Document:

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                                                                    EXHIBIT 10.2

                                    AMENDED
                        ELECTRIC POWER SUPPLY AGREEMENT

                   Between Ameren Energy Generating Company

                                      And

                        Ameren Energy Marketing Company

THIS ELECTRIC POWER SUPPLY AGREEMENT (hereinafter "EPSA") made as of the 1st day
of May, 2000 and amended as of this 14th day of August, 2000 by and between
AMEREN ENERGY GENERATING COMPANY (hereinafter "Company" or "Genco") and AMEREN
ENERGY MARKETING COMPANY (hereinafter "Customer" or "Marketing") (Genco and
Marketing may be identified collectively as "Parties" or individually as a
"Party") is for the supply by Genco to Marketing of electric capacity and energy
available from Genco's electric generating units.

WHEREAS, Genco is a newly-formed generation-only company that has acquired all
electric generating units formerly owned and operated by Central Illinois Public
Service Company ("AmerenCIPS") and may acquire additional electric generating
units thereafter; and

WHEREAS, the electric generating units acquired by Genco from AmerenCIPS are and
will continue to be dispatched by an Agent designated for that purpose ("Agent")
pursuant to a Joint Dispatch Agreement ("JDA") between AmerenCIPS and Union
Electric Company ("AmerenUE"), subsequently amended among AmerenCIPS, AmerenUE
and Genco; and

WHEREAS, Marketing is or will be engaged in the business of purchasing and
reselling electric capacity and energy at wholesale and retail; and

WHEREAS, a portion of the capacity and energy supplied by Genco to Marketing
will be resold to AmerenCIPS for resale as bundled retail electric service
within its existing retail electric service area in Illinois at rates specified
by the Illinois Commerce Commission ("ICC") ("Bundled Sales"), or to wholesale
requirements customers of Marketing or retail customers of either Marketing
and/or AmerenCIPS that are allowed choice of an electric supplier under state
law at market-based prices ("Market Price Sales"); and

WHEREAS, Genco desires to sell and deliver to Marketing and Marketing desires to
purchase and receive from Genco capacity and energy available from the
generating units transferred by AmerenCIPS to Genco and from any additional
generating units that may be acquired by Genco in the future pursuant to the
rates, terms and conditions as amended and set forth herein;

NOW THEREFORE, in consideration for the agreements and undertakings established
herein and the mutual benefits derived therefrom, it is agreed as follows:
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1.       ELECTRIC CAPACITY AND ENERGY SERVICE

Genco shall make available or cause to be made available to Marketing all of the
electric capacity and energy which shall be available from the electric
generating units that have been transferred to Genco by AmerenCIPS and any
additional generating units that may be acquired by Genco in the future
(hereinafter "Power"), and Marketing shall purchase and pay for such Power in
accordance with the terms of this Agreement. The parties acknowledge the
existence of the JDA, and Genco's obligations associated therewith. To the
extent that (i) Marketing cannot resell the capacity and/or energy to which it
has the right and the obligation to purchase hereunder, and (ii) the Agent can
economically sell such capacity and/or energy, Marketing shall release its right
and shall be released from its obligation to purchase capacity and/or energy
under this EPSA equal to the amount of capacity and/or energy to be sold by the
Agent. Marketing shall coordinate with the Agent with respect to the scheduling
and dispatch of Power consistent with the JDA.

2.       TERM

Supply and delivery of Power pursuant to the original EPSA began on the Transfer
Date established in the Asset Transfer Agreement dated May 1, 2000 between Genco
and AmerenCIPS. The term of the Amended EPSA shall commence on the effective
date approved by the Federal Energy Regulatory Commission ("FERC") and shall
remain in effect until terminated by either Party upon at least one year's
written notice to the other Party; but in no event shall the EPSA be terminated
prior to 12:00 P.M. CPT on December 31, 2004.

3.       DELIVERY POINTS

All Power supplied under this EPSA that is provided by generation sources
acquired by Genco from AmerenCIPS shall be deemed to be delivered at the bus bar
connecting each such generation source to the AmerenCIPS transmission system
("Delivery Point A"). All Power supplied under this EPSA that is provided by
other generation sources shall be deemed to be delivered at the generation bus
("Delivery Point B;" collectively with Delivery Point A, hereinafter referred to
as "Points of Delivery"). Energy supplied under this EPSA shall be sixty (60)
hertz, three (3) phase alternating current.

4.       TRANSMISSION

Genco shall be responsible for making all necessary arrangements for
transmission and delivery of Power to the Points of Delivery identified above,
and for any communication with any transmission provider relating to the
transmission and delivery of Power to such Points of Delivery, including
communications concerning scheduling, tagging, displacements, disputes, or other
operational issues. Marketing shall cooperate with Genco for the purpose of
attaining the necessary transmission service and for implementing the
transmission service required for supplying the Power to the Points of Delivery.

5.       METERING

The Parties recognize that certain meters used to measure the amount of energy
supplied by Genco are owned by AmerenCIPS. In order that the accuracy of
registration is maintained in

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accordance with good utility practice, Marketing will provide for such metering
equipment to be tested by AmerenCIPS at suitable intervals. At the request of
Genco, Marketing shall arrange for special tests to be performed, but if less
than two-percent inaccuracy is found, Genco shall pay for the test. The expense
of all other tests shall be borne by Marketing.

If requested to do so, Marketing shall arrange for representatives of Genco to
be present at all routine or special tests or whenever any readings for the
purposes of settlements are taken from meters not having an automatic record. If
any test of metering equipment discloses an inaccuracy exceeding two percent,
the accounts of the Parties shall be adjusted for the period, not exceeding 90
days, that such inaccuracy is estimated to have existed. Should any metering
equipment fail to register, the amounts of energy delivered and demands
established shall be estimated from the best available data. Meters shall be
adjusted as nearly as practicable to 100.0% at the time of any meter tests, and
Marketing shall furnish a copy of any meter test results when requested by
Genco.

