FORTY-SEVENTH SUPPLEMENTAL INDENTURE

THIS FORTY-SEVENTH SUPPLEMENTAL INDENTURE , dated as of February 19, 2009, is between OGLETHORPE POWER CORPORATION (AN ELECTRIC MEMBERSHIP CORPORATION) , formerly known as Oglethorpe Power Corporation (An Electric Membership Generation & Transmission Corporation), an electric membership corporation organized and existing under the laws of the State of Georgia, as Grantor (hereinafter called the “Company”), and U.S. BANK NATIONAL ASSOCIATION , a national banking association, as successor to SunTrust Bank, formerly SunTrust Bank, Atlanta, as Trustee (in such capacity, the “Trustee”).

WHEREAS , the Company has heretofore executed and delivered to the Trustee an Indenture, dated as of March 1, 1997 (hereinafter called the “Original Indenture”), for the purpose of securing its Existing Obligations and providing for the authentication and delivery of Additional Obligations by the Trustee from time to time under the Original Indenture (capitalized terms used herein and not otherwise defined shall have the meanings assigned to them in the Original Indenture);

WHEREAS, the Original Indenture has heretofore been amended and supplemented by forty-six Supplemental Indentures (the Original Indenture, as heretofore, hereby and hereafter supplemented and modified, hereinafter sometimes called the “Indenture”), and the Original Indenture and the forty-six Supplemental Indentures have been recorded as set forth on Schedule 1 attached hereto;

WHEREAS , by executing and delivering this Forty-Seventh Supplemental Indenture, in accordance with the provisions of the Original Indenture, the Company desires to amend Sections 1.1, 4.1, 4.2, 4.3, 4.7, 4.8 and 4.9 of the Indenture and to add new Sections 4.11 and 4.12 to the Indenture so as to give the Company the ability (i) to use certain certified progress payments under certain engineering, procurement or construction contracts as a basis for the issuance of Additional Obligations and (ii) to convert Obligations originally issued on the basis of such certified progress payments to Obligations deemed to have been delivered on the basis of Bondable Additions;

WHEREAS , the Indenture currently includes Section 13.16, which places a restriction on the Company’s Short-Term Indebtedness, such that the Company may not permit on any date Short-Term Indebtedness to exceed 15% of the Company’s long-term debt and equities as of the end of the fiscal quarter immediately preceding such date;

WHEREAS , by executing and delivering this Forty-Seventh Supplemental Indenture, in accordance with the provisions of the Original Indenture, the Company also desires to delete and reserve Section 13.16 of the Indenture so as to remove such restriction on the Company’s Short-Term Indebtedness;

WHEREAS , Section 12.2 of the Original Indenture provides that, with the consent of the Holders of not less than a majority in principal amount of the Obligations of all series then Outstanding affected thereby (which consent is evidenced by one or more Acts of the Holder pursuant to Section 1.2 of the Original Indenture), the Company and the Trustee may enter into a Supplemental Indenture for the purpose of adding any provisions to or changing in any manner

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or eliminating any of the provisions of the Indenture or of modifying in any manner the rights of the Holders under the Indenture, subject to the conditions set forth in Section 12.2;

WHEREAS , the Holders of a majority in principal amount of all Obligations Outstanding under the Indenture have executed and delivered Acts of the Holder to the Company and the Trustee in accordance with Sections 1.2 and 12.2 of the Original Indenture; and

WHEREAS , the execution and delivery of this Forty-Seventh Supplemental Indenture has been in all respects duly authorized by the Company;

NOW, THEREFORE, THIS FORTY-SEVENTH SUPPLEMENTAL INDENTURE WITNESSETH , that, to amend Sections 1.1, 4.1, 4.2, 4.3, 4.7, 4.8 and 4.9 of the Original Indenture, to add new Sections 4.11 and 4.12 to the Original Indenture and to delete and reserve Section 13.16 of the Original Indenture, all pursuant to Section 12.2 of the Original Indenture, the Company does hereby covenant and agree to and with the Trustee as follows:

ARTICLE I

AMENDMENT OF ORIGINAL INDENTURE

Section 1.1                                 Amendment of Granting Clause First of the Original Indenture; Grant of Qualified EPC Contracts .  Paragraph C of Granting Clause First of the Original Indenture is hereby amended so as to add the following as C(ii):  “(ii) that constitute Qualified EPC Contracts,” and the numbering in Paragraph C of Granting Clause First is hereby renumbered accordingly.  To secure the payment of the principal of (and premium, if any) and interest on the Outstanding Secured Obligations, to confirm the lien of the Indenture upon any Qualified EPC Contracts, now or hereafter entered into by the Company, to secure performance of the covenants herein contained and contained in the Indenture, and in consideration of the premises thereof and hereof, the Company by these presents does grant, bargain, sell, alienate, remise, release, convey, assign, transfer, mortgage, hypothecate, pledge, set over and confirm to the Trustee, and its successors and assigns in the trust created thereby and hereby, in trust, all Qualified EPC Contracts, whether now or hereafter entered into, subject to all exceptions, reservations and matters of the character referred to in the Indenture, and does grant a security interest therein for the purposes expressed herein and in the Original Indenture subject in all cases to Section 11.2B of the Original Indenture and to the rights of the Company under the Original Indenture, including the rights set forth in Article V thereof.

