<PAGE>

                                                                    Exhibit 4(h)

                      INTEREST CALCULATION AGENCY AGREEMENT

          THIS AGREEMENT dated as of _______________ between
          Constellation Energy Group, Inc. (hereinafter called the
          "Issuer"), having its principal office at 750 E. Pratt
          Street, Baltimore, Maryland 21202, and The Bank of New York,
          a New York banking corporation (hereinafter sometimes called
          the "Calculation Agent or Paying Agent" which terms shall,
          unless the context shall otherwise require, include its
          successors and assigns), having its principal corporate
          trust office at 101 Barclay Street, Floor 21 West, New York,
          New York 10286 Attn: Corporate Trust Administration.

                             Recitals of the Issuer

          The Issuer proposes to issue _______________________________ (the
"Notes") under an indenture dated as of March 24, 1999 (the "Indenture"),
between the Issuer and The Bank of New York (the "Trustee"), as Trustee as
supplemented by a Supplemental Indenture dated as of January 24, 2003.
Capitalized terms used in this Agreement and not otherwise defined herein are
used as defined in the Indenture. The Notes will bear interest at a floating
rate determined by reference to an interest rate formula and the Issuer desires
to engage the

<PAGE>

Calculation Agent to perform certain services in connection therewith.

          NOW IT IS HEREBY AGREED THAT:

          1.   The Issuer hereby appoints The Bank of New York as Calculation
Agent for the Notes, upon the terms and subject to the conditions herein
mentioned, and The Bank of New York hereby accepts such appointment. The
Calculation Agent shall act as an agent of the Issuer for the purpose of
determining the interest rate or rates of the Notes.

          2.   The Issuer agrees to deliver to the Calculation Agent, prior to
the issuance of the Notes, copies of the proposed forms of such Notes, including
copies of all terms and conditions relating to the determination of the interest
rate thereunder. The Issuer shall not issue the Notes prior to the receipt of
confirmation from the Calculation Agent of its acceptance of the proposed form
of such Note. The Calculation Agent hereby acknowledges its acceptance of the
proposed form of Note previously delivered to it.

          3.   The Calculation Agent shall calculate the applicable interest
rates for Notes in accordance with the terms of such Notes, the Indenture and
the provisions of this Agreement.

                                        2

<PAGE>

          4.   Promptly following the determination of each change to the
interest rate applicable to the Notes, the Calculation Agent will cause to be
forwarded to the Issuer, the Trustee and the principal Paying Agent information
regarding the interest rate then in effect for the Notes.

          5.   The Issuer will pay such compensation as shall be agreed upon
with the Calculation Agent and the expenses, including reasonable counsel fees
and expenses, incurred by the Calculation Agent in connection with its duties
hereunder, upon receipt of such invoices as the Issuer shall reasonably require.

          6.   Notwithstanding any satisfaction or discharge of the Notes or the
Indenture, the Issuer will indemnify the Calculation Agent against any losses,
liabilities, costs, claims, actions or demands which it may incur or sustain or
which may be made against it in connection with its appointment or the exercise
of its powers and duties hereunder as well as the reasonable costs, including
the expenses and fees of counsel in defending any claim, action or demand,
except such as may result from the negligence or willful misconduct of the
Calculation Agent or any of its employees. The Calculation Agent shall incur no
liability and shall be indemnified and held harmless by the Issuer for, or in
respect of, any actions taken or suffered to be taken in good faith by the
Calculation Agent in reliance upon written instructions from the Issuer. In case
any action is brought against the Calculation Agent with respect to which the

                                        3

<PAGE>

Calculation Agent intends to seek indemnification from the Issuer pursuant to
this paragraph 6, the Calculation Agent will notify the Issuer in writing of the
commencement thereof, and the Issuer will be entitled to participate therein and
to assume the defense thereof, with counsel satisfactory to the Calculation
Agent; provided, however, that if the defendants in any such action include both
the Issuer and the Calculation Agent and the Calculation Agent shall have
reasonably concluded, after consultation with legal counsel of its choosing,
that there may be legal defenses available to it which are different from or
additional to those available to the Issuer, the Calculation Agent shall have
the right to select separate counsel to assert such legal defenses and otherwise
to participate in the defense of such action on behalf of the Calculation Agent,
and in such event the Issuer will indemnify the Calculation Agent against the
reasonable compensation and expenses and disbursements of such separate counsel.

