Exhibit 10.1

WAIVER, CONSENT AND AGREEMENT TO FORFEIT FOUNDER SHARES

This Waiver, Consent and Agreement to Forfeit Founder Shares (this “ Agreement ”), dated as of March 20, 2018, is entered into by and among the parties listed on the signature pages hereto.

WHEREAS, reference is made to the Agreement and Plan of Merger, dated as of November 3, 2017 (as amended, the “ Merger Agreement ”), by and among IEA Energy Services LLC, a Delaware limited liability company (the “ Company ”), M III Acquisition Corp., a Delaware corporation (the “ Buyer ”), Wind Merger Sub I, Inc., a Delaware corporation and a wholly owned subsidiary of the Buyer (“ Merger Sub I ”), Wind Merger Sub II, LLC, a Delaware limited liability company and a wholly owned subsidiary of the Buyer (“ Merger Sub II ”), Infrastructure and Energy Alternatives, LLC, a Delaware limited liability company (the “ Seller ”), Oaktree Power Opportunities Fund III Delaware, L.P., a Delaware limited partnership, solely in its capacity as the representative of the Seller (“ Seller’s Representative ”), and, solely for purposes of Section 10.3 thereof, and, to the extent related thereto, Article 12 thereof, M III Sponsor I LLC (“ Sponsor I ”), a Delaware limited liability company, and M III Sponsor I LP, a Delaware limited partnership (together with Sponsor I, the “ Sponsors ”).  Capitalized terms used but not defined herein shall have the respective meanings assigned thereto in the Merger Agreement;

WHEREAS, subject to the terms and conditions described herein, pursuant to and in accordance with Section 12.2 of the Merger Agreement, the parties wish to provide certain waivers and consents and agree to certain amendments, in each case as set forth herein;

WHEREAS, the Sponsors have agreed to forfeit to the Buyer (i) 425,000 Founder Shares upon the closing of the transactions contemplated by the Merger Agreement (the “ Closing ”) and (ii) following the determination of Final 2019 EBITDA, a number of additional Founder Shares depending upon the number of Earnout Shares issued to the Seller in accordance with Section 3.6 of the Merger Agreement; and

WHEREAS, the Buyer has agreed to issue to the Seller a number of Buyer Common Shares equal to the number of Founder Shares forfeited hereunder at such time as such Founder Shares are forfeited.

NOW, THEREFORE, in consideration of the rights and obligations contained herein, and for other good and valuable consideration, the adequacy of which is hereby acknowledged, the parties agree as follows:

Section 1.                                      Representations and Warranties of the Buyer .  The Buyer hereby represents and warranties to the Seller and the Company that  prior to the date hereof, the Buyer has delivered to the Seller and the Company true, correct and complete copies of the Required Commitment Agreements (as defined below) to the extent executed prior to the date hereof, and any other agreements or understandings (whether written or oral) entered into after the date of the Merger Agreement by any of the Sponsors, the Buyer, IEA Intermediate Holdco, LLC, Merger Sub I or Merger Sub II with any Person with respect to any equity interests of the Buyer or any options, warrants, convertible or

exchangeable securities, subscriptions, derivatives, rights, calls, commitments or agreements relating to the equity interests of the Buyer, in each case  as in effect on the date hereof and no amendments thereto are pending.

Section 2.                                      Waivers and Consents by Seller and the Company .  Seller and the Company:

(a)                                  hereby waive the condition to Closing set forth in Section 9.14 of the Merger Agreement and the termination right set forth in Section 10.1(g)(ii) of the Merger Agreement; provided , in each case that (i) Available Cash is not less than $72,000,000 (and the Seller’s Representative shall be entitled to terminate the Merger Agreement pursuant to Section 10.1(g)(ii) thereof (subject to the time periods set forth therein) if Available Cash is less than $72,000,000), (ii) any agreements (the “ Required Commitment Agreements ”) providing for the issuance by the Company of shares of Common Stock have been approved by the Seller’s Representative and (iii) the amount available to be drawn on the Closing Date under the Replacement Credit Facility shall not be less than (x) the amount required by Section 3.4(c) of the Merger Agreement plus (y) an amount equal to the amount by which Available Cash is less than $100,000,000;

