STOCK PURCHASE WARRANT To Purchase Shares of Common Stock of RENEWABLE ENERGY GROUP, INC.

Exhibit 4.5

THIS WARRANT, AND ANY SHARES OF COMMON STOCK ACQUIRED UPON THE EXERCISE OF THIS WARRANT, HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ ACT ”) OR ANY OTHER APPLICABLE SECURITIES LAWS. THIS WARRANT HAS BEEN ACQUIRED FOR INVESTMENT AND NEITHER THIS WARRANT NOR ANY OF SUCH SHARES MAY BE SOLD OR TRANSFERRED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION OF THEM UNDER THE ACT AND ANY OTHER APPLICABLE SECURITIES LAW, OR RECEIPT BY THE COMPANY OF AN OPINION OF COUNSEL OR OTHER EVIDENCE ACCEPTABLE TO THE COMPANY THAT SUCH SALE OR TRANSFER IS EXEMPT FROM REGISTRATION UNDER THE ACT. NEITHER THIS WARRANT NOR ANY OF SUCH SHARES MAY BE TRANSFERRED EXCEPT UPON THE CONDITIONS SPECIFIED IN THIS WARRANT, AND NO TRANSFER OF THIS WARRANT OR ANY OF SUCH SHARES SHALL BE VALID OR EFFECTIVE UNLESS AND UNTIL SUCH CONDITIONS SHALL HAVE BEEN COMPLIED WITH. TRANSFER OF THIS WARRANT OR ANY OF SUCH SHARES IS FURTHER RESTRICTED AS PROVIDED IN THE AMENDED AND RESTATED STOCKHOLDER AGREEMENT DATED JULY 18, 2007 (THE “ STOCKHOLDER AGREEMENT ”), A COPY OF WHICH IS AVAILABLE AT THE COMPANY’S OFFICES.

STOCK PURCHASE WARRANT

To Purchase Shares of

Common Stock of

RENEWABLE ENERGY GROUP, INC.

THIS CERTIFIES THAT, for value received, the receipt and sufficiency of which is hereby acknowledged:

Subject to the conditions set forth herein, Natural Gas Partners VIII, L.P., together with any of its registered assigns or any transferee of all or any portion of its rights hereunder and the holder of any shares of Common Stock issued hereunder (the “ Holder ” or “ Holders ”), is entitled to subscribe for and purchase from Renewable Energy Group, Inc., a Delaware corporation (the “ Company ”), at any time or from time to time after the date hereof and continuing during the Exercise Period (as defined hereinafter),              fully paid and nonassessable shares of the Company’s common stock, par value $0.0001 per share (the “ Common Stock ”), at an exercise price of $11.00 per share (the “ Exercise Price ”), subject to adjustment from time to time pursuant to the provisions of this Warrant (the “ Warrant Shares ”). This Warrant is subject to the following provisions, terms and conditions:

1. Definitions . For the purpose of the Warrants, the following terms, whether or not capitalized or underlined is the text of this Warrant, shall have the following meanings:

“ Capital Stock ” shall mean any and all shares, interests, participations, or other equivalents (however designated) of capital stock of the Company, including, without limitation, shares of Common Stock or Preferred Stock.

“ Common Stock ” shall mean the common stock, par value $0.0001 per share, of the Company.

“ Company ” shall have the meaning specified in the introduction to this Warrant, and shall include any corporation or business entity resulting from the merger, consolidation, or conversion of the Company.

“ Exercise Agreement ” shall have the meaning specified in paragraph 2(a) hereof.

“ Exercise Period ” shall have the meaning specified in paragraph 2(c) hereof.

“ Exercise Price ” shall have the meaning specified in the introduction to this Warrant.

“ Expiration Date ” means the eighth anniversary of the Date of Issuance.

“ Preferred Stock ” shall mean any shares of preferred stock issued by the Company on or after the Date of Issuance, whether or not convertible into or exchangeable for Common Stock.

“ Series B Certificate ” means the Certificate of Designation of Series and Determination of Rights and Preferences of Series B Convertible Preferred Stock of the Company as the terms thereof may be amended from time to time.

“ Trading Days ” shall mean any days during the course of which the principal securities exchange on which the Common Stock is listed or admitted to trading is open for the exchange of securities.

“ Warrant(s) ” shall mean this Warrant of even date herewith, including all amendments to any such Warrants and all warrants issued in exchange, transfer or replacement therefor.

