Document:

Exhibit 10.6

 

INDEMNITY
AGREEMENT

 

THIS
INDEMNITY AGREEMENT (this “Agreement”) is made as of July 14, 2021, by and between CleanTech Acquisition Corp.,
a Delaware corporation (the “Company”), and (“Indemnitees”).

 

RECITALS

 

WHEREAS,
highly competent persons have become more reluctant to serve publicly held corporations as directors, officers or in other capacities
unless they are provided with adequate protection through insurance or adequate indemnification against inordinate risks of claims and
actions against them arising out of their service to and activities on behalf of such corporations.

 

WHEREAS,
the Board of Directors of the Company (the “Board”) has determined that, in order to attract and retain qualified individuals,
the Company will attempt to maintain on an ongoing basis, at its sole expense, liability insurance to protect persons serving the Company
and its Subsidiaries from certain liabilities. Although the furnishing of such insurance has been a customary and widespread practice
among United States-based corporations and other business enterprises, the Company believes that, given current market conditions and
trends, such insurance may be available to it in the future only at higher premiums and with more exclusions. At the same time, directors,
officers and other persons in service to corporations or business enterprises are being increasingly subjected to expensive and time-consuming
litigation relating to, among other things, matters that traditionally would have been brought only against the Company or business enterprise
itself. The Amended and Restated Certificate of Incorporation (the “Charter”) and the Bylaws (the “Bylaws”) of
the Company require indemnification of the officers and directors of the Company. Indemnitees may also be entitled to indemnification
pursuant to applicable provisions of the Delaware General Corporation Law (the “DGCL”). The Bylaws and the DGCL expressly
provide that the indemnification provisions set forth therein are not exclusive, and thereby contemplate that contracts may be entered
into between the Company and members of the board of directors, officers and other persons with respect to indemnification, hold harmless,
exoneration, advancement and reimbursement rights.

 

WHEREAS,
the uncertainties relating to such insurance and to indemnification have increased the difficulty of attracting and retaining such persons.

 

WHEREAS,
the Board has determined that the increased difficulty in attracting and retaining such persons is detrimental to the best interests
of the Company’s stockholders and that the Company should act to assure such persons that there will be increased certainty of
such protection in the future.

 

WHEREAS,
it is reasonable, prudent and necessary for the Company contractually to obligate itself to indemnify, hold harmless, exonerate and
to advance expenses on behalf of, such persons to the fullest extent permitted by applicable law so that they will serve or continue
to serve the Company free from undue concern that they will not be so protected against liabilities.

 

WHEREAS,
this Agreement is a supplement to and in furtherance of the Charter and Bylaws of the Company and any resolutions adopted pursuant thereto,
and shall not be deemed a substitute therefor, nor to diminish or abrogate any rights of Indemnitees thereunder.

 

WHEREAS,
Indemnitees may not be willing to serve as an officer or director without adequate protection, and the Company desires Indemnitees to
serve in such capacity. Indemnitees is willing to serve, continue to serve and to take on additional service for or on behalf of the
Company on the condition that he or she be so indemnified.

 

     

     

    

 

NOW,
THEREFORE, in consideration of the premises and the covenants contained herein, the Company and Indemnitees do hereby covenant and
agree as follows:

 

TERMS
AND CONDITIONS

 

		1.	SERVICES
TO THE COMPANY. Indemnitees will serve or continue to serve as an officer, director, advisor, key employee or in any other capacity
of the Company, as applicable, for so long as Indemnitees is duly elected, appointed or retained or until Indemnitees tenders his or
her resignation, or is removed or dies. The foregoing notwithstanding, this Agreement shall continue in full force and effect after Indemnitees
has ceased to serve as an officer, director, advisor, key employee or in any other capacity of the Company, as provided in Section 17.
This Agreement, however, shall not impose any obligation on Indemnitees or the Company to continue Indemnitees’s service to the
Company beyond any period otherwise required by law or by other agreements or commitments of the parties, if any

 

		2.	DEFINITIONS.
                                            As used in this Agreement:

 

 (a) References to “agent” shall mean any person who is or was a director, officer or employee of the Company or a Subsidiary of the Company or other person authorized by the Company to act for the Company, to include such person serving in such capacity as a director, officer, employee, fiduciary or other official of another corporation, partnership, limited liability company, joint venture, trust or other enterprise at the request of, for the convenience of, or to represent the interests of the Company or a Subsidiary of the Company.

 

 (b) The terms “Beneficial Owner” and “Beneficial Ownership” shall have the meanings set forth in Rule 13d-3 promulgated under the Exchange Act as in effect on the date hereof.

 

 (c) A “Change in Control” shall be deemed to occur upon the earliest to occur after the date of this Agreement of any of the following events:

 

(i) Acquisition
of Stock by Third Party. Other than CleanTech Sponsor I LLC or CleanTech Investments, LLC (the
“Co-Sponsors”) or an affiliate thereof, any Person is or becomes the Beneficial Owner, directly or
indirectly, of securities of the Company representing fifteen percent (15%) or more of the combined voting power of the
Company’s then outstanding securities entitled to vote generally in the election of directors, unless (1) the change in the
relative Beneficial Ownership of the Company’s securities by any Person results solely from a reduction in the aggregate
number of outstanding shares of securities entitled to vote generally in the election of directors, or (2) such acquisition was
approved in advance by the Continuing Directors and such acquisition would not constitute a Change in Control under part (iii) of
this definition;

 

