Capital Facility Lender to make the
Working Capital Loan required to be made by it as part of any Working Capital
Facility Borrowing shall not relieve any other Working Capital Facility Lender
of its obligation hereunder to make its respective Working Capital Loan on such
Borrowing Date, but no Working Capital Facility Lender shall be responsible for
the failure of any other Working Capital Facility Lender to make the Working
Capital Loan to be made by such other Working Capital Facility Lender on any
date.

     Section 2.2 Procedure for Working Capital Facility Borrowings.

          (a) All Working Capital Loans to be made as part of each Working
Capital Facility Borrowing shall consist of Working Capital Loans of the same
Type and Interest Period.

          (b) Not later than the fifth (5th) Business Day prior to the date of
any proposed Working Capital Facility Borrowing (or such later date agreed to by
the Working Capital Facility Administrative Agent in its sole discretion), the
Borrower shall deliver a Working Capital Facility Notice of Borrowing to the
Working Capital Facility Administrative Agent and the Independent Engineer
accompanied by the documents specified in the Working Capital Facility Notice of
Borrowing and specifying therein (i) the requested date of such Working Capital
Facility Borrowing and (ii) the aggregate amount of such proposed Working
Capital Facility Borrowing. The Borrower shall be entitled to request only one
Working Capital Facility Borrowing during any calendar month; provided, however,
that in any calendar month in which any interest or Fee is due and payable
pursuant to Section 2.6 or Section 2.10(a), as applicable, the Borrower shall be
entitled to request additional Working Capital Facility Borrowings (with each
such Working Capital Facility Borrowing limited to the amount of, and


                                        5

<PAGE>

for the purposes of paying, such interest and Fees due and payable pursuant to
Section 2.6 or Section 2.10(a), as applicable, and any Taxes payable with
respect to such interest and Fees) or with the prior written consent of the
Working Capital Facility Administrative Agent, which may be granted or withheld
in its sole discretion. Each Working Capital Facility Notice of Borrowing shall
be irrevocable and binding on the Borrower.

          (c) In connection with each proposed Working Capital Facility
Borrowing (other than any Working Capital Facility Borrowing limited to the
amount of, and for the purposes of paying, interest and Fees due and payable
pursuant to Section 2.6 or Section 2.10(a), as applicable, and any Taxes payable
with respect to such interest and Fees), the Borrower shall deliver a further
notice (an "Interest Rate Notice") to the Working Capital Facility
Administrative Agent in substantially the form of Exhibit B hereto, specifying
the requested Interest Period for each such Working Capital Loan (and, subject
to Section 2.2(a), the Type of such Working Capital Loans). Each Interest Rate
Notice shall be given by the Borrower to the Working Capital Facility
Administrative Agent not later than 11:00 a.m. (New York City time) on the third
Business Day prior to the date of the proposed Working Capital Facility
Borrowing. The Working Capital Facility Administrative Agent shall give each
Working Capital Facility Lender notice of each Interest Rate Notice within one
(1) Business Day after the receipt thereof by the Working Capital Facility
Administrative Agent. Each Interest Rate Notice shall be irrevocable and binding
on the Borrower. If no Interest Rate Notice is received by the Working Capital
Facility Administrative Agent as provided in this Section 2.2(c), the interest
rate applicable to such Working Capital Facility Borrowing shall be the
Eurodollar Rate with an Interest Period of one (1) month (or such other Interest
Period designated by the Working Capital Facility Administrative Agent).

          (d) Each Working Capital Facility Lender shall, before 11:00 a.m. (New
York City time) on the date of any Working Capital Facility Borrowing, make
available to the Working Capital Facility Administrative Agent such Working
Capital Facility Lender's ratable portion of the Working Capital Facility
Borrowing, in accordance with Section 2.01(a) of the Common Agreement.

          (e) Notwithstanding anything to the contrary herein, in the event that
on the date on which any interest or Fees in respect of the Financing Documents
are due and payable, the Borrower has not delivered a Working Capital Facility
Notice of Borrowing in accordance with this Agreement and the other Financing
Documents requesting a Working Capital Facility Borrowing in an amount and on
the date necessary to pay such interest or Fees, the Working Capital Facility
Lenders shall have the right to, and the Borrower hereby irrevocably authorizes
the Working Capital Facility Lenders to, make Working Capital Loans in the
aggregate amount of such interest or Fees in respect of the Financing Documents.
In the event that the Borrower so fails to deliver such Working Capital Facility
Notice of Borrowing, the Working Capital Facility Administrative Agent may
notify each Working Capital Facility Lender of the failure of the Borrower to so
deliver such Working Capital Facility Notice of Borrowing and request that each
Working Capital Facility Lender make available to the Working Capital Facility
Administrative Agent the ratable share of such aggregate amount of interest or
Fees due and payable by the Borrower in respect of the Financing Documents. Each
Working Capital Facility Lender agrees to make available to the Working Capital
Facility Administrative Agent no later than 11:00 a.m. (New York City time on
the date so requested by the Working Capital Facility Administrative


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<PAGE>

Agent) its ratable share of the aggregate amount requested by the Working
Capital Facility Administrative Agent to be disbursed by the Working Capital
Facility Lenders. Notwithstanding the foregoing, the Borrower and each other
party hereto hereby agrees that any delay in giving or any failure to give the
request referenced in this Section 2.2(e) or to make any such disbursement
referenced in this Section 2.2(e) shall not affect the rights of any Working
Capital Facility Lender or of the Working Capital Facility Administrative Agent
under this Working Capital Facility Credit Agreement or any other Transaction
Document and the Borrower expressly acknowledges and agrees that neither the
Working Capital Facility Administrative Agent nor any of the Working Capital
Facility Lenders shall have any liability to the Borrower arising therefrom or
in connection therewith.

          (f) Notwithstanding the foregoing, if the date for any proposed
Working Capital Facility Borrowing is a date on which the Borrower is obligated
to pay interest on any Working Capital Loan pursuant to Section 2.6 hereof, any
Fees in respect of any Working Capital Facility Commitment pursuant to Section
2.10(a) hereof or any Fees pursuant to any Fee Letters, then the Working Capital
Facility Administrative Agent may instruct, and in that event each Working
Capital Facility Lender shall, set off against its ratable portion of the
Working Capital Loan to be made on such day the entire amount of interest and
Fees due and owing on such date in respect of such Working Capital Facility
Lender's Working Capital Loans.

     Section 2.3 Repayment of Working Capital Loans. All Working Capital Loans
then outstanding and all accrued interest thereon shall be due and payable in
full on the Loan Maturity Date.

     Section 2.4 Optional Prepayments. The Borrower may at any time and from
time to time prepay the Working Capital Loans, in whole or in part, without
premium or penalty, upon irrevocable notice delivered to the Working Capital
Facility Administrative Agent no later than 11:00 A.M., New York City time,
three Business Days prior thereto, in the case of Eurodollar Loans, and no later
than 11:00 A.M., New York City time, one Business Day prior thereto, in the case
of ABR Loans, which notice shall specify the date and amount of prepayment and
whether the prepayment is of Eurodollar Loans or ABR Loans; provided, that if a
Eurodollar Loan is prepaid on any day other than the last day of the Interest
Period applicable thereto, the Borrower shall also pay any amounts owing
pursuant to Section 3.04 of the Common Agreement. Upon receipt of any such
notice the Working Capital Facility Administrative Agent shall promptly notify
each Working Capital Facility Lender thereof. If any such notice is given, the
amount specified in such notice shall be due and payable on the date specified
therein, together with accrued interest to such date on the amount prepaid.
Partial prepayments of the Working Capital Loans shall be in an aggregate
principal amount of $1,000,000.

     Section 2.5 Conversion and Continuation Options. (a) The Borrower may elect
from time to time to convert Eurodollar Loans to ABR Loans by giving the Working
Capital Facility Administrative Agent prior irrevocable notice of such election
no later than 11:00 A.M., New York City time, on the Business Day preceding the
proposed conversion date, provided that any such conversion of Eurodollar Loans
may only be made on the last day of an Interest Period with respect thereto. The
Borrower may elect from time to time to convert ABR Loans to Eurodollar Loans by
giving the Working Capital Facility Administrative Agent prior irrevocable
notice of such election no later than 11:00 A.M., New York City time, on the
third Business Day


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<PAGE>

preceding the proposed conversion date (which notice shall specify the length of
the initial Interest Period therefor), provided that no ABR Loan may be
converted into a Eurodollar Loan when any Event of Default has occurred and is
continuing and the Working Capital Facility Administrative Agent or the Working
Capital Facility Majority Lenders have determined in its or their sole
discretion not to permit such conversions. Upon receipt of any such notice the
Working Capital Facility Administrative Agent shall promptly notify each Working
Capital Facility Lender thereof.

          (b) Any Eurodollar Loan may be continued as such upon the expiration
of the then current Interest Period with respect thereto by the Borrower giving
irrevocable notice to the Working Capital Facility Administrative Agent, in
accordance with the applicable provisions of the term "Interest Period" set
forth in Section 1.1, of the length of the next Interest Period to be applicable
to such Eurodollar Loans, provided that no Eurodollar Loan may be continued as
such when any Event of Default has occurred and is continuing and the Working
Capital Facility Administrative Agent has or the Working Capital Facility
Majority Lenders have determined in its or their sole discretion not to permit
such continuations, and provided, further, that if the Borrower shall fail to
give any required notice as described above in this paragraph or if such
continuation is not permitted pursuant to the preceding proviso such Eurodollar
Loans shall be automatically converted to ABR Loans on the last day of such then
expiring Interest Period. Upon receipt of any such notice the Working Capital
Facility Administrative Agent shall promptly notify each Working Capital
Facility Lender thereof.

     Section 2.6 Interest Rates and Payment Dates. (a) Each Eurodollar Loan
shall bear interest for each day during each Interest Period with respect
thereto at a rate per annum equal to the Eurodollar Rate determined for such day
plus the Applicable Margin.

          (b) Each ABR Loan shall bear interest at a rate per annum equal to the
ABR plus the Applicable Margin.

          (c) Following the occurrence and during the continuance of an Event of
Default, a rate per annum equal to 2.00% above the rate per annum required to be
paid on a Eurodollar Loan or an ABR Loan, as the case may be.

          (d) Any other amounts payable hereunder and under the other Working
Capital Facility Loan Documents that are not paid when due shall (to the fullest
extent permitted by law) bear interest, from the date when due until paid in
full, at a rate per annum equal at all times to the Working Capital Facility
Lender Default Rate.

          (e) Interest shall be payable in arrears on each Interest Payment
Date, provided that interest accruing pursuant to paragraph (c) or (d) of this
Section shall be payable from time to time on demand.

          (f) In connection with each Working Capital Facility Borrowing
pursuant to Section 2.2 and each continuation and/or conversion pursuant to
Section 2.5, the Working Capital Facility Administrative Agent shall promptly
notify each Working Capital Facility Lender of the applicable interest rate with
respect thereto promptly after determination thereof.


                                        8

<PAGE>

     Section 2.7 Computation of Interest and Fees. (a) Interest and fees payable
pursuant hereto shall be calculated on the basis of a 360-day year for the
actual days elapsed, except that, with respect to ABR Loans the rate of interest
on which is calculated on the basis of the Prime Rate, the interest thereon
shall be calculated on the basis of a 365- (or 366-, as the case may be) day
year for the actual days elapsed. The Working Capital Facility Administrative
Agent shall as soon as practicable notify the Borrower and the Working Capital
Facility Lenders of each determination of a Eurodollar Rate. Any change in the
interest rate on a Working Capital Loan resulting from a change in the ABR or
the Eurocurrency Reserve Requirements shall become effective as of the opening
of business on the day on which such change becomes effective. The Working
Capital Facility Administrative Agent shall as soon as practicable notify the
Borrower and the Working Capital Facility Lenders of the effective date and the
amount of each such change in interest rate.

          (b) Each determination of an interest rate by the Working Capital
Facility Administrative Agent pursuant to any provision of this Agreement shall
be conclusive and binding on the Borrower and the Working Capital Facility
Lenders in the absence of manifest error. The Working Capital Facility
Administrative Agent shall, at the request of the Borrower, deliver to the
Borrower a statement showing the quotations used by the Working Capital Facility
Administrative Agent in determining any interest rate pursuant to Section 2.6.

