Exhibit 10(aaa)

Execution Copy

SENIOR UNSECURED GUARANTEE

THIS SENIOR UNSECURED GUARANTEE dated as of October 10, 2007, by US Holdings (as
identified below), each of the other signatories listed on the signature pages
hereto and each of the other entities that becomes a party hereto pursuant to
Section 19 (the “Subsidiary Guarantors” together with US Holdings, the
“Guarantors” and individually, a “Guarantor”), in favor of Morgan Stanley Senior
Funding, Inc., as the Administrative Agent for the benefit of the Guaranteed
Parties.

W I T N E S S E T H:

WHEREAS, reference is made to that certain Senior Unsecured Interim Loan
Agreement, dated as of October 10, 2007 (as the same may be amended, restated,
supplemented or otherwise modified, refinanced or replaced from time to time,
the “Loan Agreement”) among Energy Future Competitive Holdings Company, a Texas
corporation (“US Holdings”), Texas Competitive Electric Holdings Company LLC, a
Delaware limited liability company (the “Company”), TCEH Finance, Inc., a
Delaware corporation (“TCEH” together with the Company, the “Borrower”), the
lenders or other financial institutions or entities from time to time party
thereto (the “Lenders”), Morgan Stanley Senior Funding, Inc., as Administrative
Agent, and the other Agents party thereto, pursuant to which, among other
things, the Lenders have severally agreed to make Loans to the Borrower (the
“Extensions of Credit”) upon the terms and subject to the conditions set forth
therein;

WHEREAS, the Company is a wholly-owned Subsidiary of US Holdings;

WHEREAS, each Subsidiary Guarantor is a direct or indirect wholly-owned
Subsidiary of the Company;

WHEREAS, the proceeds of the Extensions of Credit will be used in part to enable
the Borrower to make valuable transfers to the Guarantors in connection with the
operation of their respective businesses;

WHEREAS, each Guarantor acknowledges that it will derive substantial direct and
indirect benefit from the making of the Extensions of Credit; and

WHEREAS, it is a condition precedent to the obligation of the Lenders to make
their respective Extensions of Credit to the Borrower under the Loan Agreement
that the Guarantors shall have executed and delivered this Guarantee to the
Administrative Agent for the benefit of the Guaranteed Parties;

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NOW, THEREFORE, in consideration of the premises and to induce the
Administrative Agent and the Lenders to enter into the Loan Agreement and to
induce the respective Lenders to make their respective Extensions of Credit to
the Borrower under the Loan Agreement, the Guarantors hereby agree with the
Administrative Agent, for the benefit of the Guaranteed Parties, as follows:

1. Defined Terms.

(a) Unless otherwise defined herein, terms defined in the Loan Agreement and
used herein shall have the meanings given to them in the Loan Agreement.

(b) The words “hereof”, “herein” and “hereunder” and words of similar import
when used in this Guarantee shall refer to this Guarantee as a whole and not to
any particular provision of this Guarantee, and Section references are to
Sections of this Guarantee unless otherwise specified. The words “include”,
“includes” and “including” shall be deemed to be followed by the phrase “without
limitation”.

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

2. Guarantee.

(a) Subject to the provisions of Section 2(b) in the case of the Subsidiary
Guarantors, each of the Guarantors hereby, jointly and severally,
unconditionally and irrevocably, guarantees, as primary obligor and not merely
as surety, to the Administrative Agent, for the ratable benefit of the
Guaranteed Parties, the prompt and complete payment and performance when due
(whether at the stated maturity, by acceleration or otherwise) of the
Obligations of anyone other than such Guarantor (including amounts that would
become due for operation of the automatic stay under 362(a) of the Bankruptcy
Code, 11 U.S.C. § 362(a)).

(b) Anything herein or in any other Loan Document to the contrary
notwithstanding, the maximum liability of each Subsidiary Guarantor hereunder
and under the other Loan Documents shall in no event exceed the amount that can
be guaranteed by such Guarantor under the Bankruptcy Code or any applicable laws
relating to fraudulent conveyances, fraudulent transfers or the insolvency of
debtors.

(c) Each Guarantor further agrees to pay any and all expenses (including all
reasonable fees and disbursements of counsel) that may be paid or incurred by
the Administrative Agent or any other Guaranteed Party in enforcing, or
obtaining advice of counsel in respect of, any rights with respect to, or
collecting, any or all of the Obligations and/or enforcing any rights with
respect to, or collecting against, such Guarantor under this Guarantee.