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(ii) Change
in Board of Directors. Individuals who, as of the date hereof, constitute the Board, and any new director whose election by the Board
or nomination for election by the Company’s stockholders was approved by a vote of at least two thirds of the directors then still
in office who were directors on the date hereof or whose election for nomination for election was previously so approved (collectively,
the “Continuing Directors”), cease for any reason to constitute at least a majority of the members of the Board;

 

(iii) Corporate
Transactions. The effective date of a merger, share exchange, asset acquisition, stock purchase, recapitalization or other similar
business combination involving the Company and one or more businesses or entities (a “Business Combination”),
in each case, unless, following such Business Combination: (1) all or substantially all of the individuals and entities who were the
Beneficial Owners of securities entitled to vote generally in the election of directors immediately prior to such Business Combination
beneficially own, directly or indirectly, more than fifty-one percent (51%) of the combined voting power of the then outstanding securities
of the Company entitled to vote generally in the election of directors resulting from such Business Combination (including, without limitation,
a corporation which as a result of such transaction owns the Company or all or substantially all of the Company’s assets either
directly or through one or more Subsidiaries) in substantially the same proportions as their ownership immediately prior to such Business
Combination, of the securities entitled to vote generally in the election of directors; (2) other than any Co-Sponsor or an affiliate
thereof, no Person (excluding any corporation resulting from such Business Combination) is the Beneficial Owner, directly or indirectly,
of fifteen percent (15%) or more of the combined voting power of the then outstanding securities entitled to vote generally in the election
of directors of the surviving corporation except to the extent that such ownership existed prior to the Business Combination; and (3)
at least a majority of the Board of Directors of the corporation resulting from such Business Combination were Continuing Directors at
the time of the execution of the initial agreement, or of the action of the Board of Directors, providing for such Business Combination;

 

 (iv) Liquidation. The approval by the stockholders of the Company of a complete liquidation of the Company or an agreement or series of agreements for the sale or disposition by the Company of all or substantially all of the Company’s assets, other than factoring the Company’s current receivables or escrows due (or, if such approval is not required, the decision by the Board to proceed with such a liquidation, sale, or disposition in one transaction or a series of related transactions); or

 

(v) Other
Events. There occurs any other event of a nature that would be required to be reported in response to Item 6(e) of Schedule 14A of
Regulation 14A (or a response to any similar item on any similar schedule or form) promulgated under the Exchange Act, whether or not
the Company is then subject to such reporting requirement.

 

(d) “Corporate
Status” describes the status of a person who is or was a director, officer, trustee, general partner, manager, managing
member, fiduciary, employee or agent of the Company or of any other Enterprise which such person is or was serving at the request of
the Company.

 

 (e) “Delaware Court” shall mean the Court of Chancery of the State of Delaware.

 

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(f) “Disinterested Director” shall mean a director of the Company who is not and was not a party to the Proceeding in respect of which indemnification is sought by Indemnitees.

 

(g) “Enterprise”
shall mean the Company and any other corporation, constituent corporation (including any constituent of a constituent) absorbed in a
consolidation or merger to which the Company (or any of its wholly owned Subsidiaries) is a party, limited liability company, partnership,
joint venture, trust, employee benefit plan or other enterprise of which Indemnitees is or was serving at the request of the Company
as a director, officer, trustee, general partner, managing member, fiduciary, employee or agent.

 

 (h) “Exchange Act” shall mean the Securities Exchange Act of 1934, as amended.

 

 (i) “Expenses” shall include all direct and indirect costs, fees and expenses of any type or nature whatsoever, including, without limitation, all reasonable attorneys’ fees and costs, retainers, court costs, transcript costs, fees of experts, witness fees, travel expenses, fees of private investigators and professional advisors, duplicating costs, printing and binding costs, telephone charges, postage, delivery service fees, fax transmission charges, secretarial services and all other disbursements, obligations or expenses in connection with prosecuting, defending, preparing to prosecute or defend, investigating, being or preparing to be a witness in, settlement or appeal of, or otherwise participating in, a Proceeding, including reasonable compensation for time spent by the Indemnitees for which he or she is not otherwise compensated by the Company or any third party. Expenses also shall include Expenses incurred in connection with any appeal resulting from any Proceeding, including without limitation the principal, premium, security for, and other costs relating to any cost bond, supersedeas bond, or other appeal bond or its equivalent. Expenses, however, shall not include amounts paid in settlement by Indemnitees or the amount of judgments or fines against Indemnitees.

 

(j) References
to “fines” shall include any excise tax assessed on Indemnitees with respect to any employee benefit plan;
references to “serving at the request of the Company” shall include any service as a director, officer, employee, agent or
fiduciary of the Company which imposes duties on, or involves services by, such director, officer, employee, agent or fiduciary with
respect to an employee benefit plan, its participants or beneficiaries; and if Indemnitees acted in good faith and in a manner Indemnitees
reasonably believed to be in the best interests of the participants and beneficiaries of an employee benefit plan, Indemnitees shall
be deemed to have acted in a manner “not opposed to the best interests of the Company” as referred to in this Agreement.

 

(k) “Independent
Counsel” shall mean a law firm or a member of a law firm with significant experience in matters of corporate law and that
neither presently is, nor in the past five years has been, retained to represent: (i) the Company or Indemnitees in any matter material
to either such party (other than with respect to matters concerning the Indemnitees under this Agreement, or of other indemniteess under
similar indemnification agreements); or (ii) any other party to the Proceeding giving rise to a claim for indemnification hereunder.
Notwithstanding the foregoing, the term “Independent Counsel” shall not include any person who, under the applicable standards
of professional conduct then prevailing, would have a conflict of interest in representing either the Company or Indemnitees in an action
to determine Indemnitees’s rights under this Agreement.

