**Exhibit 10.73****CATALYTICA ENERGY SYSTEMS, INC.****CONSULTING AGREEMENT**     This Consulting Agreement (“**Agreement**”) is entered into effective as of January 1, 2007 by andbetween Catalytica Energy Systems, Inc. (together with its direct and indirect subsidiaries,including but not limited to SCR-Tech LLC (“SCR-Tech”) and CESI-SCR, Inc., the “**Company**”) andRichard A. Abdoo (“**Consultant**”). The Company desires to retain Consultant as an independentcontractor to perform consulting services for the Company with respect to SCR-Tech, and Consultantis willing to perform such services, on the terms described below. In consideration of the mutualpromises contained herein, the parties agree as follows:     1*. Services and Compensation*. Consultant agrees to perform for the Company the servicesdescribed in Exhibit A (the “**Services**”), and the Company agrees to pay Consultant thecompensation described in Exhibit A for Consultant’s performance of the Services and toreimburse Consultant for all reasonable and necessary expenses incurred by Consultant in theperformance of the Services in accordance with Exhibit A.     2. *Confidentiality*.          A*. Definition*. “**Confidential Information**” means any non-public information that relates to theactual or anticipated business or research and development of the Company, technical data, tradesecrets or know-how, including, but not limited to, research, product plans or other informationregarding the Company’s products or services and markets therefor, customer lists and customers(including, but not limited to, customers of the Company on whom Consultant called or with whomConsultant became acquainted during the term of this Agreement), software, developments,inventions, processes, formulas, technology, designs, drawing, engineering, hardware configurationinformation, marketing, finances or other business information. Confidential Information does notinclude information that (i) is known to Consultant at the time of disclosure to Consultant by theCompany as evidenced by written records of Consultant, (ii) has become publicly known and madegenerally available through no wrongful act of Consultant or (iii) has been rightfully received byConsultant from a third party who is authorized to make such disclosure.          B. *Nonuse and Nondisclosure*. Consultant will not, during or subsequent to the term of thisAgreement, (i) use the Confidential Information for any purpose whatsoever other than theperformance of the Services on behalf of the Company or (ii) disclose the Confidential Informationto any third party. Consultant agrees that all Confidential Information will remain the soleproperty of the Company. Consultant also agrees to take all reasonable precautions to prevent anyunauthorized disclosure of such Confidential Information.          C. *Former Client Confidential Information*. Consultant agrees that Consultant will not, duringthe term of this Agreement, improperly use or disclose any proprietary information or trade secretsof any former or current employer of Consultant or other person or entity with which Consultant hasan agreement or duty to keep in confidence information acquired by Consultant, if
 

 
any. Consultant also agrees that Consultant will not bring onto the Company’s premises anyunpublished document or proprietary information belonging to any such employer, person or entityunless consented to in writing by such employer, person or entity.          D. *Third Party Confidential Information*. Consultant recognizes that the Company has receivedand in the future will receive from third parties their confidential or proprietary informationsubject to a duty on the Company’s part to maintain the confidentiality of such information and touse it only for certain limited purposes. Consultant agrees that, during the term of this Agreementand thereafter, Consultant owes the Company and such third parties a duty to hold all suchconfidential or proprietary information in the strictest confidence and not to disclose it to anyperson, firm or corporation or to use it except as necessary in carrying out the Services for theCompany consistent with the Company’s agreement with such third party.     3. *Ownership*.          A. *Assignment*. Consultant agrees that all copyrightable material, notes, records, drawings,designs, inventions, improvements, developments, discoveries and trade secrets conceived,discovered, developed or reduced to practice by Consultant, solely or in collaboration with others,during the term of this Agreement that relate in any manner to the business of the Company thatConsultant may be directed to undertake, investigate or experiment with or that Consultant maybecome associated with in work, investigation or experimentation in the Company’s line of businessin performing the Services under this Agreement (collectively, “**Inventions**”), are the sole propertyof the Company. Consultant also agrees to assign (or cause to be assigned) and hereby assigns fullyto the Company all Inventions and any copyrights, patents, mask work rights or other intellectualproperty rights relating to all Inventions.          