Exhibit 10.31
                         SOUTHERN ENERGY RESOURCES, INC.
                     SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN








                              Troutman Sanders LLP
                          NationsBank Plaza, Suite 5200
                           600 Peachtree Street, N.E.
                             Atlanta, Georgia 30308





                             Effective June 25, 1998


<PAGE>


                         SOUTHERN ENERGY RESOURCES, INC.
                     SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN

                    ARTICLE I - PURPOSE AND ADOPTION OF PLAN
         1.1 As of the Effective  Date,  Southern  Energy Resources, Inc. hereby
adopts  and  establishes  the  Southern   Energy  Resources,  Inc.  Supplemental
Executive Retirement Plan. The Plan shall be an unfunded  deferred  compensation
arrangement whose benefits  shall be  paid solely from the general assets of the
Company.
         1.2 The Plan is  designed  to provide  deferred  compensation  benefits
primarily for a select group of management or highly compensated employees which
are not otherwise payable under the Southern Company Pension Plan as a result of
the exclusion of incentive  pay from the  definition of earnings set forth under
such plan.
                            ARTICLE II - DEFINITIONS
         2.1  "Accrued  SERP  Benefit"  shall  mean the  actuarially  determined
present  value of a  Participant's  monthly  SERP Benefit  determined  as of the
Participant's  retirement  date  under  the  Pension  Plan  or,  if  later,  the
Resolution Date, or, in the case of Plan  termination or amendment,  the date of
such Plan termination or amendment.

         2.2  "Administrative  Committee" shall mean the committee  appointed by
the Board of Directors under Section 3.1 hereof to administer the Plan.

<PAGE>

         2.3 "Affiliated  Employer" shall mean any  corporation,  other than the
Company,  which is a member of the controlled group of corporations of which The
Southern Company is the common parent corporation,  which the Board of Directors
may from time to time determine to identify under the Plan. The initial group of
Affiliated Employers shall be as follows:

                  Alabama Power Company
                  Georgia Power Company
                  Gulf Power Company
                  Mississippi Power Company
                  Savannah Electric and Power Company
                  Southern Nuclear Operating Company, Inc.
                  Southern Company Services, Inc.
                  Southern Company Energy Solutions, Inc.
                  Southern Communications Services, Inc.

         2.4 "Affiliated  Employer  Incentive Pay" shall mean such incentive pay
paid  to a  Participant  by an  Affiliated  Employer  which  the  Administrative
Committee  shall from time to time  identify  as  incentive  pay under the Plan,
including,  but not limited to any incentive pay paid under the Southern Company
Performance Pay Plan, the Southern Company  Executive  Productivity  Improvement
Plan and the Southern Company  Productivity  Improvement Plan, as such plans may
be  amended  from time to time,  provided,  however,  that  Affiliated  Employer
Incentive  Pay shall not  include  any  post-employment  payments to an employee
whose  employment  has been  transferred to a  "Non-Adopting  Employer," as such
payments  are  identified  under the  provisions  of Section 2.4 of the Southern
Company Productivity Improvement Plan.
<PAGE>

         2.5 "Base Pay Percentage"  shall mean the percentage of a Participant's
base pay for purposes of Section  5.1(b)(3)  hereof, as established by the Board
of Directors upon the  recommendation of the  Administrative  Committee for each
Plan Year prior to the  beginning of such Plan Year. In the event that the Board
of Directors does not consider the Base Pay  Percentage for any particular  Plan
Year,  the Base Pay Percentage for such Plan Year shall be deemed to be the Base
Pay  Percentage in effect for the  immediately  preceding Plan Year. The initial
Base Pay  Percentage  for the  Company's  Chief  Executive  Officer shall be ten
percent (10%) and for all other Participants shall be fifteen percent (15%).

         2.6 "Beneficiary" shall mean any person,  estate, trust or organization
entitled to receive any payment under the Plan upon the death of a Participant.

