STOCK PURCHASE AGREEMENT

Exhibit 10.2

STOCK PURCHASE AGREEMENT

by and among

CONSTELLATION ENERGY GROUP, INC.,

EDF DEVELOPMENT INC.

and

ÉLECTRICITÉ DE FRANCE INTERNATIONAL, SA

December 17, 2008

TABLE OF CONTENTS

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STOCK PURCHASE AGREEMENT

STOCK PURCHASE AGREEMENT, dated as of December 17, 2008 (this " Agreement "), by and between CONSTELLATION ENERGY GROUP, INC., a Maryland corporation (the " Company "), EDF DEVELOPMENT INC., a Delaware corporation (the " Purchaser ") and ÉLECTRICITÉ DE FRANCE INTERNATIONAL, SA, a société anonyme organized under the laws of France and the parent company of Purchaser (" Purchaser’s Parent ").

WHEREAS, the Company has authorized the issuance of up to 11,600 shares of its Series B Preferred Stock, par value $0.01 per share (the " Preferred Stock ") which shares may be redeemable under certain circumstances with one or more 10% Senior Unsecured Notes of the Company, containing the same terms and conditions as set forth in the form of note attached hereto as Exhibit A (the " 10% Senior Notes ").

WHEREAS, the Company desires to sell to the Purchaser, and the Purchaser desires to purchase from the Company, as an investment in the Company, shares of Preferred Stock, subject to the terms and conditions set forth herein.

NOW THEREFORE, in consideration of the mutual agreements, representations, warranties and covenants in this Agreement contained, the parties agree as follows:

1. Definitions . As used in this Agreement, the following terms shall have the following respective meanings:

" 10% Senior Notes " shall have the meaning set forth in the recitals.

" Affiliate " shall mean, with respect to any Person, any other Person directly or indirectly controlling, controlled by or under direct or indirect common control with such Person. For the purposes of this definition, "control" when used with respect to any specified Person shall mean the power to direct the management and policies of such Person, directly or indirectly, whether through ownership of voting securities, by contract or otherwise; and the terms "controlled by" and "controlled" have meanings correlative to the foregoing.

" Amended and Restated Investor Agreement " means the Amended and Restated Investor Agreement dated as of the Closing Date, by and between the Company and the Purchaser, in substantially the form attached hereto as Exhibit B .

" Board of Directors " means the Board of Directors of the Company.

" Business Day " means any day other than the days on which banks in New York, New York or Baltimore, Maryland are required or authorized to close.

" Company Joint Venture " means any Person that is not a Company Subsidiary, in which the Company or one or more of the Company Subsidiaries owns directly or indirectly any Equity Interests, other than Equity Interests that represent less than 5% of each class of the outstanding voting securities or other Equity Interests of such Person, and in which the invested capital associated with the Company’s or the Company Subsidiary’s interest exceeds $100,000,000.

" Company Subsidiary " means a Subsidiary of the Company.

" Dividend Shares " means shares of Preferred Stock initially issuable upon any payment-in-kind dividend with respect to the Preferred Stock pursuant to Section 3(a) of the Articles Supplementary.

" Equity Interests " means any share, capital stock, partnership, membership or similar interests of a Person or any option therefor.

" Exchange Act " means the Securities Exchange Act of 1934, as amended.

" Governmental Authority " means any nation or government or any agency, public or regulatory authority, instrumentality, department, commission, court, arbitrator, ministry, tribunal or board of any nation or any government or political subdivision thereof, in each case, whether national, federal, tribal, provincial, state, regional, local or municipal, or any self-regulatory organization.

" Investor Rights Agreement " means the Investor Rights Agreement dated as of the Closing Date, by and among the Company and the Purchaser, in substantially the form attached hereto as Exhibit C .

" Law " means applicable statutes, common law, rules, ordinances, regulations, codes, licensing requirements, orders, judgments, injunctions, writs, decrees, licenses, governmental guidelines or interpretations having the force of law, permits, rules and bylaws, in each case, of a Governmental Authority.

" Master Agreement " means the Master Put Option and Membership Interest Purchase Agreement dated as of the date hereof, by and among the Company, the Purchaser, the Purchaser’s Parent and Constellation Energy Nuclear Group, LLC, attached hereto as Exhibit D , as amended from time to time.