B. *Further Assurances*. Consultant agrees to assist the Company, or its designee, at theCompany’s expense, in every proper way to secure the Company’s rights in Inventions and anycopyrights, patents, mask work rights or other intellectual property rights relating to allInventions in any and all countries, including the disclosure to the Company of all pertinentinformation and data with respect to all Inventions, the execution of all applications,specifications, oaths, assignments and all other instruments that the Company may deem necessary inorder to apply for and obtain such rights and in order to assign and convey to the Company, itssuccessors, assigns and nominees the sole and exclusive right, title and interest in and to allInventions, and any copyrights, patents, mask work rights or other intellectual property rightsrelating to all Inventions. Consultant also agrees that Consultant’s obligation to execute or causeto be executed any such instrument or papers shall continue after the termination of thisAgreement.          C. *Attorney-in-Fact*. Consultant agrees that, if the Company is unable because of Consultant’sunavailability, dissolution, mental or physical incapacity, or for any other reason, to secureConsultant’s signature for the purpose of applying for or pursuing any application for any UnitedStates or foreign patents or mask work or copyright registrations covering the Inventions assignedto the Company in **Section 3.A**, then Consultant hereby irrevocably designates and appoints theCompany and its duly authorized officers and agents as Consultant’s agent and attorney-in-fact, toact for and on Consultant’s behalf to execute and file any such applications and
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to do all other lawfully permitted acts to further the prosecution and issuance of patents,copyright and mask work registrations with the same legal force and effect as if executed byConsultant.     4. *Conflicting Obligations*.          Consultant certifies that Consultant has no outstanding agreement or obligation that is inconflict with any of the provisions of this Agreement or that would preclude Consultant fromcomplying with the provisions of this Agreement. Consultant will not enter into any suchconflicting agreement during the term of this Agreement. Consultant’s violation of this **Section 4**will be considered a material breach under **Section 5.B**.     5. *Term and Termination*.          A. *Term*. The term of this Agreement will begin on the date of this Agreement and will continueuntil the earlier of (i) December 31, 2007 or (ii) termination as provided in **Section 5.B**.          B. *Termination*.          (i) The Company may terminate this Agreement if Consultant refuses to or is unable to performthe Services or is otherwise in breach of any material provision of this Agreement by providing 15days prior written notice of such intention to terminate and the reasons therefor, and ifConsultant fails to cure such breach within such 15 day period. In the event of a termination bythe Company pursuant to this **Section 5.B(i)**, Consultant shall be deemed to have earned allcompensation and Restricted Stock Units (as defined in Exhibit A hereto) that are vestedthrough the date of termination.          (ii) The Company may terminate this Agreement for any reason other than Consultant’s refusalor inability to perform the Services or Consultant’s breach of any material provision of thisAgreement upon giving Consultant 30 days’ prior written notice of such termination pursuant to**Section 8.E**of this Agreement. In the event of a termination by the Company pursuant to this**Section 5.B(ii),**Consultant shall be deemed to have earned all compensation hereunder and allRestricted Stock Units (as defined in Exhibit A hereto) that are unvested as of the time ofsuch termination shall immediately vest.          (iii) Consultant may terminate this Agreement for any reason upon giving the Company 30 days’prior written notice of such termination pursuant to **Section 8.E**of this Agreement. In the eventof a termination by Consultant pursuant to this **Section 5.B(iii)**, Consultant shall be deemed tohave earned all compensation and Restricted Stock Units (as defined in Exhibit A hereto)that are vested through the date of termination.          C. *Survival*. Upon such termination, all rights and duties of the Company and Consultant towardeach other shall cease except:               (1) In the event of a termination pursuant to **Section 5.B(ii)**, Consultant shall be deemed tohave earned all compensation hereunder, and in the event of a termination pursuant to **Section5.B(i)**or **Section 5.B(iii)**, Consultant shall be deemed to have earned all compensation through thedate of termination; and