(d) Each Guarantor agrees that the Obligations may at any time and from time to
time exceed the amount of the liability of such Guarantor hereunder without
impairing this Guarantee or affecting the rights and remedies of the
Administrative Agent or any other Guaranteed Party hereunder.

(e) No payment or payments made by the Borrower, any of the Guarantors, any
other guarantor or any other Person or received or collected by the
Administrative Agent or any other Guaranteed Party from the Borrower, any of the
Guarantors, any other guarantor or

 

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any other Person by virtue of any action or proceeding or any set-off or
appropriation or application at any time or from time to time in reduction of or
in payment of the Obligations shall be deemed to modify, reduce, release or
otherwise affect the liability of any Guarantor hereunder, which shall,
notwithstanding any such payment or payments, other than payments made by such
Guarantor in respect of the Obligations or payments received or collected from
such Guarantor in respect of the Obligations, remain liable for the Obligations
up to the maximum liability of such Guarantor hereunder until the Obligations
under the Loan Documents are paid in full and the Commitments are terminated.

(f) Each Guarantor agrees that whenever, at any time, or from time to time, it
shall make any payment to the Administrative Agent or any other Guaranteed Party
on account of its liability hereunder, it will notify the Administrative Agent
in writing that such payment is made under this Guarantee for such purpose.

3. Right of Contribution. Each Guarantor hereby agrees that to the extent that a
Guarantor shall have paid more than its proportionate share of any payment made
hereunder (including by way of set-off rights being exercised against it), such
Guarantor shall be entitled to seek and receive contribution from and against
any other Guarantor hereunder who has not paid its proportionate share of such
payment. Each Guarantor ‘s right of contribution shall be subject to the terms
and conditions of Section 5 hereof. The provisions of this Section 3 shall in no
respect limit the obligations and liabilities of any Guarantor to the
Administrative Agent and the other Guaranteed Parties, and each Guarantor shall
remain liable to the Administrative Agent and the other Guaranteed Parties up to
the maximum liability of such Guarantor hereunder.

4. Right of Set-off. In addition to any rights and remedies of the Guaranteed
Parties provided by law, each Guarantor hereby irrevocably authorizes each
Guaranteed Party at any time and from time to time following the occurrence and
during the continuance of an Event of Default, without notice to such Guarantor
or any other Guarantor, any such notice being expressly waived by each
Guarantor, upon any amount becoming due and payable by such Guarantor hereunder
(whether at stated maturity, by acceleration or otherwise), to set-off and
appropriate and apply against such amount 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 Guaranteed Party to or for the credit or the account of such
Guarantor. Each Guaranteed Party shall notify such Guarantor promptly of any
such set-off and the appropriation and application made by such Guaranteed
Party, provided that the failure to give such notice shall not affect the
validity of such set-off and application.

5. No Subrogation. Notwithstanding any payment or payments made by any of the
Guarantors hereunder or any set-off or appropriation and application of funds of
any of the Guarantors by the Administrative Agent or any other Guaranteed Party,
no Guarantor shall be entitled to be subrogated to any of the rights (or if
subrogated by operation of law, such Guarantor hereby waives such rights to the
extent permitted by Applicable Law) of the Administrative Agent or any other
Guaranteed Party against the Borrower or any Guarantor or other guarantor or any
collateral security or guarantee or right of offset held by the Administrative
Agent or any other Guaranteed Party for the payment of any of the Obligations,

 

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nor shall any Guarantor seek or be entitled to seek any contribution or
reimbursement from the Borrower or any Guarantor or other guarantor in respect
of payments made by such Guarantor hereunder, in each case, until all amounts
owing to the Administrative Agent and the other Guaranteed Parties on account of
the Obligations under the Loan Documents are paid in full and the Commitments
are terminated. If any amount shall be paid to any Guarantor on account of such
subrogation rights at any time when all the Obligations shall not have been paid
in full, such amount shall be held by such Guarantor in trust for the
Administrative Agent and the other Guaranteed Parties, segregated from other
funds of such Guarantor, and shall, forthwith upon receipt by such Guarantor, be
turned over to the Administrative Agent in the exact form received by such
Guarantor (duly indorsed by such Guarantor to the Administrative Agent, if
required), to be applied against the Obligations, whether due or to become due,
in such order as the Administrative Agent may determine.

