ORMAT TECHNOLOGIES, INC. Common Stock AMENDED AND RESTATED UNDERWRITING AGREEMENT

EXECUTION COPY

3,100,000 Shares

ORMAT TECHNOLOGIES, INC.

Common Stock

AMENDED AND RESTATED UNDERWRITING AGREEMENT

May 9 , 2008

L EHMAN B ROTHERS I NC .

745 Seventh Avenue

New York, NY  10019

Ladies and Gentlemen:

Ormat Technologies, Inc., a Delaware corporation (the “ Company ”) and Lehman Brothers Inc. (the “ Underwriter ”) are parties to that certain Underwriting Agreement (the “ Original Underwriting Agreement ”) dated May 8, 2008 concerning the purchase of 3,100,000 shares (the “ Stock ”) of the Company’s Common Stock, par value $0.001 per share (the “ Common Stock ”) from the Company by the Underwriter. The Company and the Underwriter have agreed to make certain modifications to, and to amend and restate in its entirety, the Original Underwriting Agreement on the terms and conditions as set forth in this amended and restated underwriting agreement (the “ Agreement ”).

S ECTION 1. Representations, Warranties and Agreements of the Company . The Company represents, warrants and agrees that:

(a) A registration statement on Form S-3 relating to the Stock has (i) been prepared by the Company in conformity with the requirements of the Securities Act of 1933, as amended (the “ Securities Act ”), and the rules and regulations (the “ Rules and Regulations ”) of the Securities and Exchange Commission (the “ Commission ”) thereunder; (ii) been filed with the Commission under the Securities Act; and (iii) become effective under the Securities Act. Copies of such registration statement and each of the amendments thereto have been delivered by the Company to you as the Underwriter. As used in this Agreement:

(i) “ Applicable Time ” means 5:30 p.m. (New York City time) on the date of this Agreement;

(ii) “ Effective Date ” means any date as of which any part of such registration statement relating to the Stock became, or is deemed to have become, effective under the Securities Act in accordance with the Rules and Regulations;

(iii) “ Issuer Free Writing Prospectus ” means each “free writing prospectus” (as defined in Rule 405 of the Rules and Regulations) prepared by or on behalf of the Company or used or referred to by the Company in connection with the offering of the Stock;

(iv) “ Preliminary Prospectus ” means any preliminary prospectus relating to the Stock included in such registration statement or filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations, including any preliminary prospectus supplement thereto relating to the Stock;

(v) “ Pricing Disclosure Package ” means, as of the Applicable Time, the most recent Preliminary Prospectus, together with each Issuer Free Writing Prospectus filed or used by the Company on or before the Applicable Time, other than a road show that is an Issuer Free Writing Prospectus under Rule 433 of the Rules and Regulations;

(vi) “ Prospectus ” means the final prospectus relating to the Stock, including any prospectus supplement thereto relating to the Stock, as filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations; and

(vii) “ Registration Statement ” means, collectively, the various parts of such registration statement, each as amended as of the Effective Date for such part, including any Preliminary Prospectus or the Prospectus and all exhibits to such registration statement.

Any reference to any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include any documents incorporated by reference therein pursuant to Form S-3 under the Securities Act as of the date of such Preliminary Prospectus or the Prospectus, as the case may be. Any reference to the “most recent Preliminary Prospectus” shall be deemed to refer to the latest Preliminary Prospectus included in the Registration Statement or filed pursuant to Rule 424(b) prior to or on the date hereof (including, for purposes hereof, any documents incorporated by reference therein prior to or on the date hereof). Any reference to any amendment or supplement to any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include any document filed under the Securities Exchange Act of 1934, as amended (the “ Exchange Act ”), after the date of such Preliminary Prospectus or the Prospectus, as the case may be, and incorporated by reference in such Preliminary Prospectus or the Prospectus, as the case may be; and any reference to any amendment to the Registration Statement shall be deemed to include any annual report of the Company on Form 10-K filed with the Commission pursuant to Section 13(a) or 15(d) of the Exchange Act after the Effective Date that is incorporated by reference in the Registration Statement. The Commission has not issued any order preventing or suspending the use of any Preliminary Prospectus or the Prospectus or suspending the effectiveness of the Registration Statement, and no proceeding or examination for such purpose has been instituted or threatened by the Commission.

(b) The Company was not at the time of initial filing of the Registration Statement and at the earliest time thereafter that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2) of the Rules and Regulations) of the Stock, is not on the date hereof and will not be on the Delivery Date (as defined in Section 4) an “ineligible issuer” (as defined in Rule 405 of the Rules and Regulations). The Company has been since the time of initial filing of the Registration Statement and continues to be eligible to use Form S-3 for the offering of the Stock.

