Exhibit 4.1

WARRANT

NEITHER THIS WARRANT NOR THE SECURITIES INTO WHICH THIS WARRANT IS EXERCISABLE HAVE BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR APPLICABLE STATE SECURITIES LAWS.  THE SECURITIES MAY NOT BE OFFERED FOR SALE, SOLD, TRANSFERRED OR ASSIGNED (I) IN THE ABSENCE OF (A) AN EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR (B) AN OPINION OF COUNSEL, IN A FORM REASONABLY ACCEPTABLE TO THE COMPANY, THAT REGISTRATION IS NOT REQUIRED UNDER SAID ACT OR (II) UNLESS SOLD PURSUANT TO RULE 144 OR RULE 144A UNDER SAID ACT.

LIME ENERGY CO.

WARRANT TO PURCHASE COMMON STOCK

Warrant No.:  158

Number of Shares of Common Stock:  275,000 (subject to adjustment)

Exercise Price:  $0.51 per share (subject to adjustment) (“Exercise Price”)

Date of Issuance:  December 12, 2012 (“Issuance Date”)

Lime Energy Co., a Delaware corporation (the “Company”), hereby certifies that, for value received, Richard P. Kiphart, the registered holder hereof or his permitted assigns (the “Holder”), is entitled, subject to the terms set forth below, to purchase from the Company, at the Exercise Price (as defined below) then in effect, upon surrender of this Warrant (including any Warrants to purchase Common Stock issued in exchange, transfer or replacement hereof, the “Warrant”), at any time or times on or after the date hereof, but not after 11:59 p.m., New York time, on the Expiration Date (as defined below), Two Hundred Seventy Five Thousand (275,000) fully-paid nonassessable shares of Common Stock (as defined below) (the “Warrant Shares”).  Except as otherwise defined herein, capitalized terms in this Warrant shall have the meanings set forth in Section 15.  This Warrant is being issued pursuant to the Letter of Credit Agreement, dated as of December 7, 2012, by and among the Company and Richard P. Kiphart (the “L/C Agreement”).

1.                                      EXERCISE OF WARRANT.

(a)                                 Mechanics of Exercise.  Subject to the terms and conditions hereof, this Warrant may be exercised by the Holder, in whole or in part, at any time during the Exercise Period by (i) delivery of a written notice, in the form attached hereto as Exhibit A (the “Exercise Notice”), of the Holder’s election to exercise this Warrant, which notice shall specify the number of Warrant Shares to be purchased and (ii) (A) payment to the Company of an amount equal to the applicable Exercise Price multiplied by the number of Warrant Shares as to which this Warrant is being exercised (the “Aggregate Exercise Price”) in cash or by wire transfer of immediately available funds or (B) by notifying the Company that this Warrant is being exercised pursuant to a Cashless Exercise (as defined in Section 1(d)), and (iii) delivery to the Company of this Warrant (or an indemnity and evidence with respect to this Warrant in the case of its loss, theft, mutilation or destruction, as provided in Section 7(c)).  Execution and delivery of the Exercise Notice with respect to less than all of the Warrant Shares shall have the same effect as cancellation of the original Warrant and issuance of a new Warrant evidencing the right to purchase the remaining number of Warrant Shares.  On or before the third (3rd) Business Day following the date on which the Company has received Exercise Notice, the Aggregate Exercise Price (or