6.       SYSTEM PLANNING

In order for Marketing to be able to plan adequately to market and sell all of
the Power available from Genco, Genco shall notify Marketing no later than
November 1 of each year of the amount of Power it expects to have available in
each month of the next calendar year. Marketing shall provide Genco with its
initial annual capacity and energy forecast on or before December 1 for the next
calendar year. Marketing shall notify Genco of its updated capacity and energy
forecast on or before April 1 for the current year.

7.       RECORDS

Marketing shall provide Genco with all records that may reasonably be requested
by Genco for the purpose of administering this EPSA. The Parties shall keep such
records as may be needed to afford a clear history of all transactions under
this Agreement. The originals of all such records shall be retained by each
party for a minimum of three years and copies shall be delivered to the other
Party upon request.

8.       PRICES

         A.    Charges For Capacity and/or Energy Supplied To Customer For Sales
Other Than Market Price Sales

         1.    Capacity Charges
               ----------------

Each calendar year, Company will be compensated at a rate of $69,708/MWyr
("Rate") for the quantity ("Quantity") of capacity supplied, which shall be
equal to the greater of: (1) Customer's highest hourly capacity forecasted for
that year, or (2) Customer's actual annual peak demand ("Peak Demand"); minus
the portion of the forecasted or actual peak demand, as applicable, represented
by Market Price Sales. For the purpose of this provision, Customer's forecasted
and actual peak demand shall be adjusted for losses to the extent necessary to
be determined at the Points of Delivery.

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For capacity supplied by Company during the year ending December 31, 2000, the
annual capacity charge shall be calculated by multiplying the Quantity by the
Rate, and then multiplying the result by a fraction, (the numerator of which is
the number of days beginning with the Transfer Date and ending with December 31,
2000, and the denominator of which is 366.

Customer shall pay Company monthly for one-twelfth of the applicable annual
capacity charges for each calendar year during the Term hereunder (or a pro rata
share of such annual capacity charges during the year ending December 31, 2000)
based on Customer's forecasted peak demand. Within 10 days after the close of
each calendar year, Company shall calculate the Customer's capacity charges on
the basis of Customer's actual annual peak demand. In the event that Customer's
actual annual peak demand for such year exceeded its forecasted peak demand for
such year, Customer shall pay Company for any additional capacity charges that
are due with respect to such year at the time of payment of its next monthly
bill.

         2.   Energy
              ------

In addition to the capacity charges specified above, Customer shall pay Company
an energy charge of $21.8l/MWh for all energy supplied by Company to the Points
of Delivery for sale other than as Market Price Sales.

         B.   Charges for Energy and/or Capacity Supplied to Customer for Market
              ------------------------------------------------------------------
Price Sales
-----------

In addition to the charges for energy and/or capacity supplied to Customer as
set forth above, Customer shall pay Company all amounts received by Customer for
capacity and energy sold as Market Price Sales. Within 15 days following the
close of each calendar month, Customer shall advise Company of the estimated
amount of capacity and energy sold as Market Price Sales for such month and the
average rate per Mwh at which such capacity and/or energy was sold. Payments for
all such capacity and energy supplied to Customer for Market Price Sales shall
be remitted by Customer to Company in the month following the month in which
Customer receives payment for such capacity and energy. Within 45 days following
the close of each calendar month, Customer shall advise Company of the actual
amounts of Market Price Sales for such month, and the subsequent payments from
Customer to Company shall be adjusted accordingly.

9.       REGULATION

The Parties recognize that this EPSA is subject to regulation by the FERC
pursuant to Part II of the Federal Power Act. If the FERC should require the
modification of this EPSA prior to its acceptance, the Parties shall, in good
faith, attempt to reach agreement on modifications that would be acceptable to
the FERC in a manner that retains the economic benefits intended to be derived
by each party under this EPSA.

10.      PAYMENT OF BILLS

A.       BILLING FOR SERVICE: Bills for Power supplied to Marketing for sales
         other than Market Price Sales will be based upon the Quantity of
         capacity and amount of energy supplied by Genco at the Points of
         Delivery as set forth above. Within 15 days after the close of each
         calendar month, the Genco will issue the bill to Marketing
         electronically (commonly referred to as "EDI") or other suitable means.
         If Genco is unable to obtain

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         meter information or final Market Price Sales data is unavailable, an
         estimated bill will be issued, computed on the basis of Marketing's
         previous use together with such other information as is available. Once
         all billing information is considered final, the estimated bill will be
         adjusted and any payment due difference will be reflected on the next
         scheduled billing.

B.       PAYMENT PERIODS: The last date for payment of the "net amount" shown on
         the bill for Power supplied to Marketing for sales other than Market
         Price Sales shall be seven days after the date the EDI bill is issued
         (hereinafter "Net Payment Period"). Payment of all amounts for all
         Power supplied to Marketing for Market Price Sales shall be due on the
         same date. In the event of a disputed bill Marketing shall pay the
         undisputed portion within the Net Payment Period. When the last day of
         any Net Payment Period falls on a day other than a business day of
         Genco, such period will be automatically extended to include the next
         following business day. Genco's non-business days shall include
         Saturdays, Sundays, and the following holidays: New Year's day.
         Lincoln's Birthday, Washington's Birthday, Martin Luther King's
         Birthday, Good Friday, Memorial Day, Independence Day, Labor Day,
         Columbus Day, Veteran's Day, Thanksgiving day, Friday following
         Thanksgiving day, Christmas Eve (the last day of regular work schedule
         prior to Christmas day), Christmas day and New Year's Eve (the last day
         of regular work schedule prior to New Year's day). Whenever a holiday
         falls on Sunday the following Monday will not be considered a business
         day. Whenever a holiday falls on a Saturday, the prior Friday will not
         be considered a business day.