" Material Adverse Effect " means any event, change or occurrence or development of a set of circumstances or facts, which, individually or together with any other event, change, occurrence or development, has a material adverse effect on the business, assets, liabilities, properties, financial condition or results of operations of the Company and its Subsidiaries, taken as a whole; provided , however , that the term shall not include (i) any such effect relating to or resulting from general changes in the nuclear or electric industry, other than such effects having a disproportionate impact on the Company and its Subsidiaries, taken as a whole, as compared to similarly situated Persons, (ii) any such effect resulting from changes in Law or GAAP (as defined in the Master Agreement), other than (in the case of changes in Law only) such effects having a disproportionate impact on the Company and its Subsidiaries, taken as a whole, as compared to similarly situated Persons, and (iii) any such effect resulting from changes in financial markets or general economic conditions, other than such effects having a disproportionate impact on the Company and its Subsidiaries, taken as a whole, as compared to similarly situated Persons; provided further , however , that, notwithstanding any provision of this

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sentence to the contrary, (x) the occurrence of an Insolvency Event (as defined in the Master Agreement) in respect of the Company or any Company Subsidiary or (y) any event, change, occurrence or development that would prevent, materially delay or materially impair the consummation of the transactions contemplated by this Agreement, shall be deemed to cause a Material Adverse Effect. As used in this Agreement, the term " knowledge " when referring to the knowledge of the Company or any Subsidiary of the Company shall mean the actual knowledge of the Company officers listed on Section 4.14(b)(ii) of the Seller Disclosure Schedule (as defined in the Master Agreement) after due inquiry.

" Merger Agreement " means the Agreement and Plan of Merger, dated as of September 19, 2008, by and among the Company, MidAmerican Energy Holdings Company, an Iowa corporation, and MEHC Merger Sub Inc., a Maryland corporation.

" Person " means any individual, corporation, company, limited liability company, partnership, association, trust, joint venture, group or any other entity or organization, including any government or political subdivision or any agency or instrumentality thereof.

" Securities Act " shall mean the Securities Act of 1933, as amended, and all of the rules and regulations promulgated thereunder.

" Subsidiary " means with respect to any Person (a) any corporation with respect to which such Person, directly or indirectly, through one or more Subsidiaries, (i) owns more than 50% of the outstanding shares of capital stock having generally the right to vote in the election of directors or (ii) has the power, under ordinary circumstances, to elect, or to direct the election of, a majority of the board of directors of such corporation; (b) any partnership with respect to which (i) such Person or a Subsidiary of such Person is a general partner, (ii) such Person and its Subsidiaries together own more than 50% of the interests therein or (iii) such Person or its Subsidiaries have the right to appoint or elect or direct the appointment or election of a majority of the directors or other Person or body responsible for the governance or management thereof; (c) any limited liability company with respect to which (i) such Person or a Subsidiary of such Person is the manager or managing member, (ii) such Person or its Subsidiaries together own more than 50% of the interests therein or (iii) such Person and its Subsidiaries have the right to appoint or elect or direct the appointment or election of a majority of the directors or other Person or body responsible for the governance or management thereof; or (d) any other entity in which such Person has, and/or one or more of its Subsidiaries have, directly or indirectly, (i) at least a 50% ownership interest or (ii) the power to appoint or elect or direct the appointment or election of a majority of the directors or other Person or body responsible for the governance or management thereof.

" Transaction Agreements " shall mean this Agreement and the Investor Rights Agreement.

2. Authorization, Purchase and Sale of Stock .

2.1 Authorization . The Company has or, on or before the Closing Date, will have (i) authorized and created a series of its preferred stock consisting of 11,600 shares of Preferred Stock, par value $0.01 per share, designated as its "Series B Preferred Stock" and (ii)

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authorized the issuance of the 10% Senior Notes. The terms, limitations and relative rights and preferences, conversion and other rights, voting powers, restrictions, limitations as to dividends or other distributions, qualifications and terms and conditions of redemption of the Preferred Stock are set forth in the Articles Supplementary of the Company, a copy of which is attached hereto as Exhibit E (the " Articles Supplementary "), which will be filed by the Company on or before the Closing Date with the Maryland State Department of Assessments and Taxation.

2.2 Purchase and Sale of the Preferred Stock . Subject to and upon the terms and conditions set forth in this Agreement, at the Closing, the Company shall issue and sell to the Purchaser, and the Purchaser shall purchase from the Company, 10,000 shares of Preferred Stock (the " Investment ") at a purchase price of $100,000 per share.

2.3 Closing . The closing of the purchase and sale of the Preferred Stock (the " Closing ") shall take place (i) at the offices of Skadden, Arps, Slate, Meagher & Flom LLP, 4 Times Square, New York, New York, 10036 or (ii) at such other place and at such date and time as the Company and the Purchaser may agree (the actual date of the Closing, the " Closing Date "), as soon as reasonably practicable but, in any event, no later than the first (1st ) Business Day after the day on which the last condition set forth in Section 6 is satisfied or waived (other than those conditions that by their nature cannot be satisfied until the Closing Date, but subject to the satisfaction or waiver of such conditions). At the Closing, the Company shall deliver to the Purchaser certificates representing the shares of Preferred Stock against payment by the Purchaser of $1,000,000,000 by wire transfer of immediately available United States funds to the Company (the " Purchase Price ").