notice of a Cashless Exercise) and this Warrant (or an indemnity and evidence with respect to this Warrant in the case of its loss, theft, mutilation or destruction, as provided in Section 7(c)) (the “Exercise Delivery Documents”), the Company shall transmit by facsimile an acknowledgment of confirmation of receipt of the Exercise Delivery Documents to the Holder and the Company’s transfer agent (the “Transfer Agent”).  On or before the third (3rd) Business Day following the date on which the Company has received all of the Exercise Delivery Documents (the “Share Delivery Date”), the Company shall (X) provided that the Transfer Agent is participating in The Depository Trust Company (“DTC”) Fast Automated Securities Transfer Program, upon the request of the Holder, credit such aggregate number of shares of Common Stock to which the Holder is entitled pursuant to such exercise to the Holder’s or its designee’s balance account with DTC through its Deposit Withdrawal Agent Commission system, which balance account shall be specified in the Exercise Notice, or (Y) if the Transfer Agent is not participating in the DTC Fast Automated Securities Transfer Program, issue and dispatch by overnight courier to the address as specified in the Exercise Notice, a certificate, registered in the Company’s share register in the name of the Holder or its designee, for the number of shares of Common Stock to which the Holder is entitled pursuant to such exercise. Upon receipt by the Company of the Exercise Delivery Documents, the Holder shall be deemed for all corporate purposes to have become the holder of record of the Warrant Shares with respect to which this Warrant has been exercised, irrespective of the date of delivery of the certificates evidencing such Warrant Shares.

(b)                                 Partial Exercise. If this Warrant is submitted in connection with any exercise pursuant to this Section 1(a) and the number of Warrant Shares represented by this Warrant submitted for exercise is greater than the number of Warrant Shares being acquired upon an exercise, then the Company shall as soon as practicable and in no event later than ten (10) Business Days after any exercise and at its own expense, issue a new Warrant (in accordance with Section 7(d)) representing the right to purchase the number of Warrant Shares purchasable immediately prior to such exercise under this Warrant, less the number of Warrant Shares with respect to which this Warrant is exercised.

(c)                                  No Fractional Shares. No fractional shares of Common Stock are to be issued upon the exercise of this Warrant, but rather the number of shares of Common Stock to be issued shall be rounded up to the nearest whole number.  The Company shall pay any and all taxes which may be payable with respect to the issuance and delivery of Warrant Shares upon exercise of this Warrant.

(d)                                 Company’s Failure to Timely Deliver Securities. Upon the Company’s receipt of an Exercise Delivery Documents or request for removal of restrictive legends on the shares of Common Stock issuable in connection therewith, the Company will deliver, or cause to be delivered, the certificates evidencing such shares of Common Stock to the Holder within three (3) Trading Days.  If the certificates have not been delivered by the fifth (5th) Trading Day after valid conversion or request for removal of legend, as the case may be, and the Holder, or any third party on behalf of Holder or for Holder’s account, has purchased (in an open market transaction or otherwise) Common Stock to deliver in satisfaction of a sale by the Holder of Common Stock issuable upon such conversion or represented by such certificate that the Holder anticipated receiving from the Company (a “Buy-In”), then the Company shall, within three (3) Trading Days after the Holder’s request promptly honor its obligation to deliver to the Holder a certificate or certificates representing such Common Stock and pay in cash to the Holder (for costs incurred either directly by such Holder or on behalf of a third party) the amount by which the total purchase price paid for Common Stock as a result of the Buy-In (including brokerage commissions, if any) exceeds the proceeds received by such Holder as a result of the sale to which the Buy-In relates.  The Holder shall provide the Company written notice indicating the amounts payable to the Holder in respect of the Buy-In.

(e)                                  Cashless Exercise.  Notwithstanding anything provisions herein to the contrary, if at the time this Warrant is exercised, (a) there is no effective registration statement registering, or the

prospectus contained therein is not available for, the issuance of the Warrant Shares to the Holder, (ii) all of the Warrant Shares are not then registered for resale by the Holder into the market at market prices from time to time on an effective registration statement for use on a continuous basis (or the prospectus contained therein is not available or used) and (iii) the Current Market Price (as defined below) of one share of Common Stock is greater than the Exercise Price (at the date of calculation as set forth below), then in lieu of exercising this Warrant by payment of cash, the Holder may exercise this Warrant by a cashless exercise by surrender of this Warrant at the principal office of the Company (or at such other address as it may designate by notice in writing to the Holder) together with the properly endorsed Notice of Exercise and the Company shall issue to the Holder a number of shares of Common Stock computed using the following formula:

