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                                                                    EXHIBIT 10.2

                SIXTH AMENDMENT TO CREDIT AND SECURITY AGREEMENT

      This Amendment, dated as of December 8, 2004, is made by and between
SOUTHERN FLOW COMPANIES, INC., a Delaware corporation (the "Borrower"), and
WELLS FARGO BUSINESS CREDIT, INC., a Minnesota corporation (the "Lender").

                                    RECITALS

      The Borrower and the Lender are parties to a Credit and Security Agreement
dated as of September 24, 2001, as amended by (i) the First Amendment to Credit
and Security Agreement dated as of November 19, 2002; (ii) the Second Amendment
to Credit and Security Agreement and Waiver of Defaults dated as of March 26,
2003; (iii) the Third Amendment to Credit and Security Agreement dated as of
April 4, 2003; (iv) the Fourth Amendment to Credit and Security Agreement dated
as of September 24, 2003; and (v) the Fifth Amendment to Credit and Security
Agreement dated as of March 29, 2004 (as so amended, the "Credit Agreement").
Capitalized terms used in these recitals have the meanings given to them in the
Credit Agreement unless otherwise specified.

      The Borrower has requested that certain amendments be made to the Credit
Agreement, which the Lender is willing to make pursuant to the terms and
conditions set forth herein.

      NOW, THEREFORE, in consideration of the premises and of the mutual
covenants and agreements herein contained, it is agreed as follows:

      1. Defined Terms. Capitalized terms used in this Amendment which are
defined in the Credit Agreement shall have the same meanings as defined therein,
unless otherwise defined herein. In addition, Section 1.1 of the Credit
Agreement is amended by adding or amending, as the case may be, the following
definitions:

      "Maximum Line" means $3,260,000 unless said amount is reduced pursuant to
Section 2.9, in which event it means such lower amount.

      2. Exhibit A. Exhibit A of the Credit Agreement is amended and restated in
its entirety and replaced with Exhibit A attached hereto.

      3. No Other Changes. Except as explicitly amended by this Amendment, all
of the terms and conditions of the Credit Agreement shall remain in full force
and effect and shall apply to any advance or letter of credit thereunder.

      4. Conditions Precedent. This Amendment shall be effective when the Lender
shall have received an executed original hereof, together with each of the
following, each in substance and form acceptable to the Lender in its sole
discretion:

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            (a) The Revolving Note, properly executed by the Borrower.

            (b) The Acknowledgment and Agreement of Guarantors set forth at the
end of this Amendment, duly executed by each Guarantor.

            (c) Such other matters as the Lender may require.

      5. Representations and Warranties. The Borrower hereby represents and
warrants to the Lender as follows:

            (a) The Borrower has all requisite power and authority to execute
this Amendment and the Revolving Note and to perform all of its obligations
thereunder, and this Amendment and the Revolving Note have been duly executed
and delivered by the Borrower and constitute the legal, valid and binding
obligations of the Borrower, enforceable in accordance with their terms.

            (b) The execution, delivery and performance by the Borrower of this
Amendment and the Revolving Note has been duly authorized by all necessary
corporate action and does not (i) require any authorization, consent or approval
by any governmental department, commission, board, bureau, agency or
instrumentality, domestic or foreign, (ii) violate any provision of any law,
rule or regulation or of any order, writ, injunction or decree presently in
effect, having applicability to the Borrower, or the articles of incorporation
or by-laws of the Borrower, or (iii) result in a breach of or constitute a
default under any indenture or loan or credit agreement or any other agreement,
lease or instrument to which the Borrower is a party or by which it or its
properties may be bound or affected.

            (c) All of the representations and warranties contained in Article V
of the Credit Agreement are correct on and as of the date hereof as though made
on and as of such date, except to the extent that such representations and
warranties relate solely to an earlier date.

            6. References. All references in the Credit Agreement to "this
Agreement" shall be deemed to refer to the Credit Agreement as amended hereby;
and any and all references in the Security Documents to the Credit Agreement
shall be deemed to refer to the Credit Agreement as amended hereby.

            7. No Waiver. The execution of this Amendment and acceptance of any
documents related hereto shall not be deemed to be a waiver of any Default or
Event of Default under the Credit Agreement or breach, default or event of
default under any Security Document or other document held by the Lender,
whether or not known to the Lender and whether or not existing on the date of
this Amendment.

            8. Release. The Borrower and each Guarantor by signing the
Acknowledgment and Agreement of Guarantors set forth below, each hereby
absolutely and unconditionally releases and forever discharges the Lender, and
any and all participants, parent corporations, subsidiary

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corporations, affiliated corporations, insurers, indemnitors, successors and
assigns thereof, together with all of the present and former directors,
officers, agents and employees of any of the foregoing, from any and all claims,
demands or causes of action of any kind, nature or description, whether arising
in law or equity or upon contract or tort or under any state or federal law or
otherwise, which the Borrower or such Guarantor has had, now has or has made
claim to have against any such person for or by reason of any act, omission,
matter, cause or thing whatsoever arising from the beginning of time to and
including the date of this Amendment, whether such claims, demands and causes of
action are matured or unmatured or known or unknown.

