Registration Rights Agreement, Dated April 23, 2007

Exhibit 10.2

Execution Copy

REGISTRATION RIGHTS AGREEMENT BY AND AMONG

CONSTELLATION ENERGY PARTNERS LLC

AND

THE PURCHASERS NAMED HEREIN

Table of Contents

Page ARTICLE I DEFINITIONS 1

Section 1.01 Definitions 1

Section 1.02 Registrable Securities 2 ARTICLE II REGISTRATION RIGHTS 3

Section 2.01 Registration 3

Section 2.02 Piggyback Rights 6

Section 2.03 Underwritten Offering 8

Section 2.04 Sale Procedures 9

Section 2.05 Cooperation by Holders 12

Section 2.06 Restrictions on Public Sale by Holders of Registrable Securities 12

Section 2.07 Expenses 13

Section 2.08 Indemnification 13

Section 2.09 Rule 144 Reporting 16

Section 2.10 Transfer or Assignment of Registration Rights 16

Section 2.11 Limitation on Subsequent Registration Rights 16 ARTICLE III MISCELLANEOUS 17

Section 3.01 Communications 17

Section 3.02 Successor and Assigns 17

Section 3.03 Aggregation of Purchased Class E Units and Purchased Common Units 17

Section 3.04 Recapitalization, Exchanges, Etc. Affecting the Common Units 17

Section 3.05 Specific Performance 17

Section 3.06 Counterparts 18

Section 3.07 Headings 18

Section 3.08 Governing Law 18

Section 3.09 Severability of Provisions 18

Section 3.10 Entire Agreement 18

Section 3.11 Amendment 18

Section 3.12 No Presumption 18

Section 3.13 Obligations Limited to Parties to Agreement 18

Section 3.14 Interpretation 19

REGISTRATION RIGHTS AGREEMENT THIS REGISTRATION RIGHTS AGREEMENT (this " Agreement" ) is made and entered into as of April 23, 2007 by and among Constellation Energy Partners LLC, a Delaware limited liability company (" Constellation Energy" ), and GPS Partners LLC, Lehman Brothers MLP Partners, L.P., ZLP Fund, L.P. and Structured Finance Americas LLC (each of GPS Partners LLC, Lehman Brothers MLP Partners, L.P., ZLP Fund, L.P. and Structured Finance Americas LLC, a " Purchaser" and, collectively, the " Purchasers" ).

WHEREAS, this Agreement is made in connection with the Closing of the issuance and sale of the Purchased Class E Units and the Purchased Common Units pursuant to the Class E Unit and Common Unit Purchase Agreement, dated as of March 8, 2007, by and among Constellation Energy and the Purchasers (the " Purchase Agreement" );

WHEREAS, Constellation Energy has agreed to provide the registration and other rights set forth in this Agreement for the benefit of the Purchasers pursuant to the Purchase Agreement; and WHEREAS, it is a condition to the obligations of each Purchaser and Constellation Energy under the Purchase Agreement that this Agreement be executed and delivered.

NOW THEREFORE, in consideration of the mutual covenants and agreements set forth herein and for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged by each party hereto, the parties hereby agree as follows:

ARTICLE I

DEFINITIONS

Section 1.01 Definitions . Capitalized terms used herein without definition shall have the meanings given to them in the Purchase Agreement. The terms set forth below are used herein as so defined:

" Agreement" has the meaning specified therefor in the introductory paragraph. " Constellation Energy" has the meaning specified therefor in the introductory paragraph. " Effectiveness Period" has the meaning specified therefor in Section 2.01(a)(i) of this Agreement. " Holder" means the record holder of any Registrable Securities. " Included Registrable Securities" has the meaning specified therefor in Section 2.02(a) of this Agreement. " Liquidated Damages" has the meaning specified therefor in Section 2.01(a)(ii) of this Agreement.

" Liquidated Damages Multiplier" means (i) the product of $25.84 times the number of Class E Units purchased by such Purchaser plus (ii) the product of $26.12 times the number of Common Units purchased by such Purchaser.

" Losses" has the meaning specified therefor in Section 2.08(a) of this Agreement.

" Managing Underwriter" means, with respect to any Underwritten Offering, the book-running lead manager of such Underwritten Offering.

" Opt Out Notice" has the meaning specified therefor in Section 2.02(a) of this Agreement.

" Purchase Agreement" has the meaning specified therefor in the Recitals of this Agreement.

" Purchaser" and " Purchasers" have the meanings specified therefor in the introductory paragraph of this Agreement.

" Purchaser Underwriter Registration Statement" has the meaning specified therefor in Section 2.04(o) of this Agreement.