“Current Market Price” means on any particular date:

(a)                     if the Common Stock is traded on the NASDAQ Global Market or the NASDAQ Capital Market, the closing price of the Common Stock of the Company on such market on the Trading Day prior to the applicable date of valuation;

(b)                     if the Common Stock is traded on any registered national stock exchange but is not traded on the NASDAQ Global Market or the NASDAQ Capital Market, the closing price of the Common Stock of the Company on such exchange on the Trading Day prior to the applicable date of valuation;

(c)                      if the Common Stock is traded over-the-counter, but not on the NASDAQ Global Market, the NASDAQ Capital Market or a registered national stock exchange, the closing bid price of the Common Stock of the Company on the day prior to the applicable date of valuation; and

(d)                     if there is no active public market for the Common Stock, the value thereof, as determined in good faith by the Board of Directors of the Company.

(f)                                   Disputes.  In the case of a dispute as to the determination of the Exercise Price or the arithmetic calculation of the Warrant Shares, the Company shall promptly issue to the Holder the number of Warrant Shares that are not disputed and resolve such dispute in accordance with Section 11.

(g)                                  Insufficient Authorized Shares.  If at any time while any of the Warrants remain outstanding the Company does not have a sufficient number of authorized and unreserved shares of Common Stock (an “Authorized Share Failure”) to satisfy its obligation to reserve for issuance upon exercise of the Warrants no less than the number of shares of Common Stock as shall from time to time be necessary to effect the exercise of all of the Warrants then outstanding (in addition to all other convertible securities) (the “Required Reserve Amount”), then the Company shall immediately take all action necessary to increase the Company’s authorized shares of Common Stock to an amount sufficient to allow the Company to reserve the Required Reserve Amount for the Warrants then outstanding.  Without limiting the generality of the foregoing sentence, as soon as practicable after the date of the occurrence of an Authorized Share Failure, but in no event later than ninety (90) days after the occurrence

of such Authorized Share Failure, the Company shall hold a meeting of its stockholders for the approval of an increase in the number of authorized shares of Common Stock.  In connection with such meeting, the Company shall provide each stockholder with a proxy statement and shall use its best efforts to solicit its stockholders’ approval of such increase in authorized shares of Common Stock and to cause its board of directors to recommend to the stockholders that they approve such proposal.

(h)                                 Limitations on Conversions.  The Company shall not be obligated to issue any shares of Common Stock upon exercise of this Warrant, and no Holder shall be entitled to receive any shares of Common Stock if the issuance of such shares of Common Stock would exceed that number of shares of Common Stock which the Company may issue upon conversion of the Convertible Notes and exercise of the Convertible Note Warrants, this Warrant or otherwise without breaching the Company’s obligations under the rules or regulations of the Principal Market (the “Exchange Cap”), except that such limitation shall not apply in the event that the Company (i) obtains the approval of its stockholders as required by the applicable rules of the Principal Market for issuances of shares of Common Stock in excess of such amount or (ii) obtains a written opinion from outside counsel to the Company that such approval is not required, which opinion shall be reasonably satisfactory to the holders of the Convertible Notes, the Convertible Note Warrants and this Warrant.  Until such approval or written opinion is obtained, no Holder shall be issued in the aggregate, upon exercise of this Warrant, shares of Common Stock in an amount greater than the product of the Exchange Cap multiplied by a fraction, the numerator of which is the total number of shares of Common Stock underlying the Convertible Notes, the Convertible Note Warrants and this Warrant determined as of the Issuance Date and the denominator of which is the aggregate number of shares of Common Stock underlying all the outstanding Convertible Notes, the Convertible Note Warrants and this Warrant (with respect to such holder, the “Exchange Cap Allocation”).  In the event that the Holder shall sell or otherwise transfer any of this Warrant, the transferee shall be allocated a pro rata portion of the Holder’s Exchange Cap Allocation, and the restrictions of the prior sentence shall apply to such transferee with respect to the portion of the Exchange Cap Allocation allocated to such transferee.  In the event that any holder of this Warrant, or portion thereof, shall exercise this Warrant, or a portion thereof, for a number of shares of Common Stock which, in the aggregate, is less than such holder’s Exchange Cap Allocation, then the difference between such holder’s Exchange Cap Allocation and the number of shares of Common Stock actually issued to such holder shall be allocated to the respective Exchange Cap Allocations of the remaining holders of any portion of this Warrant on a pro rata basis in proportion to the total number of shares of Common Stock underlying the portion of this Warrant then held by each such holder