C.       PAYMENT AND LATE PAYMENTS: Marketing shall make payment to Genco by
         wire transfer, or other acceptable means, within the Net Payment Period
         in immediately available U.S. funds. When a bill is paid after the last
         date for payment in the "net amount" shown on the bill a late payment
         charge equivalent to one and one half (1 1/2) percent will be assessed
         each month on the unpaid balance.

11.      GOOD UTILITY PRACTICE

Genco shall operate and maintain each of the electric generating units and
appurtenant facilities that are transferred to it by AmerenCIPS or that it
subsequently acquires in good working order in compliance with all requirements
of any governmental agency and in accordance with good utility practice. Insofar
as practicable, Genco shall advise Marketing of any significant change in its
ability to supply Power to Marketing.

12.      INDEMNIFICATION

Marketing shall indemnify and save harmless and defend Genco from and against
any and all claims, demands, damages, costs or expenses arising, growing out of
or resulting in any manner from implementation of this EPSA.

13.      FORCE MAJEURE

In the event of Force Majeure, Genco shall notify Marketing immediately by oral
communication, confirmed in writing, of such occurrence, reporting the
commencement time and date, estimated duration, and estimated magnitude of the
reduction in capacity and/or energy

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deliveries resulting from the Force Majeure situation. Genco shall not be liable
for the failure to deliver the full amount or any part of the capacity and
energy to be supplied pursuant to this EPSA for the duration of the Force
Majeure. For the purpose of this provision, "Force Majeure" means an event or
circumstances which prevents Genco from performing its obligations under this
EPSA, which is not within the reasonable control of Genco, and which, by
exercise of due diligence, Genco is unable to overcome or avoid or cause to be
avoided. Force Majeure includes, but is not restricted to, fires, strikes, labor
stoppages, epidemics, floods, earthquakes, lightning storms, ice, acts of God,
riots, civil disturbances, civil war, invasion, insurrection, military or
usurped power, war, sabotage, explosions, failure of equipment or of contractors
or suppliers of materials or fuel, inability to obtain or ship material, fuel or
equipment because of the effect of similar causes on suppliers or carriers, or
an action or restraint by court order or public or governmental authority (so
long as the Genco has not applied for or assisted in the application for such
court or governmental action). Force Majeure shall not include Genco's ability
to sell capacity and/or energy to another purchaser at a more advantageous price
than that contained in this EPSA. The settlement of strikes, walkouts, lockouts,
and other labor disputes shall be entirely within the discretion of Genco, and
Genco may make settlement at such time and on such terms and conditions as it
may deem to be advisable. Interruption by a transmission provider shall not be
deemed to be an event of Force Majeure unless (i) Genco shall have made
arrangements with such transmission provider for the firm transmission, as
defined under the transmission provider's Open Access Transmission Tariff, of
the energy and (ii) such interruption is due to "force majeure" or
"uncontrollable force" or a similar term as defined under the transmission
provider's Open Access Transmission Tariff, and (iii) no other path is available
and no other remedy is available.

14.      ASSIGNMENT

This EPSA shall inure to the benefit of, and be binding upon, the respective
successors and assigns of Marketing and Genco. No assignment of this EPSA shall
be made by a Party except to a wholly-owned subsidiary or successor to
substantially all of that Party's business who assumes possession and operates
substantially the same facilities and business as the assignor. Notwithstanding
the foregoing, either Party shall be free to assign this EPSA to any of its
subsidiaries or affiliates, without the written consent of the other Party. The
assignment by a Party shall not relieve the Party, without the written consent
of the other Party, of any obligation to provide, or to accept and pay for, as
the case may be, the services contracted for hereunder.

15.      NOTICES

All notices to be given under this EPSA shall be in writing via First Class U.S.
mail, FAX or e-mail and shall be deemed given when sent. Notices shall be
addressed as set forth below, or to such other address as the party to be
notified may designate from time to time.

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         Notice to Genco:

         R. Alan Kelley
         Senior Vice President
         Ameren Energy Generating Company
         One Ameren Plaza
         1901 Chouteau Avenue
         St. Louis, MO 63103

         Notice to Marketing:

         Andrew M. Sem
         Vice President, Marketing and Sales
         Ameren Energy Marketing Company
         400 S. Fourth Street
         St. Louis, MO 63102

16.      WRITTEN MODIFICATION

Nothing contained herein shall be construed as affecting in any way the right of
Genco to unilaterally make application to the FERC for a change in rates and
charges under Section 205 of the Federal Power Act and pursuant to the
Commission's Rules and Regulations promulgated thereunder. Except with respect
to rates and charges, this EPSA shall not be modified except in writing by
amendment, executed by both parties, making express reference to the EPSA and
the specific provisions hereof modified or amended.

17.      LIMITS OF LIABILITY

IN THE EVENT OF LITIGATION UNDER THIS EPSA, THE PREVAILING PARTY SHALL BE
ENTITLED TO COMPENSATION FOR ANY REASONABLE ATTORNEYS FEES AND OTHER COSTS THAT
MAY BE INCURRED. UNLESS EXPRESSLY HEREIN PROVIDED, NEITHER PARTY SHALL BE LIABLE
FOR ANY CONSEQUENTIAL, INCIDENTAL, PUNITIVE, EXEMPLARY OR INDIRECT DAMAGES, LOST
PROFITS OR OTHER BUSINESS INTERRUPTION DAMAGES, BY STATUTE, IN TORT OR CONTRACT,
UNDER ANY INDEMNITY PROVISION OR OTHERWISE. IT IS THE INTENT OF THE PARTIES THAT
THE LIMITATIONS HEREIN IMPOSED ON REMEDIES AND THE MEASURE OF DAMAGES BE WITHOUT
REGARD TO THE CAUSE OR CAUSES RELATED THERETO, INCLUDING THE NEGLIGENCE OF ANY
PARTY, WHETHER SUCH NEGLIGENCE BE SOLE, JOINT OR CONCURRENT, OR ACTIVE OR
PASSIVE.