     Section 2.8 Inability to Determine Interest Rate. If prior to the first day
of any Interest Period:

          (a) the Working Capital Facility Administrative Agent shall have
determined (which determination shall be conclusive and binding upon the
Borrower) that, by reason of circumstances affecting the relevant market,
adequate and reasonable means do not exist for ascertaining the Eurodollar Rate
for such Interest Period, or

          (b) the Working Capital Facility Administrative Agent shall have
received notice from the Working Capital Facility Majority Lenders that the
Eurodollar Rate determined or to be determined for such Interest Period will not
adequately and fairly reflect the cost to such Working Capital Facility Lenders
(as conclusively certified by such Working Capital Facility Lenders) of making
or maintaining their affected Working Capital Loans during such Interest Period,

the Working Capital Facility Administrative Agent shall give telecopy or
telephonic notice thereof to the Borrower and the Working Capital Facility
Lenders as soon as practicable thereafter. If such notice is given (x) any
Eurodollar Loans requested to be made on the first day of such Interest Period
shall be made as ABR Loans, (y) any Working Capital Loans that were to have been
converted on the first day of such Interest Period to Eurodollar Loans shall be
continued as ABR Loans and (z) any outstanding Eurodollar Loans shall be
converted, on the last day of the then-current Interest Period, to ABR Loans.
Until such notice has been withdrawn by the Working Capital Facility
Administrative Agent, no further Eurodollar Loans shall be made or continued as
such, nor shall the Borrower have the right to convert Working Capital Loans to
Eurodollar Loans.


                                        9

<PAGE>

     Section 2.9 Pro Rata Treatment and Payments. (a) Each Working Capital
Facility Borrowing by the Borrower from the Working Capital Facility Lenders
hereunder, each payment by the Borrower on account of any commitment fee and any
reduction of the Working Capital Facility Commitments of the Working Capital
Facility Lenders shall be made pro rata according to the respective Working
Capital Facility Percentages of the Working Capital Facility Lenders.

     (b) Each payment (including each prepayment) by the Borrower on account of
principal of and interest on the Working Capital Loans (or any portion thereof)
shall be made pro rata according to the respective outstanding principal amounts
of the Working Capital Loans then held by the Working Capital Facility Lenders.

     (c) Each prepayment by the Borrower pursuant to either Section 2.4 of this
Agreement or Section 3.01(b) of the Common Agreement shall be applied to the
Working Capital Loans in chronological order of when each such Working Capital
Loan was made, with the Working Capital Loan that has been outstanding for the
longest period of time being prepaid first.

     (d) All payments (including prepayments) to be made by the Borrower
hereunder, whether on account of principal, interest, fees or otherwise, shall
be made without setoff or counterclaim and shall be made prior to 11:00 a.m.,
New York City time, on the due date thereof to the Working Capital Facility
Administrative Agent, for the account of the Working Capital Facility Lenders,
at the Funding Office, in Dollars and in immediately available funds. The
Working Capital Facility Administrative Agent shall distribute such payments to
each Working Capital Facility Lender promptly upon receipt in like funds as
received, net of any amounts owing by such Working Capital Facility Lender
pursuant to Section 9.7. If any payment hereunder (other than payments on the
Eurodollar Loans) becomes due and payable on a day other than a Business Day,
such payment shall be extended to the next succeeding Business Day. If any
payment on a Eurodollar Loan becomes due and payable on a day other than a
Business Day, the maturity thereof shall be extended to the next succeeding
Business Day unless the result of such extension would be to extend such payment
into another calendar month, in which event such payment shall be made on the
immediately preceding Business Day. In the case of any extension of any payment
of principal pursuant to the preceding two sentences, interest thereon shall be
payable at the then applicable rate during such extension.

     (e) Unless the Working Capital Facility Administrative Agent shall have
been notified in writing by any Working Capital Facility Lender prior to a
Working Capital Facility Borrowing that such Working Capital Facility Lender
will not make the amount that would constitute its share of such Working Capital
Facility Borrowing available to the Working Capital Facility Administrative
Agent, the Working Capital Facility Administrative Agent may assume that such
Working Capital Facility Lender is making such amount available to the Working
Capital Facility Administrative Agent, and the Working Capital Facility
Administrative Agent may, in reliance upon such assumption, make available to
the Borrower a corresponding amount. If such amount is not made available to the
Working Capital Facility Administrative Agent by the required time on the
Borrowing Date therefor, such Working Capital Facility Lender shall pay to the
Working Capital Facility Administrative Agent, on demand, such amount with
interest thereon, at a rate equal to the greater of (i) the Federal Funds
Effective Rate and (ii) a rate determined by the Working Capital Facility
Administrative Agent in accordance with banking


                                       10

<PAGE>

industry rules on interbank compensation, for the period until such Working
Capital Facility Lender makes such amount immediately available to the Working
Capital Facility Administrative Agent. A certificate of the Working Capital
Facility Administrative Agent submitted to any Working Capital Facility Lender
with respect to any amounts owing under this paragraph shall be conclusive in
the absence of manifest error. If such Working Capital Facility Lender's share
of such Working Capital Facility Borrowing is not made available to the Working
Capital Facility Administrative Agent by such Working Capital Facility Lender
within three Business Days after such Borrowing Date, the Working Capital
Facility Administrative Agent shall also be entitled to recover such amount with
interest thereon at the rate per annum applicable to ABR Loans, on demand, from
the Borrower.

          (f) Unless the Working Capital Facility Administrative Agent shall
have been notified in writing by the Borrower prior to the date of any payment
due to be made by the Borrower hereunder that the Borrower will not make such
payment to the Working Capital Facility Administrative Agent, the Working
Capital Facility Administrative Agent may assume that the Borrower is making
such payment, and the Working Capital Facility Administrative Agent may, but
shall not be required to, in reliance upon such assumption, make available to
the Working Capital Facility Lenders their respective pro rata shares of a
corresponding amount. If such payment is not made to the Working Capital
Facility Administrative Agent by the Borrower within three Business Days after
such due date, the Working Capital Facility Administrative Agent shall be
entitled to recover, on demand, from each Working Capital Facility Lender to
which any amount which was made available pursuant to the preceding sentence,
such amount with interest thereon at the rate per annum equal to the daily
average Federal Funds Effective Rate. Nothing herein shall be deemed to limit
the rights of the Working Capital Facility Administrative Agent or any Working
Capital Facility Lender against the Borrower.

     Section 2.10 Fees.

          (a) The Borrower agrees to pay to the Working Capital Facility
Administrative Agent for the account of each Working Capital Facility Lender a
commitment fee on the average daily unused amount of such Working Capital
Facility Lender's Working Capital Facility Commitment from the Signing Date, in
the case of each Working Capital Facility Lender initially a party hereto, and
from the effective date specified in the Assignment pursuant to which an
Assignee becomes a Working Capital Facility Lender, until the Loan Maturity
Date, at the rate of 0.25% per annum, payable monthly in arrears on each Monthly
Payment Date, commencing on the first such date to occur on or following the
earlier of (i) the date that is thirty (30) days following the Signing Date or
(ii) the date of the initial Working Capital Facility Borrowing.

          (b) The Borrower further agrees to pay the fees set forth in the
WestLB Fee Letter in accordance with the terms thereof.

          (c) The Borrower further agrees to pay upon demand any transfer fee
payable in connection with any Disbursement LC.

     Section 2.11 Cancellation of Working Capital Facility Commitments. Subject
to the Working Capital Facility Administrative Agent's approval thereof, the
Borrower may, by notice


                                       11

<PAGE>

to the Working Capital Facility Administrative Agent, irrevocably request that
all or any portion of the unutilized Working Capital Facility Commitments be
cancelled effective as of any Interest Payment Date.

                                    ARTICLE 3
                         REPRESENTATIONS AND WARRANTIES

     Section 3.1 Representations and Warranties of the Borrower. To induce the
Working Capital Facility Administrative Agent and the Working Capital Facility
Lenders to enter into this Agreement and to make the Working Capital Loans, the
Borrower hereby confirms each of the representations and warranties set forth in
Section 5.01 of the Common Agreement, which representations and warranties shall
apply, mutatis mutandis, to this Agreement as if they had been fully set out in
this Agreement and made as of the dates specified in the Common Agreement
(unless and to the extent waived or amended from time to time in accordance with
the terms of the Common Agreement). All of these representations and warranties
shall survive the execution and delivery of this Agreement, the Initial Closing
Date and all Working Capital Facility Borrowings and Working Capital Facility
Commitments made hereunder.

                                    ARTICLE 4
                              CONDITIONS PRECEDENT

     Section 4.1 Conditions Precedent to the Initial Closing Date and the
Initial Working Capital Facility Borrowing. The Initial Closing Date and the
initial Working Capital Facility Borrowing are subject to satisfaction, in a
manner satisfactory to each Lender, of each of the conditions set forth in
Sections 4.01, 4.02 and 4.05 of the Common Agreement, which conditions shall
apply, mutatis mutandis, to this Agreement as if they had been fully set out
herein (provided, that, a waiver of any condition under Section 4.01, 4.02 or
4.05 of the Common Agreement shall be deemed a waiver of such condition
hereunder) and, in a manner satisfactory to each Working Capital Facility
Lender, of each of the following conditions:

          (a) The Working Capital Facility Administrative Agent shall have
received Disbursement LCs in an amount not less than U.S.$30,000,000, each
issued or confirmed in favor of the Working Capital Facility Administrative
Agent by the Disbursement LC Providers;

          (b) With respect to each Disbursement LC Provider, evidence has been
provided to the Working Capital Facility Administrative Agent that each such
Disbursement LC Provider is an Acceptable LC Provider;

          (c) Each of the conditions set forth in Section 4.2 of this Agreement
shall be satisfied.

     Section 4.2 Conditions Precedent to Each Working Capital Facility
Borrowing. The obligation of each Working Capital Facility Lender to make any
Working Capital Loan is subject to satisfaction, in a manner satisfactory to (x)
in the case of the initial Working Capital Facility Borrowing, each Lender and
(y) in the case of any subsequent Working Capital Facility Borrowing, the
Working Capital Facility Administrative Agent, of each of the conditions set
forth in Sections 4.02 and 4.05 of the Common Agreement, which conditions shall
apply, mutatis mutandis, to this Agreement as if they had been fully set out
herein (provided, that, a waiver of


                                       12

<PAGE>

any condition under Section 4.02 or 4.05 of the Common Agreement shall be deemed
a waiver of such condition hereunder) and, in a manner satisfactory to each
Working Capital Facility Lender with respect to the initial Working Capital
Facility Borrowing or in a manner satisfactory to the Working Capital Facility
Administrative Agent with respect to each subsequent Working Capital Facility
Borrowing, of each of the following conditions:

          (a) The proceeds of such Working Capital Facility Borrowing shall be
used solely to pay Project Costs (other than the repayment or prepayment of any
Loans) to be incurred by the Borrower within the thirty (30) day period
immediately following the date of the applicable Working Capital Facility
Borrowing;

          (b) After giving effect to such Working Capital Facility Borrowing,
the aggregate amount of all outstanding Working Capital Loans shall not exceed
the product of (i) two (2) times (ii) the sum of the available undrawn amount of
all Disbursement LCs and all cash deposits held in the Dollar Disbursement
Guarantee Account;

          (c) The Working Capital Facility Administrative Agent shall have
received, no later than three (3) Business Days prior to such Working Capital
Facility Borrowing, a certificate of the Independent Engineer certifying that
(i) the Independent Engineer has reviewed the Working Capital Facility Notice of
Borrowing in respect of such Working Capital Facility Borrowing and does not
disagree in any material respect with any of the statements or calculations
therein, (ii) all Works for which payment will be made with the proceeds of such
Working Capital Facility Borrowing and all other Works for which payment was
made with the proceeds of all prior Working Capital Facility Notices of
Borrowing have been performed properly in accordance with the Public Works
Contract and all other Project Documents and (iii) construction of the Project
is proceeding substantially in accordance with the Public Works Contract and all
other Project Documents and, in the Independent Engineer's opinion, the Borrower
will achieve each Critical Event not later than the date set forth therefor in
the Construction Schedule (as such dates may be extended not more than two
hundred seventy (270) days for Permissible Critical Event Delays, Permissible
Provisional Acceptance Delays or Permissible Project Completion Delays, as
applicable);

          (d) With respect only to the first Working Capital Facility Borrowing
to occur on or after the date that is sixty (60) days following the Initial
Closing Date, the Construction Facility Closing Date shall have occurred;

          (e) The construction of the Project shall be proceeding substantially
in accordance with the Public Works Contract and all other Project Documents and
no Project Party shall be in breach of any of its obligations under any Project
Document; and

          (f) The Borrower (i) shall have achieved each Critical Event no later
than the Critical Event Date required therefor in the Public Works Contract or
(ii) if the Borrower shall not have achieved any Critical Event on or before the
corresponding Critical Event Date, but shall have achieved such Critical Event
by the date that is not more than ninety (90) days following the Critical Event
Date required therefor in the Public Works Contract, the Borrower shall provide
a written certification (concurred in by the Independent Engineer) stating that
(i) the Borrower reasonably anticipates to achieve Provisional Acceptance of the
First Unit not later


                                       13
<PAGE>

than January 2, 2012 and the Project Completion Date not later than June 11,
2012 and (ii) the Borrower will achieve each other Critical Event by the date
that is not more than thirty (30) days following the applicable Critical Event
Date required therefor in the Public Works Contract.