2.                                      ADJUSTMENT OF EXERCISE PRICE AND NUMBER OF WARRANT SHARES.  The Exercise Price and the number of Warrant Shares shall be adjusted from time to time as follows:

(a)                                 Adjustment upon Subdivision or Combination of Common Stock.  If the Company at any time on or after the Issuance Date subdivides (by any stock split, stock dividend, recapitalization or otherwise) one or more classes of its outstanding shares of Common Stock into a greater number of shares, the Exercise Price in effect immediately prior to such subdivision will be proportionately reduced and the number of Warrant Shares will be proportionately increased.  If the Company combines (by combination, reverse stock split or otherwise) one or more classes of its outstanding shares of Common Stock into a smaller number of shares, the Exercise Price in effect immediately prior to such combination will be proportionately increased and the number of Warrant Shares will be proportionately decreased.  Any adjustment under this Section 2(a) shall become effective at the close of business on the date the subdivision or combination becomes effective.

(b)                                 Minimum Adjustment.  No adjustment in the Exercise Price and the number of Warrants shall be required unless such adjustment would require an increase or decrease of at least 1% in the Exercise Price as last adjusted; provided, however, that any adjustments which would be required to

be made but for this Section 2(b) shall be carried forward and taken into account in any subsequent adjustment.  All calculations under this Section 2 shall be made to the nearest cent, with one half cent being rounded upward.

(c)                                  Notification of Adjustment. Upon any adjustment of the Warrant Exercise Price or number of issuable Warrant Shares pursuant to this Section 2, the Company shall give written notification to the Holder, setting forth in reasonable detail, the calculation of such adjustment.

3.                                      COVENANTS OF THE COMPANY.

(a)                                 Covenants as to Exercise Shares.  The Company covenants and agrees that it will at all times during the Exercise Period, have authorized and reserved, free from preemptive rights, a sufficient number of shares of its Common Stock to provide for the exercise of the rights represented by this Warrant.  All Warrant Shares will, upon issuance, be validly issued and outstanding, fully paid and nonassessable, and free from all taxes, liens and charges with respect to the issuance thereof. If at any time during the Exercise Period the number of authorized but unissued shares of Common Stock shall not be sufficient to permit exercise of this Warrant, 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 (or other securities as provided herein) to such number of shares as shall be sufficient for such purposes.

(b)                                 No Impairment.  Except and to the extent as waived or consented to by the Holder, the Company will not, by amendment of its Certificate of Incorporation (as such may be amended from time to time), or through any means, avoid or seek to avoid the observance or performance of any of the terms to be observed or performed hereunder by the Company, but will at all times assist in the carrying out of all the provisions of this Warrant and in the taking of all such action as may be necessary or appropriate in order to protect the exercise rights of the Holder against impairment.