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(c) The Registration Statement conformed and will conform in all material respects on the Effective Date and on the Delivery Date, and any amendment to the Registration Statement filed after the date hereof will conform in all material respects when filed, to the requirements of the Securities Act and the Rules and Regulations. The Preliminary Prospectus conformed, and the Prospectus will conform, in all material respects when filed with the Commission pursuant to Rule 424(b) and on the Delivery Date to the requirements of the Securities Act and the Rules and Regulations. The documents incorporated by reference in any Preliminary Prospectus or the Prospectus conformed, and any further documents so incorporated will conform, when filed with the Commission, in all material respects to the requirements of the Exchange Act or the Securities Act, as applicable, and the rules and regulations of the Commission thereunder.

(d) The Registration Statement did not, as of the Effective Date, 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; provided that no representation or warranty is made as to information contained in or omitted from the Registration Statement in reliance upon and in conformity with written information furnished to the Company through the Underwriter by or on behalf of the Underwriter specifically for inclusion therein.

(e) The Prospectus will not, as of its date and on the Delivery Date, 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, in the light of the circumstances under which they were made, not misleading; provided that no representation or warranty is made as to information contained in or omitted from the Prospectus in reliance upon and in conformity with written information furnished to the Company through the Underwriter by or on behalf of the Underwriter specifically for inclusion therein.

(f) The documents incorporated by reference in any Preliminary Prospectus or the Prospectus did not, and any further documents filed and incorporated by reference therein will not, when filed with the Commission, 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, in the light of the circumstances under which they were made, not misleading.

(g) The Pricing Disclosure Package did not, as of the Applicable Time, 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, in the light of the circumstances under which they were made, not misleading, except that the price of the Stock and disclosures directly relating thereto will be included on the cover page of the Prospectus; provided that no representation or warranty is made as to information contained in or omitted from the Pricing Disclosure Package in reliance upon and in conformity with written information furnished to the Company through the Underwriter by or on behalf of the Underwriter specifically for inclusion therein.

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(h) Each Issuer Free Writing Prospectus (including, without limitation, any road show that is a free writing prospectus under Rule 433), when considered together with the Pricing Disclosure Package as of the Applicable Time, did 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, in the light of the circumstances under which they were made, not misleading, except that the price of the Stock and disclosures directly relating thereto will be included on the cover page of the Prospectus.

(i) Each Issuer Free Writing Prospectus conformed or will conform in all material respects to the requirements of the Securities Act and the Rules and Regulations on the date of first use, and the Company has complied with any filing requirements applicable to such Issuer Free Writing Prospectus pursuant to the Rules and Regulations. The Company has not made any offer relating to the Stock that would constitute an Issuer Free Writing Prospectus without the prior written consent of the Underwriter. The Company has retained in accordance with the Rules and Regulations all Issuer Free Writing Prospectuses that were not required to be filed pursuant to the Rules and Regulations.

(j) The Company and each of its subsidiaries (as defined in Section 16) have been duly incorporated or formed, as applicable, and are validly existing as corporations, limited liability companies or partnerships, as applicable, in good standing under the laws of their respective jurisdictions of incorporation, are duly qualified to do business and are in good standing as foreign corporations, limited liability companies or partnerships, as applicable, in each jurisdiction in which their respective ownership or lease of property or the conduct of their respective businesses requires such qualification, except where the failure to be so qualified or in good standing would not have, individually or in the aggregate, a material adverse effect on the general affairs, management, business, prospects, financial condition, revenues or expenses, properties, stockholders’ equity or results of operations of the Company and its subsidiaries taken as a whole (a “ Material Adverse Effect ”), and have all power and authority necessary to own or hold their respective properties and to conduct the businesses in which they are engaged; and none of the subsidiaries of the Company other than those listed on Schedule 1 hereto is a “significant subsidiary”, as such term is defined in Rule 405 of the Rules and Regulations.

(k) The Company has an authorized capitalization as set forth in the Pricing Disclosure Package. All of the issued shares of capital stock of the Company have been duly and validly authorized and issued, and were issued in compliance with federal and state securities laws. All of the Company’s options, warrants and other rights to purchase or exchange any securities for shares of the Company’s capital stock have been duly and validly authorized and issued, were issued in compliance with federal and state securities laws, and conform to the description thereof contained in the most recent Preliminary Prospectus and the Prospectus. All of the issued shares of capital stock, limited liability company interests or partnership interests, as applicable, of each subsidiary of the Company have been duly and validly authorized and issued and are fully paid and non-assessable and are owned directly or indirectly by the Company, free and clear of all liens, encumbrances, equities or claims, except in each case as otherwise set forth in the most recent Preliminary Prospectus and the Prospectus. Except for the Registration Rights Agreement (the “ OIL Registration Rights Agreement ”) dated November 10, 2004, between the Company and Ormat Industries Ltd., pursuant to which, as described more fully in the OIL Registration Rights Agreement, Ormat Industries Ltd. may require the Company to register the Common Stock held by it or its directors, officers and employees or to include the Common Stock held by it or its directors, officers and employees in an offering and sale by the Company, the Company has not, at any time, granted any preemptive rights, resale rights, rights of first refusal or similar rights with respect to its capital stock.