6. Amendments, etc. with Respect to the Obligations; Waiver of Rights. Each
Guarantor shall remain obligated hereunder notwithstanding that, without any
reservation of rights against any Guarantor and without notice to or further
assent by any Guarantor, (a) any demand for payment of any of the Obligations
made by the Administrative Agent or any other Guaranteed Party may be rescinded
by such party and any of the Obligations continued, (b) the Obligations, or the
liability of any other party upon or for any part thereof, or any collateral
security or guarantee therefor or right of offset with respect thereto, may,
from time to time, in whole or in part, be renewed, extended, amended, modified,
accelerated, compromised, waived, surrendered or released by the Administrative
Agent or any other Guaranteed Party, (c) the Loan Agreement, the other Loan
Documents, and any other documents executed and delivered in connection
therewith may be amended, modified, supplemented or terminated, in whole or in
part, as the Administrative Agent (or the Required Lenders, as the case may be)
may deem advisable from time to time, and (d) any collateral security, guarantee
or right of offset at any time held by the Administrative Agent or any other
Guaranteed Party for the payment of any of the Obligations may be sold,
exchanged, waived, surrendered or released. Neither the Administrative Agent nor
any other Guaranteed Party shall have any obligation to protect, secure, perfect
or insure any Lien at any time held by it as security for the Obligations or for
this Guarantee or any property subject thereto. When making any demand hereunder
against any Guarantor, the Administrative Agent or any other Guaranteed Party
may, but shall be under no obligation to, make a similar demand on the Borrower
or any Guarantor or any other person, and any failure by the Administrative
Agent or any other Guaranteed Party to make any such demand or to collect any
payments from the Borrower or any Guarantor or any other person or any release
of the Borrower or any Guarantor or any other person shall not relieve any
Guarantor in respect of which a demand or collection is not made or any
Guarantor not so released of its several obligations or liabilities hereunder,
and shall not impair or affect the rights and remedies, express or implied, or
as a matter of law, of the Administrative Agent or any other Guaranteed Party
against any Guarantor. For the purposes hereof “demand” shall include the
commencement and continuance of any legal proceedings.

Further, each Guarantor expressly waives each and every right to which it may be
entitled by virtue of the suretyship law of the state of Texas, including
without limitation, any rights pursuant to Rule 31, Texas Rules of Civil
Procedure, Articles 1986 and 1987, Revised Civil Statutes of Texas and Chapter
34 of the Texas Business and Commerce Code.

 

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7. Guarantee Absolute and Unconditional.

(a) Each Guarantor waives any and all notice of the creation, contraction,
incurrence, renewal, extension, amendment, waiver or accrual of any of the
Obligations, and notice of or proof of reliance by the Administrative Agent or
any other Guaranteed Party upon this Guarantee or acceptance of this Guarantee.
All Obligations shall conclusively be deemed to have been created, contracted or
incurred, or renewed, extended, amended, waived or accrued, in reliance upon
this Guarantee, and all dealings between the Borrower and any of the Guarantors,
on the one hand, and the Administrative Agent and the other Guaranteed Parties,
on the other hand, likewise shall be conclusively presumed to have been had or
consummated in reliance upon this Guarantee. To the fullest extent permitted by
Applicable Law, each Guarantor waives diligence, promptness, presentment,
protest and notice of protest, demand for payment or performance, notice of
default or nonpayment, notice of acceptance and any other notice in respect of
the Obligations or any part of them, and any defense arising by reason of any
disability or other defense of the Borrower or any of the Guarantors with
respect to the Obligations. Each Guarantor understands and agrees that this
Guarantee shall be construed as a continuing, absolute and unconditional
guarantee of payment without regard to (a) the validity, regularity or
enforceability of the Loan Agreement, any other Loan Document, any of the
Obligations or any collateral security therefor or guarantee or right of offset
with respect thereto at any time or from time to time held by the Administrative
Agent or any other Guaranteed Party, (b) any defense, set-off or counterclaim
(other than a defense of payment or performance) that may at any time be
available to or be asserted by the Borrower against the Administrative Agent or
any other Guaranteed Party or (c) any other circumstance whatsoever (with or
without notice to or knowledge of the Borrower or such Guarantor) that
constitutes, or might be construed to constitute, an equitable or legal
discharge of the Borrower for the Obligations, or of such Guarantor under this
Guarantee, in bankruptcy or in any other instance. When pursuing its rights and
remedies hereunder against any Guarantor, the Administrative Agent and any other
Guaranteed Party may, but shall be under no obligation to, pursue such rights
and remedies as it may have against the Borrower or any other Person or against
any collateral security or guarantee for the Obligations or any right of offset
with respect thereto, and any failure by the Administrative Agent or any other
Guaranteed Party to pursue such other rights or remedies or to collect any
payments from the Borrower or any such other Person or to realize upon any such
collateral security or guarantee or to exercise any such right of offset, or any
release of the Borrower or any such other Person or any such collateral
security, guarantee or right of offset, shall not relieve such Guarantor of any
liability hereunder, and shall not impair or affect the rights and remedies,
whether express, implied or available as a matter of law, of the Administrative
Agent and the other Guaranteed Parties against such Guarantor.