Section 1.2                                 Amendment of Section 1.1 of the Original Indenture .   Section 1.1 of the Original Indenture is hereby amended so as to add the following definitions:

“Certified Progress Payments” means payments, made by the Company under or in connection with a Qualified EPC Contract, for generation and related facilities (including electric transmission and fuel supply facilities) that will constitute Property Additions upon the performance of such Qualified EPC Contract, that are certified by the Company to the Trustee as the basis for (i) loans or advances under Conditional Obligations under Section 4.8 or (ii) the authentication and delivery of Additional Obligations under Section 4.11.

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“Qualified EPC Contract” means any contract providing for the engineering, procurement or construction of generation or related facilities (including electric transmission and fuel supply facilities) intended to be owned by the Company, payments made under or in connection with which are used as the basis for (i) loans or advances under Conditional Obligations under Section 4.8 or (ii) the authentication and delivery of Additional Obligations under Section 4.11.

Section 1.3                                 Amendment of Section 4.1 of the Original Indenture .  The introductory paragraph in Section 4.1 of the Original Indenture is hereby amended in its entirety, such that the introductory paragraph in Section 4.1, as amended, will read in its entirety as follows:

“Additional Obligations of any one or more series, or within a series, may from time to time be executed by the Company and delivered to the Trustee for authentication and thereupon the same shall be authenticated and delivered by the Trustee upon Company Request, upon the basis permitted by, and upon compliance with the conditions of, Section 4.2 (upon the basis of Bondable Additions), Section 4.3 (upon the basis of retirement or defeasance of, or payments on, Obligations previously Outstanding), Section 4.4 (upon the basis of Designated Qualifying Securities), Section 4.5 (upon the basis of Deposited Cash), Section 4.7 (in connection with Credit Enhancement), Section 4.9 (in connection with RUS Reimbursement Obligations), Section 4.10 (in connection with certain indebtedness issued to refinance indebtedness previously secured under the Existing Mortgage) and Section 4.11 (upon the basis of Certified Progress Payments) upon receipt in each case by the Trustee of the following (as modified by such Sections) upon or prior to the date of the initial issuance of Additional Obligations of such series:”

Section 1.4                                 Amendment of Section 4.2 of the Original Indenture .

(a)                                   The second paragraph of Section 4.2 is hereby amended in its entirety, such that the second paragraph of Section 4.2, as amended, will read in its entirety as follows:

“Whenever requesting (i) the authentication and delivery of Additional Obligations under this Section, (ii) the withdrawal of Deposited Cash under Section 4.6 upon the basis of Bondable Additions, (iii) loans and advances under Conditional Obligations under Section 4.8 upon the basis of Bondable Additions; (iv) the withdrawal of Trust Moneys under Section 6.2, (v) the use of Bondable Additions as a basis, in whole or in part, for the release of any part of the Trust Estate under Section 5.2, (vi) the use of Bondable Additions as a basis, in whole or in part, for the redesignation or surrender of Designated Qualifying Securities under Section 16.3 or (vii) the conversion of outstanding principal amounts under Section 4.12 upon the basis of Bondable Additions, the Company shall deliver to the Trustee the relevant instruments (comprising the related Application) specified in the following paragraphs A through H:”

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(b)                                  Section 4.2 A of the Original Indenture is hereby amended in its entirety, such that Section 4.2 A, as amended, will read in its entirety as follows:

“A.                              (i) In the case of a request for the authentication and delivery of Additional Obligations, the documents and any cash deposit required by Section 4.1 and an Available Margins Certificate; (ii) in the case of a request for the withdrawal of Deposited Cash under Section 4.6 upon the basis of Bondable Additions, the Company Request, Board Resolution and Officers’ Certificate required by Section 4.6; (iii) in the case of a request for a loan or advance under a Conditional Obligation under Section 4.8 upon the basis of Bondable Additions, the Available Margins Certificate, Officers’ Certificate and Opinion of Counsel required by Section 4.8; (iv) in the case of a request for the withdrawal of Trust Moneys under Section 6.2, the Company Request, Board Resolution and Officers’ Certificate required by Section 6.2; (v) in the case of a request for the use of Bondable Additions as a basis for the release of any part of the Trust Estate under Section 5.2, the relevant documents required by Section 5.2 in addition to those specified in the following paragraphs B through H below, which documents may be modified under certain circumstances as stated in the proviso to Section 5.2D(2); (vi) in the case of a request for the use of Bondable Additions as a basis for the redesignation or surrender of Designated Qualifying Securities under Section 16.3, the relevant documents required by Section 16.3; and (vii) in the case of a request for the conversion of outstanding principal amounts under Section 4.12 upon the basis of Bondable Additions, the documents required by Section 4.12.”

(c)                                   Section 4.2 B(7) of the Original Indenture is hereby amended in its entirety, such that Section 4.2 B(7), as amended, will read in its entirety as follows:

“(7)                             The total amount (item 8 in Summary) of Bondable Additions which are then being used, which shall equal (in any combination) (i) 110% of the aggregate principal amount of any Additional Obligations whose authentication and delivery are then being applied for under this Section, (ii) 110% of the aggregate principal amount of the advances or issuances under Conditional Obligations which are then being applied for und