 

(l)
The term “Person” shall have the meaning as set forth in Sections 13(d) and 14(d) of the Exchange Act as
in effect on the date hereof; provided, however, that “Person” shall exclude: (i) the Company; (ii) any Subsidiaries of
the Company; (iii) any employment benefit plan of the Company or of a Subsidiary of the Company or of any corporation owned,
directly or indirectly, by the stockholders of the Company in substantially the same proportions as their ownership of stock of the
Company; and (iv) any trustee or other fiduciary holding securities under an employee benefit plan of the Company or of a Subsidiary
of the Company or of a corporation owned directly or indirectly by the stockholders of the Company in substantially the same
proportions as their ownership of stock of the Company.

 

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(m) The
term “Proceeding” shall include any threatened, pending or completed action, suit, arbitration, mediation,
alternate dispute resolution mechanism, investigation, inquiry, administrative hearing or any other actual, threatened or completed proceeding,
whether brought in the right of the Company or otherwise and whether of a civil (including intentional or unintentional tort claims),
criminal, administrative or investigative or related nature, in which Indemnitees was, is, will or might be involved as a party or a
participant (as a witness or otherwise), by reason of his or her Corporate Status or by reason of any action (or failure to act) taken
by him or of any action (or failure to act) on his part while acting as a director or officer of the Company, in each case whether or
not serving in such capacity at the time any liability or expense is incurred for which indemnification, reimbursement, or advancement
of expenses can be provided under this Agreement.

 

(n) The
term “Subsidiary,” with respect to any Person, shall mean any corporation, limited liability company, partnership,
joint venture, trust or other entity of which a majority of the voting power of the voting equity securities or equity interest is owned,
directly or indirectly, by that Person.

 

		3.	INDEMNITY
                                            IN THIRD-PARTY PROCEEDINGS. To the fullest extent permitted by applicable law, the Company
                                            shall indemnify, hold harmless and exonerate Indemnitees in accordance with the provisions
                                            of this Section 3 if Indemnitees was, is, or is threatened to be made, a party to or a participant
                                            (as a witness, deponent or otherwise) in any Proceeding, other than a Proceeding by or in
                                            the right of the Company to procure a judgment in its favor. Pursuant to this Section 3,
                                            Indemnitees shall be indemnified, held harmless and exonerated against all Expenses, judgments,
                                            liabilities, fines, penalties and amounts paid in settlement (including all interest, assessments
                                            and other charges paid or payable in connection with or in respect of such Expenses, judgments,
                                            fines, penalties and amounts paid in settlement) actually and reasonably incurred by Indemnitees
                                            or on his or her behalf in connection with such Proceeding or any claim, issue or matter
                                            therein, if Indemnitees acted in good faith and in a manner he or she reasonably believed
                                            to be in or not opposed to the best interests of the Company and, in the case of a criminal
                                            Proceeding, had no reasonable cause to believe that his or her conduct was unlawful.

 

		4.	INDEMNITY
                                            IN PROCEEDINGS BY OR IN THE RIGHT OF THE COMPANY. To the fullest extent permitted by
                                            applicable law, the Company shall indemnify, hold harmless and exonerate Indemnitees in accordance
                                            with the provisions of this Section 4 if Indemnitees was, is, or is threatened to be made,
                                            a party to or a participant (as a witness, deponent or otherwise) in any Proceeding by or
                                            in the right of the Company to procure a judgment in its favor. Pursuant to this Section
                                            4, Indemnitees shall be indemnified against all Expenses actually and reasonably incurred
                                            by him or her or on his or her behalf in connection with such Proceeding or any claim, issue
                                            or matter therein, if Indemnitees acted in good faith and in a manner he or she reasonably
                                            believed to be in or not opposed to the best interests of the Company. No indemnification,
                                            hold harmless or exoneration for Expenses shall be made under this Section 4 in respect of
                                            any claim, issue or matter as to which Indemnitees shall have been finally adjudged by a
                                            court to be liable to the Company, unless and only to the extent that any court in which
                                            the Proceeding was brought or the Delaware Court shall determine upon application that, despite
                                            the adjudication of liability but in view of all of the circumstances of the case, Indemnitees
                                            is fairly and reasonably entitled to indemnification, to be held harmless or to exoneration.

 

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		5.	INDEMNIFICATION
FOR EXPENSES OF A PARTY WHO IS WHOLLY OR PARTLY SUCCESSFUL. Notwithstanding any other provisions of this Agreement except for Section
27, to the extent that Indemnitees was or is a party to or a participant (as a witness, deponent or otherwise) in and is successful,
on the merits or otherwise, in any Proceeding or in defense of any claim, issue or matter therein, in whole or in part, the Company shall,
to the fullest extent permitted by applicable law, indemnify, hold harmless and exonerate Indemnitees against all Expenses actually and
reasonably incurred by him or her in connection therewith. If Indemnitees is not wholly successful in such Proceeding but is successful,
on the merits or otherwise, as to one or more but less than all claims, issues or matters in such Proceeding, the Company shall, to the
fullest extent permitted by applicable law, indemnify, hold harmless and exonerate Indemnitees against all Expenses actually and reasonably
incurred by him or her or on his or her behalf in connection with each successfully resolved claim, issue or matter. If the Indemnitees
is not wholly successful in such Proceeding, the Company also shall, to the fullest extent permitted by applicable law, indemnify, hold
harmless and exonerate Indemnitees against all Expenses actually and reasonably incurred in connection with a claim, issue or matter
related to any claim, issue, or matter on which the Indemnitees was successful. For purposes of this Section and without limitation,
the termination of any claim, issue or matter in such a Proceeding by dismissal, with or without prejudice, shall be deemed to be a successful
result as to such claim, issue or matter.