" Registrable Securities" means: (i) the Purchased Common Units, (ii) the Common Units issuable upon conversion of the Purchased Class E Units, (iii) any Common Units issued as Liquidated Damages pursuant to this Agreement and (iv) any Common Units issuable upon conversion of Class E Units issued as Liquidated Damages pursuant to this Agreement, all of which Registrable Securities are subject to the rights provided herein until such rights terminate pursuant to the provisions hereof.

" Registration Expenses" has the meaning specified therefor in Section 2.07(a) of this Agreement.

" Registration Statement" has the meaning specified therefor in Section 2.01(a)(i) of this Agreement.

" Selling Expenses" has the meaning specified therefor in Section 2.07(a) of this Agreement.

" Selling Holder" means a Holder who is selling Registrable Securities pursuant to a registration statement.

" Underwritten Offering" means an offering (including an offering pursuant to a Registration Statement) in which Common Units are sold to an underwriter on a firm commitment basis for reoffering to the public or an offering that is a " bought deal" with one or more investment banks. Section 1.02 Registrable Securities . Any Registrable Security will cease to be a Registrable Security when: (a) a registration statement covering such Registrable Security has


2

been declared effective by the Commission and such Registrable Security has been sold or disposed of pursuant to such effective registration statement; (b) such Registrable Security has been disposed of pursuant to any section of Rule 144 (or any similar provision then in force) under the Securities Act; (c) such Registrable Security can be disposed of pursuant to Rule 144(k) (or any similar provision then in force) under the Securities Act; (d) such Registrable Security is held by Constellation Energy or one of its Subsidiaries; or (e) such Registrable Security has been sold in a private transaction in which the transferor' s rights under this Agreement are not assigned to the transferee of such securities.

ARTICLE II REGISTRATION RIGHTS

Section 2.01 Registration .

(a) Registration .

(i) Deadline To Go Effective . As soon as practicable following the Closing, but in any event within 75 days of the Closing Date, Constellation Energy shall prepare and file a registration statement under the Securities Act to permit the resale of the Registrable Securities from time to time, including as permitted by Rule 415 under the Securities Act (or any similar provision then in force under the Securities Act) with respect to all of the Registrable Securities (the " Registration Statement" ). Constellation Energy shall use its commercially reasonable efforts to cause the Registration Statement to become effective no later than 120 days following the Closing Date. A Registration Statement filed pursuant to this Section 2.01 shall be on such appropriate registration form of the Commission as shall be selected by Constellation Energy. Constellation Energy will use its commercially reasonable efforts to cause the Registration Statement filed pursuant to this Section 2.01 to be continuously effective under the Securities Act until the earlier of (i) the date as of which all such Registrable Securities are sold by the Purchasers or (ii) the date when such Registrable Securities become eligible for resale under Rule 144(k) (or any similar provision then in force) under the Securities Act (the " Effectiveness Period" ). The Registration Statement when declared effective (including the documents incorporated therein by reference) shall comply as to form with all applicable requirements of the Securities Act and the Exchange Act and shall not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading.

(ii) Failure To Go Effective . If the Registration Statement required by Section 2.01 of this Agreement is not declared effective within 150 days after the Closing Date, then each Purchaser shall be entitled to a payment with respect to the Purchased Class E Units and the Purchased Common Units of each such Purchaser, as liquidated damages and not as a penalty, of 0.25% of the Liquidated Damages Multiplier per 30-day period for the first 90 days following the 150th day after the Closing Date, increasing by an additional 0.25% of the Liquidated Damages Multiplier per 30-day period for each subsequent 30 days, up to a maximum of 1.00% of the Liquidated Damages Multiplier per 30-day period (the " Liquidated Damages" ). Initially there shall be no limitation on the aggregate amount of the Liquidated Damages payable by Constellation Energy under this Agreement to each Purchaser; provided ,