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(l) The shares of the Stock to be issued and sold by the Company to the Underwriter hereunder have been duly and validly authorized and, when issued and delivered against payment therefor in accordance with this Agreement, will be duly and validly issued, fully paid and non-assessable and free of statutory and contractual preemptive rights, resale rights, rights of first refusal and similar rights; and the Stock will conform to the description of the material terms thereof contained in the most recent Preliminary Prospectus and the Prospectus under the caption “Description of Common Stock We May Offer”. Upon payment for and delivery of the Stock to be sold by the Company pursuant to this Agreement, the Underwriter will acquire good and valid title to such Stock, in each case free and clear of all liens, encumbrances, equities, preemptive rights, subscription rights, other rights to purchase, voting or transfer restrictions and other claims.

(m) This Agreement has been duly authorized, executed and delivered by the Company.

(n) The execution, delivery and performance of this Agreement by the Company and the consummation of the transactions contemplated hereby and the application of the proceeds from the sale of Stock as described under “Use of Proceeds” in the most recent Preliminary Prospectus and the Prospectus will not conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any of the property or assets of the Company or any of its subsidiaries is subject, nor will such actions result in any violation of the provisions of the charter or by-laws of the Company or any of its subsidiaries or any statute or any order, rule or regulation of any court or governmental agency or body having jurisdiction over the Company or any of its subsidiaries or any of their properties or assets; and except for the registration of the Stock under the Securities Act and such consents, approvals, authorizations, registrations or qualifications as may be required under the Exchange Act, the applicable state securities laws or by the New York Stock Exchange, Inc., if any, in connection with the purchase and distribution of the Stock by the Underwriter, no consent, approval, authorization or order of, or filing or registration with, any such court or governmental agency or body is required for the execution, delivery and performance of this Agreement by the Company and the consummation of the transactions contemplated hereby.

(o) Except for the OIL Registration Rights Agreement and as otherwise described in the most recent Preliminary Prospectus , there are no contracts, agreements or understandings between the Company and any person granting such person the right to require the Company to file a registration statement under the Securities Act with respect to any securities of the Company owned or to be owned by such person or to require the Company to include such securities in the securities registered pursuant to the Registration Statement or in any securities being registered pursuant to any other registration statement filed by the Company under the Securities Act. The holders of outstanding shares of the Company’s capital stock are not entitled to preemptive rights, rights of first refusal or other rights to subscribe for or purchase any shares of the Stock and there are no contracts, agreements or understandings between the Company and

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any person granting such person such preemptive rights, rights of first refusal or other rights to subscribe for or purchase the Stock. Except for the options to purchase from the Company 1,259,856 shares of Common Stock, in the aggregate, granted to directors, officers and employees of the Company under the Company’s Ormat Technologies, Inc. 2004 Incentive Compensation Plan (the “ 2004 Plan ”), there are no options, warrants or other rights to purchase from the Company, agreements or other obligations of the Company to issue, or right to convert any obligations of the Company into or exchange any securities of the Company for shares of Capital Stock of or ownership interests in the Company.

(p) The Company has not sold or issued any shares of Common Stock during the six-month period preceding the date of the Prospectus, including any sales pursuant to Rule 144A or Regulation D or S under the Securities Act other than (i) shares underlying options issued pursuant to the 2004 Plan and (ii) 693,750 shares of Common Stock sold to Ormat Industries Ltd. on January 8, 2008, in an unregistered transaction pursuant to Regulation S under the Securities Act.

(q) Neither the Company nor any of its subsidiaries has sustained, since the date of the latest audited financial statements included or incorporated by reference in the most recent Preliminary Prospectus, any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the most recent Preliminary Prospectus; and, since such date, there has not been any change in the capital stock, limited liability company interests or partnership interests, as applicable, or long-term debt of the Company or any of its subsidiaries or any material adverse change, or any development reasonably likely to have a Material Adverse Effect, otherwise than as set forth or contemplated in the most recent Preliminary Prospectus.

(r) The financial statements (including the related notes and supporting schedules) included or incorporated by reference in the most recent Preliminary Prospectus present fairly the financial condition and results of operations of the entities purported to be shown thereby, at the dates and for the periods indicated, and have been prepared in conformity with generally accepted accounting principles applied on a consistent basis throughout the periods involved. There are no material off-balance sheet arrangements (as defined in Regulation S-K Item 303(a)(4)(ii)) that are reasonably likely to have a current or future material effect on the Company’s financial condition, revenues or expenses, results of operations, liquidity, capital expenditures or capital resources.

