ASSIGNMENT
AGREEMENT

       

      This
ASSIGNMENT AGREEMENT (the “Assignment”), dated
as of October 6, 2008, is entered into by and between Pringle Wind II, LLC, a
Texas limited liability company (“Assignor”), and
LittlePringle1, LLC, a Delaware limited liability company (“Assignee”).

       

      WHEREAS,
Higher Power Energy, LLC (“Higher Power Energy”)
holds 100% of the limited liability company interest in the
Assignor;

       

      WHEREAS,
Higher Power Energy and Perpetual Energy Ltd. (“Perpetual”) hold in
aggregate 100% of the limited liability company interest in Higher Perpetual
Energy, LLC (“Higher
Perpetual”);

       

      WHEREAS,
Higher Perpetual and DeWind Energy Development Company, LLC (“DeWind”) have
established DeWind SWI Wind Farms, LLC (”Company”) with the
intent of developing certain wind farm projects, have entered into a limited
liability company agreement with the Company in furtherance of such pursuit, and
will initially hold in aggregate 100% of the limited liability company interest
in the Company;

       

      WHEREAS,
the Company holds 100% of the limited liability company interest in the
Assignee;

       

      WHEREAS,
Higher Perpetual, DeWind, Higher Power Energy, the Company, Assignee and others
have entered into a Conveyance and Contribution Agreement which sets out, among
other things, the contributions that each of Higher Perpetual and DeWind will
make or will cause to be made to the Company in exchange for the respective
limited liability company interest that Higher Perpetual and DeWind will
initially receive in the Company;

       

      WHEREAS,
as part of Higher Perpetual’s contribution to the Company, Higher Power Energy
is obligated to cause Assignor to assign all of Assignor’s rights, title and
interest that Assignor may have in certain assets to the Assignee;
and

       

      WHEREAS,
Assignor wishes to assign all such rights, title and interest that it may have
in such certain assets to Assignee, and Assignee wishes to accept such
assignment,

       

      NOW,
THEREFORE, in consideration of the sum of TEN AND No/100 DOLLARS ($10.00) and
other good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, the undersigned parties hereby agree as
follows:

       

      1.           Assignment.  Assignor
hereby transfers and assigns to Assignee and Assignee hereby accepts, all of
Assignor’s right, title, and interest in and to the following (collectively, the
“Assets”):

       

      
        	
                 
      

              	
                (a)

              	
                Assessment
      of the Energy Production of the Proposed Little Pringle Wind Farm, dated
      April 29, 2008, by Garrad Hassan America, Inc., for Higher Perpetual
      Energy, LLC (to the extent applicable to
  Grantee).

              


      


      
        
           


        

        
          -1-

          
            

          

        

        
           


        

      

       

      
        	
                 
      

              	
                (b)

              	
                Assessment
      of the Energy Production of the Proposed Pringle Wind I & II Wind
      Farms, dated June 17, 2008, by Garrad Hassan America, Inc., for Higher
      Perpetual Energy, LLC (to the extent applicable to
    Grantee).

              


      

       

      
        	
                 
      

              	
                (c)

              	
                Boundary
      Survey dated May 2, 2008 by Dwayne R. Gresham, Gresham & Associates,
      Inc., of Pringle Wind I and II, Section 7, Jno M Swisher Survey, &
      Section 2, Block M24, T. C. & Ry. Co. Survey, Hutchison County, Texas
      (to the extent applicable to
Grantee).

              


      

       

      
        	
                 
      

              	
                (d)

              	
                Boundary
      Survey dated September 4, 2007 by Dwayne R. Gresham, Gresham &
      Associates, Inc., of Little Pringle Site, Section 1, Block M24, T C &
      Ry Co Survey, Hutchison County, Texas (to the extent applicable to
      Grantee).

              


      

       

      
        	
                 
      

              	
                (e)

              	
                Construction
      Notice of Intent, filed by Higher Power Energy, LLC on August 25, 2008
      with the Texas Commission on Environmental
  Quality.