3

however , that if there is a change in the Law or accounting principles generally accepted in the United States that would result in the Purchased Common Units or the Purchased Class E Units being treated as debt securities instead of equity securities for purposes of Constellation Energy' s financial statements, then the aggregate amount of the Liquidated Damages payable by Constellation Energy under this Agreement to each Purchaser shall not exceed the maximum amount of the Liquidated Damages Multiplier with respect to such Purchaser allowed for the Purchased Common Units not to be treated as debt securities for purposes of Constellation Energy' s financial statements. The Liquidated Damages payable pursuant to the immediately preceding sentence shall be payable within ten Business Days of the end of each such 30-day period. Any Liquidated Damages shall be paid to each Purchaser in cash or immediately available funds; provided , however , if Constellation Energy certifies that it is unable to pay Liquidated Damages in cash or immediately available funds because such payment would result in a breach under any of Constellation Energy' s or Constellation Energy' s Subsidiaries' credit facilities or other indebtedness filed as exhibits to the Constellation Energy SEC Documents, then Constellation Energy may pay the Liquidated Damages in kind in the form of the issuance of additional (A) Common Units or (B) Common Units and Class E Units. Class E Units may only be issued as Liquidated Damages if and to the extent required by NYSE Arca or similar regulation. If Class E Units are issued as Liquidated Damages as a result of a requirement by NYSE Arca or similar regulation, then such Common Units and/or Class E Units will be issued to each Purchaser in such a manner as to maximize the number of Common Units issued to each such Purchaser. Upon any issuance of Common Units and/or Class E Units as Liquidated Damages, Constellation Energy shall promptly prepare and file an amendment to the Registration Statement prior to its effectiveness adding such Common Units and/or Common Units issuable upon conversion of Class E Units to such Registration Statement as additional Registrable Securities. The determination of the number of Common Units to be issued as Liquidated Damages shall be equal to the amount of Liquidated Damages divided by the volume weighted average closing price of the Common Units (as reported by NYSE Arca) for the ten (10) trading days immediately preceding the date on which the Liquidated Damages payment is due, less a discount of 1.5%. The determination of the number of Class E Units to be issued as Liquidated Damages shall be equal to the amount of Liquidated Damages divided by the volume weighted average closing price of the Common Units (as reported by NYSE Arca) for the ten (10) trading days immediately preceding the date on which the Liquidated Damages payment is due, less a discount of 3%. The payment of Liquidated Damages to a Purchaser shall cease at such time as the Purchased Class E Units and the Purchased Common Units of such Purchaser become eligible for resale under Rule 144(k) under the Securities Act. As soon as practicable following the date that the Registration Statement becomes effective, but in any event within two Business Days of such date, Constellation Energy shall provide the Purchasers with written notice of the effectiveness of the Registration Statement.

(iii) Waiver of Liquidated Damages . If Constellation Energy is unable to cause a Registration Statement to go effective within 150 days following the Closing Date as a result of an acquisition, merger, reorganization, disposition or other similar transaction, then Constellation Energy may request a waiver of the Liquidated Damages, which may be granted or withheld by the consent of the Holders of a majority of the Purchased Class E Units and the Purchased Common Units, taken as a whole, in their sole discretion.


4

(b) Delay Rights . Notwithstanding anything to the contrary contained herein, Constellation Energy may, upon written notice to any Selling Holder whose Registrable Securities are included in the Registration Statement, suspend such Selling Holder' s use of any prospectus which is a part of the Registration Statement (in which event the Selling Holder shall discontinue sales of the Registrable Securities pursuant to the Registration Statement, but such Selling Holder may settle any such sales of Registrable Securities) if (i) Constellation Energy is pursuing an acquisition, merger, reorganization, disposition or other similar transaction and Constellation Energy determines in good faith that Constellation Energy' s ability to pursue or consummate such a transaction would be materially adversely affected by any required disclosure of such transaction in the Registration Statement or (ii) Constellation Energy has experienced some other material non-public event the disclosure of which at such time, in the good faith judgment of Constellation Energy, would materially adversely affect Constellation Energy; provided , however , in no event shall the Purchasers be suspended for a period that exceeds an aggregate of 30 days in any 90-day period or 90 days in any 365-day period; provided further, however , that during any period where Registrable Securities are registered on a Form S-1, the failure of the Registration Statement to be effective while updated quarterly or annual financial information is being included in the Registration Statement shall not result in the accrual of Liquidated Damages if such period is no longer than 30 consecutive days. No additional registration rights may be granted to any other Person that would be superior to the Purchasers' registration rights. Upon disclosure of such information or the termination of the condition described above, Constellation Energy shall provide prompt notice to the Selling Holders whose Registrable Securities are included in the Registration Statement, shall promptly terminate any suspension of sales it has put into effect and shall take such other actions to permit registered sales of Registrable Securities as contemplated in this Agreement. (c) Additional Rights to Liquidated Damages . If (i) the Holders shall be prohibited from selling their Registrable Securities under the Registration Statement as a result of a suspension pursuant to Section 2.01(b) of this Agreement in excess of the periods permitted therein or (ii) the Registration Statement is filed and declared effective but, during the Effectiveness Period, shall thereafter cease to be effective or fail to be usable for its intended purpose without being succeeded by a post-effective amendment to the Registration Statement, a supplement to the prospectus or a report filed with the Commission pursuant to Section 13(a), 13(c), 14 or l5(d) of the Exchange Act, then, until the suspension is lifted or a post-effective amendment, supplement or report is filed with the Commission, but not including any day on which a suspension is lifted or such amendment, supplement or report is filed and declared effective, if applicable, Constellation Energy shall owe the Holders an amount equal to the Liquidated Damages, following (x) the date on which the suspension period exceeded the permitted period under Section 2.01(b) of this Agreement or (y) the day after the Registration Statement ceased to be effective or failed to be useable for its intended purposes, as liquidated damages and not as a penalty. For purposes of this Section 2.01(c), a suspension shall be deemed lifted on the date that notice that the suspension has been lifted is delivered to the Holders pursuant to Section 3.01 of this Agreement. (d) Claw-Back of Purchaser Securities . Constellation Energy may exclude Registrable Securities from the Registration Statement if required by the Commission in order