 

		6.	INDEMNIFICATION
                                            FOR EXPENSES OF A WITNESS. Notwithstanding any other provision of this Agreement except
                                            for Section 27, to the extent that Indemnitees is a participant (as a witness or otherwise)
                                            in any Proceeding to which Indemnitees is not a party, he or she shall, to the fullest extent
                                            permitted by applicable law, be indemnified, held harmless and exonerated against all Expenses
                                            actually and reasonably incurred by him or her or on his or her behalf in connection therewith.

 

		7.	ADDITIONAL
                                            INDEMNIFICATION, HOLD HARMLESS AND EXONERATION RIGHTS.

 

Notwithstanding
any limitation in Sections 3, 4, or 5, the Company shall, to the fullest extent permitted by applicable law, indemnify, hold harmless
and exonerate Indemnitees if Indemnitees is a party to or threatened to be made a party to any Proceeding (including a Proceeding by
or in the right of the Company to procure a judgment in its favor) against all Expenses, judgments, fines, penalties and amounts paid
in settlement (including all interest, assessments and other charges paid or payable in connection with or in respect of such Expenses,
judgments, fines, penalties and amounts paid in settlement) actually and reasonably incurred by Indemnitees in connection with the Proceeding.
No indemnification, hold harmless or exoneration rights shall be available under this Section 7 on account of Indemnitees’s conduct
which constitutes a breach of Indemnitees’s duty of loyalty to the Company or its stockholders, including an act or omission of
Indemnitees not in good faith, or which involves intentional misconduct or a knowing violation of the law.

 

		8.	CONTRIBUTION
                                            IN THE EVENT OF JOINT LIABILITY.

 

(a) To
the fullest extent permissible under applicable law, if the indemnification, hold harmless and/or exoneration rights provided for in
this Agreement are unavailable to Indemnitees in whole or in part for any reason whatsoever, the Company, in lieu of indemnifying, holding
harmless or exonerating Indemnitees, shall pay, in the first instance, the entire amount incurred by Indemnitees, whether for judgments,
liabilities, fines, penalties, amounts paid or to be paid in settlement and/or for Expenses, in connection with any Proceeding without
requiring Indemnitees to contribute to such payment, and the Company hereby waives and relinquishes any right of contribution it may
have at any time against Indemnitees.

 

 (b) The Company shall not enter into any settlement of any Proceeding in which the Company is jointly liable with Indemnitees (or would be if joined in such Proceeding) unless such settlement provides for a full and final release of all claims asserted against Indemnitees.

 

 (c) The Company hereby agrees to fully indemnify, hold harmless and exonerate Indemnitees from any claims for contribution which may be brought by officers, directors or employees of the Company, other than Indemnitees, who may be jointly liable with Indemnitees.

 

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		9.	EXCLUSIONS.
Notwithstanding any provision in this Agreement except for Section 27, the Company shall not be obligated under this Agreement to make
any indemnification, hold harmless or exoneration payment in connection with any claim made against Indemnitees:

 

(a) for
which payment has actually been received by or on behalf of Indemnitees under any insurance policy or other indemnity provision, except
with respect to any excess beyond the amount actually received under any insurance policy, contract, agreement, other indemnity provision
or otherwise;

 

(b) for
an accounting of profits made from the purchase and sale (or sale and purchase) by Indemnitees of securities of the Company within the
meaning of Section 16(b) of the Exchange Act or similar provisions of state statutory law or common law; or

 

(c) except
as otherwise provided in Sections 14(e)-(f) hereof, prior to a Change in Control, in connection with any Proceeding (or any part of any
Proceeding) initiated by Indemnitees, including any Proceeding (or any part of any Proceeding) initiated by Indemnitees against the Company
or its directors, officers, employees or other indemniteess, unless (i) the Board authorized the Proceeding (or any part of any Proceeding)
prior to its initiation or (ii) the Company provides the indemnification, hold harmless or exoneration payment, in its sole discretion,
pursuant to the powers vested in the Company under applicable law.

 

		10.	ADVANCES
                                            OF EXPENSES; DEFENSE OF CLAIM.

 

(a) Notwithstanding
any provision of this Agreement to the contrary except for Section 27, and to the fullest extent not prohibited by applicable law, the
Company shall pay the Expenses incurred by Indemnitees (or reasonably expected by Indemnitees to be incurred by Indemnitees within three
months) in connection with any Proceeding within ten (10) days after the receipt by the Company of a statement or statements requesting
such advances from time to time, prior to the final disposition of any Proceeding. Advances shall be unsecured and interest free. Advances
shall be made without regard to Indemnitees’s ability to repay the Expenses and without regard to Indemnitees’s ultimate
entitlement to be indemnified, held harmless or exonerated under the other provisions of this Agreement. Advances shall include any and
all reasonable Expenses incurred pursuing a Proceeding to enforce this right of advancement, including Expenses incurred preparing and
forwarding statements to the Company to support the advances claimed. To the fullest extent required by applicable law, such payments
of Expenses in advance of the final disposition of the Proceeding shall be made only upon the Company’s receipt of an undertaking,
by or on behalf of the Indemnitees, to repay the advance to the extent that it is ultimately determined that Indemnitees is not entitled
to be indemnified by the Company under the provisions of this Agreement, the Charter, the Bylaws of the Company, applicable law or otherwise.
This Section 10(a) shall not apply to any claim made by Indemnitees for which an indemnification, hold harmless or exoneration payment
is excluded pursuant to Section 9.