                                    ARTICLE 5
                              AFFIRMATIVE COVENANTS

     Section 5.1 Affirmative Covenants of the Borrower. The Borrower hereby
agrees to comply with each of the covenants set forth in Section 6.01 of the
Common Agreement and to otherwise perform and observe all of the obligations
undertaken by it in the Common Agreement, the terms of which shall apply,
mutatis mutandis, to this Agreement as if fully set forth herein (unless and to
the extent waived or amended from time to time in accordance with the terms of
the Common Agreement).

                                    ARTICLE 6
                               NEGATIVE COVENANTS

     Section 6.1 Negative Covenants of the Borrower. The Borrower hereby agrees
to comply with each of the covenants set forth in Section 6.02 of the Common
Agreement and to otherwise perform and observe all of the obligations undertaken
by it in the Common Agreement, the terms of which shall apply, mutatis mutandis,
to this Agreement as if fully set forth herein (unless and to the extent waived
or amended from time to time in accordance with the terms of the Common
Agreement).

                                    ARTICLE 7
                              REPORTING OBLIGATIONS

     Section 7.1 Reporting Obligations of the Borrower. The Borrower hereby
agrees to comply with each of the obligations set forth in Section 6.03 of the
Common Agreement and to otherwise perform and observe all of the obligations
undertaken by it in the Common Agreement, the terms of which shall apply,
mutatis mutandis, to this Agreement as if fully set forth herein (unless and to
the extent waived or amended from time to time in accordance with the terms of
the Common Agreement).

                                    ARTICLE 8
                                EVENTS OF DEFAULT

     Section 8.1 Events of Default; Remedies.

          (a) An Event of Default shall occur hereunder upon the occurrence of
any Event of Default set forth in Section 7.01 of the Common Agreement, the
terms of which shall apply, mutatis mutandis, to this Agreement as if fully set
forth herein.

          (b) If any Event of Default shall have occurred and be continuing, the
Working Capital Facility Administrative Agent, subject to the terms of the
Common Agreement and, once executed, the Intercreditor Agreement, may take any
of the actions specified in Section 7.02(a), 7.02(c), 7.03 or 7.04 of the Common
Agreement.


                                       14

<PAGE>

          (c) Subject to the Intercreditor Agreement (once executed), upon the
acceleration of the Working Capital Loans pursuant to Section 8.1(b) hereof or
Section 7.02 of the Common Agreement, each of the Working Capital Facility
Lenders and the Working Capital Facility Administrative Agent may take all such
actions as it deems reasonable to recover any amounts due hereunder.

          (d) All distributions to or for the benefit of the Working Capital
Facility Lenders under or in respect of any of the Financing Documents shall be
received on account of the Working Capital Facility Obligations owed to the
Working Capital Facility Lenders without prejudice to any claim by the Working
Capital Facility Administrative Agent and the Working Capital Facility Lenders
for any deficiency after such distributions are distributed to the Working
Capital Facility Administrative Agent and the Working Capital Facility Lenders;
the Working Capital Facility Administrative Agent shall deliver notice to the
Borrower of any such deficiency and the Borrower shall remain liable for the
same. After the occurrence and during the continuance of an Event of Default,
all such distributions shall be applied to such part of the Working Capital
Facility Obligations as is determined by the Working Capital Facility Lenders in
their sole discretion or, in the event the Working Capital Facility Lenders fail
to advise the Working Capital Facility Administrative Agent of their
determination, by the Working Capital Facility Administrative Agent. After the
occurrence and during the continuance of an Event of Default, the Working
Capital Facility Lenders may at any time change any application of any such
distributions or other moneys received by the Working Capital Facility
Administrative Agent and may reapply the same to any part of the Working Capital
Facility Obligations as the Working Capital Facility Lenders may from time to
time in their absolute discretion determine.

                                    ARTICLE 9
                THE WORKING CAPITAL FACILITY ADMINISTRATIVE AGENT

     Section 9.1 Appointment. Each Working Capital Facility Lender hereby
irrevocably designates and appoints the Working Capital Facility Administrative
Agent as the agent of such Working Capital Facility Lender under this Agreement
and the other Financing Documents, and each such Working Capital Facility Lender
irrevocably authorizes the Working Capital Facility Administrative Agent, in
such capacity, to take such action on its behalf under the provisions of this
Agreement and the other Financing Documents and to exercise such powers and
perform such duties as are expressly delegated to the Working Capital Facility
Administrative Agent by the terms of this Agreement and the other Financing
Documents, together with such other powers as are reasonably incidental thereto.
Notwithstanding any provision to the contrary elsewhere in this Agreement, the
Working Capital Facility Administrative Agent shall not have any duties or
responsibilities, except those expressly set forth herein, or any fiduciary
relationship with any Working Capital Facility Lender, and no implied covenants,
functions, responsibilities, duties, obligations or liabilities shall be read
into this Agreement or any other Financing Document or otherwise exist against
the Working Capital Facility Administrative Agent.

     Section 9.2 Delegation of Duties. The Working Capital Facility
Administrative Agent may execute any of its duties under this Agreement and the
other Financing Documents by or through agents or attorneys in fact and shall be
entitled to advice of counsel concerning all matters pertaining to such duties.
The Working Capital Facility Administrative Agent shall not


                                       15

<PAGE>

be responsible for the negligence or misconduct of any agents or attorneys in
fact selected by it with reasonable care.

     Section 9.3 Exculpatory Provisions. Neither the Working Capital Facility
Administrative Agent nor any of its officers, directors, employees, agents,
advisors, attorneys in fact or affiliates shall be (a) liable for any action
lawfully taken or omitted to be taken by it or such Person under or in
connection with this Agreement or any other Financing Document (except to the
extent that any of the foregoing are found by a final and nonappealable decision
of a court of competent jurisdiction to have resulted from its or such Person's
own gross negligence or willful misconduct) or (b) responsible in any manner to
any of the Working Capital Facility Lenders for any recitals, statements,
representations or warranties made by any Project Party or any officer thereof
contained in this Agreement or any other Financing Document or in any
certificate, report, statement or other document referred to or provided for in,
or received by the Working Capital Facility Administrative Agent under or in
connection with, this Agreement or any other Financing Document or for the
value, validity, effectiveness, genuineness, enforceability or sufficiency of
this Agreement or any other Financing Document or for any failure of any Project
Party a party thereto to perform its obligations hereunder or thereunder. The
Working Capital Facility Administrative Agent shall not be under any obligation
to any Working Capital Facility Lender to ascertain or to inquire as to the
observance or performance of any of the agreements contained in, or conditions
of, this Agreement or any other Financing Document, or to inspect the
properties, books or records of any Project Party.

     Section 9.4 Reliance by Working Capital Facility Administrative Agent. The
Working Capital Facility Administrative Agent shall be entitled to rely, and
shall be fully protected in relying, upon any instrument, writing, resolution,
notice, consent, certificate, affidavit, letter, telecopy or email message,
statement, order or other document or conversation believed by it to be genuine
and correct and to have been signed, sent or made by the proper Person or
Persons and upon advice and statements of legal counsel (including counsel to
the Borrower), independent accountants and other experts selected by the Working
Capital Facility Administrative Agent. The Working Capital Facility
Administrative Agent shall be fully justified in failing or refusing to take any
action under this Agreement or any other Financing Document unless it shall
first receive such advice or concurrence of the Working Capital Facility
Majority Lenders (or, if so specified by this Agreement, all Working Capital
Facility Lenders) as it deems appropriate or it shall first be indemnified to
its satisfaction by the Working Capital Facility Lenders against any and all
liability and expense that may be incurred by it by reason of taking or
continuing to take any such action. The Working Capital Facility Administrative
Agent shall in all cases be fully protected in acting, or in refraining from
acting, under this Agreement and the other Financing Documents in accordance
with a request of the Working Capital Facility Majority Lenders (or, if so
specified by this Agreement, all Working Capital Facility Lenders), and such
request and any action taken or failure to act pursuant thereto shall be binding
upon all the Working Capital Facility Lenders and all future holders of the
Working Capital Loans.

     Section 9.5 Notice of Default. The Working Capital Facility Administrative
Agent shall not be deemed to have knowledge or notice of the occurrence of any
Default or Event of Default unless the Working Capital Facility Administrative
Agent has received notice from a Working Capital Facility Lender or the Borrower
referring to this Agreement, describing such


                                       16

<PAGE>

Default or Event of Default and stating that such notice is a "notice of
default". In the event that the Working Capital Facility Administrative Agent
receives such a notice, the Working Capital Facility Administrative Agent shall
give notice thereof to the Working Capital Facility Lenders. Subject to the
Intercreditor Agreement, the Working Capital Facility Administrative Agent shall
take such action with respect to such Default or Event of Default as shall be
reasonably directed by the Working Capital Facility Majority Lenders (or, if so
specified by this Agreement, all Working Capital Facility Lenders); provided
that unless and until the Working Capital Facility Administrative Agent shall
have received such directions, the Working Capital Facility Administrative Agent
may (but shall not be obligated to) take such action, or refrain from taking
such action, with respect to such Default or Event of Default as it shall deem
advisable in the best interests of the Working Capital Facility Lenders (subject
to the Intercreditor Agreement).

     Section 9.6 Non-Reliance on Working Capital Facility Administrative Agent
and Other Working Capital Facility Lenders. Each Working Capital Facility Lender
expressly acknowledges that neither the Working Capital Facility Administrative
Agent nor any of its officers, directors, employees, agents, advisors, attorneys
in fact or affiliates have made any representations or warranties to it and that
no act by the Working Capital Facility Administrative Agent hereafter taken,
including any review of the affairs of a Project Party or any affiliate of a
Project Party, shall be deemed to constitute any representation or warranty by
the Working Capital Facility Administrative Agent to any Working Capital
Facility Lender. Each Working Capital Facility Lender represents to the Working
Capital Facility Administrative Agent that it has, independently and without
reliance upon the Working Capital Facility Administrative Agent or any other
Working Capital Facility Lender, and based on such documents and information as
it has deemed appropriate, made its own appraisal of and investigation into the
business, operations, property, financial and other condition and
creditworthiness of the Project Parties and their affiliates and made its own
decision to make its Working Capital Loans hereunder and enter into this
Agreement. Each Working Capital Facility Lender also represents that it will,
independently and without reliance upon the Working Capital Facility
Administrative Agent or any other Working Capital Facility Lender, and based on
such documents and information as it shall deem appropriate at the time,
continue to make its own credit analysis, appraisals and decisions in taking or
not taking action under this Agreement and the other Financing Documents, and to
make such investigation as it deems necessary to inform itself as to the
business, operations, property, financial and other condition and
creditworthiness of the Project Parties and their affiliates. Except for
notices, reports and other documents expressly required to be furnished to the
Working Capital Facility Lenders by the Working Capital Facility Administrative
Agent hereunder, the Working Capital Facility Administrative Agent shall not
have any duty or responsibility to provide any Working Capital Facility Lender
with any credit or other information concerning the business, operations,
property, condition (financial or otherwise), prospects or creditworthiness of
any Project Party or any affiliate of a Project Party that may come into the
possession of the Working Capital Facility Administrative Agent or any of its
officers, directors, employees, agents, attorneys in fact or affiliates.