(s) PricewaterhouseCoopers LLP, who have certified certain financial statements of the Company, whose report appears in the most recent Preliminary Prospectus or is incorporated by reference therein and who have delivered the letters referred to in Section 7(h) hereof, are independent public accountants as required by the Securities Act and the Rules and Regulations. Except as described in the most recent Preliminary Prospectus and as preapproved in accordance with the requirements set forth in Section 10A of the Exchange Act, since May 6, 2003, PricewaterhouseCoopers LLP has, to the best of the Company’s knowledge, not engaged in any “prohibited activities” (as defined in Section 10A of the Exchange Act) on behalf of the Company.

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(t) The Company and each of its subsidiaries have good and marketable title in fee simple to all real property owned by them and good and marketable title to all personal property owned by them that is material to the business of the Company and its subsidiaries, in each case, free and clear of all liens, encumbrances and defects, except such as are described in the most recent Preliminary Prospectus or such as do not materially affect the value of such property and do not materially interfere with the use made and proposed to be made of such property by the Company and its subsidiaries; and all assets held under lease by the Company and its subsidiaries (including, without limitation, all geothermal resources held under lease) are held by them under valid, subsisting and enforceable leases, with such exceptions as are not material and do not interfere with the use made and proposed to be made of such property and buildings by the Company and its subsidiaries, in each case, except as described in or contemplated by the most recent Preliminary Prospectus.

(u) The statistical and market-related data included in the most recent Preliminary Prospectus and the consolidated financial statements of the Company and its subsidiaries included or incorporated by reference in the most recent Preliminary Prospectus are based on or derived from sources that the Company believes to be reliable and accurate.

(v) The leases (including, without limitation, all geothermal resources leases), easements, licenses, rights of way and other rights possessed by the Company and its subsidiaries provide the Company and its subsidiaries with all rights and property interests required to enable them to obtain, in all material respects, all services, materials (including, without limitation, geothermal resources) or rights (including, without limitation, access rights and rights to extract and develop such geothermal resources that may exist in the properties covered by such geothermal resources leases) required for the operation and maintenance of their operating projects, as contemplated by the most recent Preliminary Prospectus.

(w) Each of the power purchase agreements, transmission agreements, interconnection agreements, financing documents, leases and other agreements referred to in the most recent Preliminary Prospectus is a valid and binding agreement, enforceable against each party thereto in accordance with its terms, except as such enforceability (i) may be limited by applicable bankruptcy, insolvency, reorganization, fraudulent conveyance, moratorium or other similar laws affecting the enforcement of creditors’ rights generally and (ii) is subject to general principles of equity (regardless of whether enforceability is considered in a proceeding in equity or at law) and, except as described in the most recent Preliminary Prospectus, the Company and any subsidiary of the Company are not in any material default, and have no knowledge of any material default of any of the counterparties thereto, under any such power purchase agreement, transmission agreement, interconnection agreement, financing document, lease or other agreement referred to in the most recent Preliminary Prospectus.

(x) The Company and each of its subsidiaries carry, or are covered by, insurance in such amounts and covering such risks as is adequate for the conduct of their respective businesses and the value of their respective properties and as is customary for companies engaged in similar businesses in similar industries.

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(y)   The Company conducts no business other than as described in the most recent Preliminary Prospectus (other than non-material business activities, which in the aggregate do not represent an investment expense in excess of $2 million, and business activities relating to the development of the Company’s solar power technology and potential involvement in solar energy generation projects, and to the application of its Recovered Energy Generation technology to the liquefied natural gas industry, which activities in the aggregate are not currently material to the Company’s business).

(z) The Company and its subsidiaries own or possess adequate rights to use all patents, patent applications, trademarks, service marks, service names, trade names, trademark registrations, service mark registrations, copyrights, inventions, trade secrets, licenses and other intellectual property necessary for the conduct of their respective businesses (collectively, the “ Intellectual Property ”) and, other than with respect to Intellectual Property covered by licenses permitting Company, Ormat Industries Ltd. or OPTI Canada Inc. use, are not aware of any rights of third parties to any such Intellectual Property. The Company and its subsidiaries have no reason to believe that the conduct of their respective businesses conflict, infringe or misappropriate, or will conflict with, infringe or misappropriate, the intellectual property rights of others, and have not received any notice of any claim of conflict with, infringement or misappropriation of, the intellectual property rights of others. There is no pending or, to the Company’s best knowledge, threatened action, suit, proceeding or claim by others challenging the validity or scope of such Intellectual Property (and the Company and its subsidiaries are not aware of any facts which would form a reasonable basis for such claim). To the Company’s and its subsidiaries’ best knowledge: (a) there is no infringement by third parties of any such Intellectual Property and (b) there is no U.S. patent or published U.S. patent application which contains claims that dominate or may dominate any Intellectual Property or that interferes with the issued or pending claims of any such Intellectual Property. There is no prior art of which the Company or its subsidiaries is aware that may render any U.S. patent held by the Company or its subsidiaries invalid or any U.S. patent application held by the Company or its subsidiaries unpatentable, which has not been disclosed to the U.S. Patent and Trademark Office.