              


      

       

      
        	
                 
      

              	
                (f)

              	
                Determination
      of No Hazard to Air Navigation, concerning Wind Turbine PW I-1 at
      Stinnett, TX, issued by the Federal Aviation Administration by letter
      dated August 16, 2008 to Higher Power Energy, LLC (Aeronautical Study No.
      2008-WTW-2899-OE).

              


      

       

      
        	
                 
      

              	
                (g)

              	
                Determination
      of No Hazard to Air Navigation, concerning Wind Turbine PW I-2 at
      Stinnett, TX, issued by the Federal Aviation Administration by letter
      dated August 16, 2008 to Higher Power Energy, LLC (Aeronautical Study No.
      2008-WTW-2900-OE).

              


      

       

      
        	
                 
      

              	
                (h)

              	
                Determination
      of No Hazard to Air Navigation, concerning Wind Turbine PW I-3 at
      Stinnett, TX, issued by the Federal Aviation Administration by letter
      dated August 16, 2008 to Higher Power Energy, LLC (Aeronautical Study No.
      2008-WTW-2901-OE).

              


      

       

      
        	
                 
      

              	
                (i)

              	
                Determination
      of No Hazard to Air Navigation, concerning Wind Turbine PW I-4 at
      Stinnett, TX, issued by the Federal Aviation Administration by letter
      dated August 16, 2008 to Higher Power Energy, LLC (Aeronautical Study No.
      2008-WTW-2902-OE).

              


      

       

      
        	
                 
      

              	
                (j)

              	
                Determination
      of No Hazard to Air Navigation, concerning Wind Turbine PW I-5 at
      Stinnett, TX, issued by the Federal Aviation Administration by letter
      dated August 16, 2008 to Higher Power Energy, LLC (Aeronautical Study No.
      2008-WTW-2903-OE).

              


      


      
        
           


        

        
          -2-

          
            

          

        

        
           


        

      

       

      
        	
                 
      

              	
                (k)

              	
                Document
      “JV_KeyFamilyLease_UnsignedCopy.doc”, a blank form of a lease agreement
      between Higher Power Energy, LLC and a landowner (to the extent applicable
      to Grantee).

              


      

       

      
        	
                 
      

              	
                (l)

              	
                Document
      “JV_Generic_NonDisturbanceAgreement.DOC”, a blank form of a Nondisturbance
      and Attornment Agreement between a mortgagee and a project company (to the
      extent applicable to Grantee).

              


      

       

      
        	
                 
      

              	
                (m)

              	
                Document
      “LP1_InterconnectAgmnt_Addendum.doc”, titled “Addendum to Interconnection
      Agreement”.

              


      

       

      
        	
                 
      

              	
                (n)

              	
                Document  “LP_RevisedTitleSearch.pdf”,
      titled “Little Pringle Title
Search”.

              


      

       

      
        	
                 
      

              	
                (o)

              	
                Document
      “LP_SiteDescription.doc”, titled “Little Pringle Site:  Approx.
      505 Acres”.

              


      

       

      
        	
                 
      

              	
                (p)

              	
                Document
      “LP_SPSAvoidedCosts_GeneralNotes.doc”, titled “Subject: Avoided costs-SPS”
      (to the extent applicable to
Grantee).

              


      

       

      
        	
                 
      

              	
                (q)

              	
                Draft
      dated February 2008 of Wind Generation Purchase Agreement between Higher
      Power Energy, LLC and Southwestern Public Service
  Company.

              


      

       

      
        	
                 
      

              	
                (r)

              	
                Draft
      dated September 2008 of Wind Generation Purchase Agreement between Sunray
      Wind, LLC and Southwestern Public Service
  Company.

              


      

       

      
        	
                 
      

              	
                (s)

              	
                Electrical
      One Line Diagram for “Higher Power Energy, LLC; Pringle I - 10 MW Wind
      Turbine Generator Project; Hutchison County, Texas”, dated June 26, 2008,
      by Richard C. Gross P.E., Inc.

              


      

       

      
        	
                 
      

              	
                (t)

              	
                Electrical
      Substation Conceptual Equipment Plan and Elevations for “Pringle, Texas;
      Higher Power Energy LLC; 10 MW Wind Farm”, dated June 26, 2008, by Richard
      C. Gross P.E., Inc. (to the extent applicable to
  Grantee).