      9. Costs and Expenses. The Borrower hereby reaffirms its agreement under
the Credit Agreement to pay or reimburse the Lender on demand for all costs and
expenses incurred by the Lender in connection with the Loan Documents, including
without limitation all reasonable fees and disbursements of legal counsel.
Without limiting the generality of the foregoing, the Borrower specifically
agrees to pay all fees and disbursements of counsel to the Lender for the
services performed by such counsel in connection with the preparation of this
Amendment and the documents and instruments incidental hereto. The Borrower
hereby agrees that the Lender may, at any time or from time to time in its sole
discretion and without further authorization by the Borrower, make a loan to the
Borrower under the Credit Agreement, or apply the proceeds of any loan, for the
purpose of paying any such fees, disbursements, costs and expenses.

      10. Miscellaneous. This Amendment and the Acknowledgment and Agreement of
Guarantors may be executed in any number of counterparts, each of which when so
executed and delivered shall be deemed an original and all of which
counterparts, taken together, shall constitute one and the same instrument.

      IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed as of the date first written above.

WELLS FARGO BUSINESS CREDIT, INC.               SOUTHERN FLOW COMPANIES, INC.

By:    /s/ Patti Scudder                        By:   /s/ Gary J. Zuiderveen
       --------------------------                     --------------------------
Name:  Patti Scudder                            Name: Gary J. Zuiderveen
Its:   Commercial Banking Officer               Its:  Secretary

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                                      Exhibit A to Credit and Security Agreement

                       AMENDED AND RESTATED REVOLVING NOTE

$3,260,000                                                     Denver, Colorado
                                                               December 8, 2004

      For value received, the undersigned, SOUTHERN FLOW COMPANIES, INC., a
Delaware corporation (the "Borrower"), hereby promises to pay on the Termination
Date under the Credit Agreement (defined below), to the order of WELLS FARGO
BUSINESS CREDIT, INC., a Minnesota corporation (the "Lender"), at its main
office in Denver, Colorado, or at any other place designated at any time by the
holder hereof, in lawful money of the United States of America and in
immediately available funds, the principal sum of Three Million Two Hundred
Sixty Thousand Dollars ($3,260,000) or, if less, the aggregate unpaid principal
amount of all Revolving Advances made by the Lender to the Borrower under the
Credit Agreement (defined below) together with interest on the principal amount
hereunder remaining unpaid from time to time, computed on the basis of the
actual number of days elapsed and a 360-day year, from the date hereof until
this Note is fully paid at the rate from time to time in effect under the Credit
and Security Agreement dated as of September 24, 2001 (as amended, supplemented
or restated from time to time, the "Credit Agreement") by and between the Lender
and the Borrower. The principal hereof and interest accruing thereon shall be
due and payable as provided in the Credit Agreement. This Note may be prepaid
only in accordance with the Credit Agreement.

      This Note has been executed and delivered in substitution for and not in
repayment of (i) the Revolving Note of the Borrower dated September 24, 2001 and
(ii) the Amended and Restated Revolving Note of the Borrower dated September 24,
2003, and is issued pursuant, and is subject, to the Credit Agreement, which
provides, among other things, for acceleration hereof. This Note is the
Revolving Note referred to in the Credit Agreement. This Note is secured, among
other things, pursuant to the Credit Agreement and the Security Documents as
therein defined, and may now or hereafter be secured by one or more other
security agreements, mortgages, deeds of trust, assignments or other instruments
or agreements.

      The Borrower shall pay all costs of collection, including reasonable
attorneys' fees and legal expenses if this Note is not paid when due, whether or
not legal proceedings are commenced.

      Presentment or other demand for payment, notice of dishonor and protest
are expressly waived. SOUTHERN FLOW COMPANIES, INC.

                                                By:  ___________________________
                                                      Gary J. Zuiderveen
                                                      Secretary

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                   ACKNOWLEDGMENT AND AGREEMENT OF GUARANTORS

      The undersigned, each a guarantor of the indebtedness of Southern Flow
Companies, Inc. (the "Borrower") to Wells Fargo Business Credit, Inc. (the
"Lender") pursuant to a separate Guaranty dated as of September 24, 2001, and
for the Guaranty of Metretek Contract Manufacturing Company, Inc., as of
September 24, 2003, (the "Guaranty"), each hereby (i) acknowledges receipt of
the foregoing Amendment; (ii) consents to the terms (including without
limitation the release set forth in Paragraph 8 of the Amendment) and execution
thereof; (iii) reaffirms its obligations to the Lender pursuant to the terms of
its Guaranty; and (iv) acknowledges that the Lender may amend, restate, extend,
renew or otherwise modify the Credit Agreement and any indebtedness or agreement
of the Borrower, or enter into any agreement or extend additional or other
credit accommodations, without notifying or obtaining the consent of the
undersigned and without impairing the liability of the undersigned under its
Guaranty for all of the Borrower's present and future indebtedness to the
Lender.

METRETEK CONTRACT MANUFACTURING                 METRETEK TECHNOLOGIES, INC.
COMPANY, INC.

By:    /s/ Gary J. Zuiderveen                   By:   /s/ Gary J. Zuiderveen
       -----------------------                        --------------------------
Name:  Gary J. Zuiderveen                       Name: Gary J. Zuiderveen
Its:   Secretary                                Its:  Secretary

POWERSECURE, INC.                               METRETEK, INCORPORATED

By:   /s/ Gary J. Zuiderveen                    By:   /s/ Gary J. Zuiderveen
       -----------------------                        --------------------------
Name: Gary J. Zuiderveen                        Name: Gary J. Zuiderveen
Its:  Secretary                                 Its:  Secretary