     Section 9.7 Indemnification. The Working Capital Facility Lenders agree to
indemnify the Working Capital Facility Administrative Agent and its officers,
directors, employees, affiliates, agents, advisors and controlling persons
(each, an "Agent Indemnitee") (to the extent not reimbursed by the Borrower and
without limiting the obligation of the Borrower to do so), ratably according to
their respective Working Capital Facility Percentages in effect on the


                                       17

<PAGE>

date on which indemnification is sought under this Section (or, if
indemnification is sought after the date upon which the Working Capital Facility
Commitments shall have terminated and the Working Capital Loans shall have been
paid in full, ratably in accordance with such Working Capital Facility
Percentages immediately prior to such date), from and against any and all
liabilities, obligations, losses, damages, penalties, actions, judgments, suits,
costs, expenses or disbursements of any kind whatsoever that may at any time
(whether before or after the payment of the Working Capital Loans) be imposed
on, incurred by or asserted against such Agent Indemnitee in any way relating to
or arising out of, the Working Capital Facility Commitments, this Agreement, any
of the other Financing Documents or any documents contemplated by or referred to
herein or therein or the transactions contemplated hereby or thereby or any
action taken or omitted by such Agent Indemnitee under or in connection with any
of the foregoing; provided that no Working Capital Facility Lender shall be
liable for the payment of any portion of such liabilities, obligations, losses,
damages, penalties, actions, judgments, suits, costs, expenses or disbursements
that are found by a final and nonappealable decision of a court of competent
jurisdiction to have resulted from such Agent Indemnitee's gross negligence or
willful misconduct. The agreements in this Section shall survive the payment of
the Working Capital Loans and all other amounts payable hereunder.

     Section 9.8 Agent in Its Individual Capacity. The Working Capital Facility
Administrative Agent and its affiliates may make loans to, accept deposits from
and generally engage in any kind of business with any Project Party as though
the Working Capital Facility Administrative Agent did not serve in such
capacity. With respect to its Working Capital Loans made or renewed by it, the
Working Capital Facility Administrative Agent shall have the same rights and
powers under this Agreement and the other Financing Documents as any Working
Capital Facility Lender and may exercise the same as though it were not the
Working Capital Facility Administrative Agent, and the terms "Working Capital
Facility Lender" and "Working Capital Facility Lenders" shall include the
Working Capital Facility Administrative Agent in its individual capacity.

     Section 9.9 Successor Working Capital Facility Administrative Agent. The
Working Capital Facility Administrative Agent may resign as Working Capital
Facility Administrative Agent upon 90 days' notice to the Working Capital
Facility Lenders and the Borrower. If the Working Capital Facility
Administrative Agent shall resign as Working Capital Facility Administrative
Agent under this Agreement and the other Financing Documents, then the Working
Capital Facility Required Lenders shall appoint from among the Working Capital
Facility Lenders a successor agent for the Working Capital Facility Lenders,
which successor agent shall (unless a Default shall have occurred and be
continuing) be subject to approval by the Borrower (which approval shall not be
unreasonably withheld or delayed), whereupon such successor agent shall succeed
to the rights, powers and duties of the Working Capital Facility Administrative
Agent, and the term "Working Capital Facility Administrative Agent" shall mean
such successor agent effective upon such appointment and approval, and the
former Working Capital Facility Administrative Agent's rights, powers and duties
as Working Capital Facility Administrative Agent shall be terminated, without
any other or further act or deed on the part of such former Working Capital
Facility Administrative Agent or any of the parties to this Agreement or any
holders of the Working Capital Loans. If no successor agent has accepted
appointment as Working Capital Facility Administrative Agent by the date that is
90 days following a retiring Working Capital Facility Administrative Agent's
notice of resignation, the


                                       18

<PAGE>

retiring Working Capital Facility Administrative Agent's resignation shall
nevertheless thereupon become effective, and the Working Capital Facility
Lenders shall assume and perform all of the duties of the Working Capital
Facility Administrative Agent hereunder until such time, if any, as the Working
Capital Facility Required Lenders appoint a successor agent as provided for
above. Notwithstanding anything herein to the contrary, if no successor agent
has accepted appointment as Working Capital Facility Administrative Agent by the
date that is sixty (60) days following the effective date of the retiring
Working Capital Facility Administrative Agent's resignation, the Intercreditor
Agent may appoint a successor Working Capital Facility Administrative Agent from
among the Working Capital Facility Lenders (without obtaining the approval of
any such Working Capital Facility Lenders). After any retiring Working Capital
Facility Administrative Agent's resignation as Working Capital Facility
Administrative Agent, the provisions of this Section 9 and of Section 10.04 of
the Common Agreement shall continue to inure to its benefit.

                                   ARTICLE 10
                                  MISCELLANEOUS

     Section 10.1 Incorporation of Miscellaneous Provisions by Reference.
Sections 10.03, 10.08, 10.10, 10.13, 10.14 and 10.15 of the Common Agreement are
hereby incorporated by reference herein as if fully set forth herein.

     Section 10.2 Amendments and Waivers. No amendment, supplement,
modification, waiver, cancellation, consent or approval with regard to any
provision of this Agreement shall in any event be effective unless the same
shall be in writing and signed or approved by the Borrower, the Working Capital
Facility Administrative Agent and the Working Capital Facility Majority Lenders
and then such amendment, supplement, modification, cancellation, consent or
approval shall be effective only in the specific instance and for the specific
purpose for which given; provided that:

          (a) no amendment, supplement, modification, waiver, cancellation,
consent or approval shall, unless in writing and signed by all of the Working
Capital Facility Lenders, do any of the following: (i) take any action which is
defined as a Fundamental Decision in the Common Agreement, (ii) take any action
that changes the Working Capital Facility Commitment of any Working Capital
Facility Lender or the obligation of any Working Capital Facility Lender to make
a Working Capital Loan, (iii) take any action which requires the consent of each
Working Capital Facility Lender pursuant to the terms of any Transaction
Document or (iv) amend or modify this Section 10.2;

          (b) any amendment, supplement, modification, determination, waiver,
cancellation, consent or approval which is or effects a Working Capital Facility
Administrative Decision may be effected by the Working Capital Facility
Administrative Agent; and

          (c) no amendment, supplement, modification, waiver, cancellation,
consent or approval shall, unless in writing and signed by the Working Capital
Facility Administrative Agent in addition to the Working Capital Facility
Lenders required hereinabove to take such action, affect the rights or duties of
the Working Capital Facility Administrative Agent under this Agreement.


                                       19

<PAGE>

Any amendment, supplement, modification, determination, waiver, cancellation,
consent or approval so made shall be binding on all of the Working Capital
Facility Lenders. The terms of this Section 10.2 shall be subject to the terms
of the Intercreditor Agreement, once executed, and Section 10.01 of the Common
Agreement.

     Section 10.3 Notices. All notices and other communications provided for
hereunder shall be given or made in accordance with the provisions of Section
10.02 of the Common Agreement.

     Section 10.4 Survival of Representations and Warranties. All
representations and warranties made hereunder, in the other Financing Documents
and in any document, certificate or statement delivered pursuant hereto or in
connection herewith shall survive the execution and delivery of this Agreement
and the making of the Working Capital Loans and other extensions of credit
hereunder.

     Section 10.5 Successors and Assigns; Participations and Assignments. (a)
The provisions of this Agreement shall be binding upon and inure to the benefit
of the parties hereto and their respective successors and assigns permitted
hereby, except that (i) the Borrower may not assign or otherwise transfer any of
its rights or obligations hereunder without the prior written consent of each
Working Capital Facility Lender (and any attempted assignment or transfer by the
Borrower without such consent shall be null and void) and (ii) no Working
Capital Facility Lender may assign or otherwise transfer its rights or
obligations hereunder except in accordance with this Section.

          (b) (i) Subject to the conditions set forth in paragraph (b)(ii)
below, any Working Capital Facility Lender may assign to one or more assignees
(each, an "Assignee") all or a portion of its rights and obligations under this
Agreement (including all or a portion of its Working Capital Facility
Commitments and the Working Capital Loans at the time owing to it) with the
prior written consent of:

                    (A) the Borrower (such consent not to be unreasonably
withheld), provided that no consent of the Borrower shall be required for an
assignment to a Working Capital Facility Lender, an affiliate of a Working
Capital Facility Lender, an Approved Fund (as defined below) or, if an Event of
Default has occurred and is continuing, any other Person; and

                    (B) the Working Capital Facility Administrative Agent,
provided that no consent of the Working Capital Facility Administrative Agent
shall be required for an assignment of all or any portion of a Working Capital
Loan to a Working Capital Facility Lender, an affiliate of a Working Capital
Facility Lender or an Approved Fund.

               (ii) Assignments shall be subject to the following additional
conditions:

                    (A) except in the case of an assignment to a Working Capital
Facility Lender, an affiliate of a Working Capital Facility Lender or an
Approved Fund or an assignment of the entire remaining amount of the assigning
Working Capital Facility Lender's Working Capital Facility Commitments or
Working Capital Loans, the amount of the Working


                                       20

<PAGE>

Capital Facility Commitments or Working Capital Loans of the assigning Working
Capital Facility Lender subject to each such assignment (determined as of the
date the Assignment with respect to such assignment is delivered to the Working
Capital Facility Administrative Agent) shall not be less than $5,000,000 unless
each of the Borrower and the Working Capital Facility Administrative Agent
otherwise consent, provided that (1) no such consent of the Borrower shall be
required if an Event of Default has occurred and is continuing and (2) such
amounts shall be aggregated in respect of each Working Capital Facility Lender
and its affiliates or Approved Funds, if any;

                    (B) each such assignment shall be of a constant, and not a
varying, percentage of all of the assigning Working Capital Facility Lender's
rights (including with respect to its Working Capital Loans) and obligations
(including with respect to its Working Capital Facility Commitments);

                    (C) (1) the parties to each assignment shall execute and
deliver to the Working Capital Facility Administrative Agent an Assignment,
together with a processing and recordation fee of $3,500 and (2) the assigning
Working Capital Facility Lender shall have paid in full any amounts owing by it
to the Working Capital Facility Administrative Agent; and

                    (D) the Assignee, if it shall not be a Working Capital
Facility Lender, shall deliver to the Working Capital Facility Administrative
Agent an administrative questionnaire in which the Assignee designates one or
more credit contacts to whom all syndicate-level information (which may contain
material non-public information about the Borrower and its Affiliates and their
related parties or their respective securities) will be made available and who
may receive such information in accordance with the assignee's compliance
procedures and applicable laws, including Federal and state securities laws.

     For the purposes of this Section 10.5, "Approved Fund" means any Person
(other than a natural person) that is engaged in making, purchasing, holding or
investing in bank loans and similar extensions of credit in the ordinary course
of its business and that is administered or managed by (a) a Working Capital
Facility Lender, (b) an affiliate of a Working Capital Facility Lender or (c) an
entity or an affiliate of an entity that administers or manages a Working
Capital Facility Lender.

               (iii) Subject to acceptance and recording thereof pursuant to
paragraph (b)(iv) below, from and after the effective date specified in each
Assignment the Assignee thereunder shall be a party hereto and, to the extent of
the interest assigned by such Assignment, have the rights and obligations of a
Working Capital Facility Lender under this Agreement, and the assigning Working
Capital Facility Lender thereunder shall, to the extent of the interest assigned
by such Assignment, be released from its obligations under this Agreement (and,
in the case of an Assignment covering all of the assigning Working Capital
Facility Lender's rights and obligations under this Agreement, such Working
Capital Facility Lender shall cease to be a party hereto but shall continue to
be entitled to the benefits of Sections 3.02, 3.03, 3.04 and 10.04 of the Common
Agreement). Any assignment or transfer by a Working Capital Facility Lender of
rights or obligations under this Agreement that does not comply with this
Section 10.5 shall be treated for purposes of this Agreement as a sale by such
Working Capital Facility Lender of a participation in such rights and
obligations in accordance with paragraph (c) of this Section.


                                       21

<PAGE>

               (iv) The Working Capital Facility Administrative Agent, acting
for this purpose as an agent of the Borrower, shall maintain at one of its
offices a copy of each Assignment delivered to it and a register for the
recordation of the names and addresses of the Working Capital Facility Lenders,
and the Working Capital Facility Commitments of, and principal amount of the
Working Capital Loans owing to, each Working Capital Facility Lender pursuant to
the terms hereof from time to time (the "Register"). The entries in the Register
shall be conclusive, and the Borrower, the Working Capital Facility
Administrative Agent and the Working Capital Facility Lenders may treat each
Person whose name is recorded in the Register pursuant to the terms hereof as a
Working Capital Facility Lender hereunder for all purposes of this Agreement,
notwithstanding notice to the contrary.

               (v) Upon its receipt of a duly completed Assignment executed by
an assigning Working Capital Facility Lender and an Assignee, the Assignee's
completed administrative questionnaire (unless the Assignee shall already be a
Working Capital Facility Lender hereunder), the processing and recordation fee
referred to in paragraph (b) of this Section and any written consent to such
assignment required by paragraph (b) of this Section, the Working Capital
Facility Administrative Agent shall accept such Assignment and record the
information contained therein in the Register. No assignment shall be effective
for purposes of this Agreement unless it has been recorded in the Register as
provided in this paragraph.