18.      DUTY TO MITIGATE

Each Party agrees that it has a duty to mitigate damages and covenants that it
will use commercially reasonable efforts to minimize any damages it may incur as
a result of the other Party's performance or non-performance of this EPSA.

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19.      WAIVERS

Any waiver at any time by either Genco or Marketing of its rights with respect
to a default under this EPSA or with respect to any other matter arising in
connection with this EPSA shall not be deemed a waiver with respect to any
subsequent default or matter. Any delay, short of the statutory period of
limitation, in asserting or enforcing any right under this EPSA shall not be
deemed a waiver of such right.

20.      ENTIRE AGREEMENT

This EPSA contains the entire agreement between the Parties in respect to the
subject matter contained herein, and there are no other understandings or
agreements between Genco and Marketing in respect thereof.

21.      WARRANTIES

The warranties expressly set forth in this EPSA are the sole warranties given by
either Party to the other Party in connection with the sale and purchase of
Power hereunder. EXCEPT AS SET FORTH HEREIN, GENCO EXPRESSLY NEGATES ANY OTHER
REPRESENTATION OR WARRANTY, WRITTEN OR ORAL, EXPRESSED OR IMPLIED, INCLUDING,
WITHOUT LIMITATION, ANY REPRESENTATION OR WARRANTY WITH RESPECT TO CONFORMITY TO
MODELS OR EXAMPLES, OR MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE.

22.      LIMITATION

This EPSA is not intended to and shall not create rights of any character
whatsoever in favor of any person, corporation, association, or entity other
than the parties to this EPSA, and the obligations herein assumed are solely for
the use and benefit of the parties to this EPSA, their successors in interest,
or assigns.

23.      SURVIVORSHIP OF OBLIGATIONS

The termination of this EPSA shall not discharge any Party from any obligation
it owed to the other Party under the EPSA by reason of any transaction, loss,
cost, damage, expense or liability which shall occur or arise prior to such
termination. It is the intent of the Parties that any such obligation owed
(whether the same shall be known or unknown as of the termination of this EPSA)
shall survive the termination of this EPSA. The Parties also intend that the
indemnification and limitation of liability provisions contained in this EPSA
shall remain operative and in full force and effect, regardless of any
termination of this EPSA, except with respect to actions or events occurring or
arising after such termination is effective.

24.      GOVERNING LAW

The interpretation and performance of this EPSA shall be in accordance with and
controlled by the laws of the State of Illinois (including any applicable orders
and regulations issued by the ICC), except as to matters governed by federal
statute.

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<PAGE>

25.      SAVINGS CLAUSE

The provisions of this EPSA shall be interpreted where possible in a manner to
sustain their legality and enforcement. If at any time a provision of this EPSA
is found to be unenforceable, such provision shall be removed and the rest of
this EPSA shall remain intact and in effect as if the removed provision was
never contained therein.

26.      RESOLUTION OF DISPUTES

If a question or controversy arises between the Parties concerning the
observance or performance of any of the terms, provisions or conditions
contained herein or the rights or obligations of either Party under this EPSA,
such question or controversy shall in the first instance be the subject of a
meeting between the Parties to negotiate a resolution of such dispute. Such
meeting shall be held within fifteen (15) days of a request by either Party. If
within fifteen (15) days after that meeting, the Parties have not negotiated a
resolution or mutually extended the period of negotiation, either Party may seek
resolution of the question or controversy by arbitration, subject, however, to
any prohibition thereto by any governmental law or regulation.

The Party calling for arbitration ("Initiating Party") shall give written notice
to the other Party setting forth (a) a short and plain statement of the issue(s)
to be arbitrated; (b) a short and plain statement of the claim showing that the
Initiating Party is entitled to relief; and (c) a statement of the relief to
which the Initiating Party claims to be entitled. Such written notice including
sections (a), (b) and (c) defined above shall not exceed a document length of 20
pages, double spaced utilizing a font of 12. Within twenty (20) days from the
date of receipt of such notice, the other Party ("Receiving Party") may submit
its written response and give notice in the same manner required above of
additional issues to be arbitrated. The Initiating Party shall have twenty (20)
days to respond to any issues submitted for arbitration by the Receiving Party.

Within thirty (30) days of the date of the Initiating Party's written notice
requesting arbitration, each party shall designate a competent and disinterested
person to act as that party's designated arbitrator, with the two (2) persons
designated selecting a third neutral arbitrator within twenty (20) days of their
designation. In the event the first two (2) arbitrators cannot agree on a
mutually acceptable third arbitrator, they shall apply to the American
Arbitration Association ("AAA") to appoint the third arbitrator. The arbitration
shall be conducted pursuant to the Federal Rules of Civil Procedure, the Federal
Rules of Evidence, and the Commercial Arbitration Rules of the AAA.

Any decision and award of the majority of arbitrators shall be binding upon both
parties. The arbitrators shall not award any indirect, special, incidental or
consequential damages against either party. Judgment upon the award rendered may
be entered in any court of competent jurisdiction.

27.      HEADINGS

The descriptive headings of the sections of this EPSA have been inserted for
convenience of reference only and shall not modify or restrict any of the terms
and provisions thereof.

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<PAGE>

IN WITNESS WHEREOF, the Parties hereto have caused this Amended EPSA to be
executed in duplicate, by its authorized officers, day and year first above
written.