         2.7 "Business Unit Pay" shall mean, with respect to Participants who do
not participate in the Short Term Plan, the amount paid in cash to a Participant
from his or her  respective  Company  business  unit bonus plan for a respective
Plan Year, not to exceed the maximum amount the Participant  could have received
under  the terms of the Short  Term Plan for his Job  Category,  as such term is
defined in Section 4.1 of the Short Term Plan.

         2.8  "Board of Directors" shall mean the Board of Directors of Southern
Energy, Inc.

         2.9  "Code" shall mean the  Internal Revenue  Code of 1986, as  amended
from time to time.

         2.10 "Company"   shall  mean  Southern  Energy   Resources,  Inc.,  its
successors and assigns.

         2.11 "Effective Date" shall mean June 25, 1998.

         2.12  "Employee"  shall  mean  any  person  who is an  employee  of the
Company, excluding any person represented by a collective bargaining agent.
<PAGE>

         2.13 "Incentive Pay" shall mean those incentive  awards, if any, earned
by an  Employee  under the  terms of the Short  Term  Plan,  Business  Unit Pay,
Project Pay and such other incentive awards as may be approved from time to time
by the Board of Directors.

         2.14  "Participant"  shall mean an Employee or former  Employee  who is
eligible to participate in the Plan pursuant to Section 4.1 hereof.

         2.15 "Pension  Plan" shall mean The Southern  Company  Pension Plan, as
amended from time to time.

         2.16 "Plan" shall mean the Southern Energy Resources, Inc. Supplemental
Executive Retirement Plan, as amended from time to time.

         2.17 "Plan Year" shall mean the calendar year.

         2.18 "Project Incentive Plan"  shall  mean the  Southern  Energy,  Inc.
Project Incentive Plan, as amended from time to time.

         2.19     "Project Pay" shall mean amounts received by a Participant for
any given Plan Year under the Project Incentive Plan not  to  exceed  the amount
the  Participant would have received under the Short Term Plan using the maximum
Individual Component plus the actual Corporate Component for such Plan Year,  as
such terms are defined in Section 4.1 of the Short Term Plan.

         2.20  "Resolution  Date"  shall mean the first date on which all of the
amount  deferred  with respect to a  Participant  under this Plan is  reasonably
ascertainable within the meaning of Treasury Regulation 31.3121(v)(2).

         2.21  "SERP  Benefit"  shall  mean  the  supplemental  pension  benefit
described in Section 5.1 hereof.

         2.22  "Short Term Plan" shall mean the Southern Energy, Inc. Short Term
 Incentive Plan, as amended from time to time.
<PAGE>

         2.23  "Southern Company" shall mean The Southern Company.

         2.24 "Southern SERP Benefit"  shall mean the pension  benefit,  if any,
that is  payable  to a  Participant  under  the  Southern  Company  Supplemental
Executive Retirement Plan, as amended from time to time.

         2.25 "Southern Excess Benefit" shall mean the pension benefit,  if any,
that is payable to a participant under the Southern Company Supplemental Benefit
Plan, as amended from time to time.

         Where the context  requires,  the definitions of all terms set forth in
the  Pension  Plan  shall  apply with equal  force and  effect for  purposes  of
interpretation  and  administration of the Plan, unless said terms are otherwise
specifically  defined in the Plan.  The masculine  pronoun shall be construed to
include the feminine  pronoun and the singular  shall include the plural,  where
the context so requires.
<PAGE>

                      ARTICLE III - ADMINISTRATION OF PLAN

         3.1 Administrative  Committee.  The general administrative functions of
the Plan shall be managed by the Administrative Committee appointed by the Board
of Directors.  The initial members of the Administrative  Committee shall be the
Chief  Financial  Officer of the Southern  Company,  the Vice President of Human
Resources of the Southern  Company,  the Chief Financial Officer of the Company,
the Vice President of  Administration  of the Company and such other officers of
the  Company  as the  Board  of  Directors  shall  appoint  from  time to  time.
Administrative  Committee  members  shall serve at the  pleasure of the Board of
Directors and may be removed and appointed as the Board of Directors in its sole
discretion shall determine.