          (c) (i) Any Working Capital Facility Lender may, without the consent
of the Borrower or the Working Capital Facility Administrative Agent, sell
participations to one or more banks or other entities (a "Participant") in all
or a portion of such Working Capital Facility Lender's rights and obligations
under this Agreement (including all or a portion of its Working Capital Facility
Commitments and the Working Capital Loans owing to it); provided that (A) such
Working Capital Facility Lender's obligations under this Agreement shall remain
unchanged, (B) such Working Capital Facility Lender shall remain solely
responsible to the other parties hereto for the performance of such obligations
and (C) the Borrower, the Working Capital Facility Administrative Agent and the
other Working Capital Facility Lenders shall continue to deal solely and
directly with such Working Capital Facility Lender in connection with such
Working Capital Facility Lender's rights and obligations under this Agreement.
Any agreement pursuant to which a Working Capital Facility Lender sells such a
participation shall provide that such Working Capital Facility Lender shall
retain the sole right to enforce this Agreement and to approve any amendment,
modification or waiver of any provision of this Agreement. Subject to paragraph
(c)(ii) of this Section, the Borrower agrees that each Participant shall be
entitled to the benefits of Sections 3.02, 3.03 and 3.04 of the Common Agreement
to the same extent as if it were a Working Capital Facility Lender and had
acquired its interest by assignment pursuant to paragraph (b) of this Section.
To the extent permitted by law, each Participant also shall be entitled to the
benefits of Section 10.6(b) as though it were a Working Capital Facility Lender,
provided such Participant shall be subject to Section 10.6(a) as though it were
a Working Capital Facility Lender.

               (ii) A Participant shall not be entitled to receive any greater
payment under the Common Agreement than the applicable Working Capital Facility
Lender 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. Any Participant
that is a non-U.S. Lender shall not be entitled to the benefits of Section 3.02
of the


                                       22

<PAGE>

Common Agreement unless such Participant complies with Section 3.02(e) of the
Common Agreement.

          (d) Any Working Capital Facility Lender may at any time pledge or
assign a security interest in all or any portion of its rights under this
Agreement to secure obligations of such Working Capital Facility Lender,
including any pledge or assignment to secure obligations to a Federal Reserve
Bank, and this Section shall not apply to any such pledge or assignment of a
security interest; provided that no such pledge or assignment of a security
interest shall release a Working Capital Facility Lender from any of its
obligations hereunder or substitute any such pledgee or Assignee for such
Working Capital Facility Lender as a party hereto.

          (e) Notwithstanding the foregoing, any Conduit Lender may assign any
or all of the Working Capital Loans it may have funded hereunder to its
designating Working Capital Facility Lender without the consent of the Borrower
or the Working Capital Facility Administrative Agent and without regard to the
limitations set forth in Section 10.5(b). Each of the Borrower, each Working
Capital Facility Lender and the Working Capital Facility Administrative Agent
hereby confirms that it will not institute against a Conduit Lender or join any
other Person in instituting against a Conduit Lender any bankruptcy,
reorganization, arrangement, insolvency or liquidation proceeding under any
state bankruptcy or similar law, for one year and one day after the payment in
full of the latest maturing commercial paper note issued by such Conduit Lender;
provided, however, that each Working Capital Facility Lender designating any
Conduit Lender hereby agrees to indemnify, save and hold harmless each other
party hereto for any loss, cost, damage or expense arising out of its inability
to institute such a proceeding against such Conduit Lender during such period of
forbearance.

     Section 10.6 Adjustments; Set off. (a) Except to the extent that this
Agreement, any other Financing Document or a court order expressly provides for
payments to be allocated to a particular Working Capital Facility Lender, if any
Working Capital Facility Lender (a "Benefitted Lender") shall receive any
payment of all or part of the Working Capital Facility Obligations owing to it
(other than in connection with an assignment made pursuant to Section 10.5), or
receive any collateral in respect thereof (whether voluntarily or involuntarily,
by set off, or otherwise), in a greater proportion than any such payment to or
collateral received by any other Working Capital Facility Lender, if any, in
respect of the Working Capital Facility Obligations owing to such other Working
Capital Facility Lender, such Benefitted Lender shall purchase for cash from the
other Working Capital Facility Lenders a participating interest in such portion
of the Working Capital Facility Obligations owing to each such other Working
Capital Facility Lender, or shall provide such other Working Capital Facility
Lenders with the benefits of any such collateral, as shall be necessary to cause
such Benefitted Lender to share the excess payment or benefits of such
collateral ratably with each of the Working Capital Facility Lenders; provided,
however, that if all or any portion of such excess payment or benefits is
thereafter recovered from such Benefitted Lender, such purchase shall be
rescinded, and the purchase price and benefits returned, to the extent of such
recovery, but without interest.

          (b) In addition to any rights and remedies of the Working Capital
Facility Lenders provided by law, each Working Capital Facility Lender shall
have the right, without notice to the Borrower, any such notice being expressly
waived by the Borrower to the extent permitted by applicable law, upon any
Working Capital Facility Obligations becoming due and


                                       23

<PAGE>

payable by the Borrower (whether at the stated maturity, by acceleration or
otherwise), to apply to the payment of such Obligations, by setoff or otherwise,
any and all deposits (general or special, time or demand, provisional or final),
in any currency, and any other credits, indebtedness or claims, in any currency,
in each case whether direct or indirect, absolute or contingent, matured or
unmatured, at any time held or owing by such Working Capital Facility Lender,
any affiliate thereof or any of their respective branches or agencies to or for
the credit or the account of the Borrower. Each Working Capital Facility Lender
agrees promptly to notify the Borrower and the Working Capital Facility
Administrative Agent after any such application made by such Working Capital
Facility Lender, provided that the failure to give such notice shall not affect
the validity of such application.

     Section 10.7 Counterparts. This Agreement may be executed by one or more of
the parties to this Agreement on any number of separate counterparts, and all of
said counterparts taken together shall be deemed to constitute one and the same
instrument. Delivery of an executed signature page of this Agreement by
facsimile transmission shall be effective as delivery of a manually executed
counterpart hereof. A set of the copies of this Agreement signed by all the
parties shall be lodged with the Borrower and the Working Capital Facility
Administrative Agent.

     Section 10.8 Severability. Any provision of this Agreement that is
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction,
be ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining provisions hereof, and any such prohibition or
unenforceability in any jurisdiction shall not invalidate or render
unenforceable such provision in any other jurisdiction.

     Section 10.9 Integration. This Agreement and the other Financing Documents
represent the entire agreement of the Borrower, the Working Capital Facility
Administrative Agent and the Working Capital Facility Lenders with respect to
the subject matter hereof and thereof, and there are no promises, undertakings,
representations or warranties by the Working Capital Facility Administrative
Agent or any Working Capital Facility Lender relative to the subject matter
hereof not expressly set forth or referred to herein or in the other Financing
Documents.

     Section 10.10 GOVERNING LAW, SUBMISSION TO JURISDICTION, ETC.

          (a) THIS AGREEMENT AND EACH OF THE OTHER FINANCING DOCUMENTS (UNLESS
SUCH DOCUMENT EXPRESSLY STATES OTHERWISE THEREIN) SHALL BE GOVERNED BY, AND
CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

          (b) Each of the parties hereto hereby (i) expressly and irrevocably
submits and consents to the jurisdiction of any State or Federal court sitting
in the Borough of Manhattan, and any appellate court having jurisdiction over
appeals from any of such courts, in any action to resolve any controversy or
claim arising out of this Agreement or any other Financing Document, (ii) agrees
that all claims in such action may be decided in any such court, (iii) waives,
to the fullest extent it may effectively do so, the defense of an inconvenient
forum and (iv) consents to the service of process by registered or certified
mail (or any substantially similar


                                       24

<PAGE>

form of mail), postage prepaid and return receipt requested, or by personal
service within or without the State of New York, at the address for notices
referred to in Section 10.3. A final judgment in any such action shall be
conclusive and may be enforced in other jurisdictions. Furthermore, each party
hereby submits to the competent courts of its corporate domicile in any action
or proceeding against it in connection with this Agreement or any other
Financing Document. Nothing herein shall affect the right of any party to bring
legal action or proceedings in any other competent jurisdiction.

          (c) To the extent the Borrower may, in any action or proceeding
arising out of or relating to any of the Financing Documents brought in Mexico
or elsewhere, be entitled under applicable Law to require or claim that any
Working Capital Facility Lender or the Working Capital Facility Administrative
Agent post security for costs or take similar action, the Borrower hereby
irrevocably waives and agrees not to claim the benefit of such entitlement.


                                       25
<PAGE>

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

                                        CONSTRUCTORA DE PROYECTOS
                                        HIDROELECTRICOS, S.A. DE C.V., as the
                                        Borrower


                                        By: /s/ GABRIEL DE LA CONCHA
                                            ------------------------------------
                                        Name: GABRIEL DE LA CONCHA
                                        Title: LEGAL REPRESENTATIVE

           Signature Page to Working Capital Facility Credit Agreement

<PAGE>

                                        WESTLB AG, NEW YORK BRANCH, as Working
                                        Capital Facility Administrative Agent


                                        By: /s/ Jared Brenner
                                            ------------------------------------
                                        Name: Jared Brenner
                                        Title: Executive Director


                                        By: /s/ Isaac Deutsch
                                            ------------------------------------
                                        Name: Isaac Deutsch
                                        Title: Executive Director

           Signature Page to Working Capital Facility Credit Agreement

<PAGE>

                                        WESTLB AG, NEW YORK BRANCH, as a Working
                                        Capital Facility Lender


                                        By: /s/ Jared Brenner
                                            ------------------------------------
                                        Name: Jared Brenner
                                        Title: Executive Director


                                        By: /s/ Isaac Deutsch
                                            ------------------------------------
                                        Name: Isaac Deutsch
                                        Title: Executive Director

           Signature Page to Working Capital Facility Credit Agreement

<PAGE>

                                                                   SCHEDULE 1 TO
                                       WORKING CAPITAL FACILITY CREDIT AGREEMENT

                           COMMITMENTS AND PERCENTAGES

<TABLE>
<CAPTION>
          LENDER                 COMMITMENT          PERCENTAGE
          ------             -----------------   -----------------
<S>                          <C>                 <C>
WESTLB AG, NEW YORK BRANCH    U.S.$80,000,000           100%

                             TOTAL COMMITMENTS   TOTAL PERCENTAGES
                              U.S.$80,000,000           100%
</TABLE>
<PAGE>

                                                                    EXHIBIT A TO
                                       WORKING CAPITAL FACILITY CREDIT AGREEMENT

                              [FORM OF ASSIGNMENT]

     THIS ASSIGNMENT AND ASSUMPTION AGREEMENT, dated as of [______], 20[__]
(this "Agreement") is made [between](1) [among](2) [ASSIGNOR] (the "Assignor"),
[ASSIGNEE] (the "Assignee"), [Constructora de Proyectos Hidroelectricos, S.A. de
C.V. (the "Borrower")](3) and [WestLB AG, New York Branch, as working capital
facility administrative agent (together with its successors and assigns in such
capacity, the "Working Capital Facility Administrative Agent") for the Working
Capital Facility Lenders (as defined below)](4). All capitalized terms used
herein and not otherwise defined herein shall have the meanings specified in the
Working Capital Facility Credit Agreement referred to below.

                             PRELIMINARY STATEMENTS

          1. This Agreement relates to the Working Capital Facility Credit
Agreement dated, as of October 19, 2007 (as the same may be amended,
supplemented or otherwise modified from time to time, the "Working Capital
Facility Credit Agreement"), among the Borrower, the working capital facility
lenders named on the signature pages thereto and from time to time parties
thereto (the "Working Capital Facility Lenders"), and the Working Capital
Facility Administrative Agent.

          2. Working Capital Loans in the principal amount of U.S.$[________]
made to the Borrower by the Assignor under the Working Capital Facility Credit
Agreement are outstanding on the date hereof.

          3. The Assignor proposes to assign to the Assignee all of its rights
under the Working Capital Facility Credit Agreement in respect of
U.S.$[________] of its Working Capital Facility Commitment thereunder (the
"Assigned Commitment"), together with a portion of its outstanding Working
Capital Loans in the principal amount equal to U.S.$[________] (the "Assigned
Loans") and the Assignee proposes to accept assignment of such rights and assume
the corresponding obligations from the Assignor on the terms herein.(5)

          NOW THEREFORE, in consideration of the foregoing and the mutual
agreements contained herein, the parties hereto agree as follows:

----------
(1)  Insert if this agreement is between the Assignor and Assignee only.