4.                                      CERTAIN ADJUSTMENTS.

(a)                                 Subdivisions, Combinations and Other Issuances.  In the event the Company pays a dividend in Common Stock or makes a distribution in Common Stock or any other equity or equity equivalent securities payable in shares of Common Stock to holders of its outstanding Common Stock; subdivides its outstanding Common Stock into a greater number of shares; combines its outstanding Common Stock into a smaller number of shares; or issues any shares of its capital stock in a reclassification of the Common Stock, the number and class of shares available under this Warrant in the aggregate and the Exercise Price shall be correspondingly adjusted to give the Holder of this Warrant, on exercise for the same aggregate Exercise Price, the total number, class, and kind of shares as the Holder would have owned had this Warrant been exercised prior to the event and had the Holder continued to hold such shares until after the event requiring adjustment.  The form of this Warrant need not be changed because of any adjustment in the number, class, and kind of shares subject to this Warrant. Upon request, the Company shall promptly provide to the Holder a certificate from its Chief Financial Officer, which certificate shall specify the Exercise Price and number, class and kind of shares under this Warrant after giving effect to such adjustment.

(b)                                 Pro Rata Distributions.  If the Company, at any time while this Warrant is outstanding, distributes to holders of Common Stock (i) evidences of its indebtedness, (ii) any security (other than a distribution of Common Stock subject to Section 4(a), (iii) rights or warrants to subscribe for or purchase any security, or (iv) any other asset (in each case, “Distributed Property”), then in each such case the Holder shall be entitled upon exercise of this Warrant for the purchase of any or all of the Warrant Shares, to receive the amount of Distributed Property which would have been payable to the Holder had such Holder been the holder of such Warrant Shares on the record date for the determination

of stockholders entitled to such Distributed Property. The Company will at all times set aside and keep available for distribution to the Holder upon exercise of this Warrant a portion of the Distributed Property to satisfy the distribution to which such Holder is entitled pursuant to the preceding sentence.

(c)                                  Fundamental Transactions.  If the Company consummates (i) a merger or consolidation with or into another entity, as a result of which the holders of the Company’s outstanding voting securities as of immediately prior to such merger or consolidation hold less than a majority of the outstanding voting securities of the surviving or successor entity as of immediately after such merger or consolidation or (ii) a sale, transfer or other disposition of all or substantially all its property, assets or business to another person or entity (any such transaction being hereinafter referred to as a “Fundamental Transaction”), then the Company shall ensure that lawful and adequate provision shall be made whereby the Holder shall thereafter have the right to purchase and receive upon the basis and upon the terms and conditions herein specified and in lieu of the Warrant Shares immediately theretofore issuable upon exercise of this Warrant, such shares of stock, securities or assets as would have been issuable or payable with respect to or in exchange for a number of Warrant Shares equal to the number of Warrant Shares immediately theretofore issuable upon exercise of this Warrant, had such Fundamental Transaction not taken place.  The provisions of this Section 4(c) shall similarly apply to successive consolidations, mergers, sales, transfers or other dispositions.

5.                                      FRACTIONAL SHARES.  No fractional shares shall be issued upon the exercise of this Warrant as a consequence of any adjustment pursuant hereto.  All Warrant Shares (including fractions) issuable upon exercise of this Warrant may be aggregated for purposes of determining whether the exercise would result in the issuance of any fractional share.  If, after aggregation, the exercise would result in the issuance of a fractional share, the Company shall, in lieu of issuance of any fractional share, at its option, pay the Holder otherwise entitled to such fraction a sum in cash equal to the product resulting from multiplying the then Current Market Price of a Warrant Share by such fraction, or round up such fraction to the next whole number of Warrant Shares.

6.                                      NO STOCKHOLDER RIGHTS.  This Warrant in and of itself shall not entitle the Holder to any voting rights or other rights as a stockholder of the Company.

7.                                      REGISTRATION, TRANSFER AND REISSUANCE.

(a)                                 Registration.  The Company shall register this Warrant, upon the records to be maintained by the Company for that purpose (the “Warrant Register”), in the name of the record Holder hereof from time to time.  The Company may deem and treat the registered Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary.  The Company also shall register any transfer, exchange, reissuance or cancellation of any portion of this Warrant in the Warrant Register.