(b) This Guarantee shall remain in full force and effect and be binding in
accordance with and to the extent of its terms upon each Guarantor and the
successors and assigns thereof and shall inure to the benefit of the
Administrative Agent and the other Guaranteed Parties and their respective
successors, indorsees, transferees and assigns until all Obligations (other than
any contingent indemnity obligations not then due) shall have been satisfied by
payment in full and the Commitments thereunder shall be terminated,
notwithstanding that from time to time during the term of the Loan Agreement,
the Loan Parties may be free from any Obligations.

 

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(c) A Guarantor shall automatically be released from its obligations hereunder
and the Guarantee of such Guarantor shall be automatically released under the
circumstances described in Section 13.1(d) of the Loan Agreement.

8. Reinstatement. This Guarantee shall continue to be effective, or be
reinstated, as the case may be, if at any time payment, or any part thereof, of
any of the Obligations is rescinded or must otherwise be restored or returned by
the Administrative Agent or any other Guaranteed Party upon the insolvency,
bankruptcy, dissolution, liquidation or reorganization of the Borrower or any
Guarantor, or upon or as a result of the appointment of a receiver, intervenor
or conservator of, or trustee or similar officer for, the Borrower or any
Guarantor or any substantial part of its property, or otherwise, all as though
such payments had not been made.

9. Payments. Each Guarantor hereby guarantees that payments hereunder will be
paid to the Administrative Agent without set-off or counterclaim in Dollars at
the Administrative Agent’s Office. Each Guarantor agrees that the provisions of
Sections 5.4 and 13.20 of the Loan Agreement shall apply to such Guarantor ‘s
obligations under this Guarantee.

10. Representations and Warranties; Covenants.

(a) Each Guarantor hereby represents and warrants that the representations and
warranties set forth in Section 8 of the Loan Agreement as they relate to such
Guarantor and in the other Loan Documents to which such Guarantor is a party,
each of which is hereby incorporated herein by reference, are true and correct
in all material respects as of the Closing Date (except where such
representations and warranties expressly relate to an earlier date, in which
case such representations and warranties were true and correct in all material
respects as of such earlier date), and the Administrative Agent and each other
Guaranteed Party shall be entitled to rely on each of them as if they were fully
set forth herein.

(b) Each Guarantor hereby covenants and agrees with the Administrative Agent and
each other Guaranteed Party that, from and after the date of this Guarantee
until the Obligations are paid in full and the Commitments are terminated, such
Guarantor shall take, or shall refrain from taking, as the case may be, all
actions that are necessary to be taken or not taken so that no violation of any
provision, covenant or agreement contained in Section 9 of the Loan Agreement,
and no Default or Event of Default, is caused by any act or failure to act of
such Guarantor or any of its Subsidiaries.

11. Authority of the Administrative Agent.

(a) The Administrative Agent enters into this Guarantee in its capacity as agent
for the Guaranteed Parties from time to time. The rights and obligations of the
Administrative Agent under this Guarantee at any time are the rights and
obligations of the Guaranteed Parties at that time. Each of the Guaranteed
Parties has (subject to the terms of the Loan Documents) a several entitlement
to each such right, and a several liability in respect of each such obligation,
in the proportions described in the Loan Documents. The rights, remedies and
discretions of the Guaranteed Parties, or any of them, under this Guarantee may
be exercised by the Administrative Agent. No party to this Guarantee is obliged
to inquire whether an exercise by the Administrative Agent of any such right,
remedy or discretion is within the Administrative Agent’s authority as agent for
the Guaranteed Parties.