 

 (b) The Company will be entitled to participate in the Proceeding at its own expense.

 

(c) The
Company shall not settle any action, claim or Proceeding (in whole or in part) which would impose any Expense, judgment, fine, penalty
or limitation that is not entitled to be indemnified under this Agreement on the Indemnitees without the Indemnitees’s prior written
consent.

 

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		11.	PROCEDURE
FOR NOTIFICATION AND APPLICATION FOR INDEMNIFICATION

 

(a) Indemnitees
agrees to promptly notify the Company in writing upon being served with any summons, citation, subpoena, complaint, indictment, information
or other document relating to any Proceeding or matter which may be subject to indemnification, hold harmless or exoneration rights,
or advancement of Expenses covered hereunder. The failure of Indemnitees to so notify the Company shall not relieve the Company of any
obligation which it may have to the Indemnitees under this Agreement, or otherwise.

 

(b) Indemnitees
may deliver to the Company a written application to indemnify, hold harmless or exonerate Indemnitees in accordance with this Agreement.
Such application(s) may be delivered from time to time and at such time(s) as Indemnitees deems appropriate in his or her sole discretion.
Following such a written application for indemnification by Indemnitees, the Indemnitees’s entitlement to indemnification shall
be determined according to Section 12(a) of this Agreement.

 

		12.	PROCEDURE
                                            UPON APPLICATION FOR INDEMNIFICATION.

 

(a) A
determination, if required by applicable law, with respect to Indemnitees’s entitlement to indemnification shall be made in the
specific case by one of the following methods, which shall be at the election of Indemnitees: (i) by a majority vote of the Disinterested
Directors, even though less than a quorum of the Board, (ii) by a committee of such directors designated by majority vote of such directors,
or (iii) by Independent Counsel in a written opinion to the Board, a copy of which shall be delivered to Indemnitees. The Company will
promptly advise Indemnitees in writing with respect to any determination that Indemnitees is or is not entitled to indemnification, including
a description of any reason or basis for which indemnification has been denied. If it is so determined that Indemnitees is entitled to
indemnification, payment to Indemnitees shall be made within ten (10) days after such determination. Indemnitees shall reasonably cooperate
with the person, persons or entity making such determination with respect to Indemnitees’s entitlement to indemnification, including
providing to such person, persons or entity upon reasonable advance request any documentation or information which is not privileged
or otherwise protected from disclosure and which is reasonably available to Indemnitees and reasonably necessary to such determination.
Any costs or Expenses (including reasonable attorneys’ fees and disbursements) incurred by Indemnitees in so cooperating with the
person, persons or entity making such determination shall be borne by the Company (irrespective of the determination as to Indemnitees’s
entitlement to indemnification) and the Company hereby agrees to indemnify and to hold Indemnitees harmless therefrom.

 

(b)
In the event the determination of entitlement to indemnification is to be made by Independent Counsel pursuant to Section 12(a)
hereof, the Independent Counsel shall be selected as provided in this Section 12(b). The Independent Counsel shall be selected by
Indemnitees (unless Indemnitees shall request that such selection be made by the Board), and Indemnitees shall give written notice
to the Company advising it of the identity of the Independent Counsel so selected and certifying that the Independent Counsel so
selected meets the requirements set forth in Section 2(k) hereof. If the Independent Counsel is selected by the Board, the Company
shall give written notice to Indemnitees advising him of the identity of the Independent Counsel so selected and certifying that the
Independent Counsel so selected meets the requirements set forth in Section 2(k) hereof. In either event, Indemnitees or the
Company, as the case may be, may, within ten (10) days after such written notice of selection shall have been received, deliver to
the Company or to Indemnitees, as the case may be, a written objection to such selection; provided, however, that such objection may
be asserted only on the ground that the Independent Counsel so selected does not meet the requirements so selected meets the
requirements set forth in Section 2(k) hereof, and the objection shall set forth with particularity the factual basis of such
assertion. Absent a proper and timely objection, the person so selected shall act as Independent Counsel. If such written objection
is so made and substantiated, the Independent Counsel so selected may not serve as Independent Counsel unless and until such
objection is withdrawn or a court of competent jurisdiction has determined that such objection is without merit. If, within twenty
(20) days after submission by Indemnitees of a written request for indemnification pursuant to Section 11(b) hereof, no Independent
Counsel shall have been selected and not objected to, either the Company or Indemnitees may petition the Delaware Court for
resolution of any objection which shall have been made by the Company or Indemnitees to the other’s selection of Independent
Counsel and/or for the appointment as Independent Counsel of a person selected by the Delaware Court, and the person with respect to
whom all objections are so resolved or the person so appointed shall act as Independent Counsel under Section 12(a) hereof. Upon the
due commencement of any judicial proceeding or arbitration pursuant to Section 14(a) of this Agreement, Independent Counsel shall be
discharged and relieved of any further responsibility in such capacity (subject to the applicable standards of professional conduct
then prevailing).

 

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(c) The
Company agrees to pay the reasonable fees and expenses of Independent Counsel and to fully indemnify and hold harmless such Independent
Counsel against any and all Expenses, claims, liabilities and damages arising out of or relating to this Agreement or its engagement
pursuant hereto.

