CARBON SUPPLY AGREEMENT BETWEEN RED RIVER ENVIRONMENTAL PRODUCTS, LLC SELLER AND LUMINANT GENERATION COMPANY LLC BUYER Dated as of September 3, 2008

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SECTION 1.

DEFINED TERMS

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SECTION 2.

CONTRACT TERM

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2.1      Effective Date

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2.2      Starting Delivery Date

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2.3      Term

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2.4      Term Extensions

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SECTION 3.

OUTLINE OF THE OBLIGATIONS OF THE PARTIES

3.1      Purpose

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3.2      Obligations of Seller or Seller’s Affiliate(s)

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3.3      Obligations of Buyer

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SECTION 4.

CARBON QUANTITIES AND DELIVERY SCHEDULES

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4.1      Quantity Obligations

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4.2      Nominations

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4.3      Poundage Variations

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4.4      Additional Pounds

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SECTION 5.

PRODUCT WARRANTY AND PERFORMANCE GUARANTY

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5.1      Warranty

5.2      Performance Benchmark

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9

SECTION 6.

SOURCE OF CARBON

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6.1      Source of Carbon

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SECTION 7.

DELIVERY OF CARBON

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7.1      Delivery Terms

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7.2      Title and Risk of Loss

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SECTION 8.

TRANSPORTATION OBLIGATIONS

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8.1      Transport

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SECTION 9.

PRICE OF CARBON

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9.1      Contract Price

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9.2      Calculation of Base Price

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    9.2.1     Base Price

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    9.2.2     * Adjustment

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    9.2.3     Notice of Calculations

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9.3      Taxes, Fees and Royalties

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9.4      Annual Reconciliation of Carbon Purchase Quantity

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9.5      Rounding

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9.6      End of Term Reconciliation of Carbon Purchased Versus Carbon Purchase Commitment

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9.7      *

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SECTION 10.

INVOICING AND PAYMENT

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10.1    Invoicing Procedures

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10.2    Payment Procedures

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10.3    Disputed Invoices

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SECTION 11.

COMPLIANCE WITH LAWS

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11.1    Construction

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11.2    Severability

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SECTION 12.

WEIGHING, SAMPLING, AND ANALYSIS

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12.1    Procedures

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12.2    Duties to Sample Carbon

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12.3    Duties of Seller to Weigh Carbon.

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    12.3.1    Duty to Weigh; Use of Weighing Data

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    12.3.2    Inspection and Certification of Scales

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    12.3.3    Seller’s Certification of Scales and Weights; Correction of Errors

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12.4    Failure of Weighing, Sampling or Analytical Procedures.

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    12.4.1    SubstituteProcedures

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    12.4.2    Inaccurateor Unreliable Sample or Final Analysis

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12.5    Rights of Buyer and Seller in Weighing, Sampling and Analysis.

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    12.5.1    Resultsof Sampling and Analysis Binding

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    12.5.2    IndependentAnalysis of Samples

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    12.5.3    RefereeAnalysis

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    12.5.4    Observationof Sampling and Analysis

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SECTION 13.

RECORDS AND AUDITS

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13.1    Record Review.

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    13.1.1    Records of Seller

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    13.1.2    Records of Buyer

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    13.1.3    Overpayment or Underpayment

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13.2    Timing of Record Review

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SECTION 14.

FORCE MAJEURE

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14.1    Definition of Force Majeure

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14.2    Effect of Force Majeure

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SECTION 15.

EVENTS OF DEFAULT; REMEDIES

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15.1    Event of Default

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    15.1.1    Payment Default

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    15.1.2    Failure to Meet Milestone Schedules.

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    15.1.3    Failure to Perform Material Provisions

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    15.1.4    Continued Failure to Supply

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15.2    Remedies for Default and Event(s) of Default

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15.3    Extension of Cure Periods.

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15.5    Waiver of Breach

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15.6    Seller’s Right to Suspend Deliveries

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15.7    Limitation of Liabilities

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15.8    Intellectual Property

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SECTION 16.

CHOICE OF LAW

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16.1    Choice of Law

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SECTION 17.

ASSIGNMENTS AND COOPERATION WITH FINANCING

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17.1    Assignment Not Allowed

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17.2    Assignment to Affiliate

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17.3    Assignment for Financing

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17.4    Successors and Assigns

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17.5    Cooperation with Financing

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SECTION 18.

CONFIDENTIALITY

23

SECTION 19.

NOTICES

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19.1    General Notices

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19.2    Effectiveness

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19.3    Changes in Persons and Addresses

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SECTION 20.

WAIVERS

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SECTION 21.

HEADINGS AND SECTION NUMBERS - CONSTRUCTION

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21.1    Headings Not to Affect Construction

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21.2    References to Section Numbers

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SECTION 22.

AMENDMENTS

25

SECTION 23.

COMPLETE AGREEMENT

26

SECTION 24.

COUNTERPARTS

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SECTION 25.

SECURITY

SECTION 26.

INDEMNITY