 

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(b) Each party to this Guarantee acknowledges and agrees that any changes (in
accordance with the provisions of the Loan Documents) in the identity of the
persons from time to time comprising the Guaranteed Parties gives rise to an
equivalent change in the Guaranteed Parties, without any further act. Upon such
an occurrence, the persons then comprising the Guaranteed Parties are vested
with the rights, remedies and discretions and assume the obligations of the
Guaranteed Parties under this Guarantee. Each party to this Guarantee
irrevocably authorizes the Administrative Agent to give effect to the change in
Lenders contemplated in this Section 11(b) by countersigning an Assignment and
Acceptance.

12. Notices. All notices, requests and demands pursuant hereto shall be made in
accordance with Section 13.2 of the Loan Agreement. All communications and
notices hereunder to any Guarantor shall be given to it in care of the Borrower
at the Borrower’s address set forth in Section 13.2 of the Loan Agreement.

13. Counterparts. This Guarantee may be executed by one or more of the parties
to this Guarantee on any number of separate counterparts (including by facsimile
or other electronic transmission), and all of said counterparts taken together
shall be deemed to constitute one and the same instrument. A set of the copies
of this Guarantee signed by all the parties shall be lodged with the
Administrative Agent and the Borrower.

14. Severability. Any provision of this Guarantee 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. The parties hereto shall endeavor in good-faith negotiations
to replace the invalid, illegal or unenforceable provisions with valid
provisions the economic effect of which comes as close as possible to that of
the invalid, illegal or unenforceable provisions.

15. Integration. THIS GUARANTEE TOGETHER WITH THE OTHER LOAN DOCUMENTS REPRESENT
THE AGREEMENT OF EACH GUARANTOR AND THE ADMINISTRATIVE AGENT WITH RESPECT TO THE
SUBJECT MATTER HEREOF, AND THERE ARE NO PROMISES, UNDERTAKINGS, REPRESENTATIONS
OR WARRANTIES BY THE ADMINISTRATIVE AGENT OR ANY OTHER GUARANTEED PARTY RELATIVE
TO THE SUBJECT MATTER HEREOF NOT EXPRESSLY SET FORTH OR REFERRED TO HEREIN OR IN
THE OTHER LOAN DOCUMENTS.

16. Amendments in Writing; No Waiver; Cumulative Remedies.

(a) None of the terms or provisions of this Guarantee may be waived, amended,
supplemented or otherwise modified except by a written instrument executed by
the affected Guarantors and the Administrative Agent in accordance with
Section 13.1 of the Loan Agreement.

 

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(b) Neither the Administrative Agent nor any other Guaranteed Party shall by any
act (except by a written instrument pursuant to Section 16(a)), delay,
indulgence, omission or otherwise be deemed to have waived any right or remedy
hereunder or to have acquiesced in any Default or Event of Default or in any
breach of any of the terms and conditions hereof. No failure to exercise, nor
any delay in exercising, on the part of the Administrative Agent or any other
Guaranteed Party, any right, power or privilege hereunder shall operate as a
waiver thereof. No single or partial exercise of any right, power or privilege
hereunder shall preclude any other or further exercise thereof or the exercise
of any other right, power or privilege. A waiver by the Administrative Agent or
any other Guaranteed Party of any right or remedy hereunder on any one occasion
shall not be construed as a bar to any right or remedy that the Administrative
Agent or any Guaranteed Party would otherwise have on any future occasion.

(c) The rights, remedies, powers and privileges herein provided are cumulative,
may be exercised singly or concurrently and are not exclusive of any other
rights or remedies provided by law.

17. Section Headings. The Section headings used in this Guarantee are for
convenience of reference only and are not to affect the construction hereof or
be taken into consideration in the interpretation hereof.

18. Successors and Assigns. This Guarantee shall be binding upon the successors
and assigns of each Guarantor and shall inure to the benefit of the
Administrative Agent and the other Guaranteed Parties and their respective
successors and assigns except that no Guarantor may assign, transfer or delegate
any of its rights or obligations under this Guarantee without the prior written
consent of the Administrative Agent.