(aa) Except as disclosed in the most recent Preliminary Prospectus, there are no legal or governmental proceedings pending to which the Company or any of its subsidiaries is a party or of which any property or assets of the Company or any of its subsidiaries is the subject which, if determined adversely to the Company or any of its subsidiaries, could reasonably be expected to have a Material Adverse Effect; and to the best of the Company’s knowledge no such proceedings are threatened or contemplated by governmental authorities or threatened by others.

(bb) Except as disclosed in the most recent Preliminary Prospectus, the Company and each of its subsidiaries possess adequate certificates, authorizations or permits issued by appropriate governmental agencies or bodies necessary to conduct the business described in the most recent Preliminary Prospectus, except for such certificates, authorizations or permits that the failure to so possess would not, individually or in the aggregate, have a Material Adverse Effect and except for those not yet required to be obtained by the Company, which the Company intends to obtain in due course. The Company, and each of its subsidiaries have not received any notice of proceedings relating to the revocation or modification of any such certificate, authorization or permit that would, individually or in the aggregate, have a Material Adverse Effect.

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(cc) There are no contracts or other documents, which are required to be described in the documents incorporated by reference into the most recent Preliminary Prospectus or filed as exhibits to such documents by the Securities Act or by the Rules and Regulations, which have not been described in such documents or filed as exhibits to such documents. Each contract, agreement or arrangement to which the Company or any of its subsidiaries is a party or by which it may be bound, or to which any of the property or assets of the Company or any of its subsidiaries is subject, has been duly and validly authorized, executed and delivered by the Company or any of its subsidiaries, as the case may be; neither the Company nor any of its subsidiaries knows of any present condition or fact which would prevent compliance by the Company or any of its subsidiaries or any other party thereto with the terms of any such contract, agreement or arrangement in accordance with its terms; except as described in the most recent Preliminary Prospectus, neither the Company nor any of its subsidiaries has any present intention to exercise any right that it may have to cancel any such contract, agreement or arrangement or otherwise to terminate its rights and obligations thereunder other than in the ordinary course of business, and neither the Company nor any of its subsidiaries has any knowledge that any other party to any such contract, agreement or arrangement has any current intention not to render full performance as contemplated by the terms thereof.

(dd) Except as described in the most recent Preliminary Prospectus and except for a software development consulting contract between the Company and Yuval Bronicki involving compensation that does not exceed $100,000 annually, no relationships (including without limitation any loans or advances), direct or indirect, exists, nor has any transaction been entered into since January 1, 2001, between or among the Company and its subsidiaries on the one hand, and the directors, officers, shareholders of the Company or any subsidiary on the other hand. Since July 30, 2002, the Company has not, directly or indirectly, including through any subsidiary, extended or maintained credit, or arranged for the extension of credit, or renewed or amended any extension of credit, in the form of a personal loan to or for any of its directors or executive officers.

(ee) No labor disturbance by the employees of the Company exists or, to the knowledge of the Company, is imminent, which could reasonably be expected to have a Material Adverse Effect.

(ff) Each of the Company’s operating projects in the United States, other than the Puna Facility, is a “qualifying small power production facility” within the meaning of Section 3(17)(C) of the Federal Power Act, as amended (“ FPA ”) and a “qualifying facility” within the meaning of 18 C.F.R. §292.101(b)(1) that is eligible for the regulatory exemptions set forth in 18 C.F.R. Sections 292.601 and 292.602 from the FPA and from certain state laws and regulations.

(gg) Puna Geothermal Venture is the owner of the Puna Facility and is an “exempt wholesale generator” as such term is defined in Section 1262(6) of the Public Utility Holding Company Act of 2005 (“ PUHCA ”).

(hh) The Company and its subsidiaries are eligible for an exemption from PUHCA.

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(ii) The Company is in compliance in all material respects with all presently applicable provisions of the Employee Retirement Income Security Act of 1974, as amended, including the regulations and published interpretations thereunder (“ ERISA ”); no “ reportable event ” (as defined in Section 4043 of ERISA) has occurred with respect to any “ pension plan ” subject to Title IV of ERISA (a “Title IV Plan”) (as defined in ERISA) for which the Company would have any liability; the Company has not incurred and does not expect to incur liability under (i) Title IV of ERISA with respect to the termination of, or withdrawal from, any Title IV Plan or (ii) Sections 412 or 4971 of the Internal Revenue Code of 1986, as amended, including the regulations and published interpretations thereunder (the “ Code ”); and each “pension plan” for which the Company would have any liability that is intended to be qualified under Section 401(a) of the Code is so qualified in all material respects and nothing has occurred, whether by action or by failure to act, which would cause the loss of such qualification.