AMEREN ENERGY                                   AMEREN ENERGY
MARKETING COMPANY                               GENERATING COMPANY

By:  /s/ James F. Whitsides                     By:  /s/ Gary L. Rainwater
    ------------------------------------            ----------------------------
     (Officer Signature)                             (Officer Signature)

     James F. Whitsides                              Gary L. Rainwater
    ------------------------------------            ----------------------------
     (Printed Name)                                  (Printed Name)

     President                                       President
    ------------------------------------            ----------------------------
     (Title)                                         (Title)

                                      -10-<PAGE>

                                                                    EXHIBIT 10.3

                        ELECTRIC POWER SUPPLY AGREEMENT

                    Between Ameren Energy Marketing Company

                                      And

                    Central Illinois Public Service Company

THIS ELECTRIC POWER SUPPLY AGREEMENT (hereinafter "EPSA") made as of this 1st
day of May, 2000, by and between AMEREN ENERGY MARKETING COMPANY, (hereinafter
"Company") and CENTRAL ILLINOIS PUBLIC SERVICE COMPANY, d.b.a. AmerenCIPS
(hereinafter "Customer")  (Company and Customer may be identified collectively
as "Parties" or individually as a "Party") is for the supply by Company of all
electric power and energy needed to meet the Customer's full requirements for
electric power and energy.

WHEREAS, Company is engaged in the business of purchasing and reselling electric
power and energy; and

WHEREAS, Customer, which is a vertically-integrated electric public utility in
Illinois, is restructuring its operations in response to and in accordance with
the Illinois Electric Service Customer Choice and Rate Relief Law of 1997 (the
"Customer Choice Law") by transferring all of its existing generating facilities
to a newly-formed generation-company affiliate ("Ameren Energy Generating
Company" or "Genco"); and

WHEREAS, Company intends to enter into an agreement to purchase from Genco all
of the capacity and energy available from the generating units that are
transferred by Customer to Genco and any additional generating units that may be
acquired by Genco in the future; and

WHEREAS, Customer is required by the Customer Choice Law to continue to offer
bundled retail electric service within its existing retail electric service area
in Illinois at rates specified by the Illinois Commerce Commission ("ICC")
through December 31, 2004; and

WHEREAS, Customer may continue to make bundled sales of electricity to existing
wholesale electric service customers; and

WHEREAS, Customer is also obligated by the Customer Choice Law to offer retail
electric service to customers in Illinois under unbundled, market-priced tariffs
on file with the ICC and may also sell power to others at market-based rates
("Market Price Sales") through December 31, 2004; and

WHEREAS, Customer desires to acquire from Company all the electric power and
energy that is needed to enable it to provide electric service after the
transfer of its generating units; and

WHEREAS, Company is capable of supplying all such power and energy to Customer
and desires to do so pursuant to the rates, terms and conditions set forth
herein;

NOW THEREFORE, in consideration for the agreements and undertakings established
herein and the mutual benefits derived therefrom, it is agreed as follows:

1.  FIRM ELECTRIC POWER AND ENERGY SERVICE

Company will supply and deliver to Customer all of the firm electric capacity
and energy (hereinafter  "Energy") needed by Customer to serve its native load,
to operate its transmission and distribution system and to provide transmission
and distribution services, to fulfill its obligations under all applicable
federal and state tariffs or contracts, to satisfy regional reliability
requirements, and for any other purpose related to the provision of wholesale or
retail electric service and Customer shall purchase and pay for such Energy in
accordance with the terms of this Agreement.

2.  TERM

Subject to acceptance of this EPSA by the Federal Energy Regulatory Commission
("FERC"), supply and delivery of Energy pursuant to the EPSA shall begin on the
Transfer Date established in the "Asset Transfer Agreement" dated May 1, 2000
between Customer and Genco and terminate at 12:00 P.M. CPT on December 31, 2004.

3.  DELIVERY POINTS

All Energy supplied under this EPSA that is provided by generation sources
acquired by Genco from Customer shall be deemed to be delivered at the bus bar
connecting each such generation source to the Customer's transmission system.
All Energy supplied under this EPSA that is provided by other generation sources
shall be deemed to be delivered at the point of interconnection between
Customer's transmission system and the transmission system over which the Energy
is being delivered.  Energy supplied under this EPSA shall be sixty (60) hertz,
three (3) phase alternating current.

4.  TRANSMISSION

Transmission of Energy to Customer shall be firm transmission as such is defined
in the transmission provider's Open Access Transmission
<PAGE>

Tariff. Company shall be responsible for making all necessary transmission
arrangements for transmission of Energy to the Points of Delivery identified
above from sources not directly interconnected to the Ameren transmission
system, and for any communication with any transmission provider relating to the
transmission and delivery of Energy to Customer, including communications
concerning scheduling, tagging, displacements, disputes, or other operational
issues. Customer shall cooperate with Company for the purpose of attaining the
necessary firm transmission service and for implementing the transmission
service required for supplying the Energy to the Points of Delivery.

5.  METERING

The Parties recognize that certain meters used to measure the amount of Energy
received by Customer are owned by Customer.  In order that the accuracy of
registration is maintained in accordance with good utility practice, metering
equipment shall be tested by Customer at suitable intervals.  At the request of
Company, special tests shall be performed, but if less than two percent
inaccuracy is found, Company shall pay for the test.  The expense of all other
tests shall be borne by Customer.

Representatives of each Party may be present at all routine or special tests or
whenever any readings for the purposes of settlements are taken from meters not
having an automatic record.  If any test of metering equipment discloses an
inaccuracy exceeding two percent, the accounts of the Parties shall be adjusted
for the period, not exceeding 90 days, that such inaccuracy is estimated to have
existed.  Should any metering equipment fail to register, the amounts of Energy
delivered and demands established shall be estimated from the best available
data.  Meters shall be adjusted as nearly as practicable to 100.0% at the time
of any meter tests, and Customer shall furnish a copy of any meter test results
when requested by Company.