19. Additional Guarantors. Each Subsidiary of the Company that is required to
become a party to this Guarantee pursuant to Section 9.13 of the Loan Agreement
shall become a Guarantor, with the same force and effect as if originally named
as a Guarantor herein, for all purposes of this Guarantee, upon execution and
delivery by such Subsidiary of a written supplement substantially in the form of
Annex A hereto or in such other form as is reasonably satisfactory to the
Administrative Agent. The execution and delivery of any instrument adding an
additional Guarantor as a party to this Guarantee shall not require the consent
of any other Guarantor hereunder. The rights and obligations of each Guarantor
hereunder shall remain in full force and effect notwithstanding the addition of
any new Guarantor as a party to this Guarantee.

20. WAIVER OF JURY TRIAL. EACH GUARANTOR HEREBY IRREVOCABLY AND UNCONDITIONALLY
WAIVES TRIAL BY JURY IN ANY LEGAL ACTION OR PROCEEDING RELATING TO THIS
GUARANTEE, ANY OTHER LOAN DOCUMENT AND FOR ANY COUNTERCLAIM THEREIN.

21. Submission to Jurisdiction; Waivers; Service of Process. Each Guarantor
hereby irrevocably and unconditionally:

(a) submits for itself and its property in any legal action or proceeding
relating to this Guarantee and the other Loan Documents to which it is a party,
or for recognition and enforcement of any judgment in respect thereof, to the
non-exclusive general jurisdiction of the courts of the State of New York, the
courts of the United States of America for the Southern District of New York and
appellate courts from any thereof;

 

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(b) consents that any such action or proceeding may be brought in such courts
and waives any objection that it may now or hereafter have to the venue of any
such action or proceeding in any such court or that such action or proceeding
was brought in an inconvenient court and agrees not to plead or claim the same;

(c) agrees that service of process in any such action or proceeding may be
effected by mailing a copy thereof by registered or certified mail (or any
substantially similar form of mail), postage prepaid, to such Guarantor in care
of the Borrower at the Borrower’s address set forth in the Loan Agreement, and
such Person hereby irrevocably authorizes and directs the Borrower to accept
such service on its behalf;

(d) agrees that nothing herein shall affect the right of the Administrative
Agent or any other Guaranteed Party to effect service of process in any other
manner permitted by law or shall limit the right of the Administrative Agent or
any other Guaranteed Party to sue in any other jurisdiction;

(e) waives, to the maximum extent not prohibited by law, any right it may have
to claim or recover in any legal action or proceeding referred to in this
Section 21 any special, exemplary, punitive or consequential damages; and

(f) agrees that a final judgment in any action or proceeding shall be conclusive
and may be enforced in other jurisdictions by suit on the judgment or in any
other manner provided by Applicable Law.

22. GOVERNING LAW. THIS GUARANTEE AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES
HEREUNDER SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN ACCORDANCE
WITH, THE LAW OF THE STATE OF NEW YORK.

23. Oncor Separateness. (a) The Administrative Agent, on behalf of itself and
the Guaranteed Parties, hereby acknowledges (i) the legal separateness of the
Borrower and the Guarantors from Oncor Holdings and its Subsidiaries, (ii) that
the lenders under the Oncor Electric Delivery Facility and the noteholders under
the Existing Oncor Notes and under the transition bonds have likely advanced
funds thereunder in reliance upon the separateness of Oncor and its Subsidiaries
from the Borrower and the Guarantors, (iii) that Oncor Holdings and its
Subsidiaries have assets and liabilities that are separate from those of the
Borrower and its other Subsidiaries, (iv) that the Obligations are obligations
and liabilities of the Borrower and the Guarantors only, and are not the
obligations or liabilities of Oncor Holdings or any of its Subsidiaries,
(v) that the Guaranteed Parties shall look solely to the Borrower, the
Guarantors and their assets, and not to any assets, or to the pledge of any
assets, owned by Oncor Holdings or any of its Subsidiaries, for the repayment of
any amounts payable pursuant to the Loan Documents and for satisfaction of any
other Obligations, and (vi) that none of Oncor Holdings or its Subsidiaries
shall be personally liable to the Guaranteed Parties for any amounts payable, or
any other Obligation, under the Loan Documents.