              


      

       

      
        	
                 
      

              	
                (u)

              	
                Feasibility
      Study of the Energy Production of the Proposed Big Pringle, Little
      Pringle, and H&H Wind Farms in Texas, dated December 21, 2007, by
      Garrad Hassan America, Inc., for Higher Perpetual Energy, LLC (to the
      extent applicable to Grantee).

              


      

       

      
        	
                 
      

              	
                (v)

              	
                Letter
      dated August 20, 2007 from Brittany Seward, Cooley Manion Jones LLP, to
      Mark Patkunas and Jeff Martin, with attached Title Search for Little
      Pringle (to the extent applicable to
Grantee).

              


      


      
        
           


        

        
          -3-

          
            

          

        

        
           


        

      

       

      
        	
                 
      

              	
                (w)

              	
                Letter
      dated February 4, 2008 from James R. Brannen, Southwestern Public Service
      Company d/b/a Xcel Energy, to Mark Patkunas, Higher Power Energy, LLC,
      with attached Design Guide and Engineering Estimate executed as of
      February 8, 2008 by Southwestern Public Service Company d/b/a Xcel Energy
      and as of April 10, 2008 by Higher Power Energy,
  LLC.

              


      

       

      
        	
                 
      

              	
                (x)

              	
                Letter
      dated October 1, 2007 from James R. Brannen, Southwestern Public Service
      Company d/b/a Xcel Energy, to Mark Patkunas, Higher Power Energy, LLC,
      with attached Design Guide and Engineering
  Estimate.

              


      

       

      
        	
                 
      

              	
                (y)

              	
                Letter
      from the Texas Commission on Environmental Quality regarding TPDES General
      Permit for Construction Storm Water Runoff: Storm Water Notice of Intent
      Authorization.

              


      

       

      
        	
                 
      

              	
                (z)

              	
                Letter
      from Xcel Energy Services Inc. to the Public Utility Commission of Texas,
      dated February 28, 2008, regarding “Project No. 18692 Avoided Cost
      Availability of Electric Utility System Cost Data Pursuant to Subst. R.
      25.242(e)(2) [formerly Subst. R. 23.66(c)(1)]” with attached update to
      Southwestern Public Service Company’s February 15, 2008 informational data
      filing pursuant to the Commission’s Substantive Rule 25.242(e)(2),
      Availability of Electric Utility System Cost Data (to the extent
      applicable to Grantee).

              


      

       

      
        	
                 
      

              	
                (aa)

              	
                Map
      “LP_GeographicLayout.bmp” by DeLorme of Little Pringle Wind Farm (to the
      extent applicable to Grantee).

              


      

       

      
        	
                 
      

              	
                (bb)

              	
                Map
      “LP_Map.jpg” by DeLorme of Little Pringle Wind Farm (to the extent
      applicable to Grantee).

              


      

       

      
        	
                 
      

              	
                (cc)

              	
                Map
      “LP_ProposedExpansion.bmp” by DeLorme of Little Pringle Wind Farm (to the
      extent applicable to Grantee).

              


      

       

      
        	
                 
      

              	
                (dd)

              	
                Map
      “LP1and2_FAA_TurbineLayout.bmp” by DeLorme of Little Pringle Wind Farm (to
      the extent applicable to Grantee).

              


      

       

      
        	
                 
      

              	
                (ee)

              	
                Preliminary
      Geotechnical Evaluation: Little Pringle Wind Farm, Hutchinson County,
      Texas, Apex Project No. 107-229, dated November 2007, prepared by Apex
      Geoscience Inc. for Higher Power Energy, LLC (to the extent applicable to
      Grantee).

              


      

       

      
        	
                 
      

              	
                (ff)

              	
                Proposed
      Wind Power Site: Pringle Wind, Site Reconnaissance and Avian Report, dated
      August 26, 2007, prepared by Dr. Richard Harris Podolsky for Higher Power
      Energy, LLC (to the extent applicable to
  Grantee).