(jj) The Company has filed all tax returns required to be filed through the date hereof (other than any tax returns not so required to be filed through the date hereof as a result of the existence of waiver or extension granted in connection with any such tax returns) and has paid all taxes shown to be due thereon, and no tax deficiency has been determined adversely to the Company or any of its subsidiaries which has had (nor does the Company have any knowledge of any tax deficiency which, if determined adversely to the Company or any of its subsidiaries, could reasonably be expected to have) a Material Adverse Effect.

(kk) Since the date as of which information is given in the most recent Preliminary Prospectus through the date hereof, and except as may otherwise be disclosed in the most recent Preliminary Prospectus, the Company has not (i) issued or granted any securities (other than options issued pursuant to the 2004 Plan as described in the Prospectus), (ii) incurred any liability or obligation, direct or contingent, other than non-material liabilities and obligations which were incurred in the ordinary course of business, (iii) entered into any transaction not in the ordinary course of business or (iv) declared or paid any dividend on its capital stock.

(ll) The Company (i) makes and keeps accurate books and records and (ii) maintains internal accounting controls which provide reasonable assurance that (A) transactions are executed in accordance with management’s authorization, (B) transactions are recorded as necessary to permit preparation of its financial statements and to maintain accountability for its assets, (C) access to its assets is permitted only in accordance with management’s authorization and (D) the reported accountability for its assets is compared with existing assets at reasonable intervals. No action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the applicable financial recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the money laundering statutes of all jurisdictions, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency is pending or, to the knowledge of the Company, threatened, except, in each case, as would not reasonably be expected to have a Material Adverse Effect.

(mm) Neither the Company nor any of its subsidiaries (i) is in violation of its charter or by-laws or other governing documents, (ii) is in default, and no event has occurred which, with notice or lapse of time or both, would constitute such a default, in the due performance or observance of any term, covenant or condition contained in any material indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which it is a party or by which

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it is bound or to which any of its properties or assets is subject or (iii) except as disclosed in the most recent Preliminary Prospectus, is in violation of any law, ordinance, governmental rule, regulation or court decree to which it or its property or assets may be subject or has failed to obtain any license, permit, certificate, franchise variance, special exception or other governmental authorization or permit or municipal government approval necessary to the ownership of its property or to the conduct of its business, except, in the case of clauses (ii) and (iii), for such defaults, violations or failures to obtain as would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

(nn) Neither the Company nor any of its subsidiaries, nor any director, officer, employee or other person acting on behalf of the Company or any of its subsidiaries nor, to the best of the Company’s knowledge, any agent or other person associated with the Company, has used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; made any direct or indirect unlawful payment to any foreign or domestic government official or employee from corporate funds; violated or is in violation of any provision of the Foreign Corrupt Practices Act of 1977; or made any bribe, rebate, payoff, influence payment, kickback or other unlawful payment.

(oo) Except as disclosed in the most recent Preliminary Prospectus, there has been no storage, disposal, generation, manufacture, refinement, transportation, handling or treatment of toxic wastes, medical wastes, hazardous wastes or hazardous substances by the Company or any of its subsidiaries (or, to the knowledge of the Company, any of their predecessors in interest) at, upon or from any of the property now or previously owned or leased by the Company or its subsidiaries in violation of any applicable environmental law, ordinance, rule, regulation, order, judgment, decree or permit or which would require remedial action under any applicable environmental law, ordinance, rule, regulation, order, judgment, decree or permit, except for any violation or remedial action which would not have, or would not be reasonably likely to have, individually or in the aggregate with respect to all such violations and remedial actions, a Material Adverse Effect; there has been no material spill, discharge, leak, emission, injection, escape, dumping or release of any kind onto such property or into the environment surrounding such property of any toxic wastes, medical wastes, solid wastes, hazardous wastes or hazardous substances due to or caused by the Company or any of its subsidiaries or with respect to which the Company or any of its subsidiaries have knowledge, except for any such spill, discharge, leak, emission, injection, escape, dumping or release which is authorized pursuant to an applicable law or permit or which would not have or would not be reasonably likely to have, individually or in the aggregate with respect to all such spills, discharges, leaks, emissions, injections, escapes, dumpings and releases, a Material Adverse Effect. The terms “ hazardous wastes ”, “ toxic wastes ”, “ hazardous substances ” and “ medical wastes ” shall have the meanings specified in any applicable local, state, federal and foreign laws or regulations with respect to environmental protection.

(pp) Neither the Company nor any of its subsidiaries is, or, after giving effect to the offering and sale of the Stock and the application of the net proceeds therefrom as described in the Prospectus will be, an “investment company” as defined in the Investment Company Act of 1940, as amended together with the rules and regulations promulgated thereunder (the “ Investment Company Act ”).

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(qq) Except for this Agreement, there are no contracts, agreements or understandings between the Company and any person that would give rise to a valid claim against the Company or the Underwriter for a brokerage commission, finder’s fee or other like payment in connection with the offering and sale of the Stock contemplated by this Agreement.

