Forward Purchase Agreement Side Letter

On January 20, 2022, ECP Environmental Growth Opportunities Corp. (“ENNV”), ENNV Holdings, LLC (the “Sponsor”) and Goldman Sachs Asset Management, L.P., in its capacity as investment adviser on behalf of its clients (“GSAM”), entered into a side letter (the “Side Letter”) to that certain forward purchase agreement, dated as of January 24, 2021, by and among ENNV, Sponsor and GSAM, as amended by that certain First Amendment to Forward Purchase Agreement dated as of January 31, 2021, and that certain Letter Agreement, dated as of July 18, 2021 (as so amended, the “Forward Purchase Agreement”). As previously disclosed, pursuant to the Forward Purchase Agreement, GSAM irrevocably consented to purchase twenty-five million dollars ($25,000,000) of units (“Forward Purchase Units”), each consisting of one share of Class A common stock, par value $0.0001 per share, of ENNV (“Class A Common Stock”) and one-quarter of one redeemable warrant (“Forward Purchase Warrant”), each whole redeemable warrant of which is exercisable to purchase one share of Class A Common Stock at an exercise price of $11.50 per share, in connection with the closing of ENNV’s previously announced business combination with Fast Radius, Inc. (the “Closing”). Pursuant to the Side Letter, if GSAM acquires any shares of Class A Common Stock (i) on or after the date of the Side Letter but prior to 4:00 p.m. New York City time on January 25, 2022 (the “Cutoff Time”) and does not exercise any right to redeem such shares in connection with ENNV’s redemption of Class A Common Stock in accordance with ENNV’s organizational documents in connection with the Closing (the “Redemption”) (and, if necessary to revoke any prior redemption elections made with respect to such shares, does so effectuate such revocation) or (ii) on or after the Cutoff Time but prior to February 1, 2022 and delivers evidence reasonably satisfactory to ENNV that (a) the stockholder from whom such shares were acquired had, prior to such acquisition, validly elected to redeem such shares in connection with the Redemption and (b) such stockholder or GSAM, as applicable, has, prior to Closing, validly revoked such election to redeem such shares in connection with the Redemption (such shares of Class A Common Stock described in clauses (i) and (ii), the “Eligible Shares”), and, in each case, does not transfer such Eligible Shares prior to the date of the Closing (the “Closing Date”), then such Eligible Shares shall be “Non-Redeemed Shares,” and the number of Forward Purchase Units GSAM is obligated to purchase under the Forward Purchase Agreement will be reduced by the number of Non-Redeemed Shares. Notwithstanding any such reduction in the number of Forward Purchase Units that GSAM is obligated to purchase under the Forward Purchase Agreement, upon consummation of the sale of such Forward Purchase Units, ENNV shall issue to GSAM a number of redeemable warrants, each of which is exercisable to purchase one share of Class A Common Stock at an exercise price of $11.50 per share, which warrants shall have the same terms as ENNV’s private placement warrants (the “Additional Warrants”), such that GSAM shall receive 625,000 Forward Purchase Warrants and Additional Warrants in the aggregate. Pursuant to the merger agreement, dated as of July 18, 2021 and amended on December 26, 2021 (the “Merger Agreement”), Fast Radius is required to provide its consent in order for ENNV to take certain actions under the Merger Agreement, including but not limited to, making amendments to the Forward Purchase Agreement. Fast Radius has provided its consent under the Merger Agreement for ENNV to enter into the Side Letter.

The foregoing description of the Side Letter does not purport to be complete and is qualified in its entirety by the terms and conditions of the Side Letter filed as Exhibit 10.1 hereto and incorporated by reference herein.

Cautionary Statement Regarding Forward Looking Statements

This Report contains certain forward-looking statements within the meaning of the federal securities laws with respect to the proposed Transactions between ENNV and Fast Radius. These forward-looking statements generally are identified by the words “believe,” “project,” “expect,” “anticipate,” “estimate,” “intend,” “strategy,” “future,” “scales,” “representative of,” “valuation,” “opportunity,” “plan,”