6.  SYSTEM PLANNING

In order for Company to plan adequately for Customer's Energy requirements,
Customer shall notify Company no later than November 1 of each year of its
annual load plan for the next calendar year during the Term.  Such annual load
plan shall be consistent with the forecasted peak demand reported to the Mid-
American Interconnected Network ("MAIN") for such year.  Customer shall also
provide to Company an update to its annual load plan on or before March 1 of
each year during the Term.

7.  RECORDS

Customer shall provide Company with all records that may reasonably be requested
by Company for the purpose of administering this EPSA.  The Parties shall keep
such records as may be needed to afford a clear history of all transactions
under this Agreement.  The originals of all such records shall be retained by
each party for a minimum of three years and copies shall be delivered to the
other Party upon request.

8.  PRICES

    A.  Charges For Energy Supplied To Customer For Sales Other Than Market
        -------------------------------------------------------------------
        Price Sales
        -----------

    1.  Capacity Charges
        ----------------

Each calendar year, Company will be entitled to be compensated at a rate of
$69,708/MW/Yr. for the quantity ("Quantity") of capacity supplied, which shall
be equal to the greater of:  (1) Customer's forecasted peak demand reported to
MAIN for that year, or (2) Customer's actual annual peak demand ("Peak Demand");
minus the portion of the forecasted or actual peak demand, as applicable,
represented by Market Price Sales.  For the purpose of this provision,
Customer's forecasted peak demand and actual annual peak demand shall be
adjusted for losses to the extent necessary to be determined at the Points of
Delivery.

For capacity supplied by Company during the year ending December 31, 2000, the
annual capacity charge shall be calculated by multiplying the Quantity by the
Rate, and then multiplying the result by a fraction, the numerator of which is
the number of days beginning with the Transfer Date and ending with December 31,
2000, and the denominator of which is 365.

Customer shall pay Company monthly for one-twelfth of the applicable annual
capacity charges for each calendar year during the Term (or a pro rata share of
such annual capacity charges during the year ending December 31, 2000) based on
Customer's forecasted peak demand for such year as reported to MAIN.  Within 10
days after the close of each calendar year, Company shall calculate the
Customer's capacity charges on the basis of Customer's actual annual peak
demand.  In the event that Customer's actual annual peak demand for such year
exceeded its forecasted peak demand that had been reported to MAIN for such
year, Customer shall pay Company for any additional capacity charges that are
due with respect to such year at the time of payment of its next monthly bill.

    2.  Energy Charges
        --------------

In addition to the capacity charges specified above, Customer shall pay Company
an energy charge of $21.81/Mwh for all energy supplied by Company to the Points
of Delivery for sale other than as Market Price Sales.

    B.  Charges For Energy Supplied To Customer For Market Price Sales
        --------------------------------------------------------------

In addition to the charges for Energy supplied to Customer as set forth above,
Customer shall pay Company an amount equal to the amount Customer receives from
retail customers for power and energy sold as Market Price Sales.  Within 15
days following the close of each calendar month, Customer shall advise Company
of the estimated amount of power and energy sold as Market Price Sales for such
month and the average rate per Mwh at which such power and energy was sold.
Payments for all Energy supplied to Customer for Market Price Sales shall be
remitted by Customer to Company in the month following the month in which
Customer receives payment for such Energy.  Within 45 days following the close
of each calendar month, Customer shall advise Company of the actual amounts of
Market Price Sales for such month, and the subsequent payments from Customer to
Company shall be adjusted accordingly.

                                       2
<PAGE>

9.   REGULATION

The parties recognize that this EPSA is subject to regulation by the FERC
pursuant to Part II of the Federal Power Act.  If the FERC should require the
modification of this EPSA prior to its acceptance, the parties shall, in good
faith, attempt to reach agreement on modifications that would be acceptable to
the FERC in a manner that retains the economic benefits intended to be derived
by each party under this EPSA.

10.  ACCESS

Customer shall provide, at no cost to Company, a suitable place (including means
of support) on and access to Customer's property for Company to install,
maintain, operate, repair, replace, and remove all equipment and facilities
necessary for Company to perform its obligations under this EPSA.  Customer
shall use reasonable diligence to protect all of Company's equipment located on
Customer's property.

11.  PAYMENT OF BILLS

A. BILLING FOR SERVICE: Bills for Energy supplied to Customer for sales other
   than Market Price Sales will be based upon the Quantity of capacity and
   amount of energy supplied by Company at the Points of Delivery. Within 15
   days after the close of each calendar month, the Company will issue the bill
   to Customer electronically (commonly referred to as "EDI"), or other suitable
   means. If the Company is unable to obtain meter information or final Market
   Price Sales data is unavailable, an estimated bill will be issued, computed
   on the basis of Customer's previous use together with such other information
   as is available. Once all billing information is considered final, the
   estimated bill will be adjusted and any payment due difference will be
   reflected on the next scheduled billing.

B. PAYMENT PERIODS: The last date for payment of the "net amount" shown on the
   bill for Energy supplied to Customer for sales other than Market Price Sales
   shall be seven days after the date the bill is issued (hereinafter "Net
   Payment Period"). Payment of all amounts for all Energy supplied to Customer
   for Market Price Sales shall be due on the same date. In the event of a
   disputed bill Customer shall pay the undisputed portion within the Net
   Payment Period. When the last day of any Net Payment Period falls on a day
   other than a business day of Company, such period will be automatically
   extended to include the next following business day. Other than a business
   day of Company shall include Saturdays, Sundays, and the following holidays:
   New Year's day, Lincoln's Birthday, Washington's Birthday, Martin Luther
   King's Birthday, Good Friday, Memorial Day, Independence Day, Labor Day,
   Columbus Day, Veteran's Day, Thanksgiving day, Friday following Thanksgiving
   day, Christmas Eve (the last day of regular work schedule prior to Christmas
   day), Christmas day and New Year's Eve (the last day of regular work schedule
   prior to New Year's day). Whenever a holiday falls on Sunday the following
   Monday will not be considered a business day. Whenever a holiday falls on a
   Saturday, the prior Friday will not be considered a business day.