         3.2 Powers. The  Administrative  Committee shall administer the Plan in
accordance  with its terms and shall have all powers  necessary to carry out the
provisions of the Plan more  particularly set forth herein.  The  Administrative
Committee shall have the discretionary authority to interpret the Plan and shall
determine  all  questions  arising  in the  administration,  interpretation  and
application  of the Plan. Any such  determination  by it shall be conclusive and
binding on all persons.  It may adopt such regulations as it deems desirable for
the conduct of its affairs. It may appoint such accountants, counsel, actuaries,
specialists  and other persons as it deems  necessary or desirable in connection
with the  administration of this Plan, and shall be the agent for the service of
process.
<PAGE>

         3.3      Duties of the Administrative Committee.
                  (a) The Administrative  Committee is responsible for the daily
         administration of the Plan. It may appoint other persons or entities to
         perform any of its fiduciary  functions.  The Administrative  Committee
         and any such appointee may employ advisors and other persons  necessary
         or convenient to help it carry out its duties,  including its fiduciary
         duties. The Administrative Committee shall have the right to remove any
         such  appointee  from his  position.  Any  person,  group of persons or
         entity may serve in more than one fiduciary capacity.
                  (b) The  Administrative  Committee shall maintain accurate and
         detailed records and accounts of Participants and of their rights under
         the  Plan  and of all  receipts,  disbursements,  transfers  and  other
         transactions  concerning  the Plan.  Such  accounts,  books and records
         relating  thereto shall be open at all  reasonable  times to inspection
         and audit by persons designated by the Administrative Committee.
                  (c)  The   Administrative   Committee  shall  take  all  steps
         necessary to ensure that the Plan  complies  with the law at all times.
         These steps shall include such items as the  preparation  and filing of
         all  documents  and  forms   required  by  any   governmental   agency;
         maintaining adequate Participants' records;  recording and transmission
         of  all  notices  required  to  be  given  to  Participants  and  their
         Beneficiaries;  securing of such  fidelity  bonds as may be required by
         law; and doing such other acts necessary for the proper  administration
         of the Plan. The Administrative Committee shall keep a record of all of
         its  proceedings  and acts,  and shall keep all such books of  account,
         records and other data as may be necessary for proper administration of
         the Plan.
<PAGE>

         3.4  Indemnification.  The Company shall  indemnify the  Administrative
Committee against any and all claims,  losses,  damages,  expenses and liability
arising  from an action  or  failure  to act,  except  when the same is  finally
judicially   determined  to  be  the  result  of  gross  negligence  or  willful
misconduct.  The Company may  purchase at its own expense  sufficient  liability
insurance for the Administrative  Committee to cover any and all claims, losses,
damages and  expenses  arising  from any action or failure to act in  connection
with the execution of the duties of the Administrative  Committee.  No member of
the  Administrative  Committee shall receive any compensation  from the Plan for
his or her service as such.

                            ARTICLE IV - ELIGIBILITY

         4.1 Determination of Participation. The Administrative Committee in its
sole and  absolute  discretion  shall  determine  those  Employees  who shall be
eligible to  participate in the Plan.  Upon being named as a  Participant,  such
Participant  shall be deemed to have assented to the Plan and to any  amendments
hereafter adopted.  The Administrative  Committee shall be authorized to rescind
the  eligibility  of any  Participant  if  necessary  to ensure that the Plan is
maintained  primarily for the purpose of providing  deferred  compensation  to a
select group of management or highly compensated employees within the meaning of
the Employee Retirement Income Security Act of 1974, as amended.

         4.2 Eligibility for Benefits.  Any Participant whose benefits under the
Pension Plan are limited by the exclusion of all or a portion of Incentive  Pay,
Business  Unit Pay,  Project Pay or Affiliated  Employer  Incentive Pay from the
definition of Earnings  thereunder (or his spouse,  as the case may be) shall be
eligible to receive  benefits  under the Plan provided such  Participant  (a) is
participating  in the Plan (or is deemed to have  participated  in the Plan,  as
determined by the  Administrative  Committee in its sole discretion) at the time
of termination of employment  with the Company while  retirement  eligible,  (b)
participated in the Plan within ten (10) years of termination of employment with
an Affiliated  Employer  while  retirement  eligible under the Pension Plan, (c)
dies  while in  active  service  with the  Company  or (d) dies  while in active
service  with an  Affiliated  Employer  within  ten (10)  years of  transfer  of
employment from the Company to such Affiliated Employer, provided in the case of
death such  Employee's  spouse is eligible to receive a survivor  benefit  under
Article VII of the Pension Plan.
<PAGE>