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               (2) the Company will pay, within 30 days after the effective date of termination, all amountsowing to Consultant for unpaid expenses in accordance with the provisions of **Section 1**of thisAgreement; and               (3) **Section 2**(Confidentiality), **Section 3**(Ownership), **Section 4**(Conflicting Obligations),**Section 6**(Independent Contractor; Benefits), and **Section 7**(Equitable Relief) will survivetermination of this Agreement.     6. *Independent Contractor; Benefits*.          A. *Independent Contractor.*It is the express intention of the Company and Consultant thatConsultant perform the Services as an independent contractor to the Company. Nothing in thisAgreement shall in any way be construed to constitute Consultant as an agent, employee orrepresentative of the Company. Without limiting the generality of the foregoing, Consultant is notauthorized to bind the Company to any liability or obligation or to represent that Consultant hasany such authority. Consultant agrees to furnish (or reimburse the Company for) all tools andmaterials necessary to accomplish this Agreement and shall incur all expenses associated withperformance, except as expressly provided in Exhibit A. Consultant acknowledges and agreesthat Consultant is obligated to report as income all compensation received by Consultant pursuantto this Agreement. Consultant agrees to and acknowledges the obligation to pay all self-employmentand other taxes on such income.          B. *Benefits*. The Company and Consultant agree that Consultant will receive noCompany-sponsored benefits from the Company for Consultant’s services hereunder. If Consultant isreclassified by a state or federal agency or court as the Company’s employee, Consultant willbecome a reclassified employee and will receive no benefits from the Company for services as aConsultant, except those mandated by state or federal law, even if by the terms of the Company’sbenefit plans or programs of the Company in effect at the time of such reclassification, Consultantwould otherwise be eligible for such benefits.     7. *Equitable Relief*.          CONSULTANT AGREES THAT EITHER THE COMPANY OR CONSULTANT MAY PETITION A COURT FOR PROVISIONALRELIEF, INCLUDING INJUNCTIVE RELIEF, AS PERMITTED BY THE RULES, INCLUDING, BUT NOT LIMITED TO,WHERE EITHER THE COMPANY OR CONSULTANT ALLEGES OR CLAIMS A VIOLATION OF THIS AGREEMENT BETWEENCONSULTANT AND THE COMPANY OR ANY OTHER AGREEMENT REGARDING TRADE SECRETS OR CONFIDENTIALINFORMATION. CONSULTANT UNDERSTANDS THAT ANY BREACH OR THREATENED BREACH OF SUCH AN AGREEMENT(INCLUDING THIS AGREEMENT) WILL CAUSE IRREPARABLE INJURY AND THAT MONEY DAMAGES WILL NOT PROVIDE ANADEQUATE REMEDY THEREFOR AND BOTH CONSULTANT AND THE COMPANY HEREBY CONSENT TO THE ISSUANCE OF ANINJUNCTION.
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     8. *Miscellaneous*.          A. *Governing Law*. This Agreement shall be governed by the laws of Delaware without regard toDelaware’s conflicts of law rules.          B. *Assignability*. Except as otherwise provided in this Agreement, Consultant may not sell,assign or delegate any rights or obligations under this Agreement.          C. *Entire Agreement*. This Agreement constitutes the entire agreement between the parties withrespect to the subject matter of this Agreement and supersedes all prior written and oralagreements between the parties regarding the subject matter of this Agreement.          D. *Headings; Signatures*. Headings are used in this Agreement for reference only and shall notbe considered when interpreting this Agreement. This Agreement may be executed in counterparts andby facsimile signatures.          E. *Notices*. Any notice or other communication required or permitted by this Agreement to begiven to a party shall be in writing and shall be deemed given if delivered personally or bycommercial messenger or courier service, or mailed by U.S. registered or certified mail (returnreceipt requested), to the party at the party’s address written below or at such other address asthe party may have previously specified by like notice. If by mail, delivery shall be deemedeffective three business days after mailing in accordance with this **Section 8.E**.               (1) If to the Company, to:Catalytica Energy Systems, Inc.