PROMISSORY NOTE

$___________________________ ___, 2001

  For value received, [TURBINE LLC], a Delaware limited liability company (A
Borrower@), hereby unconditionally promises to pay, or cause to be paid, to 
the order of NORTHWESTERN GENERATION I, LLC (ALender@), a wholly-owned and 
indirect subsidiary of NorthWestern Corporation, the principal amount of 
______________DOLLARS ($____________) (the APrincipal Amount@), in lawful 
money of the United States of America and in immediately available funds.  
Capitalized terms used but not defined herein shall have the meaning given to 
such term in the Letter Agreement, dated April [_], 2001, between Enron North 
America Corp. and Lender (the ALetter Agreement@).

     This promissory note (this ANote@) evidences the NorSub Purchase Price 
Loan made by Lender to Borrower on the date hereof pursuant to Section 2(d) 
of the Letter Agreement; and the proceeds of such Loan shall be applied by 
Borrower on the date hereof as required by Section 2(e) of the Letter 
Agreement. 

  The Principal Amount shall be due and payable, in full, on written demand 
of Lender.  No interest shall accrue on the Principal Amount.

  Borrower waives presentment, demand, protest, notice of protest, notice of 
nonpayment or dishonor and all other demands and notices in connection with 
the delivery, acceptance, performance, default or enforcement of this Note.

  This Note may not be changed or terminated orally, but only by an agreement 
in writing signed by the party against whom enforcement or any waiver, 
change, modification or discharge is sought.  

  This Note shall bind Borrower and its successors and assigns, and the 
benefits hereof shall inure to the benefit of  Lender and its successors and 
assigns.

  THIS NOTE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE 
INTERNAL LAW OF THE STATE OF NEW YORK (DETERMINED WITHOUT GIVING EFFECT TO 
PRINCIPLES OF CONFLICTS OF LAW).

[The balance of this page is intentionally left blank.]

  IN WITNESS WHEREOF, Borrower has caused this Note to be duly executed and 
delivered by its officer thereunto duly authorized as of the date hereof.

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NY/333181.1      [TURBINE LLC]

      By: NorthWestern Generation I, LLC,
       its Manager

      By:  NorthWestern Growth Corporation,
       its Manager


      By: _______________________________
       Name:
       Title: