Document:

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                                                                   EXHIBIT 10.52

                                 LOAN AGREEMENT

This Loan Agreement (hereinafter called "Agreement") is effective June 30, 1999
and is between SouthStar Energy Services, LLC (hereinafter called "SouthStar"),
Georgia Natural Gas Company (hereinafter called "GNG"), Piedmont Energy Company
(hereinafter called "Piedmont") and Dynegy Hub Services Inc. (hereinafter called
"Dynegy").

WHEREAS, SouthStar, a joint venture of GNG, Piedmont and Dynegy, was formed for
the purpose of selling, on a non-regulated basis, energy commodities to retail
customers; and

WHEREAS, SouthStar wishes to establish lines of credit in the maximum aggregate
available principal amount of $75,000,000.00 which lines of credit contemplate
borrowing directly from GNG and Piedmont and Dynegy; and

WHEREAS, GNG, Piedmont and Dynegy wish to facilitate such credit arrangements on
the terms and conditions set forth herein.

NOW, THEREFORE FOR AND IN CONSIDERATION of the premises, the mutual covenants
contained herein and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto, intending to
be legally bound, hereby agree as follows:

<PAGE>   2

1.       GNG agrees to loan to SouthStar, from time to time upon the terms and
         conditions set forth herein, up to Thirty-Seven Million Five Hundred
         Thousand and no/100 Dollars (US$37,500,000.00). Piedmont agrees to loan
         to SouthStar, from time to time upon the terms and conditions set forth
         herein, up to Twenty-Two Million Five Hundred Thousand and no/100
         Dollars (US$22,500,000.00). Dynegy agrees to loan to SouthStar, from
         time to time upon the terms and conditions set forth herein, up to
         Fifteen Million and no/100 Dollars (US$15,000,000.00).

         Whenever SouthStar shall desire to borrow funds pursuant to this
         Agreement (each such borrowing being hereinafter referred to as a
         "Loan" and all such borrowings requested or outstanding at any given
         time being hereinafter referred to as "Loans"), SouthStar shall borrow
         50% of the requested Loan amount from GNG, 30% of the requested Loan
         amount from Piedmont and 20% of the requested Loan amount from Dynegy.

         Neither GNG, Piedmont nor Dynegy shall have any obligation to SouthStar
         whatsoever to make any Loan pursuant to this Agreement if at the time
         of the proposed funding thereof the aggregate principal amount of all
         Loans then outstanding exceeds, or upon the funding of such proposed
         Loan would exceed, $75,000,000.00. Similarly, (i) GNG shall have no
         obligation to SouthStar whatsoever to make any Loan pursuant to this
         Agreement if at the time of the proposed funding thereof the aggregate
         principal amount of all Loans then outstanding from GNG to SouthStar
         exceeds, or upon the funding of such proposed Loan would exceed,
         Thirty-Seven Million Five Hundred Thousand and no/100 Dollars
         (US$37,500,000.00), (ii) Piedmont, shall have no obligation to
         SouthStar

<PAGE>   3

         whatsoever to make any Loan pursuant to this Agreement if at the time
         of the proposed funding thereof the aggregate principal amount of all
         Loans then outstanding exceeds, or upon the funding of such proposed
         Loan would exceed, Twenty-Two Million Five Hundred Thousand and no/100
         Dollars (US$22,500,000.00), and (iii) Dynegy, shall have no obligation
         to SouthStar whatsoever to make any Loan pursuant to this Agreement if
         at the time of the proposed funding thereof the aggregate principal
         amount of all Loans then outstanding exceeds, or upon the funding of
         such proposed Loan would exceed, Fifteen Million and no/100 Dollars
         (US$15,000,000.00). In the event that any one of the parties, GNG,
         Piedmont or Dynegy, shall fail to fund all or part of their respective
         portions of a SouthStar requested Loan pursuant to a Loan request made
         by SouthStar under this Agreement, neither of the other parties shall
         have any obligation to make a loan pursuant to that SouthStar request.