 

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(b) The Administrative Agent, on behalf of itself and the Guaranteed Parties,
hereby acknowledges and agrees that it and the Guaranteed Parties shall not
(i) initiate any legal proceeding to procure the appointment of an
administrative receiver, or (ii) institute any bankruptcy, reorganization,
insolvency, winding up, liquidation, or any like proceeding under Applicable
Law, against Oncor Holdings, Oncor, or any of their Subsidiaries, or against any
of Oncor Holdings’, Oncor’s, or any of their Subsidiaries’ assets. The
Administrative Agent, on behalf of itself and the Guaranteed Parties, further
acknowledges and agrees that each of Oncor Holdings, Oncor, and their
Subsidiaries is a third party beneficiary of the foregoing covenant and shall
have the right to specifically enforce such covenant in any proceeding at law or
in equity.

[Signature pages follow]

 

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ENERGY FUTURE COMPETITIVE
HOLDINGS COMPANY, as Guarantor /s/ Anthony R. Horton Name:   Anthony R. Horton
Title:   Authorized Signatory

[SIGNATURE PAGE TO TCEH SENIOR UNSECURED GUARANTEE]

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BIG BROWN 3 POWER COMPANY LLC

BIG BROWN LIGNITE COMPANY LLC

BIG BROWN POWER COMPANY LLC

COLLIN POWER COMPANY LLC

DECORDOVA POWER COMPANY LLC

GENERATION MT COMPANY LLC

GENERATION SVC COMPANY

LAKE CREEK 3 POWER COMPANY LLC

LUMINANT BIG BROWN MINING COMPANY LLC

LUMINANT ENERGY COMPANY LLC

LUMINANT ENERGY SERVICES COMPANY

LUMINANT GENERATION COMPANY LLC

LUMINANT HOLDING COMPANY LLC

LUMINANT MINERAL DEVELOPMENT COMPANY LLC

LUMINANT MINING COMPANY LLC

LUMINANT MINING SERVICES COMPANY

LUMINANT POWER SERVICES COMPANY

LUMINANT RENEWABLES COMPANY LLC

MARTIN LAKE 4 POWER COMPANY LLC

MONTICELLO 4 POWER COMPANY LLC

MORGAN CREEK 7 POWER COMPANY LLC

NCA RESOURCES DEVELOPMENT COMPANY LLC

OAK GROVE MANAGEMENT COMPANY LLC

OAK GROVE MINING COMPANY LLC

OAK GROVE POWER COMPANY LLC

SANDOW POWER COMPANY LLC

TRADINGHOUSE 3 & 4 POWER COMPANY LLC

TRADINGHOUSE POWER COMPANY LLC

TXU CHILLED WATER SOLUTIONS COMPANY

TXU ENERGY RETAIL COMPANY LLC

TXU ENERGY RETAIL MANAGEMENT COMPANY LLC

TXU ENERGY SOLUTIONS COMPANY LLC

TXU ENERGY TRADING (CALIFORNIA) COMPANY

TXU ET SERVICES COMPANY

TXU RETAIL SERVICES COMPANY

TXU SEM COMPANY

TXU SESCO COMPANY LLC

TXU SESCO ENERGY SERVICES COMPANY

VALLEY NG POWER COMPANY LLC

VALLEY POWER COMPANY LLC

WICHITA/VICTORY AVE., LLC,

each, as Guarantor,

 

/s/ Anthony R. Horton Name:   Anthony R. Horton Title:   Authorized Signatory

[SIGNATURE PAGE TO TCEH SENIOR UNSECURED GUARANTEE]

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MORGAN STANLEY SENIOR
FUNDING, INC., as Administrative Agent /s/ Henry F. D’Alessandro Name:   Henry
F. D’Alessandro Title:   Vice President

[SIGNATURE PAGE TO TCEH SENIOR UNSECURED GUARANTEE]

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ANNEX A TO

THE SENIOR UNSECURED GUARANTEE

SUPPLEMENT NO. [ ] dated as of [            ] to the GUARANTEE dated as of
October 10, 2007 (the “Supplement”), among each of the Guarantors listed on the
signature pages thereto (each such signatory individually, a “Guarantor “ and,
collectively, the “Guarantors”), and Morgan Stanley Senior Funding, Inc., as
Administrative Agent for the Lenders from time to time parties to the Loan
Agreement referred to below.