C. PAYMENT AND LATE PAYMENTS: Customer shall make payment to Company by wire
   transfer, or other acceptable means, within the Net Payment Period in
   immediately available U.S. funds. When a bill is paid after the last date for
   payment in the "net amount" shown on the bill a late payment charge
   equivalent to one and one half (1 1/2) percent will be assessed each month on
   the unpaid balance.

12.  INDEMNIFICATION

Customer shall indemnify and save harmless and defend Company from and against
any and all claims, demands, damages, costs or expenses arising, growing out of
or resulting in any manner after delivery of Energy to Customer or from improper
or negligent construction, installation, insulation, maintenance or operation of
Customer's lines and appurtenances.

13.  FORCE MAJEURE

In the event of Force Majeure, Company shall notify Customer immediately by oral
communication, confirmed in writing, of such occurrence, reporting the
commencement time and date, estimated duration, and estimated magnitude of the
reduction in Energy deliveries resulting from the Force Majeure situation.
Company shall not be liable for the failure to deliver Energy the full amount or
any part of the Energy to be supplied pursuant to this EPSA for the duration of
the Force Majeure. For the purpose of this provision, "Force Majeure" means an
event or circumstances which prevents Company from performing its obligations
under this EPSA, which is not within the reasonable control of the Company, and
which, by exercise of due diligence, the Company is unable to overcome or avoid
or cause to be avoided.  Force Majeure includes, but is not restricted to,
fires, strikes, labor stoppages, epidemics, floods, earthquakes, lightening
storms, ice, acts of God, riots, civil disturbances, civil war, invasion,
insurrection, military or usurped power, war, sabotage, explosions, failure of
equipment or of contractors or suppliers of materials or fuel, inability to
obtain or ship material, fuel or equipment because of the effect of similar
causes on suppliers or carriers, or an action or restraint by court order or
public or governmental authority (so long as the Company has not applied for or
assisted in the application for such court or governmental action).  Force
Majeure shall not include Company's ability to sell Energy to another purchaser
at a more advantageous price than that contained in this EPSA.  The settlement
of strikes, walkouts, lockouts, and other labor disputes shall be entirely
within the discretion of the Company, and Company may make settlement at such
time and on such terms and conditions as it may deem to be advisable.
Interruption by a transmission provider shall not be deemed to be an event of
Force Majeure unless (i) Company shall have made arrangements with such
transmission provider for the firm transmission, as defined under the
transmission provider's Open Access Transmission Tariff, of the Energy and (ii)
such interruption is due to "force majeure" or "uncontrollable force" or a
similar term as defined under the transmission provider's Open Access
Transmission Tariff, and (iii) no other path is available and no other remedy is
available.

14.  ASSIGNMENT

This EPSA shall inure to the benefit of, and be binding upon, the respective
successors and assigns of Customer and Company.  No assignment of this EPSA
shall be made by a Party except to a wholly owned subsidiary or successor to
substantially all of that Party's business who assumes possession and operates
substantially the same facilities and business as the assignor.
Notwithstanding the foregoing, either Party shall be free to assign this EPSA to
any of its subsidiaries or affiliates, without the written consent of the other
Party.  The assignment by a Party shall not relieve the Party, without the
written consent of the other Party, of any obligation to provide, or to accept
and pay for, as the case may be, the services contracted for hereunder.

                                       3
<PAGE>

15.  NOTICES

All notices to be given under this EPSA shall be in writing via First Class U.S.
mail, FAX or e-mail and shall be deemed given when sent.  Notices shall be
addressed as set forth below, or to such other address as the party to be
notified may designate from time to time.

     Notice to Company:
     Jim Whitesides
     President
     Ameren Energy Marketing Company
     400 S. Fourth Street
     St. Louis, MO 63102

     Notice to Customer:

     Gary L. Rainwater
     President
     AmerenCIPS
     One Ameren Plaza
     1901 Chouteau Avenue
     St. Louis, MO 63103

16.  WRITTEN MODIFICATION

The rates for service specified herein shall remain in effect for all Energy
supplied by Company through December 31, 2004, and shall not be subject to
change through application to the FERC pursuant to the provisions of Section 205
of the Federal Power Act prior to that time absent the agreement of the Parties.
This EPSA shall not be modified except in writing by amendment, executed by both
parties, making express reference to the EPSA and the specific provisions hereof
modified or amended.

17.  LIMITS OF LIABILITY

IN THE EVENT OF LITIGATION UNDER THIS EPSA, THE PREVAILING PARTY SHALL BE
ENTITLED TO COMPENSATION FOR ANY REASONABLE ATTORNEYS FEES AND OTHER COSTS THAT
MAY BE INCURRED.  UNLESS EXPRESSLY HEREIN PROVIDED, NEITHER PARTY SHALL BE
LIABLE FOR ANY CONSEQUENTIAL, INCIDENTAL, PUNITIVE, EXEMPLARY OR INDIRECT
DAMAGES, LOST PROFITS OR OTHER BUSINESS INTERRUPTION DAMAGES, BY STATUTE, IN
TORT OR CONTRACT, UNDER ANY INDEMNITY PROVISION OR OTHERWISE.  IT IS THE INTENT
OF THE PARTIES THAT THE LIMITATIONS HEREIN IMPOSED ON REMEDIES AND THE MEASURE
OF DAMAGES BE WITHOUT REGARD TO THE CAUSE OR CAUSES RELATED THERETO, INCLUDING
THE NEGLIGENCE OF ANY PARTY, WHETHER SUCH NEGLIGENCE BE SOLE, JOINT OR
CONCURRENT, OR ACTIVE OR PASSIVE.

18.  DUTY TO MITIGATE

Each Party agrees that it has a duty to mitigate damages and covenants that it
will use commercially reasonable efforts to minimize any damages it may incur as
a result of the other Party's performance or non-performance of this EPSA.