         Any person listed in Appendix A is authorized to consummate Loans from
         GNG, Piedmont and Dynegy under this Agreement on behalf of SouthStar.
         Each of GNG, Piedmont and Dynegy shall designate in writing one contact
         person for all matters concerning Loans to SouthStar which designee may
         be changed by GNG, Piedmont or Dynegy, respectively, upon written
         notice to all parties to this Agreement.

2.       The Loans shall be made by GNG, Piedmont and Dynegy under this
         Agreement from time to time upon telephonic request from any person
         listed in Appendix A. At the time of each Loan, SouthStar will confirm
         the details of such Loan by transmitting a written notice to GNG,
         Piedmont and Dynegy, substantially in the form of Appendix B, detailing

<PAGE>   4

         the borrowing including: (i) the date of the notice; (ii) the requested
         date of the Loan; (iii) the aggregate principal amount of the Loan
         requested; (iv) the bank account to which Loan funds are to be
         disbursed; and (v) that the Loan is being requested pursuant to this
         Agreement. Further, such notice shall contain an affirmative
         representation and warranty that each of GNG, Piedmont and Dynegy are
         participating in the Loan pro rata based upon the following
         percentages: 50% for GNG; 30% for Piedmont; and 20% for Dynegy.

3.       Any and all payments (whether consisting of principal or interest) on
         an outstanding Loan shall be made by SouthStar to GNG, Piedmont and
         Dynegy pro rata based on the percentage of the Loan amount lent by
         each. In other words, assuming all Loans outstanding at the time of the
         payment were made by the Parties in percentages required in Paragraph 2
         above, GNG, Piedmont and Dynegy shall each receive the following
         percentage of any principal payment or interest payment by SouthStar:
         50% for GNG; 30% for Piedmont; and 20% for Dynegy. All payments by
         SouthStar to GNG, Piedmont and Dynegy shall be applied first to accrued
         interest, then to principal. All payments shall be applied to Loans in
         the order in which each Loan was made, such that payments are applied
         first to repayment of interest and principal on the Loan that has been
         outstanding for the longest period of time. The principal balance of
         Loans outstanding to GNG, Piedmont and Dynegy may be prepaid, in whole
         or in part, at any time without penalty (provided that prepayments are
         applied in the order described in the immediately preceding sentence).
         Principal amounts repaid to GNG, Piedmont and Dynegy may be re-borrowed
         by SouthStar, provided that the aggregate outstanding principal balance
         of all Loans does not at any time exceed Seventy-Five Million and
         no/100 Dollars

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         (US$75,000,000.00) and provided further that all other terms and
         conditions of this Agreement are complied with.

4.       Interest will accrue on the outstanding principal balance of each Loan
         made by GNG, Piedmont, and Dynegy at an annual fixed rate equal to
         LIBOR (hereinafter defined), plus eighty-five basis points. Interest
         shall be calculated based upon the actual number of days the principal
         amount in question has been outstanding and based upon a year
         consisting of 360 days.

         Payments of interest on the outstanding principal balance of Loans
         shall be due and payable, in arrears, quarterly on September 30, 1999,
         December 31, 1999, March 31, 2000, and June 27, 2000. If the due date
         for an interest payment is not a business day, then such payment shall
         be due on the next succeeding business day.

         Notwithstanding anything herein to the contrary, any Loan payments
         (whether principal or interest) not made as and when due shall bear
         interest from the date due until paid at a floating rate equal to the
         Prime Rate (hereinafter defined) plus 200 basis points. Such interest
         shall be calculated on the basis of a 360 day year for the actual
         number of days elapsed.

         For purposes of this Agreement, LIBOR shall mean the London Interbank
         Offered Rate for the Applicable Period (hereinafter defined) as
         published in the "Money Rates" column of the Eastern Edition of the
         Wall Street Journal on the effective date of the Loan

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         in question, or if the Wall Street Journal is not published on such
         date, then as published in the Wall Street Journal on the next
         preceding business day.

         For purposes of this Agreement, "Applicable Period" shall mean: (i) one
         year for Loans with an effective date on or after June 30, 1999, but
         before December 28, 1999; (ii) six months for Loans with an effective
         date on or after December 28, 1999, but before March 28, 2000; (iii)
         three months for Loans with an effective date on or after March 28,
         2000, but before May 28, 2000; and (iv) one month for Loans with an
         effective date on or after May 28, 2000.

         For purposes of the Agreement, "Prime Rate" shall mean the "Prime Rate"
         as published in the "Money Rates" column of the Eastern Edition of the
         Wall Street Journal on the date in question, or if the Wall Street
         Journal is not published on such date, then as published in the Wall
         Street Journal on the next preceding business day. Changes in the Prime
         Rate shall become effective on the date on which they are published in
         the Wall Street Journal.

5.       The amount borrowed by SouthStar under each Loan shall be deposited in
         an account specified by SouthStar in the confirmation notice specified
         in Section 2 hereof. Notwithstanding anything to the contrary contained
         in this Agreement or in any confirmation notice from SouthStar to GNG,
         Piedmont or Dynegy, all Loans (principal and interest) from GNG,
         Piedmont and Dynegy to SouthStar shall mature and shall be due and
         payable in full on June 27, 2000. Simultaneously with its execution of
         this

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         Agreement, SouthStar shall execute Master Notes in favor of GNG,
         Piedmont and Dynegy in the forms set forth in Exhibit A, Exhibit B and
         Exhibit C, respectively.

6.       From the date of this Agreement until the later of (i) June 27, 2000,
         or (ii) the date on which all outstanding Loans have been paid in full,
         the Company covenants and agrees that it will not, without the prior
         written consent of each Lender, (a) pledge, sell, assign, or discount
         any of its accounts receivable, other than the discount of such
         accounts in the ordinary course of business for collection, or (b)
         pledge, sell or assign any gas storage inventory.

7.       This Agreement shall be governed by and construed under the laws of the
         State of Georgia.

IN WITNESS WHEREOF, the parties have caused this Agreement to be duly executed
by their duly authorized officers or other duly authorized representatives as of
the day and year first written above.

SOUTHSTAR ENERGY SERVICES, LLC

By:        /s/ Stephen J. Gunther
           ---------------------------
Title:     President
           ---------------------------

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GEORGIA NATURAL GAS COMPANY

By:      /s/ Stephen J. Gunther
         -----------------------------
Title:   President
         -----------------------------

PIEDMONT ENERGY COMPANY

By:      /s/ David J. Dzuricky
         -----------------------------
Title:   Vice President
         -----------------------------

DYNEGY HUB SERVICES, INC.

By:      /s/ Mathew K. Schatzman
         -----------------------------
Title:   Executive Vice President
         -----------------------------

<PAGE>   9

APPENDIX A
                              AUTHORIZED EMPLOYEES

The following SouthStar employees are authorized under the Agreement to request
Loans from GNG, Piedmont and Dynegy on behalf of SouthStar:

Stephen Gunther
Mark Chesla
Peter Welch

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                                   APPENDIX B

                            LOAN CONFIRMATION NOTICE

Pursuant to Section 2 of that certain Loan Agreement (the "Agreement") dated as
of June 30, 1999, by and among SouthStar Energy Services, LLC ("SouthStar"),
Georgia Natural Gas Company ("GNG"), Piedmont Energy Company ("Piedmont") and
Dynegy Hub Services, Inc. ("Dynegy"), the undersigned, on behalf of SouthStar,
hereby confirms to GNG, Piedmont and Dynegy the following:

1) The date of this Loan Confirmation Notice is _______________;

2) SouthStar has requested a Loan under the Agreement in the aggregate principal
amount of $_______________ (the "Requested Loan");

3) SouthStar has requested that the Requested Loan be funded on ____________'

4) The Requested Loan is to be funded by GNG, Piedmont and Dynegy as follows:

         GNG:                               $_______________
         Piedmont:                          $_______________
         Dynegy:                            $_______________

         Total Amount of Requested Loan:    $_______________

5) The undersigned hereby represents and warrants on behalf of SouthStar that
GNG, Piedmont and Dynegy are participating in the funding of the Requested Loan
as follows:

         GNG:              50%
         Piedmont:         30%
         Dynegy:           20%

6) SouthStar hereby requests that GNG, Piedmont and Dynegy fund their respective
portions of the Requested Loan by wire transferring the applicable amount to the
following SouthStar account:

         Financial Institution:  NationsBank (Bank of America)
                                 -----------------------------
         ABA#:
               ----------------------------
         Account Number:
                         -------------------------

By:
       ------------------------
Title:
       ------------------------

<PAGE>   11

                                   APPENDIX B
                                   (CONTINUED)

                          SouthStar Energy Services LLC
                             Requested Loan Journal

                    Aggregate              Amount of Requested Loan Advanced by:
Requested Loan      Principal Amount       ------------------------------------
Funding Date        of Requested Loan      GNG         Piedmont        Dynegy
--------------      -----------------      ---         --------        ------

Total
                    -----------------      -------     --------        ------

<PAGE>   12

                                    EXHIBIT A
                                      (GNG)

                                   MASTER NOTE

Effective Date: June 30, 1999

For Value Received, SouthStar Energy Services, LLC (the "Company"), hereby
promises to pay to the order of Georgia Natural Gas Company (the "Lender") at
its office located at __________________________________________________________
_______________________________________________________________________ or such
other place as Lender may designate, the principal sum of Thirty Seven Million
Five Hundred Thousand and no/100 Dollars ($37,500,000.00) or the aggregate
unpaid sum of all advances which the Lender actually makes hereunder to the
Company, whichever amount is less, together with interest at a rate computed as
set forth in that certain Loan Agreement of even date herewith by and among
Company, Lender, Piedmont Energy Company and Dynegy Hub Services, Inc. (the
"Loan Agreement"). The amount of advances hereunder, the interest rate
applicable to each such advance, and the maturity date for the payment of the
principal amount of and interest on each such advance shall be determined in
accordance with the Loan Agreement. The Company hereby agrees to pay all costs
of collection hereof, including, without limitation, reasonable attorneys' fees
actually incurred in the event amounts evidenced by this Master Note are
collected by or through an attorney-at-law. Failure or forbearance of Lender to
exercise any right hereunder or otherwise granted to it by law or another
agreement shall not constitute a waiver of such rights unless so stated by
Lender in writing. Time is of the essence in payment and performance of this
Master Note.

                                       SOUTHSTAR ENERGY SERVICES, LLC

                                       By:      ________________________________

                                       Title:   ________________________________

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                                    EXHIBIT B
                                   (Piedmont)

                                   MASTER NOTE

Effective Date: June 30, 1999

For Value Received, SouthStar Energy Services Inc. (the "Company"), hereby
promises to pay to the order of Piedmont Energy Company (the "Lender") at its
office located at ______________________________________________________________
______________________________ or such other place as Lender may designate, the
principal sum of Twenty Two Million Five Hundred Thousand and no/100 Dollars
($22,500,000.00) or the aggregate unpaid sum of all advances which the Lender
actually makes hereunder to the Company, whichever amount is less, together with
interest at a rate computed as set forth in that certain Loan Agreement of even
date herewith by and among Company, Lender, Georgia Natural Gas Company and
Dynegy Hub Services, Inc. (the "Loan Agreement"). The amount of advances
hereunder, the interest rate applicable to each such advance, and the maturity
date for the payment of the principal amount of and interest on each such
advance shall be determined in accordance with the Loan Agreement. The Company
hereby agrees to pay all costs of collection hereof, including, without
limitation, reasonable attorneys' fees actually incurred in the event amounts
evidenced by this Master Note are collected by or through an attorney-at-law.
Failure or forbearance of Lender to exercise any right hereunder or otherwise
granted to it by law or another agreement shall not constitute a waiver of such
rights unless so stated by Lender in writing. Time is of the essence in payment
and performance of this Master Note.

                                       SOUTHSTAR ENERGY SERVICES, LLC

                                       By:      ________________________________

                                       Title:   ________________________________

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                                    EXHIBIT C
                                    (Dynegy)

                                   MASTER NOTE

Effective Date: June 30, 1999

For Value Received, SouthStar Energy Services, LLC (the "Company"), hereby
promises to pay to the order of Dynegy Hub Services, Inc. (the "Lender") at its
office located at ______________________________________________________________
______________________________ or such other place as Lender may designate, the
principal sum of Fifteen Million and no/100 Dollars ($15,000,000.00) or the
aggregate unpaid sum of all advances which the Lender actually makes hereunder
to the Company, whichever amount is less, together with interest at a rate
computed as set forth in that certain Loan Agreement of even date herewith by
and among Company, Lender, Piedmont Energy Company and Georgia Natural Gas
Company (the "Loan Agreement"). The amount of advances hereunder, the interest
rate applicable to each such advance, and the maturity date for the payment of
the principal amount of and interest on each such advance shall be determined in
accordance with the Loan Agreement. The Company hereby agrees to pay all costs
of collection hereof, including, without limitation, reasonable attorneys' fees
actually incurred in the event amounts evidenced by this Master Note are
collected by or through an attorney-at-law. Failure or forbearance of Lender to
exercise any right hereunder or otherwise granted to it by law or another
agreement shall not constitute a waiver of such rights unless so stated by
Lender in writing. Time is of the essence in payment and performance of this
Master Note.

                                     SOUTHSTAR ENERGY SERVICES, LLC

                                     By:      ________________________________

                                     Title:   ________________________________<PAGE>   1
                                                                   EXHIBIT 10.53

                            INDEMNIFICATION AGREEMENT

         This Indemnification Agreement is made and entered into on this 15th
day of January 1999 by Piedmont Propane Company ("Indemnifying Party") in favor
of AGL Resources Inc. ("AGLR"). AGLR's affiliate, Atlanta Gas Light Services,
Inc., and the Indemnifying Party's affiliate, Piedmont Energy Company (the
"Affiliate"), are parties to that certain Limited Liability Company Agreement of
SouthStar Energy Services LLC dated July 1, 1998 ("LLC Agreement") as members of
SouthStar Energy Services LLC ("SouthStar"). Pursuant to that certain Guaranty
Agreement (the "Guaranty"), effective November 1, 1998, between AGLR and Atlanta
Gas Light Company, AGLR has agreed to guaranty SouthStar's obligations to
Atlanta Gas Light Company. AGLR's agreement with SouthStar to provide the
Guaranty to Atlanta Gas Light Company was subject to the condition that certain
affiliates of each member of SouthStar would indemnify AGLR against any losses
AGLR incurs as a result of AGLR providing financial support for SouthStar under
the Guaranty in accordance with the applicable SouthStar member's Allocable
Share of Net Profits and Losses, as set forth in the LLC Agreement. This
Indemnification Agreement sets forth the terms and conditions of that
indemnification.

         In consideration of the benefit the Indemnifying Party and its
affiliates derive from AGLR providing financial support to SouthStar pursuant to
the Guaranty and the benefit to AGLR of the Indemnifying Party indemnifying
AGLR, the parties agree as follows:

1.     The Indemnifying Party shall indemnify, defend and hold AGLR harmless
       against any losses, costs, fees, liabilities or other expenses AGLR
       incurs as a result of AGLR's providing financial support for SouthStar
       under the Guaranty ("Indemnified Expenses"). The Indemnifying Party shall
       be liable for indemnifying AGLR hereunder for an amount equal to the
       product of the Affiliate's Allocable Share (as set forth in the LLC
       Agreement or any successor agreement) and the Indemnified Expenses.
       Notwithstanding any statement herein to the contrary, the Indemnifying
       Party shall not be liable to AGLR to the extent that the Indemnified
       Expenses resulted from AGLR's gross negligence or willful misconduct.

2.     AGLR shall invoice the Indemnifying Party (at the address set forth in
       numbered paragraph 9 below) no later than ten days prior to the end of
       each calendar month for the Indemnifying Party's share of the Indemnified
       Expenses due from the previous calendar month or any portion thereof. The
       Indemnifying Party shall pay AGLR the amount of such invoice (via wire
       transfer to the account specified on the invoice) no later than the last
       day of

<PAGE>   2

       the calendar month during which AGLR sent the Indemnifying Party an
       invoice.

       If the Indemnifying Party fails to pay all of the amount of any invoice
       when that amount becomes due, the Indemnifying Party shall pay AGLR a
       late charge on the unpaid balance that shall accrue daily on each
       calendar day from the due date at an annual rate equal to two percentage
       points above the then-effective monthly prime commercial lending rate per
       annum announced by NationsBank, N.A. from time to time multiplied by the
       unpaid balance; provided, that for any period that such rate exceeds any
       applicable maximum rate permitted by law, the rate shall equal the
       applicable maximum rate.

3.     This Indemnification Agreement shall inure to the benefit of each party,
       its successors, assigns and creditors, and can be modified only by a
       written instrument signed by the Indemnifying Party and AGLR. No
       Indemnifying Party shall have the right to assign this Indemnification
       Agreement or its obligations hereunder to any person or entity without
       the prior written consent of AGLR, which shall not be unreasonably
       withheld.

4.     This Indemnification Agreement shall be governed by, and construed in
       accordance with the internal laws (but not the laws concerning conflicts
       of laws) of the state of Georgia.

5.     The Indemnifying Party represents and warrants to AGLR that it is
       authorized to indemnify AGLR under the terms of this Indemnification
       Agreement, that it has all of the rights and powers necessary to do so,
       and that the individual signing below is authorized to bind the
       Indemnifying Party to its obligations under this Indemnification
       Agreement.

6.     The Indemnifying Party hereby agrees to provide AGLR with copies of
       Indemnifying Party's annual financial statements (consisting of at least
       a balance sheet and statements of income and cash flows) within 90 days
       following the end of the fiscal year to which such financial statements
       relate. If such financial statements have been reviewed or audited, the
       statements provided pursuant to the immediately preceding sentence shall
       be the reviewed or audited statements, as the case may be.

7.     The Indemnifying Party hereby agrees to notify AGLR within 45 days
       following the close of each of the first three quarters of each of
       Indemnifying Party's fiscal years if at the end of such quarter,
       Indemnifying Party's stockholders' equity, determined in accordance with
       generally accepted accounting principles consistently applied, shall be
       less than $30 million.

8.     On the date of each delivery of financial statements pursuant numbered
       paragraph 6 above, Indemnifying Party represents and warrants to AGLR
       that the balance sheet delivered by Indemnifying Party on such date
       reflects

<PAGE>   3

       all obligations, contingent or otherwise, which in accordance with
       generally accepted accounting principles should be classified upon
       Indemnifying Party's balance sheet as liabilities or disclosed in
       footnotes thereto.

9.     Notices hereunder must be given in writing (which may be a facsimile
       transmission) to be effective and shall be effective upon receipt by AGLR
       or the Indemnifying Party at the address set forth below or at such other
       address as AGLR or the Indemnifying Party may notify the other:

                  If to AGLR:

                                    AGL Resources Inc.
                                    P. O. Box 4569
                                    Atlanta, Georgia 30302-4569
                                    Attention:  Chief Financial Officer
                                    Facsimile No.:  (404) 584-3419

                  If to Indemnifying Party:

                                    Piedmont Propane Company
                                    1915 Rexford Road
                                    Charlotte, NC 28211
                                    Attention:  Treasurer
                                    Facsimile No.:  (704)365-8515

10.    THE INDEMNIFYING PARTY HEREBY INTENTIONALLY AND VOLUNTARILY WAIVES ANY
       DEFENSE TO PAYMENT UNDER THIS INDEMNIFICATION AGREEMENT THAT IS BASED
       UPON OR ARISES OUT OF AGLR'S DIRECT OR INDIRECT OWNERSHIP OF AN EQUITY
       INTEREST IN SOUTHSTAR AND/OR ATLANTA GAS LIGHT COMPANY.

AGREED TO AND ENTERED INTO the date first written above by:

AGL Resources Inc.                          Piedmont Propane Company

By:      /s/ Paul R. Shlanta                By:     /s/ David J. Dzuricky
    ------------------------------              --------------------------------
Title:   Senior Vice President              Title:  Vice President
         -------------------------                  ----------------------------

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