(rr) Except as disclosed in the most recent Preliminary Prospectus, neither the Company nor any subsidiary has abandoned (or intends to abandon) any of its operating projects.

(ss) Except with respect to the Desert Peak 1 plant, the material mechanical, electrical and other operating systems on and in the Company’s operating projects are in all material respects in good working order and repair relative to their time in service (ordinary wear and tear excepted) and are adequate in all material respects for the operation of the projects by the Company and its subsidiaries as described in the most recent Preliminary Prospectus.

(tt) Except as disclosed in the most recent Preliminary Prospectus, there are no pending actions, suits or proceedings against or affecting the Company or any of its subsidiaries in connection with the condemnation or appropriation of any of its operating projects.

(uu) The Company has established and maintains disclosure controls and procedures (as such term is defined in Rule 13a-15 under the Exchange Act), which (i) are designed to ensure that material information relating to the Company, including its consolidated subsidiaries, is made known to the Company’s principal executive officer and its principal financial officer by others within those entities, particularly during the preparation of the Registration Statement, and in the future, during the periods in which the periodic reports required under the Exchange Act are being prepared and (ii) as of the date hereof are effective in all material respects to perform the functions for which they were established.

(vv) The Company is not aware of (i) any significant deficiency or material weakness in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the Company’s ability to record, process, summarize and report financial information except as disclosed in the most recent Preliminary Prospectus; or (ii) any fraud, whether or not material, that involves management or other employees who have a significant role in the Company’s internal control over financial reporting.

(ww) The Company has not distributed and, prior to the later to occur of the Delivery Date and completion of the distribution of the Stock, will not distribute any offering material in connection with the offering and sale of the Stock other than any Preliminary Prospectus, the Prospectus, any Issuer Free Writing Prospectus to which the Underwriter has consented in accordance with Section 1(i) or 5(a)(vi).

(xx) The Stock has been approved for listing, subject to official notice of issuance, on the New York Stock Exchange, Inc.

(yy) No consent, approval, authorization or order of, or filing or registration with, any court or governmental agency or body having jurisdiction over the Company or any of its subsidiaries or any of their properties or assets is required for the execution, delivery and performance of this Agreement by the Company, the consummation of the transactions contemplated hereby, the application of the proceeds from the sale of the Stock as described

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under “Use of Proceeds” in each of the most recent Preliminary Prospectus and the Prospectus, except for the registration of the Stock under the Securities Act and such consents, approvals, authorizations, registrations or qualifications as may be required under the Exchange Act and applicable state or foreign securities laws in connection with the purchase and sale of the Stock by the Underwriter.

(zz) There is and has been no failure on the part of the Company and any of the Company’s directors or officers, in their capacities as such, to comply with the provisions of the Sarbanes-Oxley Act of 2002 and the rules and regulations promulgated in connection therewith.

(aaa) No subsidiary of the Company is currently prohibited, directly or indirectly, from paying any dividends to the Company, from making any other distribution on such subsidiary’s capital stock, from repaying to the Company any loans or advances to such subsidiary from the Company or from transferring any of such subsidiary’s property or assets to the Company or any other subsidiary of the Company, except for certain restrictions contained in financing arrangements described in the most recent Preliminary Prospectus, or incorporated by reference therein.

(bbb) Neither the Company nor any of its subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee or affiliate of the Company or any of its subsidiaries is currently subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department (“ OFAC ”); and the Company will not directly or indirectly use the proceeds of the offering, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other person or entity, for the purpose of financing the activities of any person currently subject to any U.S. sanctions administered by OFAC.

(ccc) The Company has not taken and will not take, directly or indirectly, any action designed to or that has constituted or that could reasonably be expected to cause or result in the stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the shares of the Stock.

Each certificate signed by any officer of the Company and delivered to the Underwriter or counsel to the Underwriter in connection with the transaction contemplated hereunder shall be deemed to be a representation and warranty by the Company to the Underwriter as to the matters covered thereby.

S ECTION 2. Purchase of the Stock by the Underwriter . On the basis of the representations and warranties contained in, and subject to the terms and conditions of, this Agreement, the Company agrees to sell 3,100,000 shares of the Stock to the Underwriter and the Underwriter agrees to purchase from the Company 3,100,000 shares of the Stock. The price at which the Underwriter shall purchase the Stock from the Company shall be $48.36 per share.

The Company shall not be obligated to deliver any of the Stock to be delivered on the Delivery Date (as hereafter defined), except upon payment for all the Stock to be purchased on the Delivery Date as provided herein.

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S ECTION 3. Offering of Stock by the Underwriter . Upon the release of the Stock, the Underwriter proposes to offer the Stock for sale upon the terms and conditions set forth in the Prospectus.