                              ARTICLE V - BENEFITS

         5.1      SERP Benefit.
                  (a)  Subject to Article XV of the Pension Plan, a  Participant
         shall be entitled to a monthly SERP Benefit equal to:

                           (1) 1.70%  (1.0% if the  Participant  is  subject  to
                  Article XV of the Pension Plan) of the  Participant's  Average
                  Monthly  Earnings  multiplied  by his years (and fraction of a
                  year) of Accredited  Service to his Retirement  Date, death or
                  other  termination  of service,  including  a Social  Security
                  Offset,  as  adjusted,  if  necessary,  under the terms of the
                  Pension  Plan  for  commencement  prior  to the  Participant's
                  Normal Retirement Date; less
                            (2) such Participant's  Retirement  Income  that  is
                  payable under the Pension Plan; less
                            (3) such Participant's Southern Excess Benefit; less
                            (4) such Participant's Southern SERP Benefit; less
                            (5) the pension benefit, if any, that is payable  to
                                a Participant under  any  other  group    and/or
                  individual supplemental  benefit  plan  of the  Company  or an
                  Affiliated Employer; less
                            (6) the amount determined under Section 5.4 hereof.

<PAGE>

                  (b) For  purposes  of  Section  5.1(a)(1),  the  Participant's
         Average Monthly Earnings shall be calculated based on the Participant's
         Earnings that are considered  under the Pension Plan in calculating his
         Retirement  Income,  but without  regard to the  limitation  of Section
         401(a)(17) of the Code, and including the following additional amounts:
                            (1) any  portion of such Participant's base pay that
                  he may  have  elected  to  defer  under  the Southern  Company
                  Deferred  Compensation  Plan  or  the  Southern  Energy,  Inc.
                  Deferred Compensation Plan  but excluding  any  Incentive Pay,
                  Project Pay or Business Unit Pay he deferred under such plans;
                           (2) any  Affiliated  Employer  Incentive Pay that was
                  earned as of the  applicable  Plan Year while  employed  by an
                  Affiliated  Employer in excess of twenty-five percent (25%) of
                  the Participant's base pay for such Plan Year; and
                           (3) any Incentive  Pay,  Project Pay or Business Unit
                  Pay that was earned as of the  applicable  Plan Year in excess
                  of the  Participant's  Base Pay Percentage for such Plan Year.
                  In  addition,  to determine  the Plan Years which  produce the
                  highest monthly average to calculate Average Monthly  Earnings
                  under the Plan, a  Participant's  Earnings shall include those
                  additional  amounts  provided for in this Section 5.1(b).
                  (c) For purposes of Section 5.1(a)(1), the Participant's years
         of Accredited Service  shall  include  any  deemed  Accredited  Service
         provided  under  the   terms  of any  agreement concerning supplemental
         pension  payments  between  the  Participant  and  the  Company  or any
         Affiliated Employer.
                  (d) To the extent that a Participant's Retirement Income under
         the Pension  Plan is  recalculated  as a result of an  amendment to the
         Pension Plan in order to increase the amount of his Retirement  Income,
         the  Participant's  SERP Benefit shall also be recalculated in order to
         properly   reflect  such  increase  in  determining   payments  of  the
         Participant's  SERP Benefit made on or after the effective date of such
         increase.
<PAGE>

         5.2 The SERP Benefit,  as  determined  in  accordance  with Section 5.1
hereof,  shall be payable in  monthly  increments  on the first day of the month
concurrently  with the  Participant's  Retirement Income under the Pension Plan.
The form in which the SERP  Benefit  is paid shall be the same as elected by the
Participant  under the Pension Plan.  The  Beneficiary of a  Participant's  SERP
Benefit shall be the same as the Provisional Payee, if any, of the Participant's
Retirement Income under the Pension Plan.