(b)                                 Transfer.  This Warrant may be offered for sale, sold, transferred or assigned without the consent of the Company, except as may otherwise be required by applicable securities laws. Subject to applicable securities laws, if this Warrant is to be transferred, the Holder shall surrender this Warrant to the Company, together with all applicable transfer taxes, whereupon the Company will issue and deliver upon the order of the Holder a new Warrant (in accordance with Section 7(d), registered as the Holder may request, representing the right to purchase the number of Warrant Shares being transferred by the Holder and, if less than the total number of Warrant Shares then underlying this Warrant is being transferred, a new Warrant (in accordance with Section 7(d)) to the Holder representing the right to purchase the number of Warrant Shares not being transferred. The acceptance of the new Warrant by the transferee thereof shall be deemed the acceptance by such transferee of all of the rights and obligations in respect of the new Warrant that the Holder has in respect of this Warrant.

(c)                                  Lost, Stolen, Mutilated or Destroyed Warrant.  If this Warrant is lost, stolen, mutilated or destroyed, the Company may, on such terms as to indemnity or otherwise as it may reasonably impose (which shall, in the case of a mutilated Warrant, include the surrender thereof to the Company), cause the Company to issue a new Warrant of like denomination and tenor as the Warrant so lost, stolen, mutilated or destroyed.

(d)                                 Issuance of New Warrants.  Whenever the Company is required to issue a new Warrant pursuant to the terms of this Warrant, such new Warrant shall (a) be of like tenor with this Warrant, (b) represent, as indicated on the face of such new Warrant, the right to purchase the Warrant Shares then underlying this Warrant (or in the case of a new Warrant being issued pursuant to Section 7(b) or Section 7(c), the Warrant Shares designated by the Holder which, when added to the number of shares of Common Stock underlying the other new Warrants issued in connection with such issuance, does not exceed the number of Warrant Shares then underlying this Warrant), (c) have an issuance date, as indicated on the face of such new Warrant which is the same as the Issuance Date and (d) have the same rights and conditions as this Warrant.

8.                                      MODIFICATIONS AND WAIVER.  This Warrant and any provision hereof may be waived, modified or amended only by an instrument in writing signed by the Company and the Holder.

9.                                      NOTICES, ETC.  All notices required or permitted hereunder shall be in writing and shall be deemed effectively given: (a) upon personal delivery to the party to be notified, (b) when sent by confirmed email, telex or facsimile if sent during normal business hours of the recipient, if not, then on the next business day, or (c) one business day after deposit with a nationally recognized overnight courier, specifying next day delivery, with written verification of receipt. All communications shall be sent to the Company at the address listed on the signature page and to the Holders at the addresses on the Company records, or at such other address as the Company or Holder may designate by ten days’ advance written notice to the other party hereto.

10.                               ACCEPTANCE.  Receipt of this Warrant by the Holder shall constitute acceptance of and agreement to all of the terms and conditions contained herein.

11.                               GOVERNING LAW.  This Warrant shall be governed by and construed and enforced in accordance with, and all questions concerning the construction, validity, interpretation and performance of this Warrant shall be governed by, the internal laws of the State of Delaware, without giving effect to any choice of law or conflict of law provision or rule (whether of the State of Delaware or any other jurisdictions) that would cause the application of the laws of any jurisdictions other than the State of Delaware.  The Company hereby irrevocably submits to the exclusive jurisdiction of the state and federal courts sitting in the State of Illinois for the adjudication of any dispute hereunder or in connection herewith or with any transaction contemplated hereby or discussed herein, and hereby irrevocably waives, and agrees not to assert in any suit, action or proceeding, any claim that it is not personally subject to the jurisdiction of any such court, that such suit, action or proceeding is brought in an inconvenient forum or that the venue of such suit, action or proceeding is improper.  Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law.  In the event that any provision of this Warrant is invalid or unenforceable under any applicable statute or rule of law, then such provision shall be deemed inoperative to the extent that it may conflict therewith and shall be deemed modified to conform with such statute or rule of law.  Any such provision which may prove invalid or unenforceable under any law shall not affect the validity or enforceability of any other provision of this Warrant.  Nothing contained herein shall be deemed or operate to preclude the Holder from bringing suit or taking other legal action against the Company in any other jurisdiction to collect on the Company’s obligations to the Holder, to realize on any collateral or any other security for such obligations, or to enforce a judgment or other court ruling in favor of the Holder.