3. Representations and Warranties of the Company . The Company hereby represents and warrants to the Purchaser as follows:

3.1 Corporate Existence and Power . Each of the Company and its Subsidiaries is duly organized, validly existing and in good standing under the laws of its jurisdiction, except where the failure to be in good standing has not had, and would not reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect. The Company has all requisite corporate power and authority to carry on its business as now conducted.

3.2 Capitalization .

(a) The authorized capital stock of the Company consists of 600,000,000 shares of Company Common Stock, without par value (the " Company Common Stock "), and 25,000,000 shares of preferred stock, par value $0.01 per share (the " Company Preferred Stock "). Of the Company Preferred Stock, at the close of business on December 16, 2008, there were 10,000 shares of Series A Convertible Preferred Stock, par value $0.01 per share, outstanding and no shares of Preferred Stock outstanding.

(b) Other than pursuant to this Agreement, no shares of Preferred Stock have been issued or are outstanding and no shares of Preferred Stock have been or will be held by the Company in its treasury.

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(c) As of the date of this Agreement, there are (A) no options, warrants, calls, rights, convertible or exchangeable securities, commitments, contracts, arrangements or undertakings of any kind to which the Company or any of the Company Subsidiaries or the Company Joint Ventures is a party or by which any of them is bound obligating the Company or any of the Company Subsidiaries or the Company Joint Ventures to issue, deliver or sell, or cause to be issued, delivered or sold, shares of Preferred Stock and (B) no other rights the value of which is in any way based on or derived from, or that give any person the right to receive any economic benefit or right similar to or derived from the economic benefits and rights accruing to holders of Preferred Stock.

3.3 Authorization . The Company has all requisite corporate power to enter into the Transaction Agreements and to carry out and perform its obligations under the terms of the Transaction Agreements. All corporate action on the part of the Company, its officers, directors and stockholders necessary for the authorization of the Preferred Stock, and the filing of the Articles Supplementary, the authorization, execution, delivery and performance of the Transaction Agreements and the consummation of the transactions contemplated thereby, including the issuance of the 10% Senior Notes (the " Transactions ") has been taken. The execution, delivery and performance of the Transaction Agreements by the Company and the consummation of the Transactions do not require any approval of the Company’s stockholders. Assuming this Agreement constitutes the legal and binding agreement of the Purchaser, this Agreement constitutes a legal, valid and binding obligation of the Company, enforceable against the Company in accordance with its terms, except as such enforceability may be limited by bankruptcy, insolvency, reorganization, moratorium, fraudulent transfer or fraudulent conveyance and similar laws relating to or affecting creditors generally or by general equity principles (regardless of whether such enforceability is considered in a proceeding in equity or at law) and an implied covenant of good faith and fair dealing. The transactions contemplated by the Transaction Agreements will not result in the Purchaser, Purchaser’s Parent or any Affiliate of Purchaser’s Parent becoming an "interested stockholder" (as that term is defined in the Maryland Business Combination Act) of the Company, and the Company has provided the Purchaser certified resolutions of the Board of Directors effecting such action.

3.4 Valid Issuance . The Preferred Stock being purchased by the Purchaser pursuant to this Agreement will, upon issuance pursuant to the terms of this Agreement and upon payment therefor, be duly authorized, validly issued, fully paid and non-assessable, free and clear of preemptive or similar rights, except as set forth in Section 7.1(i) of the Articles Supplementary. Upon their issuance in accordance with the terms of the Articles Supplementary, Dividend Shares will be duly authorized, validly issued, fully paid and non-assessable, free and clear of preemptive or similar rights and the 10% Senior Notes will constitute legal, valid and binding obligations of the Company, enforceable against the Company in accordance with their terms. Subject to the accuracy of the representations made by the Purchaser in Section 4, the Preferred Stock will be issued to the Purchaser in compliance with applicable exemptions from the registration and prospectus delivery requirements of the Securities Act. As of the date hereof, the Company is eligible to file a registration statement on Form S-3 under the Securities Act and is current in its filings with the SEC under Section 13(a) of the Exchange Act.

3.5 No Conflict . No material consent, approval, order or authorization from any Person (other than the Purchaser and its Affiliates) or Governmental Authority that has not

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been obtained is required for the (i) execution, delivery and performance of this Agreement by the Company, (ii) the issuance of the Preferred Stock or (iii) the issuance of the 10% Senior Notes. The execution, delivery and performance of the Transaction Agreements by the Company and the consummation of the other transactions contemplated hereby will not (i) conflict with or result in any violation of any provision of the charter or bylaws of the Company, (ii) any bond, debenture, note, indenture, mortgage, deed of trust or other material agreement or instrument to which the Company, the Company Subsidiaries, the Company Joint Ventures or their respective subsidiaries is a party or by which any of them is bound or to which any of their properties is subject or (iii) conflict with or violate any applicable Law, other than, in the case of (ii) and (iii) above, as would not reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect.

3.6 Preference . The Company has no authorized or outstanding class of securities ranking as to di