2. Exercise of Warrant . While this Warrant remains outstanding and exercisable in accordance with subparagraph 2(c) below, the Holder may exercise, in whole or in part, the purchase rights evidenced hereby. Such exercise shall be effected by:

(a) Cash Exercise . The rights represented by this Warrant may be exercised in a cash exercise by (i) the surrender of the Warrant, together with a completed Exercise Agreement in the form attached hereto (“ Exercise Agreement ”) indicating a cash exercise, to the Secretary of the Company at its principal offices, (ii) the payment to the Company of an amount equal to the aggregate Exercise Price, for the number of Warrant Shares being purchased, in cash (in the form of immediately available funds in U.S. Dollars), and (iii) full compliance with the other applicable provisions of this Warrant.

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(b) Net Exercise . Notwithstanding anything contained in subparagraph 2(a) above, the holder of the Warrant may also elect to exercise this Warrant on a “net exercise” basis by (i) the surrender of the Warrant, together with a completed Exercise Agreement indicating a net exercise, to the Secretary of the Company at its principal offices and (ii) full compliance with the other applicable provisions of this Warrant. Upon a “net exercise” of the Warrant, the Company shall issue to the Holder a number of shares of Common Stock computed using the following formula:

For purposes of this Warrant, the “ Fair Market Value Price ” of a share of Common Stock shall mean the average of the closing sales prices, if available, and, if not then available, the average of the bid and asked prices for the Common Stock, as applicable, on the principal market therefor for the five (5) Trading Days preceding the day which is two (2) business days prior to the day of exercise, or if no such price is available, then the fair market value shall be determined in good faith by a majority of the Board of Directors of the Company (excluding any director nominated by or otherwise affiliated with the Holder or an affiliate of the Holder), and in making such determination it shall not give consideration to any discount related to shares representing minority interest or related to any illiquidity or lack of marketability of shares arising from restrictions on transfer under federal or state securities laws. If the Holder of the Warrant to be exercised disagrees with such determination of Fair Market Value Price, such Holder shall provide written notice to the Company thereof (a “ Value Dispute ”) and the Fair Market Value Price of a share of Common Stock as of the day of exercise shall be determined by the following procedures. Each of the Company, on the one hand, and the Holder submitting the Value Dispute, on the other hand, shall appoint an independent appraiser, each of whom shall independently determine the Fair Market Value Price per share of Common Stock (the “ Appraised Values ”). If the higher of the Appraised Values is not more than 25% higher than the lower of the Appraised Values, then the Fair Market Value Price per share will be the average of the two Appraised Values. If the higher of the Appraised Values is more than 25% higher than the lower of the Appraised Values, then the parties shall appoint a third independent appraiser who shall, within thirty (30) days following receipt of the Appraised Values, select one of the two Appraised Values as the Fair Market Value Price per share which is closest to the Fair Market Value Price per share determined by such third independent appraiser (the “ Third Appraiser’s Determination ”). The Third Appraiser’s Determination shall be binding on and non-appealable by the Company and the Holder of the Warrant to be exercised. In the event of a Third Appraiser’s Determination, if the aggregate amount by which the Fair Market Value Price of the Warrant Shares being exercised exceeds the aggregate exercise price, is less than $5,000,000, the cost of all independent appraisers shall be paid by the Holder, and if the amount of such excess is $5,000,000 or more, each of the Company and the Holder shall pay the costs of the independent appraiser approved by it and the cost of the third independent appraiser shall be

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split equally by the Company and the Holder. In calculating the aggregate value of the Warrant for purposes of the foregoing agreement regarding allocation of appraisal expenses, there shall be added to the aggregate value determined as described above, the aggregate value determined in connection with the same procedure under any Warrant held by an affiliate of the Holder and exercised as of (or within three (3) business days of) the exercise date of this Warrant. Notwithstanding the foregoing, in the event the Warrant is exercised in connection with the Company’s initial public offering of Common Stock, the fair market value per share shall be the per share offering price to the public of the Common Stock in the Company’s initial public offering.

(c) Exercise Period . This Warrant is exercisable at any time or from time to time during the period from the date hereof until the Expiration Date (the “ Exercise Period ”).

(d) Issuance of Certificates . Certificates for the Warrant Shares, representing the aggregate number of shares specified in said Exercise Agreement, shall be delivered to the Holder within a reasonable time, not exceeding five (5) business days, after the rights represented by this Warrant shall have been so exercised. The stock certificate or certificates so delivered shall be in such denominations as may be requested by the holder hereof and shall be registered in the name of said Holder or such other name as shall be designated by said Holder (subject to the transfer restrictions applicable to this Warrant and to shares purchased upon exercise of this Warrant). If this Warrant shall have been exercised only in part, then, unless this Warrant has expired, the Company shall, at its expense, at the time of delivery of said stock certificates(s), deliver to said Holder a new Warrant representing the right to purchase the number of shares of Common Stock with respect to which this Warrant shall not then have been exercised. The Company shall pay all expenses and charges payable in connection with the preparation, execution and delivery of stock certificates (and any new Warrants) pursuant to this paragraph 2 except that, in case such stock certificates shall be registered in a name or names other than the Holder of this Warrant or such Holder’s nominee, funds sufficient to pay all stock transfer taxes which shall be payable in connection with the execution and delivery of such stock certificates shall be paid by the Holder to the Company at the time of delivery of such stock certificates by the Company as mentioned above.