         5.3 If all or a portion of the  Participant's  Accrued SERP Benefit has
not yet been "taken into account" for employment tax purposes within the meaning
of Treasury  Regulation  31.3121(v)(2),  the Participant's  initial monthly SERP
Benefit or, if such "taking into account" occurs  thereafter,  his first monthly
SERP Benefit  following the  Resolution  Date,  shall be increased by the amount
necessary to pay the  Participant's  Hospital  Insurance  portion of the tax due
under the Federal Insurance  Contributions Act with respect to the amount of the
Participant's Accrued SERP Benefit then required to be "taken into account" ("HI
Tax"),  if any,  increased  by the  amount  necessary  to pay the  Participant's
federal and state income tax (at a combined estimated rate of forty-five percent
(45%)) upon such HI Tax and upon such increase.

         5.4 In the event of a one-time increase in a Participant's SERP Benefit
under Section 5.3 hereof,  the Company shall thereafter reduce the Participant's
Accrued SERP Benefit by the  aggregate  amounts,  if any, paid under Section 5.3
hereof,  and  calculate,  based upon such  reduced  Accrued  SERP  Benefit,  the
difference  between  the  Participant's  monthly  SERP  Benefit  prior  to  such
reduction and the SERP Benefit the  Participant  would have received  based upon

<PAGE>

the reduced Accrued SERP Benefit  determined on an actuarially  equivalent basis
in accordance  with the terms of the Pension Plan,  taking into account the form
of benefit elected by the Participant under the Pension Plan.

         5.5  Funding  of  Benefits.  The  Company  shall  neither  reserve  nor
otherwise set aside funds for the payment of its obligations under the Plan, and
such  obligations  shall be paid solely from the general  assets of the Company,
unless the  Administrative  Committee  in its sole  discretion  shall  determine
otherwise.

         5.6  Withholding.  There shall be deducted from the payment of any SERP
Benefit due under the Plan the amount of any tax  required  by any  governmental
authority  to be  withheld  and paid over by the  Company  to such  governmental
authority for the account of the  Participant  or  Beneficiary  entitled to such
payment.

                           ARTICLE VI - MISCELLANEOUS

         6.1 Assignment.  Neither the Participant, his Beneficiary nor his legal
representative  shall have any rights to sell,  assign,  transfer  or  otherwise
convey the right to receive the payment of any SERP Benefit due hereunder, which
payment and the right thereto are  expressly  declared to be  nonassignable  and
nontransferable.  Any  attempt to assign or  transfer  the right to any  payment
under the Plan shall be null and void and of no effect.

         6.2 Amendment and Termination. The Plan may be amended or terminated at
any time by the Board of Directors,  provided  that no amendment or  termination
shall cause a forfeiture  or  reduction  in any Accrued SERP  Benefits as of the
date of such amendment or termination.
<PAGE>

         6.3 No Guarantee of Employment.  Participation  hereunder  shall not be
construed  as  creating  any  contract of  employment  between the Company and a
Participant,  nor shall it limit the right of the Company to suspend, terminate,
alter or modify,  whether or not for cause, the employment  relationship between
the Company and a Participant.

         6.4  Construction.  This Plan shall be construed in accordance with and
governed  by the laws of the State of  Georgia,  excluding  any law which  would
require the use of the laws of any other State,  and to the extent such laws are
not otherwise superseded by the laws of the United States.

         IN WITNESS  WHEREOF,  the  Plan has  been  executed by duly  authorized
officers of Southern Energy, Inc.and Southern Energy Resources, Inc. pursuant to
resolutions  of  the  Board  of  Directors of Southern Energy, Inc. and Southern
Energy  Resources,  Inc. this ____ day of July, 1999.

                                          SOUTHERN ENERGY, INC.


                                          By: _________________________________


ATTEST: _____________________________


                                          SOUTHERN ENERGY RESOURCES, INC.


                                          By: _________________________________


ATTEST: _____________________________