 

		13.	PRESUMPTIONS
                                            AND EFFECT OF CERTAIN PROCEEDINGS.

 

(a) In
making a determination with respect to entitlement to indemnification hereunder, the person, persons or entity making such determination
shall presume that Indemnitees is entitled to indemnification under this Agreement if Indemnitees has submitted a request for indemnification
in accordance with Section 11(b) of this Agreement, and the Company shall have the burden of proof to overcome that presumption in connection
with the making by any person, persons or entity of any determination contrary to that presumption. Neither the failure of the Company
(including by its directors or Independent Counsel) to have made a determination prior to the commencement of any action pursuant to
this Agreement that indemnification is proper in the circumstances because Indemnitees has met the applicable standard of conduct, nor
an actual determination by the Company (including by its directors or Independent Counsel) that Indemnitees has not met such applicable
standard of conduct, shall be a defense to the action or create a presumption that Indemnitees has not met the applicable standard of
conduct.

 

(b) If
the person, persons or entity empowered or selected under Section 12 of this Agreement to determine whether Indemnitees is entitled to
indemnification shall not have made a determination within thirty (30) days after receipt by the Company of the request therefor, the
requisite determination of entitlement to indemnification shall be deemed to have been made and Indemnitees shall be entitled to such
indemnification, absent (i) a misstatement by Indemnitees of a material fact, or an omission of a material fact necessary to make Indemnitees’s
statement not materially misleading, in connection with the request for indemnification, or (ii) a final judicial determination that
any or all such indemnification is expressly prohibited under applicable law; provided, however, that such thirty (30) day period may
be extended for a reasonable time, not to exceed an additional fifteen (15) days, if the person, persons or entity making the determination
with respect to entitlement to indemnification in good faith require(s) such additional time for the obtaining or evaluating of documentation
and/or information relating thereto.

 

(c)
The termination of any Proceeding or of any claim, issue or matter therein, by judgment, order, settlement or conviction, or upon a
plea of nolo contendere or its equivalent, shall not (except as otherwise expressly provided in this Agreement) of itself, favor or
undermine the determination of, the right of Indemnitees to indemnification or create a presumption that Indemnitees did or did not
act in good faith and in a manner which he or she reasonably believed to be in or not opposed to the best interests of the Company
or, with respect to any criminal Proceeding, that Indemnitees had reasonable cause to believe that his or her conduct was
unlawful.

 

    9

     

    

 

(d) For
purposes of any determination of good faith, Indemnitees shall be deemed to have acted in good faith if Indemnitees’s action is
based on the records or books of account of the Enterprise, including financial statements, or on information supplied to Indemnitees
by the directors, officers or managers of the Enterprise in the course of their duties, or on the advice of legal counsel for the Enterprise,
its Board, any committee of the Board or any director, officer, trustee, general partner, manager or managing member, or on information
or records given or reports made to the Enterprise, its Board, any committee of the Board or any director, officer, trustee, general
partner, manager or managing member, by an independent certified public accountant or by an appraiser or other expert selected by the
Enterprise, its Board, any committee of the Board or any director, officer, trustee, general partner, manager or managing member. The
provisions of this Section 13(d) shall not be deemed to be exclusive or to limit in any way the other circumstances in which the Indemnitees
may be deemed or found to have or have not met the applicable standard of conduct set forth in this Agreement.

 

(e) The
knowledge and/or actions, or failure to act, of any other director, officer, trustee, partner, managing member, fiduciary, agent or employee
of the Enterprise shall not be imputed to Indemnitees for purposes of determining the right to indemnification under this Agreement.

 

		14.	REMEDIES
                                            OF INDEMNITEES.

 

(a) In
the event that (i) a determination is made pursuant to Section 12 of this Agreement that Indemnitees is not entitled to indemnification
under this Agreement, (ii) advancement of Expenses, to the fullest extent permitted by applicable law, is not timely made pursuant to
Section 10 of this Agreement, (iii) no determination of entitlement to indemnification shall have been made pursuant to Section 12(a)
of this Agreement within the timeline set forth in this Agreement, (iv) payment of indemnification is not made pursuant to Section 5,
6, 7 or the last sentence of Section 12(a) of this Agreement within the timeline set forth in this Agreement, (v) a contribution payment
is not made in a timely manner pursuant to Section 8 of this Agreement, (vi) payment of indemnification pursuant to Section 3 or 4 of
this Agreement is not made within the timeline set forth in this Agreement, or (vii) payment to Indemnitees pursuant to any hold harmless
or exoneration rights under this Agreement or otherwise is not made within the timeline set forth in this Agreement, Indemnitees shall
be entitled to an adjudication by the Delaware Court to such indemnification, hold harmless, exoneration, contribution or advancement
rights. Alternatively, Indemnitees, at his or her option, may seek an award in arbitration to be conducted by a single arbitrator pursuant
to the Commercial Arbitration Rules of the American Arbitration Association. Except as set forth herein, the provisions of Delaware law
(without regard to its conflict of laws rules) shall apply to any such arbitration. The Company shall not oppose Indemnitees’s
right to seek any such adjudication or award in arbitration.