S ECTION 4. Delivery of and Payment for the Stock . Delivery of and payment for the Stock shall be made at the offices of White & Case LLP, 1155 Avenue of the Americas, New York, New York, 10036, at 10:00 A.M., New York City time, on the third full business day following the date of this Agreement or at such other date or place as shall be determined by agreement between the Underwriter and the Company. This date and time are sometimes referred to as the “ Delivery Date .” On the Delivery Date, the Company shall deliver or cause to be delivered certificates representing the Stock to the Underwriter for the account of the Underwriter against payment to or upon the order of the Company of the purchase price by wire transfer in immediately available funds. Time shall be of the essence, and delivery at the time and place specified pursuant to this Agreement is a further condition of the obligation of the Underwriter hereunder. Upon delivery, the Stock shall be registered in such names and in such denominations as the Underwriter shall request in writing not less than two full business days prior to the Delivery Date. For the purpose of expediting the checking and packaging of the certificates for the Stock, the Company shall make the certificates representing the Stock available for inspection by the Underwriter in New York, New York, not later than 2:00 P.M., New York City time, on the business day prior to the Delivery Date.

S ECTION 5. Further Agreements of the Company . (a) The Company covenants and agrees:

(i) To prepare the Prospectus in a form approved by the Underwriter and to file such Prospectus pursuant to Rule 424(b) under the Securities Act not later than the Commission’s close of business on the second business day following the execution and delivery of this Agreement; to make no further amendment or any supplement to the Registration Statement or the Prospectus prior to the Delivery Date except as permitted herein; to advise the Underwriter, promptly after it receives notice thereof, of the time when any amendment or supplement to the Registration Statement or the Prospectus has been filed and to furnish the Underwriter with copies thereof; to file promptly all reports and any definitive proxy or information statements required to be filed by the Company with the Commission pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date of the Prospectus and for so long as the delivery of a prospectus is required in connection with the offering or sale of the Stock; to advise the Underwriter, promptly after it receives notice thereof, of the issuance by the Commission of any stop order or of any order preventing or suspending the use of the Prospectus or any Issuer Free Writing Prospectus, of the suspension of the qualification of the Stock for offering or sale in any jurisdiction, of the initiation or threatening of any proceeding for any such purpose or of any request by the Commission for the amending or supplementing of the Registration Statement, the Prospectus or any Issuer Free Writing Prospectus or for additional information; and, in the event of the issuance of any stop order or of any order preventing or suspending the use of the Prospectus or any Issuer Free Writing Prospectus or suspending any such qualification, to use promptly its best efforts to obtain its withdrawal;

(ii) To furnish promptly to each of the Underwriter and to counsel for the Underwriter a signed copy of the Registration Statement as originally filed with the Commission, and each amendment thereto filed with the Commission, including all consents and exhibits filed therewith;

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(iii) To deliver promptly to the Underwriter, without charge, such number of the following documents as the Underwriter shall reasonably request: (A) conformed copies of the Registration Statement as originally filed with the Commission and each amendment thereto (in each case excluding exhibits), (B) each Preliminary Prospectus, the Prospectus and any amended or supplemented Prospectus, (C) each Issuer Free Writing Prospectus and (D) any document incorporated by reference in any Preliminary Prospectus or the Prospectus; and, if a prospectus is required at any time after the date hereof in connection with the offering or sale of the Stock relating thereto and if at such time any events shall have occurred as a result of which the Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made when such Prospectus is delivered, not misleading, or, if for any other reason it shall be necessary to amend or supplement the Prospectus or to file under the Exchange Act any document incorporated by reference in the Prospectus in order to comply with the Securities Act or the Exchange Act, to notify the Underwriter and, upon its request, to file such document and to prepare and furnish without charge to the Underwriter and to any dealer in securities as many copies as the Underwriter may from time to time reasonably request of an amended or supplemented Prospectus which will correct such statement or omission or effect such compliance;

(iv) To file promptly with the Commission any amendment to the Registration Statement or the Prospectus or any supplement to the Prospectus that may, in the judgment of the Company or the Underwriter, be required by the Securities Act or requested by the Commission;

(v) For so long as a prospectus is required in connection with the offering or sale of the Stock, prior to filing with the Commission any amendment or supplement to the Registration Statement or the Prospectus, any document incorporated by reference in the Prospectus or any amendment to any document incorporated by reference in the Prospectus, to furnish a copy thereof to the Underwriter and counsel for the Underwriter and obtain the consent of the Underwriter to the filing (which consent shall not be unreasonably withheld);

(vi) Not to make any offer relating to the Stock that would constitute an Issuer Free Writing Prospectus without the prior written consent of the Underwriter;

(vii) To retain in accordance with the Rules and Regulations all Issuer Free Writing Prospectuses not required to be filed pursuant to the Rules and Regulations; and if at any time after the date hereof any events shall have occurred as a result of which any Issuer Free Writing Prospectus, as then amended or supplemented, would conflict with the information in the Registration Statement, the most recent Preliminary Prospectus or