12.                               CONSTRUCTION; HEADINGS.  This Warrant shall be deemed to be jointly drafted by the Company and the Holder and shall not be construed against any person as the drafter hereof.  The headings of this Warrant are for convenience of reference and shall not form part of, or affect the interpretation of, this Warrant.

13.                               SEVERABILITY.  The invalidity or unenforceability of any provision of this Warrant in any jurisdiction shall not affect the validity or enforceability of such provision in any other jurisdiction, or affect any other provision of this Warrant, which shall remain in full force and effect.

14.                               ENTIRE AGREEMENT.  This Warrant constitutes the entire agreement between the parties pertaining to the subject matter contained in it and supersedes all prior and contemporaneous agreements, representations, and undertakings of the parties, whether oral or written, with respect to such subject matter.

15.                               CERTAIN DEFINITIONS.  For purposes of this Warrant, the following terms shall have the following meanings:

(a)                                 “Business Day” means any day other than Saturday, Sunday or other day on which commercial banks in The City of New York are authorized or required by law to remain closed.

(b)                                 “Common Stock Deemed Outstanding” means, at any given time, the number of shares of Common Stock actually outstanding at such time, plus the number of shares of Common Stock deemed to be outstanding pursuant to Sections 2(a)(i) and 2(a)(ii) hereof regardless of whether the Options (including the Convertible Note Warrants)  or Convertible Securities are actually exercisable at such time, but excluding any shares of Common Stock owned or held by or for the account of the Company or issuable upon exercise of the Warrant.

(c)                                  “Common Stock” means (i) the Company’s shares of Common Stock, par value $0.0001 per share, and (ii) any share capital into which such Common Stock shall have been changed or any share capital resulting from a reclassification of such Common Stock.

(d)                                 “Convertible Notes” means all the 2012 Subordinated Secured Convertible Pay-In-Kind Notes due October 22, 2017,  issued by the Company with issuance date of October 22,2012,  and shall include all notes issued in exchange therefor or replacement thereof.

(e)                                  “Convertible Note Warrants” means all the Warrants granted by the Company with date of issuance of October 22, 2012, in connection with the Convertible Notes.

(f)                                   “Convertible Securities” means any stock or securities (other than Options) directly or indirectly convertible into or exercisable or exchangeable at the option of the holder thereof for shares of Common Stock.

(g)                                  “Eligible Market” means the Principal Market, The New York Stock Exchange, Inc., the NASDAQ Global Market, the NASDAQ Global Select Market, the NASDAQ Capital Market or the NASD’s OTC Bulletin Board.

(h)                                 “Exercise Period” means the period commencing on the Issuance Date and ending at 5:00 p.m. New York time, on the Expiration Date.

(i)                                     “Expiration Date” means the date that is the third (3rd) anniversary of the Issuance Date, or, if such date falls on a day other than a Business Day or on which trading does not take place on the Principal Market (a “Holiday”), the next date that is not a Holiday.

(j)                                    “Options” means any rights, warrants or options to subscribe for or purchase shares of Common Stock or Convertible Securities, other than those that may be issued as part of a compensation package of any employee of the Company or its Subsidiaries and which are exercisable at a price not less than the closing price of the Company’s Common Stock as reported on the Principal Market on the Trading Day immediately preceding the date of grant.