19.  WAIVERS

Any waiver at any time by either Company or Customer of its rights with respect
to a default under this EPSA or with respect to any other matter arising in
connection with this EPSA shall not be deemed a waiver with respect to any
subsequent default or matter.  Any delay, short of the statutory period of
limitation, in asserting or enforcing any right under this EPSA shall not be
deemed a waiver of such right.

20.  ENTIRE AGREEMENT

This EPSA contains the entire agreement between the Parties in respect to the
subject matter contained herein, and there are no other understandings or
agreements between Company and Customer in respect thereof.

21.  WARRANTIES

The warranties expressly set forth in this EPSA are the sole warranties given by
either Party to the other Party in connection with the sale and purchase of
Energy hereunder.  EXCEPT AS SET FORTH HEREIN, COMPANY EXPRESSLY NEGATES ANY
OTHER REPRESENTATION OR WARRANTY, WRITTEN OR ORAL, EXPRESSED OR IMPLIED,
INCLUDING, WITHOUT LIMITATION, ANY REPRESENTATION OR WARRANTY WITH RESPECT TO
CONFORMITY TO MODELS OR EXAMPLES, OR MERCHANTABILITY OR FITNESS FOR ANY
PARTICULAR PURPOSE.

22.  LIMITATION

                                       4
<PAGE>

This EPSA is not intended to and shall not create rights of any character
whatsoever in favor of any person, corporation, association, or entity other
than the parties to this EPSA, and the obligations herein assumed are solely for
the use and benefit of the parties to this EPSA, their successors in interest,
or assigns.

23.  SURVIVORSHIP OF OBLIGATIONS

The termination of this EPSA shall not discharge any Party from any obligation
it owed to the other Party under the EPSA by reason of any transaction, loss,
cost, damage, expense or liability which shall occur or arise prior to such
termination.  It is the intent of the Parties that any such obligation owed
(whether the same shall be known or unknown as of the termination of this EPSA)
shall survive the termination of this EPSA.  The Parties also intend that the
indemnification and limitation of liability provisions contained in this EPSA
shall remain operative and in full force and effect, regardless of any
termination of this EPSA, except with respect to actions or events occurring or
arising after such termination is effective.

24.  GOVERNING LAW

The interpretation and performance of this EPSA shall be in accordance with and
controlled by the laws of the State of Illinois (including any applicable orders
and regulations issued by the ICC), except as to matters governed by federal
statute.

25.  SAVING CLAUSE

The provisions of this EPSA shall be interpreted where possible in a manner to
sustain their legality and enforcement.  If at any time a provision of this EPSA
is found to be unenforceable, such provision shall be removed and the rest of
this EPSA shall remain intact and in effect as if the removed provision was
never contained therein.

26.  RESOLUTION OF DISPUTES

If a question or controversy arises between the Parties concerning the
observance or performance of any of the terms, provisions or conditions
contained herein or the rights or obligations of either Party under this EPSA,
such question or controversy shall in the first instance be the subject of a
meeting between the Parties to negotiate a resolution of such dispute.  Such
meeting shall be held within fifteen (15) days of a request by either Party.  If
within fifteen (15) days after that meeting, the Parties have not negotiated a
resolution or mutually extended the period of negotiation, either Party may seek
resolution of the question or controversy by arbitration, subject, however, to
any prohibition thereto by any governmental law or regulation.

The Party calling for arbitration ("Initiating Party") shall give written notice
to the other Party setting forth (a) a short and plain statement of the issue(s)
to be arbitrated; (b) a short and plain statement of the claim showing that the
Initiating Party is entitled to relief; and (c) a statement of the relief to
which the Initiating Party claims to be entitled.  Such written notice including
sections (a), (b) and (c) defined above shall not exceed a document length of 20
pages, double spaced utilizing a font of 12.  Within twenty (20) days from the
date of receipt of such notice, the other Party ("Receiving Party") may submit
its written response and give notice in the same manner required above of
additional issues to be arbitrated.  The Initiating Party shall have twenty (20)
days to respond to any issues submitted for arbitration by the Receiving Party.

Within thirty (30) days of the date of the Initiating Party's written notice
requesting arbitration, each party shall designate a competent and disinterested
person to act as that party's designated arbitrator, with the two (2) persons
designated selecting a third neutral arbitrator within twenty (20) days of their
designation.  In the event the first two- (2) arbitrators cannot agree on a
mutually acceptable third arbitrator, they shall apply to the American
Arbitration Association ("AAA") to appoint the third arbitrator.  The
arbitration shall be conducted pursuant to the Federal Rules of Civil Procedure,
the Federal Rules of Evidence, and the Commercial Arbitration Rules of the AAA.

Any decision and award of the majority of arbitrators shall be binding upon both
parties.  The arbitrators shall not award any indirect, special, incidental or
consequential damages against either party.  Judgment upon the award rendered
may be entered in any court of competent jurisdiction.

27.  HEADINGS

The descriptive headings of the sections of this EPSA have been inserted for
convenience of reference only and shall not modify or restrict any of the terms
and provisions thereof.

IN WITNESS WHEREOF, the Parties hereto have caused this EPSA to be executed in
duplicate, by its authorized officers, day and year first above written.

AMEREN ENERGY MARKETING COMPANY          CENTRAL ILLINOIS PUBLIC SERVICE COMPANY

By /s/ James H. Whitesides               By /s/ Gary L. Rainwater
   ------------------------------------     ------------------------------------
(Company Officer Signature)              (Customer Officer Signature)

                                       5
<PAGE>

  James H. Whitesides                      Gary L. Rainwater
---------------------------------------  ---------------------------------------
(Printed Name)                           (Printed Name)

  President                                President
---------------------------------------  ---------------------------------------
(Title)                                  (Title)

                                       6

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