(2)  Insert if this agreement is among the Assignor, the Assignee, the Working
     Capital Facility Administrative Agent and, if applicable, the Borrower.

(3)  Insert if no Event of Default has occurred and is continuing and the
     Assignee is not (A) a Working Capital Facility Lender, (B) an affiliate of
     a Working Capital Facility Lender or (C) an Approved Fund.

(4)  Insert if the Assignee is not (A) a Working Capital Facility Lender, (B) an
     affiliate of a Working Capital Facility Lender or (C) an Approved Fund.

(5)  Each assignment must be of a constant percentage of all of the assigning
     Working Capital Facility Lender's rights (including its Working Capital
     Loans) and obligations (including its Working Capital Facility
     Commitments).

<PAGE>

          SECTION 1. ASSIGNMENT AND ASSUMPTIONS.

          (a) The Assignor hereby sells, assigns, transfers and conveys to the
Assignee all of the rights of the Assignor under the Working Capital Facility
Credit Agreement in and to the Assigned Commitment and the Assigned Loans, and
the Assignee hereby accepts such assignment, transfer and conveyance from the
Assignor and assumes all of the obligations of the Assignor under the Working
Capital Facility Credit Agreement in and to the Assigned Commitment and the
Assigned Loans. Upon (i) the execution and delivery hereof by the Assignor, the
Assignee and, to the extent required pursuant to Section 3 below, the Borrower
and the Working Capital Facility Administrative Agent and (ii) the payment of
the amounts specified in Section 2 hereof required to be paid on the date
hereof, (A) the Assignee shall, as of the date hereof, succeed to the rights and
be obligated to perform the obligations of a Working Capital Facility Lender
under the Working Capital Facility Credit Agreement with a Working Capital
Facility Commitment in an amount equal to the Assigned Commitment, Working
Capital Loans outstanding in an aggregate principal amount equal to the Assigned
Loans, and a Working Capital Facility Percentage equal to [___] percent ([__]%)
and (B) the Working Capital Facility Commitment, Working Capital Loans and
Working Capital Facility Percentage of the Assignor shall, as of the date
hereof, be reduced correspondingly and the Assignor shall be released from its
obligations under the Working Capital Facility Credit Agreement to the extent
such obligations have been assumed by the Assignee. The assignment provided for
herein shall be without recourse to the Assignor.

          (b) Each party hereto agrees to comply with the terms and conditions
set forth in Section 10.5 of the Working Capital Facility Credit Agreement that
govern the making of an assignment thereunder, and such terms and conditions are
incorporated herein by reference as if fully set forth herein.

          SECTION 2. PAYMENTS. As consideration for the sale and assignment
contemplated in Section 1 hereof, the Assignee shall pay to the Assignor on the
date hereof in federal funds an amount equal to [INSERT AMOUNT OF PAYMENT IN
WORDS AND FIGURES]. It is understood that all Fees with respect to the Assigned
Commitment and the Assigned Loans accrued to the date hereof are for the account
of the Assignor. The commitment fees set forth in Section 2.10(a) of the Working
Capital Facility Credit Agreement, with respect to the Assigned Commitment
accrued from and including the date hereof, are for the account of the Assignee.
Each of the Assignor and the Assignee hereby agrees that if it receives any
amount under the Working Capital Facility Credit Agreement which is for the
account of the other party hereto, it shall receive the same for the account of
such other party to the extent of such other party's interest therein and shall
promptly pay the same to such other party.

          SECTION 3. CONSENT OF THE BORROWER AND THE WORKING CAPITAL FACILITY
ADMINISTRATIVE AGENT. This Agreement is conditioned upon the consent of the
Borrower pursuant to Section 10.5 of the Working Capital Facility Credit
Agreement if no Event of Default has occurred and is continuing and the Assignee
is not (A) a Working Capital Facility Lender, (B) an affiliate of a Working
Capital Facility Lender or (C) an Approved Fund. This Agreement is conditioned
upon the consent of the Working Capital Facility Administrative Agent pursuant
to Section 10.5 of the Working Capital Facility Credit Agreement if the Assignee
is not (A) a Working Capital Facility Lender, (B) an affiliate of a Working
Capital Facility Lender or (C) an

<PAGE>

Approved Fund. The execution of this Agreement by the Borrower and the Working
Capital Facility Administrative Agent, in each case as applicable, is evidence
of such consent.

          SECTION 4. NON-RELIANCE ON ASSIGNOR.

          (a) Neither the Assignor nor the Working Capital Facility
Administrative Agent nor any other Working Capital Facility Lender shall be
responsible to the Assignee for the execution, effectiveness, genuineness,
validity, enforceability, collectibility or sufficiency of any of the
Transaction Documents or for any representations, warranties, recitals or
statements made therein or in any written or oral statement or in any financial
or other statements, instruments, reports, certificates or any other documents
made or furnished or made available by the Assignor, the Working Capital
Facility Administrative Agent or any other Working Capital Facility Lender to
the Assignee or by or on behalf of the Borrower to the Assignor, the Working
Capital Facility Administrative Agent, such Working Capital Facility Lender or
the Assignee in connection with the Transaction Documents and the transactions
contemplated thereby. Neither the Assignor nor the Working Capital Facility
Administrative Agent nor any other Working Capital Facility Lender shall be
required to ascertain or inquire as to the performance or observance of any of
the terms, conditions, provisions, covenants or agreements contained in any of
the Transaction Documents or as to the use of the proceeds of the Working
Capital Facility Loans or as to the existence or possible existence of any
Default or Event of Default.

          (b) Neither the Assignor nor the Working Capital Facility
Administrative Agent nor any other Working Capital Facility Lender makes any
representation or warranty in connection with, and shall have no responsibility
with respect to, the solvency, financial condition, or statements of the
Borrower or any other party to any Transaction Document, or the validity and
enforceability of the Working Capital Facility Obligations or the obligations of
any party to any Transaction Document. The Assignee acknowledges that it has,
independently and without reliance on the Assignor, the Working Capital Facility
Administrative Agent or any other Working Capital Facility Lender, and based on
such documents and information as it has deemed appropriate, made its own credit
analysis and decision to enter into this Agreement and will continue to be
responsible for making its own independent appraisal of the business, affairs
and financial condition of the Borrower and each other party to the Transaction
Documents.

          SECTION 5. GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY, AND
CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK.

          SECTION 6. AMENDMENT. No term or provision of this Agreement may be
amended, changed, waived, discharged or terminated orally, but only by an
instrument in writing signed by the Assignor and the Assignee, with the consent
of the Working Capital Facility Administrative Agent, the Working Capital
Facility Majority Lenders and the Borrower.

          SECTION 7. COUNTERPARTS. This Agreement may be signed in any number of
counterparts, each of which shall be an original, with the same effect as if the
signatures thereto and hereto were upon the same instrument.

                            [SIGNATURE PAGE FOLLOWS ]

<PAGE>

          IN WITNESS WHEREOF, the parties have caused this Agreement to be
executed and delivered by their duly authorized officers as of the date first
above written.

                                        [ASSIGNOR]


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


                                        [ASSIGNEE]


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


                                        [WESTLB AG, NEW YORK BRANCH,
                                        as Working Capital Facility
                                        Administrative Agent


                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:](6)
                                                   -----------------------------


                                        [CONSTRUCTORA DE PROYECTOS
                                        HIDROELECTRICOS, S.A. DE C.V.,
                                        as the Borrower


                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:]7
                                                 -------------------------------

----------
(6)  See footnote 3.

(7)  See footnote 4.

<PAGE>


                                                                    EXHIBIT B TO
                                                                 WORKING CAPITAL
                                                                 FACILITY CREDIT
                                                                       AGREEMENT

                         [FORM OF INTEREST RATE NOTICE]

                              INTEREST RATE NOTICE

                                                            [___________ , 20__]

WestLB AG, New York Branch

     as Working Capital Facility Administrative Agent for the Working Capital
     Facility Lenders party to the Working Capital Facility Credit Agreement
     referred to below

1211 Avenue of the Americas
New York, New York 10036

Attention: Jared Brenner

Ladies and Gentlemen:

Pursuant to the Working Capital Facility Credit Agreement, dated as of October
19, 2007 (as the same may be amended, supplemented or otherwise modified from
time to time, the "Working Capital Facility Credit Agreement"), among
Constructora de Proyectos Hidroelectricos, S.A. de C.V. (the "Borrower"),
certain working capital facility lenders party thereto (the "Working Capital
Facility Lenders"), and WestLB AG, New York Branch, as Working Capital Facility
Administrative Agent for the Working Capital Facility Lenders (all capitalized
terms used herein and not otherwise defined herein having the meanings specified
in the Working Capital Facility Credit Agreement), the Borrower has delivered to
the Working Capital Facility Administrative Agent and the Independent Engineer
its Working Capital Facility Notice of Borrowing dated [_________, 20__]. With
respect thereto, the Borrower hereby gives notice of its desire to make the
Working Capital Facility Borrowing on [__________ __, 20__](8) in accordance
with the terms set forth below:

     (i) The Working Capital Facility Borrowing shall be comprised of Working
     Capital Loans that are [EURODOLLAR LOANS] [ABR LOANS].

     (ii) [The initial Interest Period for such Working Capital Loans shall be
     one month.](9)

                                        CONSTRUCTORA DE PROYECTOS
                                        HIDROELECTRICOS, S.A. DE C.V.


                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------
----------
(8)  Insert date that is not sooner than third Business Day following the date
     of delivery of this Interest Rate Notice.

(9)  Use only for Eurodollar Loans.

<PAGE>

                                                                    EXHIBIT C TO
                                       WORKING CAPITAL FACILITY CREDIT AGREEMENT

             [FORM OF WORKING CAPITAL FACILITY NOTICE OF BORROWING]

                  WORKING CAPITAL FACILITY NOTICE OF BORROWING

                                                      (Date)

WestLB AG, New York Branch
as Working Capital Facility Administrative Agent
1211 Avenue of the Americas
New York, New York 10036
Attention: Jared Brenner
Telephone: 1 (212) 852-6116
Telecopier: 1 (212)789-0075

MWH Americas, Inc.
as Independent Engineer (as defined in the Common Agreement, defined below)
[address]
Telephone: [_____________________]
Telecopier: [____________________]
Attention: Jose Mayen

Ladies and Gentlemen:

     The undersigned, Constructora de Proyectos Hidroeletricos, S.A. de C.V.
(the "Borrower"), refers to:

     (i)  the Common Agreement, dated as of October 19, 2007 (as amended,
          supplemented or otherwise modified from time to time, the "Common
          Agreement") among the Borrower; WestLB AG, New York Branch ("WestLB"),
          as intercreditor agent (the "Intercreditor Agent"); each of the banks
          and other financial institutions listed on the signature pages thereto
          as Construction Facility Lenders (the "Construction Facility
          Lenders"); [______] as Construction Facility Administrative Agent (the
          "Construction Facility Administrative Agent"); each of the banks and
          other financial institutions listed on the signature pages thereto as
          Working Capital Facility Lenders (the "Working Capital Facility
          Lenders"); WestLB, as Working Capital Facility Administrative Agent
          (the "Working Capital Facility Administrative Agent"); Citibank, N.A.,
          as Offshore Collateral Agent (the "Offshore Collateral Agent"); Banco
          Nacional de Mexico, Integrante del Grupo Financiero Banamex, as
          Onshore Collateral Agent (the "Onshore Collateral Agent"); and the
          other Lenders (as defined therein) and Lender Representatives (as
          defined therein) from time to time party thereto; and

     (ii) the Working Capital Facility Credit Agreement, dated as of October 19,
          2007 (as amended, supplemented or otherwise modified from time to
          time, the "Working

<PAGE>

          Capital Facility Credit Agreement"), among the Borrower, the Working
          Capital Facility Lenders, and the Working Capital Facility
          Administrative Agent.

and hereby gives you notice, irrevocably, pursuant to Section 2.01 of the Common
Agreement (to the extent applicable), Section 4.02(a) of the Common Agreement
and Section 2.2(b) of the Working Capital Facility Credit Agreement that the
Borrower hereby requests:

     -    a Working Capital Facility Borrowing under the Working Capital
          Facility Credit Agreement, in the aggregate amount of $_______ (the
          "Requested Borrowing"), to be made on ________ __, 20__ (the
          "Requested Borrowing Date").

     All capitalized terms used herein and not otherwise defined herein having
the meanings specified in the Working Capital Facility Credit Agreement.