A. Reference is made to that certain Senior Unsecured Interim Loan Agreement,
dated as of October 10, 2007 (as the same may be amended, restated, supplemented
or otherwise modified, refinanced or replaced from time to time, the “Loan
Agreement”), among Energy Future Competitive Holdings Company, a Texas
corporation (“US Holdings”), Texas Competitive Electric Holdings Company LLC, a
Delaware limited liability company (the “Company”), TCEH Finance, Inc., a
Delaware corporation (“TCEH” together with the Company, the “Borrower”), the
lenders or other financial institutions or entities from time to time parties
thereto (the “Lenders”), Morgan Stanley Senior Funding, Inc., as Administrative
Agent and the other Agents party thereto.

B. Capitalized terms used herein and not otherwise defined herein shall have the
meanings assigned to such terms in the Guarantee.

C. The Guarantors have entered into the Guarantee in order to induce the
Administrative Agent and the Lenders to enter into the Loan Agreement and to
induce the Lenders to make their respective Extensions of Credit to the Borrower
under the Loan Agreement.

D. Section 9.13 of the Loan Agreement and Section 19 of the Guarantee provide
that additional Subsidiaries may become Guarantors under the Guarantee by
execution and delivery of an instrument in the form of this Supplement. Each
undersigned Subsidiary (each a “New Guarantor “) is executing this Supplement in
accordance with the requirements of the Loan Agreement to become a Guarantor
under the Guarantee in order to induce the Lenders to make additional Extensions
of Credit, and as consideration for Extensions of Credit previously made.

Accordingly, the Administrative Agent and each New Guarantor agrees as follows:

SECTION 1. In accordance with Section 19 of the Guarantee, each New Guarantor by
its signature below becomes a Guarantor under the Guarantee with the same force
and effect as if originally named therein as a Guarantor, and each New Guarantor
hereby (a) agrees to all the terms and provisions of the Guarantee applicable to
it as a Guarantor thereunder and (b) represents and warrants that the
representations and warranties made by it as a Guarantor thereunder are true and
correct on and as of the date hereof (except where such representations

 

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and warranties expressly relate to an earlier date, in which case such
representations and warranties were true and correct in all material respects as
of such earlier date). Each reference to a Guarantor in the Guarantee shall be
deemed to include each New Guarantor. The Guarantee is hereby incorporated
herein by reference.

SECTION 2. Each New Guarantor represents and warrants to the Administrative
Agent and the other Guaranteed Parties that this Supplement has been duly
authorized, executed and delivered by it and constitutes its legal, valid and
binding obligation, enforceable against it in accordance with its terms, subject
to the effects of bankruptcy, insolvency or other similar laws affecting
creditors’ rights generally and general principles of equity (whether considered
in a proceeding in equity or law).

SECTION 3. This Supplement may be executed by one or more of the parties to this
Supplement on any number of separate counterparts (including by facsimile or
other electronic transmission), and all of said counterparts taken together
shall be deemed to constitute one and the same instrument. A set of the copies
of this Supplement signed by all the parties shall be lodged with the Borrower
and the Administrative Agent. This Supplement shall become effective as to each
New Guarantor when the Administrative Agent shall have received counterparts of
this Supplement that, when taken together, bear the signatures of such New
Guarantor and the Administrative Agent.

SECTION 4. Except as expressly supplemented hereby, the Guarantee shall remain
in full force and effect.

SECTION 5. THIS SUPPLEMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES
HEREUNDER SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN ACCORDANCE
WITH, THE LAW OF THE STATE OF NEW YORK.

SECTION 6. Any provision of this Supplement 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 in the Guarantee, and any such prohibition or
unenforceability in any jurisdiction shall not invalidate or render
unenforceable such provision in any other jurisdiction. The parties hereto shall
endeavor in good-faith negotiations to replace the invalid, illegal or
unenforceable provisions with valid provisions the economic effect of which
comes as close as possible to that of the invalid, illegal or unenforceable
provisions.

SECTION 7. All notices, requests and demands pursuant hereto shall be made in
accordance with Section 13.2 of the Loan Agreement. All communications and
notices hereunder to each New Guarantor shall be given to it in care of the
Borrower at the Borrower’s address set forth in Section 13.2 of the Loan
Agreement.

 

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