              


      


      
        
           


        

        
          -4-

          
            

          

        

        
           


        

      

       

      
        	
                 
      

              	
                (gg)

              	
                Storm
      Water Construction General Permit, Texas Commission on Environmental
      Quality, Permit No. TXR15MH51, issued to Pringle Wind Farm (project) and
      Higher Power Energy, LLC (operator) with coverage effective August 25,
      2008 (to the extent applicable to
Grantee).

              


      

       

      
        	
                 
      

              	
                (hh)

              	
                Spreadsheet
      “JV_OldProjectStatus_Dec07.xls” titled “HPE PROJECT LIST 12/02/2007”
      containing data regarding Little Pringle, Palo Duro, and Big Pringle (to
      the extent applicable to Grantee).

              


      

       

      
        	
                 
      

              	
                (ii)

              	
                Spreadsheet
      “JVProjects_DevelopmentCosts.xls” listing development phase cash flows for
      Little Pringle, Big Pringle, and Palo Duro (to the extent applicable to
      Grantee).

              


      

       

      
        	
                 
      

              	
                (jj)

              	
                Spreadsheet
      “LP_TypicalDayEnergyProfileForD8.2.xls” containing wind, power, and other
      data (to the extent applicable to
Grantee).

              


      

       

      
        	
                 
      

              	
                (kk)

              	
                Suggested
      Form of Agreement Between Owner and Design/Builder on the Basis of a
      Stipulated Price, between HPE DeWind, a joint venture, as owner, and
      Balfour Beatty Wind Group, a joint venture, as design/builder, for Phase I
      of the Pringle Wind Farm, with all attached schedules, exhibits, annexes,
      and other documentation (including the Escrow
  Agreement).

              


      

       

      
        	
                 
      

              	
                (ll)

              	
                Any
      and all other wind resource data, books and records, contracts, permits,
      reports and any other properties, assets and rights of any kind, whether
      tangible or intangible, real or personal, owned or hereafter acquired by
      Grantor and which are related to the following leases or the wind farm to
      be developed on the real estate subject to such
  leases:

              


      

       

      
        	
                 
      

              	
                (i)

              	
                Lease
      Agreement dated August 6, 2008 between Higher Power Energy, LLC and
      Shields and Sons; and

              


      

       

      
        	
                 
      

              	
                (ii)

              	
                Lease
      Agreement dated August 6, 2008 between Higher Power Energy, LLC and the
      Don McLain Family Limited
Partnership.

              


      

       

      Assignor hereby warrants further that:
(i) no prior assignment of the Assets, or and right or interest thereto, has
been executed by the Assignor; (ii) no act has been performed by Assignor which
might interfere with or prevent Assignee from enjoying and exercising any of its
rights and privileges evidenced hereby; and (iii) none of the Assets have been
modified.


      
        
           


        

        
          -5-

          
            

          

        

        
           


        

      

      
         

        2.           Successors and
Assigns.  This Assignment shall be binding upon and inure to
the benefit of the parties hereto and their respective successors, assigns and
legal representatives.

         

        3.           Choice of
Law.  This Assignment shall be governed by the laws of the
State of Texas.

         

        4.           Severability.  The
invalidity of any provision of this Assignment, as determined by a court of
competent jurisdiction, shall in no way affect any other provision
hereof.

         

        [ Signature page follows.
]

      


      
        
           


        

        
          -6-

          
            

          

        

        
           


        

      


      IN WITNESS WHEREOF, the parties hereto
have executed this Assignment as of the date first written above.

      


      
        
          
            
              
                
                  
                    
                      
                        	
                                ASSIGNOR

                              
	
                                PRINGLE
      WIND II, LLC

                              
	 
      	 
      
	
                                By:

                              	
                                 

                              
	 
      	 
      
	
                                Name:

                              	
                                 

                              
	 
      	 
      
	
                                Title:

                              	
                                 

                              
	 
      	 
      
	
                                ASSIGNEE

                              
	
                                LITTLEPRINGLE1,
      LLC

                              
	 
      	 
      
	
                                By:

                              	
                                 

                              
	 
      	 
      
	
                                Name:

                              	
                                 

                              
	 
      	 
      
	
                                Title:

                              	
                                 

                              


                      

                    

                  

                

              

            

          

        

      

       

      
        
           


        

        
          -7-