“may,” “should,” “will,” “would,” “will be,” “will continue,” “will likely result,” and similar expressions. Forward-looking statements are predictions, projections and other statements about future events that are based on current expectations and assumptions and, as a result, are subject to risks and uncertainties. Many factors could cause actual future events to differ materially from the forward-looking statements in this Report, including but not limited to: (i) the risk that the Transactions may not be completed in a timely manner or at all, which may adversely affect the price of ENNV’s securities, (ii) the risk that the Transactions may not be completed by ENNV’s business combination deadline and the potential failure to obtain an extension of the business combination deadline if sought by ENNV, (iii) the failure to satisfy the conditions to the consummation of the Transactions, including the requisite approvals of ENNV’s and Fast Radius’ stockholders, the satisfaction of the minimum trust account amount following any redemptions by ENNV’s public stockholders and the receipt of certain governmental and regulatory approvals, (iv) the lack of a third party valuation in determining whether or not to pursue the Transactions, (v) the risk that ENNV’s proposed private offering of public equity is not completed, (vi) the occurrence of any event, change or other circumstance that could give rise to the termination of the merger agreement relating to the Transactions, (vii) the effect of the announcement or pendency of the Transactions on Fast Radius’ business or employee relationships, operating results and business generally, (viii) the risk that the Transactions disrupts current plans and operations of Fast Radius, (ix) the risk of difficulties in retaining employees of Fast Radius as a result of the Transactions, (x) the outcome of any legal proceedings that may be instituted against Fast Radius or against ENNV related to the Merger Agreement or the Transactions, (xi) the ability to maintain the listing of ENNV’s securities on a national securities exchange, (xii) changes in the competitive industries in which Fast Radius operates, variations in operating performance across competitors, changes in laws and regulations affecting Fast Radius’ business and changes in the combined capital structure, (xiii) the ability to implement business plans, forecasts, and other expectations after the completion of the Transactions, and the ability to identify and realize additional opportunities, (xiv) risks related to the uncertainty of Fast Radius’ projected financial information, (xv) risks related to Fast Radius’ potential inability to become profitable and generate cash, (xvi) current and future conditions in the global economy, including as a result of the impact of the COVID-19 pandemic, (xvii) the risk that demand for Fast Radius’ cloud manufacturing technology does not grow as expected, (xviii) the ability of Fast Radius to retain existing customers and attract new customers, (xix) the potential inability of Fast Radius to manage growth effectively, (xx) the potential inability of Fast Radius to increase its cloud manufacturing capacity or to achieve efficiencies regarding its cloud manufacturing process or other costs, (xxi) the enforceability of Fast Radius’ intellectual property rights, including its copyrights, patents, trademarks and trade secrets, and the potential infringement on the intellectual property rights of others, (xxii) Fast Radius’ dependence on senior management and other key employees, (xxiii) the risk of downturns and a changing regulatory landscape in the highly competitive industry in which Fast Radius operates, (xxiv) the risk that Fast Radius may require additional funding for its growth plans and may not be able to obtain any additional financing on terms that are acceptable to Fast Radius or at all and (xxv) costs related to the Transactions and the failure to realize anticipated benefits of the Transactions or to realize estimated pro forma results and underlying assumptions, including with respect to estimated stockholder redemptions. The foregoing list of factors is not exhaustive. You should carefully consider the foregoing factors and the other risks and uncertainties which will be more fully described in the “Risk Factors” section of ENNV’s Quarterly Reports on Form 10-Q, the Registration Statement (as defined below), the Proxy Statement/Prospectus (as defined below) and other documents filed by ENNV from time to time with the SEC. These filings identify and address other important risks and uncertainties that could cause actual events and results to differ materially from those contained in the forward-looking statements. Forward-looking statements speak only as of the date they are made. Readers are cautioned not to put undue reliance on forward-looking statements, and Fast Radius and ENNV assume no obligation and do not intend to update or revise these forward-looking statements, whether as a result of new information, future events, or otherwise. Neither Fast Radius nor ENNV gives any assurance that either Fast Radius or ENNV, or the combined company, will achieve its expectations.

Additional Information and Where to Find It

This Report relates to the proposed Transactions between ENNV and Fast Radius. ENNV filed a registration statement on Form S-4 (as amended, the “Registration Statement”), including a proxy statement/prospectus (the “Proxy Statement/Prospectus), relating to the Transaction with the SEC on September 3, 2021, and the SEC declared the Registration Statement effective on January 13, 2022. The definitive Proxy Statement/Prospectus will be sent to all ENNV stockholders as of January 5, 2022, the record date established for voting on the proposed Transaction and the other matters to be voted upon at a meeting of ENNV’s stockholders to be held to approve the proposed Transaction and other matters. ENNV will also file other documents regarding the Transactions with the SEC. Before making any voting decision, investors and security holders of ENNV and Fast Radius are urged to read the Registration Statement, the Proxy Statement/Prospectus and all other relevant documents filed or that will be filed with the SEC in connection with the Transactions as they become available because they will contain important information about the Transactions. Investors and security holders will be able to obtain free copies of the Registration Statement, the Proxy Statement/Prospectus, and all other relevant documents filed or that will be filed with the SEC by ENNV through the website maintained by the SEC at www.sec.gov. The documents filed by ENNV with the SEC also may be obtained free of charge upon written request to ENNV at 40 Beechwood Road, Summit, New Jersey 07901.

Participants in the Solicitation

ENNV, Fast Radius and their respective directors and executive officers may be deemed to be participants in the solicitation of proxies from ENNV’s stockholders in connection with the Transactions. A list of the names of such directors and executive officers and information regarding their interests in the Transactions is included in the Proxy Statement/Prospectus when available. You may obtain free copies of these documents as described in the preceding paragraph.

No Offer or Solicitation

This Report shall not constitute an offer to sell or exchange or the solicitation of an offer to buy or exchange any securities, nor shall there be any sale or exchange of securities in any jurisdiction in which such offer, solicitation, sale or exchange would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offering of securities shall be made except by means of a prospectus meeting the requirements of the U.S. Securities Act of 1933, as amended.