I.   WIRE TRANSFER INSTRUCTIONS

          The Borrower hereby requests transfer of the amount of the Requested
Borrowing on the Requested Borrowing Date in accordance with the wire transfer
instructions set forth on Schedule I hereto.

II.  CALCULATION OF REQUESTED BORROWING

     The Borrower hereby represents and warrants that:

     a. The aggregate principal amount of the Requested Borrowing does not
exceed the aggregate amount of Project Costs (other than the repayment or
prepayment of any Loans) to be paid by the Borrower within the thirty (30) day
period immediately following the Requested Borrowing Date, as set forth on
Schedules I and II hereto in the aggregate.

     b. The available undrawn amount of all Disbursement LCs is US$________ [and
the amount of all cash deposits held in the Dollar Disbursement Guarantee
Account is US$____________]*.

     c. After giving effect to the Requested Borrowing, the amount of all
Working Capital Loans outstanding and all accrued but unpaid Debt Service in
respect of such Working Capital Loans does not exceed "X", calculated as
follows:

                                   X = (2 x C)

          where

          "C" is U.S.$___, which is the sum of the available undrawn amount of
     all Disbursement LCs [and all cash deposits held in the Dollar Disbursement
     Guarantee Account] *.

----------
*    Include bracketed language only if (i) the Construction Facility Closing
     Date has occurred and (ii) there is a balance in the Dollar Disbursement
     Guarantee Account

*    Id.

<PAGE>

     d. Each of the conditions precedent to the making of the Requested
Borrowing are satisfied and shall remain satisfied on and as of the Requested
Borrowing Date.

     e. The Borrower has delivered to the Intercreditor Agent all Monthly
Reports delivered to CFE pursuant to the Public Works Contract and all
certifications or other responses thereto received from CFE.

                                        Very truly yours,

                                        CONSTRUCTORA DE PROYECTOS
                                        HIDROELECTRICOS, S.A. DE C.V.


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

                                                                      SCHEDULE I

                                COST CERTIFICATE

<TABLE>
<CAPTION>
                                                                           CURRENT MONTH (MES EN
                                                                                  CURSO)
                                                                         ------------------------
                                                        CUMULATIVE(10)   BUDGET   ACTUAL (ACTUAL)
                                                        --------------   ------   ---------------
<S>                                                     <C>              <C>      <C>
A. DIRECT COSTS
   COSTOS DIRECTOS

      Workforce
      Mano de Obra

      Materials
      Materiales

      Machinery
      Maquinaria

      Materials Processing
      Procesamiento de Materiales

      Electromechanical
      Electromecanicos

B. INDIRECT COSTS
   COSTOS INDIRECTOS

      Construction and conservation of access roads
      Construccion y Conservacion de Accesos

      Other installations for electromechanical works
      Otras instalaciones para trabajos
      electromecanicos

      Installment and dismantling of Equipment
      Montaje y Desmantelamiento de Equipo

      Technical and Administrative Personnel
      Personal Tecnico y Administrativo

      Travel Allowance
      Pasajes y viaticos

      Other services
      Otros Servicios

      Execution of Workforce Contracts
      Suscripcion de contratos de Trabajo

      Buildings and locals
      Edificios y otras construcciones

      Maintenance and storage premises
      Locales de mantenimiento y guarda

      Warehouses
      Bodegas

      General Installations
      Instalaciones Generales

      Equipment, furniture and other fixtures
      Equipos, Muebles y enseres

      Rents (buildings, vehicles)
      Rentas (construcciones, vehiculos)

      Construction of camps
      Construccion de campamentos

      Installation of electric lines
      Instalacion de lineas electricas
</TABLE>

----------
(10) Insert cumulative amount to date including amounts included in this Notice
     of Borrowing.

<PAGE>

<TABLE>
<CAPTION>
                                                                           CURRENT MONTH (MES EN
                                                                                  CURSO)
                                                                         ------------------------
                                                        CUMULATIVE(10)   BUDGET   ACTUAL (ACTUAL)
                                                        --------------   ------   ---------------
<S>                                                     <C>              <C>      <C>
      Freight and transport of Machinery and others
      Fletes y acarreos de Maquinaria y otros.

      Telecommunications
      Telecomunicaciones

      Information Technologies (Software and
      Hardware)
      Tecnologia Informatica (Software and Hardware)

      Electricity, Gas
      Electricidad y Gas

      Bidding Costs
      Costos de Licitacion

      Construction of camps, plants and installation
      elements
      Construccion de campamentos, plantas y
      elementos para instalaciones

      Engineering, Consulting and Laboratories
      Consultoria y Laboratorio de Ingeniaria

      Insurance, Performance Bond
      Seguros, Fianza de Desempeno

      Corporate Allocation
      Gastos Corporativos

      Profits before tax
      Utilidad antes de Impuestos

      VAT Payable
      IVA a Pagar

C. AGGREGATE DEBT SERVICE
   SERVICIO DE LA DEUDA EN EL AGREGADO

      Debt Service (other than Non-Excluded Taxes,
      Other Taxes and Additional Amounts)
      Debt Service (otro que los Impuestos
      NoExcluidos, Otros Impuestos y Montos
      Adicionales)

      Non-Excluded Taxes, Other Taxes and Additional
      Amounts
      Impuestos No Excluidos, Otros Impuestos y
      Montos Adicionales

D. OTHER FINANCING-RELATED EXPENSES (e.g., legal,
   consultants, agents and the like)
   OTROS GASTOS RELACIONADOS AL
   FINANCIAMIENTO (e.g., abogados, consultores,
   agents y otros)
</TABLE>

<PAGE>

                                                                     SCHEDULE II

                           WIRE TRANSFER INSTRUCTIONS
<PAGE>

                                                                       EXHIBIT D
                                    TO WORKING CAPITAL FACILITY CREDIT AGREEMENT

                            [FORM OF DISBURSEMENT LC]

[LETTERHEAD OF ISSUING BANK]

[Date]

IRREVOCABLE STANDBY LETTER OF CREDIT NO. ________

To: WestLB AG, New York Branch,
    as Working Capital Facility Administrative Agent for the lenders
    under the Working Capital Facility Credit Agreement and the
    Common Agreement referred to below
    1211 Avenue of the Americas
    New York, New York 10036
    Attention: Jared Brenner
    Telephone: 1 (212) 852-6166
    Telecopier: 1 (212)789-0075

Dear Sirs:

At the request of our client ___________(11) we, the issuing bank (the "Issuing
Bank"), hereby establish this unconditional and irrevocable standby Letter of
Credit (this "Letter of Credit") in the amount of __________ (the "Total
Amount") in favor of WestLB AG, New York Branch, in its capacity as Working
Capital Facility Administrative Agent under (i) that certain Working Capital
Facility Credit Agreement dated as of October 19, 2007 (as the same may be
executed, amended, supplemented or otherwise modified from time to time, the
"Working Capital Facility Credit Agreement"), among Constructora de Proyectos
Hidroelectricos, S.A. de C.V. as Borrower (the "Borrower"), WestLB AG, New York
Branch as Working Capital Facility Administrative Agent (in its capacity as
Working Capital Facility Administrative Agent, the "Beneficiary"), and the
Working Capital Facility Lenders from time to time party thereto, in connection
with certain payment obligations of the Borrower under the Working Capital
Facility Credit Agreement and (ii) that certain Common Agreement, dated as of
October 19, 2007 (as amended, supplemented or otherwise modified from time to
time, the "Common Agreement") among the Borrower, the Beneficiary, WestLB AG,
New York Branch, as Intercreditor Agent and as Construction Facility
Administrative Agent, the Working Capital Facility Lenders from time to time
party thereto, the Construction Facility Lenders from time to time party
thereto, Citibank, N.A., as Offshore Collateral Agent, Banco Nacional de Mexico,
S.A., Integrante del Grupo Financiero Banamex, as Onshore Collateral Agent.

The aggregate amount required to be paid by the Issuing Bank pursuant to this
Letter of Credit shall at no time exceed the Total Amount, and all amounts paid
by the Issuing

----------
(11) Insert name of account party, which must not be the Borrower.

<PAGE>

Bank in compliance with this Letter of Credit shall constitute a pro tanto
reduction in the Total Amount.

The Beneficiary may demand payment from time to time from the Issuing Bank
pursuant hereto by presenting a certificate which conforms to the form set out
in Annex A to this Letter of Credit, and completed and purportedly signed by an
authorized officer of the Beneficiary (each such certificate, a "Certificate of
Execution"). Such Certificates of Execution may be presented in the form of a
letter or other writing transmitted by any means of telecommunication. Any such
Certificate of Execution shall be dated the date of presentation and shall be
presented at or delivered to the office of the Issuing Bank located at
________________ or, (i) if transmitted by authenticated SWIFT, address
_______________ or (ii) if transmitted by telecopy, telex or electronic mail, to
the following, respectively, _________, ____________ or _____________.

The Issuing Bank agrees that all demands for payment made by the Beneficiary
under this Letter of Credit shall be honored by the Issuing Bank, and agrees to
pay the amounts indicated in the Certificate of Execution upon presentation of
such Certificate of Execution, provided, that the form of Certificate of
Execution and the means of presentation thereof are in compliance with the
provisions set forth in the previous paragraph. The Certificate of Execution
shall be presented on a Business Day and during business hours of the Issuing
Bank, which are understood to be 9:00 a.m. to 5:00 p.m. (_______ time). If a
Certificate of Execution is presented before 3:00 p.m. (___________ time), the
Issuing Bank is required to place the corresponding funds at the disposal of the
Beneficiary no later than 10:00 a.m. (_____________ time) on the Business Day
immediately following the day on which the Certificate of Execution was
presented. In the event a Certificate of Execution is presented after 3:00 p.m.
(___________ time), the Issuing Bank is required to place the corresponding
funds at the disposal of the Beneficiary, no later than 10:00 a.m. (____________
time) on the second Business Day immediately following the day on which the
Certificate of Execution was presented. As used in this Letter of Credit, the
term "Business Day" means any day of the year other than a day on which banks
located in ________ are authorized or are required by law or regulation to
close.

In the event a Certificate of Execution fails to comply with any requirement
indicated in this Letter of Credit, the Issuing Bank shall immediately notify
the Beneficiary in writing at the address indicated in the heading of this
letter, or at such other address as the Beneficiary may provide to the Issuing
Bank in the future for such purpose, that the presentation has been rejected by
the Issuing Bank. The notice of the Issuing Bank shall indicate the reason why
the Issuing Bank considers the Certificate of Execution to be not proper and
shall place at the disposal of the Beneficiary the documents presented by the
Beneficiary in support of its demand for payment. The Beneficiary may thereafter
present a new Certificate of Execution that is in compliance with the provisions
of this Letter of Credit.

All payments made by the Issuing Bank to the Beneficiary under this Letter of
Credit shall be made by means of wire transfer in immediately available funds to
the bank account indicated by the Beneficiary in New York, New York, U.S.A., in
the

<PAGE>

corresponding request. The Issuing Bank shall make all payments under this
Letter of Credit with its own funds. All payments shall be made by the Issuing
Bank to the Beneficiary under this Letter of Credit without the exercise of any
rights of set-off, counterclaim or other similar rights.

The Issuing Bank [and any confirming bank of this Letter of Credit(12)] hereby
irrevocably waive[s] all rights and claims against the Borrower and any of its
assets in connection with the [___________________](13) and this Letter of
Credit or arising by operation of law or otherwise in connection therewith
(including without limitation pursuant to any applicable principles of
subrogation and any and all rights of the Issuing Bank pursuant to any
applicable law (including without limitation pursuant to [Sections 5-108(i)(1)
and 5-117 of the Uniform Commercial Code of the State of New York)](14) [Rule
8.01 or 8.02 of the ISP98 (as defined below))](15) until such time as the
Beneficiary has notified the Issuing Bank in writing that all of the Borrower's
payment obligations pursuant to the financing documents described in the Common
Agreement have been irrevocably and indefeasibly paid and satisfied in full and
all commitments referred to in any such financing documents have terminated. The
waiver set forth in this paragraph shall survive any expiration of this Letter
of Credit.

This Letter of Credit shall remain valid until, and expire automatically on, the
date (the "Expiration Date") that is the earlier of (i) the date on which the
Total Amount is reduced to zero, and (ii) [INSERT ONE YEAR ANNIVERSARY OF THE
DATE OF ISSUANCE] (as such date shall be extended pursuant to the immediately
following paragraph). The Beneficiary may not submit any Certificate of
Execution after the Expiration Date.

