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                                                                    Exhibit 10.1

                                      Caterpillar Financial Services Corporation

                                                          Power Finance Division
                                     14120 Ballantyne Corporate Place- Suite 425
                                                             Charlotte, NC 28277
                                                       Telephone: (704) 752-1330
                                                       Facsimile: (615) 341-3489
                                                      Email: mubeen.khan@cat.com

May 9, 2005

PowerSecure, Inc.
Attn: Sidney Hinton
President & CEO
230 Capcom Ave Suite 107
Wake Forest, NC 27587

Sidney:

Caterpillar Power Finance ("CPF") is pleased to offer a Line of Credit to
PowerSecure, Inc. ("PowerSecure") to assist in the purchase of new or used
Caterpillar generator sets. The terms and conditions of the available Line of
Credit are as follows:

Amount: $5,000,000.00. The aggregate gross borrowings will be drawn against this
        amount with the difference representing available credit as follows:

<TABLE>
<S>                  <C>
Credit Line:         $  5,000,000
Current Exposure:       1,403,381
                     ------------
Available:           $  3,596,619
</TABLE>

Conditions:

      -  Line of Credit is subject to termination by CPF if PowerSecure fails to
         perform on any contracts

      -  Finance Products Applicable: Installment Sales Contract ("ISC") or
         Promissory Note

      -  Financing for generator sets (sold by an authorized Caterpillar dealer)

      -  PowerSecure to provide invoices for affiliated equipment and services
         at the request of Cat Financial

      -  Interest Rate as determined at the time a quotation is provided for the
         individual transaction

      -  Documentation Fee of $500 per transaction

      -  Evidence of cash down payment of 10% of the total sale price; or Debt
         Service Reserve Account of three (3) months' payments to be deposited
         into an escrow account established in an Escrow Account Agreement to be
         executed

      -  Cat Financial to perform updated lien searches as required and obtain

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         Subordinations from blanket lien holders

      -  A real estate records search on the asset physical location will be
         required with Landlord and/or Mortgagee Waivers as Cat Financial deems
         necessary

      -  Copy of the Interactive Distributed Generation Services Contract and
         Assignment of Proceeds Agreement assigning the proceeds of the
         Interactive Distributed Generation Services Contract to Cat Financial
         in the event of default, with third-party acknowledgement of such
         assignment

      -  PowerSecure will provide to CPF its quarterly financial statements
         within 60 days of the end of each quarter and 120 days within the end
         of the fiscal year, while this credit line is active

Commencement
Date:    May 9, 2005

Term: Twelve (12) to sixty (60) months.

Documentation: Standard CPF documentation that provides CPF with a first
               priority security interest in the equipment being financed as
               well as other equipment related to the project. Negotiated
               amendment language for specific financing mechanisms will be
               utilized. Other documentation as listed in the Conditions section
               above or may be reasonably requested by Cat Financial.

Insurance:     Physical Damage coverage satisfactory to CPF.

Expiration:    The Line of Credit will expire April 30, 2006 or at an earlier
               date upon notice to PowerSecure at the sole discretion of CPF.
               The Line of Credit may be renewed upon request of the customer.
               The renewal request must include the current year-end statements.

This letter is intended to confirm the intent of CPF to finance equipment, but
should not be construed as an unconditional binding commitment to finance
equipment. The line of credit is contingent upon the continued creditworthiness
of PowerSecure at the sole discretion of CPF. The terms and conditions set forth
may not be changed, modified or waived except in writing signed by the parties
hereto.

Thank you for giving Cat Power Finance the opportunity to provide this Line of
Credit. We look forward to assisting you in your equipment acquisition needs.

Should you have any questions or concerns, please do not hesitate in contacting
me at (704) 752-1330.

Sincerely,

/s/ M.A. Mubeen Khan

M. A. Mubeen Khan
Southeast Region Account Manager
Cat Power Finance