GUARANTY AGREEMENT

                              GUARANTY AGREEMENT


     GUARANTY   AGREEMENT   (this   "Agreement"),   dated as of October 25, 2006, by
GREENSHIFT   CORPORATION,   a Delaware corporation,   GS AGRIFUELS   CORPORATION,   a
Delaware   corporation,   GS ENERGY   CORPORATION,   a Delaware   corporation   and GS
CLEANTECH    CORPORATION,    a   Delaware    corporation   (each   a   "Guarantor"   and
collectively, the "Guarantors") in favor or THE STILLWATER ASSET-BACKED FUND LP,
a   Delaware   limited    partnership   (the   "Lender").    The   Lender   and   NextGen
Acquisition   Inc.,   a Delaware   corporation   (the   "Borrower")   are parties to a
Credit Agreement, dated as of the date hereof, (as modified and supplemented and
in effect from time to time, the "Credit Agreement"),   providing, subject to the
terms and conditions thereof,   for extensions of credit (by the making of a Term
Loan) to be made by the   Lender   to the   Borrower   in the   principal   amount   of
$6,000,000.

     To induce   the   Lender to enter   into the   Credit   Agreement   and to extend
credit thereunder,   and for other good and valuable   consideration,   the receipt
and   sufficiency   of which are hereby   acknowledged,   the Guarantor have agreed,
subject to the terms and conditions of the Intercreditor   Agreement,   to jointly
and severally guarantee the Guaranteed   Obligations (as hereinafter   defined) on
the terms and conditions set forth in this Agreement.   Accordingly,   the parties
hereto hereby agree as follows:

     Section 1.   Definitions.   All capitalized terms used herein but not defined
herein   shall   have the   meanings   set forth in the   Credit   Agreement.   As used
herein, the following terms shall have the following meanings:

          "Costs"   shall have the   meaning   ascribed   thereto   in   Section   2.01
          hereof.

          "Guaranteed   Obligations"   shall   mean the   obligations   described   in
          Section 2.01 hereof.

     Section 2. The Guarantee.
                          
2.01 The Guarantee. (a) Each Guarantor,   hereby absolutely,   unconditionally and
     irrevocably guarantees to the Lender, the full and prompt payment when due,
     whether   at   maturity   or   earlier,   by reason of   acceleration,   mandatory
     prepayment or otherwise,   and at all times thereafter,   the principal owing
     by the   Borrower   to the   Lender   on the   Loans,   and all   fees,   costs and
     expenses under the Credit Agreement or any other Financing Agreements.

     (b)   Each   Guarantor   further   agrees to pay,   upon   demand,   all costs and
          expenses ("Costs"), including, without limitation, all court costs and
          reasonable   attorneys'   fees and   expenses,   paid or   incurred   by the
          Lender   (a)   in   endeavoring   to   collect   all   or   any   part   of   the
          Obligations from, or in prosecuting any action against, such Guarantor
          or   (b)   in    endeavoring    to   realize   upon   (whether   by   judicial,
          nonjudicial or other proceedings) any collateral   securing any of such
          Guarantor's liabilities under this Guaranty ("Guarantor Collateral").

2.02 Obligations Unconditional.   The obligations of each Guarantor under Section
     2.01 hereof are   absolute   and   unconditional,   irrespective   of the value,
     genuineness,    validity,    regularity   or    enforceability   of   the   Credit
     Agreement,   the   Note or any   other   agreement   or   instrument   (including,
     without limitation,   any other Financing   Agreements) referred to herein or
     therein,   or any   substitution,   release or exchange of any other Financing
     Agreements of or security for any of the Guaranteed   Obligations or for the
     obligations   of   such   Guarantor   hereunder,   and,   to the   fullest   extent
     permitted   by   applicable   law,   irrespective   of   any   other   circumstance
     whatsoever which might otherwise   constitute a legal or equitable discharge
     or defense of a surety or   guarantor,   it being the intent of this   Section
     2.02 that the obligations of such Guarantor hereunder shall be absolute and
     unconditional,   under   any   and all   circumstances.   Without   limiting   the
     generality of the foregoing, it is agreed that the occurrence of any one or
     more of the   following   shall   not alter or impair   the   liability   of each
     Guarantor   hereunder   which shall   remain   absolute   and   unconditional   as
     described above:

     (i)   at any time or from time to time,   without   notice to such   Guarantor,
          the   time   for   any   performance   of or   compliance   with   any   of the
          Guaranteed   Obligations   shall be   extended,   or such   performance   or
          compliance shall be waived;

     (ii) any of the   acts   mentioned   in any of the   provisions   of the   Credit
          Agreement or the Note or any other agreement or instrument referred to
          herein or therein (including,   without limitation, any other Financing
          Agreements) shall be done or omitted;

     (iii) the   maturity   of   any   of   the   Guaranteed    Obligations    shall   be
          accelerated,   or any of the Guaranteed   Obligations shall be modified,
          supplemented or amended in any respect,   or any right under the Credit
          Agreement or the Note or any other agreement or instrument referred to
          herein or therein (including,   without limitation, any other Financing
          Agreements)   shall be   waived   or any   other   guarantee   of any of the
          Guaranteed   Obligations or any security   therefor shall be released or
          exchanged in whole or in part or otherwise dealt with; or

      (iv) any lien   granted to, or in favor of the Lender as security for any of
          the Guaranteed Obligations shall be released,   exchanged,   enforced or
          shall fail to be perfected.

Except as expressly provided in this Agreement,   each Guarantor hereby expressly
waives   diligence,   presentment,   demand of   payment,   protest   and all   notices
whatsoever,   and any   requirement   that the Lender   exhaust any right,   power or
remedy to proceed against the Borrower under the Credit Agreement or the Note or
any other   agreement   or   instrument   referred to herein or therein   (including,
without limitation, any other Financing Agreements), or against any other person
under any other guarantee of, or security for, any of the Guaranteed Obligations
or any of the obligations of such Guarantor hereunder.

2.03 Reinstatement. The obligations of each Guarantor under this Section 2 shall
     be   automatically   reinstated   if and to the extent that for any reason any
     payment   by or on behalf   of the   Borrower   in   respect   of the   Guaranteed
     Obligations is rescinded or must be otherwise restored by any holder of any
     of the Guaranteed   Obligations,   whether as a result of any   proceedings in
     bankruptcy or reorganization   or otherwise,   and such Guarantor agrees that
     it will   indemnify   the   Lender   on   demand   for all   reasonable   costs and
     expenses   (including,   without   limitation,   reasonable   fees   of   counsel)
     incurred   by   the   Lender   in   connection    with   any   such   rescission   or
     restoration,   including   any such costs and expenses   incurred in defending
     against any claim   alleging   that such payment   constituted   a   preference,
     fraudulent transfer or similar payment under any bankruptcy,   insolvency or
     similar   law.   The   provisions   of this   Section   2.03   shall   survive   the
     termination of this Agreement.

2.04 Subrogation.   Each   Guarantor   hereby waives all rights of   subrogation   or
     contribution,   whether   arising by contract or operation of law (including,
     without   limitation,   any such right arising   under the Federal   Bankruptcy
     Code) or otherwise by reason of any payment by such   Guarantor   pursuant to
     the   provisions of this Section 2 and further   agrees with the Borrower for
     the benefit of such   Guarantor's   creditors   that any such   payment by such
     Guarantor   shall   constitute a contribution of capital by such Guarantor to
     the Borrower.

2.05 Remedies.   Each   Guarantor   agrees that, as between such   Guarantor and the
     Lender,   the obligations of the Borrower under the Credit Agreement and the
     Note may be   declared   to be   forthwith   due and payable as provided in the
     Credit Agreement (and shall be deemed to have become   automatically due and
     payable in the circumstances provided therein) for purposes of Section 2.01
     hereof notwithstanding any stay, injunction or other prohibition preventing
     such declaration (or such obligations from becoming   automatically   due and
     payable) as against the Borrower and that, in the event of such declaration
     (or such   obligations   being   deemed to have become   automatically   due and
     payable), such obligations (whether or not due and payable by the Borrower)
     shall   forthwith   become due and payable by such   Guarantor for purposes of
     said Section 2.01.

2.06 Continuing   Guarantee.   The   guarantee   in this   Section 2 is a   continuing
     guarantee, and shall apply to all Guaranteed Obligations whenever arising.

2.07 Interest on Defaulted Guaranteed Obligations. If any Guarantor fails to pay
     any amount when due pursuant to Section 2.01 hereof,   such Guarantor agrees
     to pay   interest   on the amount of such   payment   not so paid from said due
     date until such payment   shall be paid in full at a rate per annum equal to
     the rate set forth in   Section   2.3 of the   Credit   Agreement,   payable   on
     demand of the Lender.

2.08 Application   of   Payments.   Cash at the time   held by the   Lender   shall be
      applied by