FIRST AMENDMENT TO
REGISTRATION RIGHTS AGREEMENT
 
THIS FIRST AMENDMENT TO REGISTRATION RIGHTS AGREEMENT (this “Amendment”), dated
as of May 4, 2007, by and among Ethanex Energy, Inc., a Nevada corporation (the
“Company”), and the other parties who are signatories hereto.

WITNESSETH:
 
WHEREAS, Ethanex Energy North America, Inc., a Delaware corporation, and the
parties set forth on the signature page and Exhibit A thereto (each a
“Purchaser” and collectively, the “Purchasers”) entered into that certain
Registration Rights Agreement, dated as of August 3, 2006 (the “Agreement”);

WHEREAS, the Agreement was assumed by the Company pursuant to that certain
Agreement and Plan of Merger, by and among the Company, Ethanex North America
Acquisition Corp. and Ethanex Energy North America, Inc., dated as of September
1, 2006;

WHEREAS, due to recent, unanticipated events, the Company does not expect that
the registration statement that it filed with the Securities and Exchange
Commission (the “Commission”) on January 3, 2007 and amended on April 16, 2007
(the “Registration Statement”) will be declared effective by the Commission on
or before the Registration Default Date (as defined in the Agreement); and

WHEREAS, the Purchasers who are signatories to this Amendment constitute the
Majority Holders and desire to amend the Agreement and provide a waiver so that
the Company will have an additional 60 days to obtain effectiveness of the
Registration Statement, on and subject to the terms set forth in this Amendment,
and pursuant to Section 12(h) of the Agreement the Majority Holders have the
right to amend the Agreement and provide such waiver.

NOW THEREFORE, in consideration of the agreements and obligations set forth
herein and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto, intending to
be legally bound hereby, agree as follows:

Section 1.  Defined Terms. Capitalized terms used herein, unless otherwise
defined herein, shall have the respective meanings ascribed to them in the
Agreement.
 
Section 2.  Amendment of Registration Default Date. The definition of
“Registration Default Date” in Section 1 of the Agreement is hereby amended by
deleting the words “the date that is 120 day following the Registration Filing
Date” and inserting in their place “June 29, 2007”.
 
Section 3.  Consideration. Section 3(e) of the Agreement is hereby amended by
adding the following at the end of such provision:
 
“Notwithstanding anything to the contrary in this Section 3(e) or in any other
provision of this Agreement, if the Registration Statement is not declared
effective by Commission on or before June 29, 2007, then, in addition to the
payments required to be made by the preceding sentences of this Section 3(e) for
any periods after the Registration Default Date, the Company will also make a
one-time payment to each Qualified Purchaser, as additional partial liquidated
damages, in an amount equal to 3% of the Purchase Price per share of Registrable
Securities.
 

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Section 4.  Effectiveness and Waiver. This Amendment, even if signed by the
Majority Holders after the Registration Default Date (as defined in the
Agreement without giving effect to this Amendment) shall be deemed to have
retroactive effect to the day that is immediately prior to such original
Registration Default Date. For purposes of avoiding doubt, the Majority Holders
hereby waive any Registration Event (and any payment obligation of the Company
in connection therewith) that would be deemed to occur by the Registration
Statement not being declared effective prior to the original Registration
Default Date, subject to the Company’s obligation to make all payments pursuant
to Section 3(e), including the additional one-time payments provided for in the
addition to such Section 3(e) contained in Section 3 of this Amendment, if the
Registration Statement is not declared effective by the Commission on or before
June 29, 2007.
 
Section 5.  Effect of Amendment. Except as expressly set forth otherwise herein,
all terms of the Agreement shall remain in full force and effect. In the event
of any inconsistency or conflict between the Agreement and this Amendment, the
terms, conditions and provisions of this Amendment shall govern and control.
 
Section 6.  Entire Agreement. This Amendment and the Agreement, including the
Exhibits, Schedules and other documents referred to therein which form a part
thereof, contain the entire understanding of the parties hereto with respect to
the subject matter contained herein and therein. From and after the execution of
a counterpart hereof by the parties hereto, any reference to the Agreement shall
be deemed to be a reference to the Agreement as amended hereby.
 
Section 7.  Governing Law and Jurisdiction. The construction, validity and
interpretation of this Agreement and the exhibits and schedules hereto shall be
governed by and construed in accordance with the internal laws of the State of
New York, without giving effect to any choice of law or conflict of law
provision or rule (whether of the State of New York or any other jurisdiction)
that would cause the application of the laws of any jurisdiction other than the
State of New York.
 
Section 8.  Counterparts. This Amendment may be executed in two or more
counterparts, each of which shall constitute an original, and all of which taken
together shall constitute one instrument. Any signature page delivered by a
facsimile machine shall be binding to the same extent as an original signature
page.
 
[END OF PAGE]
[SIGNATURE PAGE FOLLOWS]
 
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        ETHANEX ENERGY, INC.  
   
   
    By:              /s/ Albert W. Knapp, III  

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By:     Albert W. Knapp, III
Title:  President & CEO

       
The Government of Singapore Investment Corporation Pte Ltd

Radian Group Inc.

Public Sector Pension Investment Board

WTC-CIF Emerging Companies Portfolio

The Dow Chemical Employees’ Retirement Plan

The Robert Wood Johnson Foundation

Howard Hughes Medical Institute

New York Nurses Association Pension Plan

The Retirement Program Plan for Employees of Union Carbide Corporation

By Wellington Management Company, LLP As investment Advisor
 
   
   
    By:              /s/ Steve Hoffman  

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           Steve Hoffman
           Vice President and Counsel

           
   
   
                 /s/ illegible  

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Y & S Nazarian Revocable Trust

           
   
   
                 /s/ Don Sanders  

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Don Sanders
Chief Investment Officer and Vice Chairman

 
 
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                 /s/ George L. Ball  

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George L. Ball

           
   
   
                 /s/ William W. Sprague  

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William W. Sprague

           
   
   
                 /s/ Don V. Weir  

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Don V. Weir
TTEE

           
   
   
                 /s/ Julie Weir  

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Julie Weir

           
   
   
                 /s/ John H. Malanga  

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John H. Malanga

           
   
   
                 /s/ Ben T. Morris  

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Ben T. Morris

 
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