5

for the Commission to declare the Registration Statement effective; provided, however , that Constellation Energy will use its commercially reasonable efforts to file and have declared effective a subsequent Registration Statement that includes the Registrable Securities excluded from the initial Registration Statement at such time as it may do so in accordance with the Securities Act as interpreted by the Commission. With respect to any Registrable Securities that are not included in the initial Registration Statement or a subsequent Registration Statement within 150 days following the Closing Date, Constellation Energy shall be required to pay the Purchasers the Liquidated Damages in accordance with Section 2.01(a)(ii) of this Agreement.

(e) No Obligation For Primary Offering By Purchasers . If the Commission deems the registration of any Registrable Securities to be a primary offering by Constellation Energy or the Purchasers, and the Commission prohibits the use of Rule 415 under the Securities Act (or any similar provision then in force) to sell Registrable Securities on a delayed or continuous basis, then the Purchasers shall not be obligated to commit to any such primary offering to allow the Registration Statement to be declared effective by the Commission. In such event, if the Registration Statement is not declared effective within 150 days following the Closing Date, then Constellation Energy shall be required to pay the Purchasers the Liquidated Damages in accordance with Section 2.01(a)(ii) of this Agreement.

(f) Conversion From Form S-1 to Form S-3 . Within 30 days of becoming eligible to file a registration statement on Form S-3, Constellation Energy agrees to convert any Registration Statement on Form S-1 covering the Purchased Common Units and Common Units underlying the Purchased Class E Units into a registration statement on Form S-3 such that the Purchased Common Units and the Common Units underlying the Purchased Class E Units may be sold from time-to-time pursuant to Rule 415 under the Securities Act (or any similar provision then in force). Section 2.02 Piggyback Rights .

(a) Participation . If at any time Constellation Energy proposes to file (i) a prospectus supplement to an effective shelf registration statement, other than the Registration Statement contemplated by Section 2.01 of this Agreement, or (ii) a registration statement, other than a shelf registration statement, in either case, for the sale of Common Units in an Underwritten Offering for its own account and/or another Person, then as soon as practicable but not less than three Business Days prior to the filing of (x) any preliminary prospectus supplement relating to such Underwritten Offering pursuant to Rule 424(b) under the Securities Act, (y) the prospectus supplement relating to such Underwritten Offering pursuant to Rule 424(b) under the Securities Act (if no preliminary prospectus supplement is used) or (z) such registration statement, as the case may be, then Constellation Energy shall give notice (including, but not limited to, notification by electronic mail) of such proposed Underwritten Offering to the Holders and such notice shall offer the Holders the opportunity to include in such Underwritten Offering such number of Registrable Securities (the " Included Registrable Securities" ) as each such Holder may request in writing, which shall not be fewer than 100,000 Registrable Securities; provided , however , that if Constellation Energy has been advised by the Managing Underwriter that the inclusion of Registrable Securities for sale for the benefit of the Holders will have a material adverse effect on the price, timing or distribution of the Common Units in


6

the Underwritten Offering, then the amount of Registrable Securities to be offered for the accounts of Holders shall be determined based on the provisions of Section 2.02(b) of this Agreement. The notice required to be provided in this Section 2.02(a) to Holders shall be provided on a Business Day pursuant to Section 3.01 hereof and receipt of such notice shall be confirmed by such Holder. Each such Holder shall then have three Business Days after receiving such notice to request inclusion of Registrable Securities in the Underwritten Offering, except that such Holder shall have one Business Day after such Holder confirms receipt of the notice to request inclusion of Registrable Securities in the Underwritten Offering in the case of a " bought deal" or " overnight transaction" where no preliminary prospectus is used. If no request for inclusion from a Hol ...