(b)                                  notwithstanding Section 7.2(b) of the Merger Agreement, consent to (i) the issuance by the Company at or prior to the Closing of Buyer Common Shares (valued at the redemption price per share) to one or more financial advisors to the Company or the Seller (each, an “ Advisor ”) in lieu of the payment of up to $5,000,000 in cash fees payable to such Advisors in the aggregate (which, for the avoidance of doubt, shall include any issuance of Buyer Common Shares by the Company pursuant to the Required Commitment Agreement described in clause (ii)(B) of Section 2(a) hereof); provided that (x) such fees would have otherwise constituted Transaction Expenses and (y) the terms of such issuance are consistent in all material respects with terms previously disclosed to the Seller’s Representative or otherwise are satisfactory to the Seller’s Representative (such fees, “ Advisor Fees ”); and (ii) the issuance by the Company of up to 217,256 Buyer Common Shares to persons to whom the Sponsors have otherwise agreed to transfer Founder Shares on or prior to the date of this Agreement in exchange for the forfeiture by the Sponsors of an equal number of Founder Shares  (the “ Replacement Shares ”);

(c)                                   agree that the amount of “Available Cash” in Section 1.1 of the Merger Agreement shall be increased by the amount of any Advisor Fees paid in Buyer Common Shares rather than cash in accordance with the terms hereof and the applicable Required Commitment Agreement, if any;

(d)                                  consent to the transactions contemplated by the Required Commitment Agreements for all purposes of Section 7.2 of the Merger Agreement, the conditions in Section 9.1 and 9.2 of the Merger Agreement and for purposes of the certificate to be delivered by Buyer pursuant to Section 9.3 of the Merger Agreement and acknowledge that notwithstanding clause (z) of Section 7.2(b) of the Merger Agreement, there shall be no increase in Cash Consideration as a result of the transactions contemplated by the Required Commitment Agreements; and

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(e)                                   acknowledge and agree that (i) all Buyer Common Shares issued to or acquired by the parties to the Required Commitment Agreements shall be “Registrable Securities” for all purposes of the Buyer A&R Registration Rights Agreement to be executed and delivered at Closing, (ii) the number of Buyer Common Shares referenced as outstanding on the date of the Investor Rights Agreement in the definition of “Sponsor Higher Condition” and “Sponsor Minimum Condition” in the Investor Rights Agreement to be executed and delivered at Closing shall be reduced by the Founder Shares forfeited in accordance with Section 4 below and (iii) the number of “Founder Shares” and “Earnout Shares” set forth opposite the name of each Sponsor on Exhibit A to the Founder Shares Amendment Agreement shall be reduced by the number of Founder Shares and “Earnout Shares”, respectively, that the Sponsors have forfeited pursuant to Section 4 below (and after giving effect to any forfeiture of Founder Shares at Closing pursuant to the Forfeiture Agreement entered into prior to the date hereof and referenced in Amendment No. 5 to the Merger Agreement).

Section 3.                                      Waivers and Agreements by Buyer and Merger Subs .  Buyer, Merger Sub I and Merger Sub II hereby:

(a)                                  waive the condition to closing set forth in Section 8.11 of the Merger Agreement; provided , that (i) Available Cash is not less than $72,000,000 million; (ii) the transactions contemplated by the Required Commitment Agreements have been consummated (or will be consummated substantially concurrently with Closing) in accordance with the terms thereof, unless the failure of such transactions to be so consummated arises out of or in connection with a breach by the Buyer of its obligations under Section 3(c) hereof, in which case the condition shall be waived; and (iii) the aggregate amount of commitments available to the Company on the Closing Date under the Replacement Credit Facility shall not be less than $100,000,000 and the amount available to be drawn on the Closing Date thereunder shall not be less than (x) the amount required by Section 3.4(c) of the Merger Agreement plus (y) an amount equal to the amount by which Available Cash is less than $100,000,000;