 

(b)
In the event that a determination shall have been made pursuant to Section 12(a) of this Agreement that Indemnitees is not entitled
to indemnification, any judicial proceeding or arbitration commenced pursuant to this Section 14 shall be conducted in all respects
as a de novo trial, or arbitration, on the merits and Indemnitees shall not be prejudiced by reason of that adverse determination.
In any judicial proceeding or arbitration commenced pursuant to this Section 14, Indemnitees shall be presumed to be entitled to be
indemnified, held harmless, exonerated to receive advances of Expenses under this Agreement and the Company shall have the burden of
proving Indemnitees is not entitled to be indemnified, held harmless, exonerated and to receive advances of Expenses, as the case
may be, and the Company may not refer to or introduce into evidence any determination pursuant to Section 12(a) of this Agreement
adverse to Indemnitees for any purpose. If Indemnitees commences a judicial proceeding or arbitration pursuant to this Section 14,
Indemnitees shall not be required to reimburse the Company for any advances pursuant to Section 10 until a final determination is
made with respect to Indemnitees’s entitlement to indemnification (as to which all rights of appeal have been exhausted or
lapsed).

 

    10

     

    

 

(c) If
a determination shall have been made pursuant to Section 12(a) of this Agreement that Indemnitees is entitled to indemnification, the
Company shall be bound by such determination in any judicial proceeding or arbitration commenced pursuant to this Section 14, absent
(i) a misstatement by Indemnitees of a material fact, or an omission of a material fact necessary to make Indemnitees’s statement
not materially misleading, in connection with the request for indemnification, or (ii) a prohibition of such indemnification under applicable
law.

 

(d) The
Company shall be precluded from asserting in any judicial proceeding or arbitration commenced pursuant to this Section 14 that the procedures
and presumptions of this Agreement are not valid, binding and enforceable and shall stipulate in any such court or before any such arbitrator
that the Company is bound by all the provisions of this Agreement.

 

(e) The
Company shall indemnify and hold harmless Indemnitees to the fullest extent permitted by law against all Expenses and, if requested by
Indemnitees, shall (within ten (10) days after the Company’s receipt of such written request) pay to Indemnitees, to the fullest
extent permitted by applicable law, such Expenses which are incurred by Indemnitees in connection with any judicial proceeding or arbitration
brought by Indemnitees (i) to enforce his or her rights under, or to recover damages for breach of, this Agreement or any other indemnification,
hold harmless, exoneration, advancement or contribution agreement or provision of the Charter or the Bylaws now or hereafter in effect;
or (ii) for recovery or advances under any insurance policy maintained by any person for the benefit of Indemnitees, regardless of the
outcome and whether Indemnitees ultimately is determined to be entitled to such indemnification, hold harmless or exoneration right,
advancement, contribution or insurance recovery, as the case may be (unless such judicial proceeding or arbitration was not brought by
Indemnitees in good faith).

 

(f) Interest
shall be paid by the Company to Indemnitees at the legal rate under Delaware law for amounts which the Company indemnifies, holds harmless
or exonerates, contributes, reimburses, advances, or is obliged to indemnify, hold harmless, exonerate, contribute, reimburse or advance
for the period commencing with the date on which the Indemnitees requests such indemnification, to be held harmless, exonerated, contribution,
reimbursement or advancement of any Expenses and ending with the date on which such payment is made to Indemnitees by the Company.

 

		15.	SECURITY.
                                            Notwithstanding anything herein to the contrary, to the extent requested by the Indemnitees
                                            and approved by the Board, the Company may at any time and from time to time provide security
                                            to the Indemnitees for the Company’s obligations hereunder through an irrevocable bank
                                            line of credit, funded trust or other collateral. Any such security, once provided to the
                                            Indemnitees, may not be revoked or released without the prior written consent of the Indemnitees.

 

    11

     

    

 

		16.	NON-EXCLUSIVITY;
                                            SURVIVAL OF RIGHTS; INSURANCE; SUBROGATION; PRIORITY OF OBLIGATIONS.

 

(a)
The rights of Indemnitees as provided by this Agreement shall not be deemed exclusive of any other rights to which Indemnitees may
at any time be entitled under applicable law, the Charter, the Bylaws, any agreement, a vote of stockholders or a resolution of
directors, or otherwise. No amendment, alteration or repeal of this Agreement or of any provision hereof shall limit or restrict any
right of Indemnitees under this Agreement in respect of any Proceeding (regardless of when such Proceeding is first threatened,
commenced or completed) or claim, issue or matter therein arising out of, or related to, any action taken or omitted by such
Indemnitees in his Corporate Status prior to such amendment, alteration or repeal. To the extent that a change in applicable law,
whether by statute or judicial decision, permits greater indemnification, hold harmless or exoneration rights or advancement of
Expenses than would be afforded currently under the Charter, the Bylaws or this Agreement, then this Agreement (without any further
action by the parties hereto) shall automatically be deemed to be amended to require that the Company indemnifies the Indemnitees to
the fullest extent permitted by law. No right or remedy herein conferred is intended to be exclusive of any other right or remedy,
and every other right and remedy shall be cumulative and in addition to every other right and remedy given hereunder or now or
hereafter existing at law or in equity or otherwise,. The assertion or employment of any right or remedy hereunder, or otherwise,
shall not prevent the concurrent assertion or employment of any other right or remedy.