(e) No Fractional Shares . This Warrant shall be exercisable only for a whole number of Warrant Shares. No fractions of shares of Common Stock, or scrip for any such fractions of shares, shall be issued upon the exercise of this Warrant. The Company shall pay a cash adjustment in respect of such fractional interest in an amount equal to the Fair Market Value Price of one share of Common Stock at the time of such exercise multiplied by such fraction computed to the nearest whole cent.

3. Shares to be Fully Paid; Reservations of Shares . The Company covenants and agrees that all Warrant Shares will be duly authorized and validly issued and upon issuance in accordance with the terms and conditions hereof, will be fully paid and nonassessable and free from all taxes, liens and charges with respect to the issue thereof. Without limiting the generality of the foregoing, the Company covenants and agrees that it will from time to time take all such action as may be required to assure that the par value per Warrant Share is at all times equal to or less than the Exercise Price then in effect. The Company further covenants and agrees that during the period within which the rights represented by this Warrant may be exercised, the

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Company shall at all times reserve and keep available out of its authorized but unissued shares of Common Stock, solely for the purpose of effecting the exercise of the rights represented by this Warrant and any other Warrants, such number of its shares of Common Stock as shall from time to time be sufficient to effect the exercise of all then outstanding Warrants; and if at any time the number of authorized but unissued shares of Common Stock shall not be sufficient to effect the exercise of all then outstanding Warrants, in addition to such other remedies as shall be available to the Holder, the Company will take such corporate action as may, in the opinion of its counsel, be necessary to increase its authorized but unissued shares of Common Stock to such number of shares as shall be sufficient for such purposes, including, without limitation, engaging in best efforts to obtain the requisite stockholder approval of any necessary amendment to the Certificate of Incorporation.

4. Anti-Dilution Provisions . The number, rights and privileges of the shares of Common Stock issuable upon exercise of this Warrant shall be subject to the following adjustments:

(a) Below Market Transactions .

(i) If the Company shall issue, after the Date of Issuance, any Additional Stock (as defined below) without consideration or for a consideration per share less than the Exercise Price in effect immediately prior to the issuance of such Additional Stock, the Exercise Price in effect immediately prior to each such issuance shall forthwith (except as otherwise provided in this subparagraph 4(a)(i)) be adjusted to a price determined by multiplying such Exercise Price by a fraction, the numerator of which shall be the number of shares of Common Stock outstanding immediately prior to such issuance (including shares of Common Stock deemed to be issued pursuant to subparagraph 4(a)(v)(A) or (B) below) plus the number of shares of Common Stock that the aggregate consideration received by the Company for such issuance would purchase at such Exercise Price; and the denominator of which shall be the number of shares of Common Stock outstanding immediately prior to such issuance (including shares of Common Stock deemed to be issued pursuant to subparagraph 4(a)(v)(A) or (B) below) plus the number of shares of such Additional Stock; provided, however, for purposes of such calculation (1) it shall not include any additional shares of Common Stock issuable with respect to shares of Preferred Stock, convertible securities, or exercisable options, warrants or other rights for the purchase of shares of stock or convertible securities, solely as a result of the adjustment of such Exercise Price resulting from the issuance of Additional Stock causing such adjustment and (2) the grant, issue or sale of Additional Stock consisting of the same class of security, and warrants to purchase such security and notes convertible into such security, issued or issuable at the same price at two or more closings within a six month period shall be aggregated and shall be treated as one sale of Additional Stock occurring on the earliest date on which such securities were granted, issued or sold.

(ii) No adjustment of the Exercise Price shall be made in an amount less than one cent per share, provided that any adjustments that are not required to be made by reason of this sentence shall be carried forward and shall be either taken into account in any subsequent adjustment made prior to three (3) years from the date of the event giving rise to the adjustment being carried forward, or shall be made at the end of three (3) years from the date of the event giving rise to the adjustment being carried forward. Except to the limited extent

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provided for in subparagraphs 4(a)(v)(C) and (D) below, no adjustment of such Exercise Price pursuant to this subparagraph 4(a) shall have the effect of increasing the Exercise Price above the Exercise Price in effect immediately prior to such adjustment.

(iii) In the case of the issuance of Common Stock for cash, the consideration shall be deemed to be the amount of cash paid th