(b)                                  agree that the amount of “Available Cash” in Section 1.1 of the Merger Agreement shall be increased by the amount of any Advisor Fees paid in Buyer Common Shares rather than cash in accordance with the terms hereof and the applicable Required Commitment Agreement, if any; and

(c)                                   agree (i) to use reasonable best efforts to consummate the transactions contemplated by the Required Commitment Agreements and (ii) not to amend, waive or otherwise modify the Required Commitment Agreements without the prior written consent of the Seller’s Representative.

Section 4.                                      Forfeiture of Founder Shares and Issuance of Buyer Common Shares to the Seller .

(a)                                  At the Closing, (i) the Sponsors shall forfeit to the Buyer for no consideration an aggregate of 425,000 Founder Shares, of which 106,250 Founder Shares shall be comprised of the “Earnout Shares” described in Section 1(a) of the Founder Share

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Amendment Agreement (“ $12 Earnout Shares ”) and 106,250 Founder Shares shall be comprised of the “Earnout Shares” described in Section 1(b) of the Founder Share Amendment Agreement (“ $14 Earnout Shares ”), and (ii) the Buyer shall issue to Seller  an aggregate of 425,000 Buyer Common Shares, of which (x) 106,250 Buyer Common Shares shall be subject to the same vesting and forfeiture terms applicable to the $12 Earnout Shares in accordance with the Founder Share Amendment Agreement and (y) 106,250 Buyer Common Shares shall be subject to the same vesting and forfeiture terms applicable to the $14 Earnout Shares in accordance with the Founder Share Amendment Agreement.

(b)                                  An additional 525,000 Founder Shares in the aggregate held by the Sponsors (twenty-five percent (25%) of which shall be comprised of $12 Earnout Shares and twenty-five percent (25%) of which shall be comprised of $14 Earnout Shares) (collectively, the “ Transfer Restricted Shares ”) shall be subject to the  transfer restrictions set forth in this Section 4(b).  Each Sponsor hereby irrevocably and unconditionally agrees that, from and after the Closing until the consummation of the transactions contemplated by Sections 4(d) and 4(e) hereof, such Sponsor shall not Transfer (as defined below) all or any portion of such Sponsor’s Transfer Restricted Shares, other than any Transfer Restricted Shares released to the Sponsors in accordance with Section 4(c) or 4(d) below.  “ Transfer ” shall mean any direct or indirect offer, sale, assignment, Encumbrance, disposition, loan or other transfer (by operation of Law or otherwise), either voluntary or involuntary, or entry into any contract, option or other arrangement or understanding with respect to any offer, sale, assignment, Encumbrance, disposition, loan or other transfer (by operation of Law or otherwise), of any Transfer Restricted Shares or interest in any Transfer Restricted Shares.  The Buyer shall be entitled to, without any further action by the Sponsors or any other Person, give effect to the forfeitures contemplated by this Section 4, and the Seller’s Representative shall be entitled to enforce the rights of the Buyer under this Section 4.

(c)                                   Upon the determination of Final 2018 EBITDA and the determination of the number of Buyer Common Shares issuable to Seller pursuant to Section 3.6(f) of the Merger Agreement, such number of Transfer Restricted Shares (twenty-five percent (25%) of which shall be comprised of $12 Earnout Shares and twenty-five percent (25%) of which shall be comprised of $14 Earnout Shares) shall be released from the transfer restrictions described in Section 4(b) hereof that is equal to  (x) 525,000 multiplied by (y) the quotient of the aggregate number of Earnout Shares issued to Seller pursuant to Section 3.6(f) of the Merger Agreement divided by 9,000,000; provided that any $12 Earnout Shares or $14 Earnout Shares that would otherwise have vested in accordance with the terms of the Founder Shares Amendment Agreement shall be deemed vested upon release from such transfer restrictions.