It is a condition of this Letter of Credit that it shall be deemed automatically
extended without amendment for additional periods of one year from the date set
forth in subsection (ii) of the immediately preceding paragraph, unless at least
ninety (90) days prior to such specified date (as it may have been extended
previously hereunder) we notify you by courier that we have elected not to renew
this Letter of Credit for any such additional period.

[APPLICABLE RULES: VERSION 1-UCP]

[This Letter of Credit shall be subject to the provisions (to the extent that
such provisions are not inconsistent with this Letter of Credit) of the Uniform
Customs and Practice for Documentary Credits, 1993 Revision, International
Chamber of Commerce Publication No. 500 (the "UCP"); provided, however, that the
provisions of Article 17 thereof are specifically excluded. With regard to all
matters not provided for herein, and, to the extent not inconsistent with the
UCP, this Letter of Credit shall be governed by and

----------
(12) If any letter of credit is confirmed, the confirming bank's form must make
     clear that that waiver described above is applicable to such bank.

(13) Insert description of relevant document(s) which governs the reimbursement
     obligations of the account party to the Issuing Bank.

(14) Include if LC governed by NY law.

(15) Insert only if LC utilizes ISP98.

<PAGE>

interpreted in accordance with the laws of [the United Mexican States][the State
of New York]. The preceding sentence notwithstanding, to the extent Articles
13(b) and 14(d)(i) of the UCP [and Sections 5-108(b) and 5-108(c) of the New
York Uniform Commercial Code](16) would or could be construed to extend the
express time periods set forth in this Letter of Credit for making payment or
giving notice to you that a demand for payment does not conform to the terms and
conditions hereunder, we knowingly and willingly waive our rights in respect of
such provisions and we will make payment hereunder or give notice in accordance
with the terms and conditions of this Letter of Credit.

Notwithstanding Article 48 of the UCP, this Letter of Credit may be transferred
to any person that is a transferee of any Beneficiary's interest under (a) the
Working Capital Facility Credit Agreement, or (b) any other agreements entered
into by the Borrower in connection with the financing of the Project (as defined
below), and the Issuing Bank [and confirming bank] hereby irrevocably consent[s]
to and agree[s] to effect any such transfer. Such transfer shall be effected
upon delivery to us of this Letter of Credit accompanied by a properly completed
notice of transfer in the form attached as Annex B. Upon written request in
connection with such transfer, we shall issue a replacement Letter of Credit on
the same terms as this Letter of Credit but with revised Annexes A and B showing
the name of the transferee where applicable. [To the extent Section 5-112(b)(2)
of the New York Uniform Commercial Code would or could be construed to impose
any additional requirement relating to any such transfer, we knowingly and
willingly waive our rights in respect of such provision and we will effect such
transfer in accordance with the terms and conditions of this Letter of
Credit.](17)

As used herein, "Project" shall mean the hydroelectric generating plant to be
developed and constructed by the Borrower in the States of Jalisco and Nayarit,
Mexico.]

[APPLICABLE RULES: VERSION 2 - ISP98 (TO BE USED ONLY IF THE LETTER OF CREDIT
PROVIDER CANNOT PROVIDE A LETTER OF CREDIT GOVERNED BY THE UCP)]

[This Letter of Credit shall be subject to the provisions (to the extent that
such provisions are not inconsistent with this Letter of Credit) of the
International Standby Practices of 1998 (the "ISP98"). With regard to all
matters not provided for herein, and, to the extent not inconsistent with the
ISP98, this Letter of Credit shall be governed by and interpreted in accordance
with the laws of [the United Mexican States][the State of New York]. The
preceding sentence notwithstanding, to the extent Rules 5.01, 5.03 or 5.04 of
the ISP98 [and Sections 5-108(b) and 5-108(c) of the New York Uniform Commercial
Code](18) would or could be construed to extend the express time periods set
forth in this Letter of Credit for making payment or giving notice to you that a
demand for payment does not conform to the terms and conditions hereunder, we
knowingly and willingly waive our rights in respect of such provisions and we
will make payment hereunder or give notice in accordance with the terms and
conditions of this Letter of Credit.

----------
(16) Include if LC governed by NY law.

(17) Include if LC governed by NY law.

(18) Include if LC governed by NY law.

<PAGE>

Notwithstanding Rules 6.02, 6.03 and 6.04 of the ISP98, this Letter of Credit is
transferable (i) to any person that is a transferee of any Beneficiary's
interest under (a) the Working Capital Facility Credit Agreement, or (b) any
other agreements entered into by the Borrower in connection with the financing
of the Project (as defined below), and the Issuing Bank [and confirming bank]
hereby irrevocably consent[s] to and agree[s] to effect any such transfer. Such
transfer shall be effected upon delivery to us of this Letter of Credit
accompanied by a properly completed notice of transfer in the form attached as
Annex B. Upon written request in connection with such transfer, we shall issue a
replacement Letter of Credit on the same terms as this Letter of Credit but with
revised Annexes A and B showing the name of the transferee where applicable. To
the extent Rule 6 of the ISP98 [or Section 5-112(b)(2) of the New York Uniform
Commercial Code](19) would or could be construed to impose any additional
requirement relating to any such transfer, we knowingly and willingly waive our
rights in respect of such provision and we will effect such transfer in
accordance with the terms and conditions of this Letter of Credit.

As used herein, "Project" shall mean the hydroelectric generating plant to be
developed and constructed by the Borrower in the States of Jalisco and Nayarit,
Mexico.]

[DISPUTE RESOLUTION: VERSION 1 - NEW YORK LAW]

We hereby submit to the nonexclusive jurisdiction of the United States District
Court for the Southern District of New York and of any New York state courts
sitting in New York County for the purposes of all legal proceedings arising out
of or relating to this Letter of Credit. We hereby waive, to the fullest extent
permitted by law, any objection which we may now or hereafter have to the laying
of the venue of any such proceeding brought in such court and any claim that any
such proceeding brought in such court has been brought in an inconvenient forum.
In addition, we hereby agree to receive and accept service of process sent by
registered or certified mail or by overnight courier to the address at which a
sight draft delivered pursuant hereto is to be presented.

[DISPUTE RESOLUTION: VERSION 2 - MEXICAN LAW (TO BE USED ONLY IF THE LETTER OF
CREDIT PROVIDER CANNOT PROVIDE A LETTER OF CREDIT GOVERNED BY NEW YORK LAW]

Any disputes and other matters in question arising out of or relating to this
Letter of Credit, or the alleged breach hereof, or in any way relating to the
subject matter of this Letter of Credit or the relationship between the Parties
created by this Letter of Credit (hereafter a "Dispute") shall be finally
resolved by binding arbitration administered by the American Arbitration
Association ("AAA") under the AAA International Arbitration Rules (the "Rules")
then in force, to the extent such Rules are not inconsistent with the provisions
of this Letter of Credit. The arbitral tribunal shall be composed of three
arbitrators (the "Tribunal") appointed and confirmed in accordance with the
Rules. The seat of the arbitration shall be New York, New York. The arbitration
shall be conducted and the award rendered in the English language. The Tribunal
shall not have the authority to modify or amend any term or provision of this
Letter of Credit. The Parties

----------
(19) Include if LC governed by NY law.

<PAGE>

agree to accept and honor any interim orders and agree that any such interim
orders may be enforced as necessary in any court having relevant jurisdiction.
The award shall be final, non-appealable and binding on the Parties and may be
enforced by a competent court. The Tribunal's award shall be entitled to all of
the protections and benefits of a final judgment as to any Dispute, including
compulsory counterclaims, that were or could have been presented to the
Tribunal. Except to the extent necessary for proceedings relating to enforcement
of the arbitration agreement, the award or other, related rights of the Parties,
the fact of the arbitration, the arbitration proceeding itself, all evidence,
memorials or other documents exchanged or used in the arbitration and the
arbitrators' award shall be maintained in confidence by the Parties to the
fullest extent permitted by applicable law. The Tribunal shall designate a
prevailing Party (or Parties) in its final award. Pursuant to this
determination, the Tribunal shall award to the prevailing Party (or Parties) its
attorneys' fees, costs and expenses of the arbitration (including the
arbitrators' fees and expenses) in full. The award shall include interest,
unless the Tribunal determines it is not appropriate. Interest shall run from
the date of any breach or violation of this Agreement, which shall be determined
by the Tribunal in its award. If the Tribunal cannot determine such date or
fails to specify such date in its award, interest shall run from the date of
filing of the request for arbitration. Interest shall continue to run from the
date of award until the award is paid in full. Interest shall be calculated
monthly at a rate equal to the one-year US$ LIBOR rate as published by the
Financial Times on the first business day of the month plus 4 percent.

Any communication from the Beneficiary regarding this Letter of Credit shall be
made in writing and delivered in accordance with the procedures for presentation
of the Certificates of Execution.

No provision of this Letter of Credit shall be amended or modified without the
express written consent of the Beneficiary hereunder.

[We hereby irrevocably waive all right to trial by jury in any action,
proceeding or counterclaim arising out of or relating to this Letter of Credit
or any instrument, certificate or document delivered in connection herewith.]20
The benefit and burden of this Letter of Credit may not be assigned or
transferred by us except with your prior written consent.

                                        Sincerely,
                                        [Name of Issuing Bank]


By:                                     By:
    ---------------------------------       ------------------------------------
Name:                                   Name:
Title: Authorized Representative        Title: Authorized Representative

----------
(20) Include if LC governed by NY law.

<PAGE>

ANNEX A

FORM OF CERTIFICATE OF EXECUTION

TO: [INSERT NAME AND ADDRESS OF ISSUING BANK]

Attention:

RE: IRREVOCABLE STANDBY LETTER OF CREDIT NO. _____________

Dear Sirs:

I refer to Irrevocable Standby Letter of Credit No. ____ dated ______, ____
issued by [Issuing Bank] in the amount of ______ Dollars (US$ __________) in
favor of [_________________](21), as [________________](22) (the "Beneficiary")
in connection with the obligations of the Borrower under the Working Capital
Facility Credit Agreement. Capitalized terms used but not otherwise defined
herein shall have the meanings given to them in the Letter of Credit.

In my capacity as an authorized officer of the Beneficiary, I hereby certify
that:

     (a) [The Borrower has failed to comply with its payment obligations under
     the Working Capital Facility Credit Agreement. Accordingly, the Beneficiary
     has the right to draw on the Letter of Credit in the amount set forth in
     paragraph (b) below.]

OR

               [You have notified us of your election not to renew the Letter of
Credit and no replacement letter of credit has been provided to us on behalf of
the Borrower.]

     (b) The amount that the Beneficiary is entitled to draw on the Letter of
     Credit is US$ ___________.

In consideration of the matters set forth above, I hereby demand the wire
transfer to bank account number _____________ at __________ in immediately
available funds of the amount indicated in paragraph (b) above. Payment by the
Issuing Bank shall be understood to be made in order to give effect to the
Letter of Credit.

----------
(21) Insert name of Beneficiary.

(22) Insert capacity of Beneficiary.

<PAGE>

[Place and Date of Execution]

                                        Sincerely,
                                        [BENEFICIARY]

                                        [_________________](23), as
                                        [_________________](24)


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


----------
(23) Insert name of Beneficiary.

(24) Insert capacity of Beneficiary.

<PAGE>

ANNEX B

[FORM OF NOTICE OF TRANSFER]

DATE: ________________

TO: [INSERT NAME AND ADDRESS OF ISSUING BANK]

Attention:

RE: IRREVOCABLE STANDBY LETTER OF CREDIT NO. _____________

The undersigned, an authorized officer of [_________________](25), hereby
certifies to [INSERT NAME OF ISSUING BANK] that:

All rights of the undersigned to draw under the Letter of Credit have been and
hereby are irrevocably transferred to:

-------------------------------------
(NAME OF TRANSFEREE)

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

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

-------------------------------------
(ADDRESS OF TRANSFEREE)

By transfer, all rights of the undersigned in the Letter of Credit are
transferred to the transferee and said transferee shall have all and exclusively
the sole rights as Beneficiary of the Letter of Credit, including (without
limitation) the right to draw funds under the Letter of Credit in accordance
with its terms.

As provided under the terms of the Letter of Credit, please issue a replacement
Letter of Credit in the name of the transferee at the address set forth above,
in an amount equal to the stated amount of the Letter of Credit on the date of
this notice, and otherwise on the same terms as the original Letter of Credit
due but with revised Annexes A and B to the Letter of Credit showing the name of
the Transferee where applicable.

                                        [_________________](26), as Transferor


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

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(25) Insert name of Beneficiary.

(26) Insert name of Transferor.