          7.   The Calculation Agent may consult with counsel of its own
selection (and notify the Issuer of such consultation) and the advice of such
counsel or any opinion of counsel shall be full and complete authorization and
protection in respect of any action taken, suffered or omitted by it hereunder
in good faith and in reliance thereon.

                                        4

<PAGE>

          8.   The Calculation Agent accepts its obligations herein set forth
upon the terms and conditions hereof, including the following, to all of which
the Issuer agrees:

               (i)   in acting under this Agreement and in connection with the
          Notes, the Calculation Agent, acting as agent for the Issuer, does not
          assume any obligation towards, or any relationship of agency or trust
          for or with, any of the Holders of the Notes;

               (ii)  unless herein otherwise specifically provided, any order,
          certificate, notice, request or communication from the Issuer made or
          given under any provision of this Agreement shall be sufficient if
          signed by any person whom the Calculation Agent reasonably believes to
          be a duly authorized officer or attorney-in-fact of the Issuer;

               (iii) the Calculation Agent shall be obligated to perform only
          such duties as are set forth specifically herein and any duties
          necessarily incidental thereto;

               (iv)  the Calculation Agent shall be protected and shall incur
          no liability for or in respect of any action taken or omitted to be
          taken or anything suffered in good faith by it in reliance upon
          anything contained in the Notes, the Indenture or any information
          supplied to it by the Issuer pursuant to this Agreement, including the
          information to be supplied pursuant to paragraph 3 above;

                                        5

<PAGE>

               (v)   the Calculation Agent, whether acting for itself or in
          any other capacity, may become the owner or pledgee of Notes with the
          same rights as it would have had if it were not acting hereunder as
          Calculation Agent; and

               (vi)  the Calculation Agent shall incur no liability hereunder
          except for loss sustained by reason of its negligence or willful
          misconduct or bad faith.

          9.   (a)   The Calculation Agent shall not be responsible to the
Issuer or any third party for any failure of banks or other financial
institutions (the "Reference Banks") that are quoting rates to fulfill their
duties or meet their obligations as Reference Banks or as a result of the
Calculation Agent having acted (except in the event of negligence or willful
misconduct) on any quotation or other information given by any Reference Bank
which subsequently may be found to be incorrect.

               (b)   Except as provided below, the Calculation Agent may at any
time resign as Calculation Agent by giving written notice to the Issuer and the
Trustee of such intention on its part, specifying the date on which its desired
resignation shall become effective, provided that such notice shall be given not
less than 60 days prior to the said effective date unless the Issuer and the
Trustee otherwise agree in writing. Except as provided below, the Calculation
Agent may be removed by the filing with it and the Trustee of an instrument in
writing signed by the Issuer specifying such removal and the date when it shall

                                        6

<PAGE>

become effective (such effective date being at least 15 days after said filing).
Any such resignation or removal shall take effect upon:

               (i)   the appointment by the Issuer as hereinafter provided of
          a successor Calculation Agent; and

               (ii)  the acceptance of such appointment by such successor
          Calculation Agent;

provided, however, that in the event the Calculation Agent has given not less
than 60 days' prior notice of its desired resignation, and during such 60 days
there has not been acceptance by a successor Calculation Agent of its
appointment as successor Calculation Agent, the Calculation Agent so resigning
may petition any court of competent jurisdiction for the appointment of a
successor Calculation Agent. The Issuer covenants that it shall appoint a
successor Calculation Agent as soon as practicable after receipt of any notice
of resignation hereunder. Upon its resignation or removal becoming effective,
the retiring Calculation Agent shall be entitled to the payment of its
compensation and the reimbursement of all reasonable expenses (including
reasonable counsel fees and expenses) incurred by such retiring Calculation
Agent pursuant to paragraph 5 hereof.