(d)                                  Upon the determination of Final 2019 EBITDA and the determination of the number of Buyer Common Shares issuable to Seller pursuant to Section 3.6(g) of the Merger Agreement, such number of Transfer Restricted Shares (twenty-five percent (25%) of which shall be comprised of $12 Earnout Shares and twenty-five percent (25%) of which shall be comprised of $14 Earnout Shares) shall be released from the transfer restrictions described in Section 4(b) hereof, in an aggregate

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amount that, together with the Founder Shares released pursuant to Section 4(b), is equal to  (x) 525,000 multiplied by (y) the quotient of the aggregate number of Earnout Shares issued to the Seller pursuant to Section 3.6(g) of the Merger Agreement divided by 9,000,000; provided that any $12 Earnout Shares or $14 Earnout Shares that would otherwise have vested in accordance with the terms of the Founder Shares Amendment Agreement shall be deemed vested upon release from such transfer restrictions.

(e)                                   Following the determination of Final 2019 EBITDA and the release from the transfer restrictions described in Section 4(b) hereof of the Transfer Restricted Shares (if any) pursuant to Section 4(d) above, any Transfer Restricted Shares that have not been released in accordance with Section 4(c) or Section 4(d) above to the Buyer shall be automatically forfeited without any action by any party hereto or any other Person, and the Buyer shall cancel such Transfer Restricted Shares for no consideration.  The Buyer shall issue to the Seller a number of Buyer Common Shares equal to the number of Transfer Restricted Shares so cancelled.  Twenty-five percent (25%) of such Buyer Common Shares shall be comprised of $12 Earnout Shares and twenty-five percent (25%) of such Buyer Common Shares shall be comprised of $14 Earnout Shares; provided that to the extent any of the Transfer Restricted Shares would otherwise have vested in accordance with the terms of the Founder Share Amendment Agreement the $12 Earnout Shares and $14 Earnout Shares that would otherwise have been issued to Seller shall be deemed vested upon issuance to the Seller.

(f)                                    At Closing, Seller shall become a party to the Founder Shares Amendment Agreement with respect to the $12 Earnout Shares and $14 Earnout Shares received at Closing and, with respect to any additional $12 Earnout Shares and $14 Earnout Shares received pursuant to Section 4(e) above that have not vested in accordance with the Founder Share Amendment Agreement prior to the date of receipt, and such $12 Earnout Shares and $14 Earnout Shares, shall be subject to the same vesting and forfeiture terms applicable to the Sponsors, which vesting and forfeiture terms shall not be shortened or otherwise favorably amended without similarly shortening or amending the terms of Founder Shares subject to the Founder Shares Amendment Agreement.

Section 5.                                      Further Assurances .  Each of the parties hereto shall execute such documents and perform such further acts as may be reasonably required to carry out the provisions hereof and the transactions contemplated hereby.

Section 6.                                      Miscellaneous .  Except as expressly modified by this Agreement, nothing contained herein is intended to or shall be deemed to limit, restrict, modify, alter, amend or otherwise change in any manner the rights and obligations of the parties under the Merger Agreement. The “Miscellaneous” provisions set forth in Article 12 of the Merger Agreement are incorporated herein by reference, mutatis mutandis, as if set forth in full herein; provided , however , that for purposes of Section 12.3, and for all other purposes, each reference to the Merger Agreement shall refer to the Merger Agreement, as amended.  Neither the Buyer (nor its Affiliates) nor the Sponsors shall issue a IRS Form 1099, Form 1042 or any other tax or information reporting to Seller in connection with the transactions contemplated by this Agreement.

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IN WITNESS WHEREOF, the parties have caused this Agreement to be duly executed as of the date first written above.

[ Signature Page to Waiver ]

[ Signature Page to Waiver ]