(k)                                 “Parent Entity” of a Person means an entity that, directly or indirectly, controls the applicable Person and whose common stock or equivalent equity security is quoted or listed on an Eligible Market, or, if there is more than one such Person or Parent Entity, the Person or Parent Entity with the largest public market capitalization as of the date of consummation of the Fundamental Transaction.

(l)                                     “Person” means an individual, a limited liability company, a partnership, a joint venture, a corporation, a trust, an unincorporated organization, any other entity and a government or any department or agency thereof.

(m)                             “Principal Market” means the NASDAQ Stock Market LLC.

(n)                                 “Trading Day” means any day on which the Common Stock are traded on the Principal Market, or, if the Principal Market is not the principal trading market for the Common Stock, then on the principal securities exchange or securities market on which the Common Stock are then traded; provided that “Trading Day” shall not include any day on which the Common Stock are scheduled to trade on such exchange or market for less than four and one-half (4.5) hours or any day that the Common Stock are suspended from trading during the final hour of trading on such exchange or market (or if such exchange or market does not designate in advance the closing time of trading on such exchange or market, then during the hour ending at 4:00:00 p.m., New York time).

[Signature Page Follows]

IN WITNESS WHEREOF, the Company has caused this Warrant to Purchase Common Stock to be duly executed as of the Issuance Date set forth above.

EXHIBIT A

EXERCISE NOTICE

TO BE EXECUTED BY THE REGISTERED HOLDER TO EXERCISE THIS

WARRANT TO PURCHASE COMMON STOCK

LIME ENERGY CO.

16810 Kenton Drive. Suite 240

Huntersville, North Carolina 28078

Attention: Chief Executive Officer

Fax No.:                    

The undersigned holder hereby elects to purchase                                    (              ) of the shares of Common Stock (“Warrant Shares”) of Lime Energy Co., a Delaware corporation (the “Company”), evidenced by the attached Warrant to Purchase Common Stock (the “Warrant”).  Capitalized terms used herein and not otherwise defined shall have the respective meanings set forth in the Warrant.

1.  Form of Exercise Price.  The Holder intends that payment of the Exercise Price shall be made as:

a “Cash Exercise” with respect to                                    (            ) Warrant Shares; and/or

a “Cashless Exercise” with respect to                                    (            ) Warrant Shares.

2.  Payment of Exercise Price.  In the event that the holder has elected a Cash Exercise with respect to some or all of the Warrant Shares to be issued pursuant hereto, the holder hereby tenders payment of the Aggregate Exercise Price in the sum of $                                       to the Company in accordance with the terms of the Warrant, together with all applicable transfer taxes, if any.

3.  Accredited Investor. At the time such Holder was offered the Warrant, it was, at the date hereof, and on each date on which it exercises any Warrants, it will be either: (i) an “accredited investor” as defined in Rule 501(a)(1), (a)(2), (a)(3), (a)(7) or (a)(8) under the Securities Act of 1933, as amended, or (ii) a “qualified institutional buyer” as defined in Rule 144A(a) under the Securities Act.  Such Buyer is not required to be registered as a broker-dealer under Section 15 of the Securities Exchange Act of 1934, as amended.

4.  Delivery of Warrant Shares.  The undersigned requests that the certificates for the Warrant Shares be issued in the name of and delivered to the following DWAC Account Numbers or by physical delivery of a certificate to:

ASSIGNMENT FORM

(To assign the foregoing Warrant, execute this form and supply required information.  Do not use this form to purchase shares.)

FOR VALUE RECEIVED, the foregoing Warrant and all rights evidenced thereby are hereby assigned to

NOTE:  The signature to this Assignment Form must correspond with the name as it appears on the face of the Warrant, without alteration or enlargement or any change whatsoever.  Officers of corporations and those acting in a fiduciary or other representative capacity should file proper evidence of authority to assign the foregoing warrant.

ACKNOWLEDGMENT

The Company hereby acknowledges this Exercise Notice and hereby directs its transfer agent to issue the above-indicated number of shares of Common Stock.