               (c)   If at any time the Calculation Agent shall resign or be
removed, or shall become incapable of acting or shall be adjudged bankrupt or
insolvent, or liquidated or dissolved, or an order is made or an effective
resolution is passed to wind up the Calculation Agent, or if the Calculation

                                        7

<PAGE>

Agent shall file a voluntary petition in bankruptcy or make an assignment for
the benefit of its creditors, or shall consent to the appointment of a receiver,
administrator or other similar official of all or any substantial part of its
property, or shall admit in writing its inability to pay or meet its debts as
they mature, or if a receiver, administrator or other similar official of the
Calculation Agent or of all or any substantial part of its property shall be
appointed, or if any order of any court shall be entered approving any petition
filed by or against the Calculation Agent under the provisions of any applicable
bankruptcy or insolvency law, or if any public officer shall take charge or
control of the Calculation Agent or its property or affairs for the purpose of
rehabilitation, conservation or liquidation, then a successor Calculation Agent
shall be appointed by the Issuer by an instrument in writing filed with the
successor Calculation Agent and the Trustee. Upon the appointment as aforesaid
of a successor Calculation Agent and acceptance by the latter of such
appointment the former Calculation Agent shall cease to be Calculation Agent
hereunder.

               (d)   Any successor Calculation Agent appointed hereunder shall
execute and deliver to its predecessor, the Issuer and the Trustee, an
instrument accepting such appointment hereunder, and thereupon such successor
Calculation Agent, without any further act, deed or conveyance, shall become
vested with all the authority, rights, powers, immunities, duties and
obligations of such predecessor with like effect as if originally named as the
Calculation Agent hereunder, and such predecessor,

                                        8

<PAGE>

upon payment of its reasonable compensation, charges and disbursements then
unpaid, shall thereupon become obliged to transfer and deliver, and such
successor Calculation Agent shall be entitled to receive, copies of any relevant
records maintained by such predecessor Calculation Agent.

               (e)   Any corporation into which the Calculation Agent may be
merged or converted or any corporation with which the Calculation Agent may be
consolidated or any corporation resulting from any merger, conversion or
consolidation to which the Calculation Agent shall be a party shall, to the
extent permitted by applicable law, be the successor Calculation Agent under
this Agreement without the execution or filing of any paper or any further act
on the part of any of the parties hereto. Notice of any such merger, conversion
or consolidation shall forthwith be given to the Issuer and the Trustee.

               (f)   The provisions of paragraph 6 hereof shall survive any
resignation or removal hereunder.

          10.  Any notice required to be given hereunder shall be delivered in
person, by overnight mail or sent by facsimile or communicated by telephone
(subject, in the case of communication by telephone, to confirmation dispatched
within two business days by letter or facsimile), in the case of the Issuer, to
it at the address set forth in the heading of this Agreement, Attention:
Treasurer; in the case of the Trustee or the Calculation Agent, to it at the
address set forth in the heading of this Agreement; or, in any case, to any
other address of which the party

                                        9

<PAGE>

receiving notice shall have notified the party giving such notice in writing.

          11.  This Agreement may be amended only by a writing duly executed and
delivered by each of the parties signing below.

          12.  The provisions of this Agreement shall be governed by, and
construed in accordance with, the laws of the State of New York.

          13.  This Agreement may be executed in counterparts and the executed
counterparts shall together constitute a single instrument.

     IN WITNESS WHEREOF, this Agreement has been executed and delivered as of
the day and year first above written.

                                        CONSTELLATION ENERGY GROUP, INC.

                                        By:
                                           -------------------------------------

                                        Title: Treasurer

                                        THE BANK OF NEW YORK

                                        By:
                                           -------------------------------------

                                        Title:
                                              ----------------------------------

                                       10