Lock-Up Agreement between Tecogen Inc. Shareholder and Roth Capital Partners, LLC (Form)

The undersigned understands that you, as the representative (the “Representative”) of the several underwriters named therein, propose to enter into an Underwriting Agreement (the “Underwriting Agreement”) with Tecogen Inc., a Delaware corporation (the “Company”), relating to a proposed offering of securities of the Company (the “Offering”) including shares of the Common Stock, $.001 (the “Common Stock”). Capitalized terms used herein and not otherwise defined shall have the meanings set forth in the Underwriting Agreement.

In consideration of the foregoing, and in order to induce you to participate in the Offering, and for other good and valuable consideration receipt of which is hereby acknowledged, the undersigned hereby agrees that, without the prior written consent of the Representative (which consent may be granted or withheld in its sole discretion), the undersigned will not, during the period (the “Lock-Up Period”) beginning on the date hereof and ending on the date 90 days after the date of the final prospectus relating to the Offering (the “Final Prospectus”), (1) offer, pledge, announce the intention to sell, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, or otherwise transfer or dispose of, directly or indirectly, or file (or participate in the filing of) a registration statement with the Securities and Exchange Commission (other than one the Company is permitted by the Underwriting Agreement to file) in respect of, any shares of Common Stock or any securities convertible into or exercisable or exchangeable for shares of Common Stock (including without limitation, shares of Common Stock which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations of the Securities and Exchange Commission and securities which may be issued upon exercise of a stock option or warrant), (2) enter into any swap or other agreement that transfers, in whole or in part, any of the economic consequences of ownership of the shares of, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of shares of Common Stock or such other securities, in cash or otherwise, (3) make any demand for or exercise any right with respect to, the registration of any shares of Common Stock or any security convertible into or exercisable or exchangeable for shares of Common Stock, or (4) publicly announce an intention to effect any transaction specific in clause (1), (2) or (3) above.

Notwithstanding the foregoing, the restrictions set forth in clause (1) and (2) above shall not apply to (a) the sale of the undersigned’s Common Stock pursuant to the Underwriting Agreement, (b) transfers (i) as a bona fide gift or gifts, including but not limited to by will or other testamentary document, or intestacy to the legal representative, heir, or beneficiary of the undersigned, provided that the donee or donees, legal representative, heir(s), beneficiary(ies)thereof agree to be bound in writing by the restrictions set forth herein, or (ii) to any trust for the direct or indirect benefit of the undersigned or the immediate family of the

undersigned, provided that the trustee of the trust agrees to be bound in writing by the restrictions set forth herein, and provided further that any such transfer shall not involve a disposition for value, (c) the acquisition or exercise of any stock option issued pursuant to the Company’s existing stock option plan, including any exercise effected by the delivery of shares of Common Stock of the Company held by the undersigned, (c) any transactions effectuated pursuant to a trading plan that satisfies all of the requirements of Rule 10b5-1 under the Exchange Act (“10b5-1 Plan”) existing on the date hereof and disclosed to the Representative, (d) the establishment of a 10b5-1 Plan, so long as no sales may occur thereunder during the Lock-Up Period. For purposes of this Lock-Up Agreement, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin.

The foregoing restrictions are expressly agreed to preclude the undersigned from engaging in any hedging or other transaction which is designed to or reasonably expected to lead to or result in a sale or disposition of shares of Common Stock even if such securities would be disposed of by someone other than the undersigned. Such prohibited hedging or other transactions would include without limitation any short sale or any purchase, sale or grant of any right (including without limitation any put option or put equivalent position or call option or call equivalent position) with respect to any of the shares of Common Stock or with respect to any security that includes, relates to, or derives any significant part of its value from such shares.

The undersigned hereby represents and warrants that the undersigned has full power and authority to enter into this Lock-Up Agreement. All authority herein conferred or agreed to be conferred and any obligations of the undersigned shall be binding upon the successors, assigns, heirs or personal representatives of the undersigned.

The undersigned also agrees and consents to the entry of stop transfer instructions with the Company’s transfer agent and registrar or depositary against the transfer of the undersigned’s shares of Common Stock except in compliance with the foregoing restrictions.

If the undersigned is an officer or director of the Company, (i) the Representative agrees that, at least three business days before the effective date of any release or waiver of the foregoing restrictions in connection with a transfer of Common Shares, the Representative will notify the Company of the impending release or waiver, and (ii) the Company will agree in the Underwriting Agreement to announce the impending release or waiver by press release through a major news service at least two business days before the effective date of the release or waiver. Any release or waiver granted by the Representative hereunder to any such officer or director shall only be effective two business days after the publication date of such press release. The provisions of this paragraph will not apply if (a) the release or waiver is effected solely to permit a transfer not for consideration and (b) the transferee has agreed in writing to be bound by the same terms described in this letter to the extent and for the duration that such terms remain in effect at the time of the transfer.

The undersigned understands that, if the Registration Statement does not become SEC effective, or if the Underwriting Agreement (other than the provisions thereof which survive termination) shall terminate or be terminated prior to payment for and delivery of the securities to be sold thereunder, the undersigned shall be released from all obligations under this Lock-Up Agreement.

The undersigned understands that, if the Registration Statement does not become SEC effective, or if the Underwriting Agreement (other than the provisions thereof which survive termination) shall terminate or be terminated prior to payment for and delivery of the securities to be sold thereunder, the undersigned shall be released from all obligations under this Lock-Up Agreement.

This Lock-Up Agreement shall be governed by and construed in accordance with the laws of the State of New York, without regard to the conflict of laws principles or policies thereof. The undersigned irrevocably (i) submits to the jurisdiction of the Supreme Court of the State of New York, Borough of Manhattan and the United States District Court for the Southern District of New York, for the purpose of any suit, action, or other proceeding arising out of this Lock-Up Agreement (each a “Proceeding”), (ii) agrees that all claims in respect of any Proceeding may be heard and determined in any such court, (iii) waives, to the fullest extent permitted by law, any immunity from jurisdiction of any such court or from any legal process therein, (iv) agrees not to commence any Proceeding other than in such courts, and (v) waives, to the fullest extent permitted by law, any claim that such Proceeding is brought in an inconvenient forum.

Very truly yours,

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