 

(b) The
DGCL and the Bylaws permit the Company to purchase and maintain insurance or furnish similar protection or make other arrangements including,
but not limited to, providing a trust fund, letter of credit, or surety bond (“Indemnification Arrangements”)
on behalf of Indemnitees against any liability asserted against him or her or incurred by or on behalf of him or her or in such capacity
as a director, officer, employee or agent of the Company, or arising out of his or her status as such, whether or not the Company would
have the power to indemnify him or her against such liability under the provisions of this Agreement or under the DGCL, as it may then
be in effect. The purchase, establishment, and maintenance of any such Indemnification Arrangement shall not in any way limit or affect
the rights and obligations of the Company or of the Indemnitees under this Agreement except as expressly provided herein, and the execution
and delivery of this Agreement by the Company and the Indemnitees shall not in any way limit or affect the rights and obligations of
the Company or the other party or parties thereto under any such Indemnification Arrangement.

 

(c) To
the extent that the Company maintains an insurance policy or policies providing liability insurance for directors, officers, trustees,
partners, managers, managing members, fiduciaries, employees, or agents of the Company or of any other Enterprise which such person serves
at the request of the Company, Indemnitees shall be covered by such policy or policies in accordance with its or their terms to the maximum
extent of the coverage available for any such director, officer, trustee, partner, manager, managing member, fiduciary, employee or agent
under such policy or policies. If, at the time the Company receives notice from any source of a Proceeding as to which Indemnitees is
a party or a participant (as a witness, deponent or otherwise), the Company has director and officer liability insurance in effect, the
Company shall give prompt notice of such Proceeding to the insurers in accordance with the procedures set forth in the respective policies.
The Company shall thereafter take all necessary or desirable action to cause such insurers to pay, on behalf of the Indemnitees, all
amounts payable as a result of such Proceeding in accordance with the terms of such policies.

 

(d) In
the event of any payment under this Agreement, the Company shall be subrogated to the extent of such payment to all of the rights of
recovery of Indemnitees, who shall execute all papers required and take all action necessary to secure such rights, including execution
of such documents as are necessary to enable the Company to bring suit to enforce such rights. No such payment by the Company shall be
deemed to relieve any insurer of its obligations.

 

    12

     

    

 

(e)
The Company’s obligation to indemnify, hold harmless, exonerate or advance Expenses hereunder to Indemnitees who is or was
serving at the request of the Company as a director, officer, trustee, partner, managing member, fiduciary, employee or agent of any
other Enterprise shall be reduced by any amount Indemnitees has actually received as indemnification, hold harmless or exoneration
payments or advancement of expenses from such Enterprise. Notwithstanding any other provision of this Agreement to the contrary
except for Section 27, (i) the Indemnitees shall have no obligation to reduce, offset, allocate, pursue or apportion any
indemnification, hold harmless, exoneration, advancement, contribution or insurance coverage among multiple parties possessing such
duties to Indemnitees prior to the Company’s satisfaction and performance of all its obligations under this Agreement, and
(ii) the Company shall perform fully its obligations under this Agreement without regard to whether Indemnitees holds, may pursue or
has pursued any indemnification, advancement, hold harmless, exoneration, contribution or insurance coverage rights against any
person or entity other than the Company.

 

(f) Notwithstanding
anything contained herein, the Company is the primary indemnitor, and any indemnification or advancement obligation of any Co-Sponsor
or its respective affiliates or any other Person is secondary.

 

		17.	DURATION
                                            OF AGREEMENT. All agreements and obligations of the Company contained herein shall continue
                                            during the period Indemnitees serves as a director or officer of the Company or as a director,
                                            officer, trustee, partner, manager, managing member, fiduciary, employee or agent of any
                                            other corporation, partnership, joint venture, trust, employee benefit plan or other Enterprise
                                            which Indemnitees serves at the request of the Company and shall continue thereafter so long
                                            as Indemnitees shall be subject to any possible Proceeding (including any rights of appeal
                                            thereto and any Proceeding commenced by Indemnitees pursuant to Section 14 of this Agreement)
                                            by reason of his Corporate Status, whether or not he is acting in any such capacity at the
                                            time any liability or expense is incurred for which indemnification or advancement can be
                                            provided under this Agreement.

 

		18.	SEVERABILITY.
                                            If any provision or provisions of this Agreement shall be held to be invalid, illegal or
                                            unenforceable for any reason whatsoever: (a) the validity, legality and enforceability of
                                            the remaining provisions of this Agreement (including, without limitation, each portion of
                                            any Section, paragraph or sentence of this Agreement containing any such provision held to
                                            be invalid, illegal or unenforceable, that is not itself invalid, illegal or unenforceable)
                                            shall not in any way be affected or impaired thereby and shall remain enforceable to the
                                            fullest extent permitted by law; (b) such provision or provisions shall be deemed reformed
                                            to the extent necessary to conform to applicable law and to give the maximum effect to the
                                            intent of the parties hereto; and (c) to the fullest extent possible, the provisions of this
                                            Agreement (including, without limitation, each portion of any Section, paragraph or sentence
                                            of this Agreement containing any such provision held to be invalid, illegal or unenforceable,
                                            that is not itself invalid, illegal or unenforceable) shall be construed so as to give effect
                                            to the intent manifested thereby.

 

		19.	ENFORCEMENT
                                            AND BINDING EFFECT.

 

(a) The
Company expressly confirms and agrees that it has entered into this Agreement and assumed the obligations imposed on it hereby in order
to induce Indemnitees to serve as a director, officer or key employee of the Company, and the Company acknowledges that Indemnitees is
relying upon this Agreement in serving as a director, officer or key employee of the Company.

 

(b) Without
limiting any of the rights of Indemnitees under the Charter or Bylaws as they may be amended from time to time, this Agreement constitutes
the entire agreement between the parties hereto with respect to the subject matter hereof and supersedes all prior agreements and understandings,
oral, written and implied, between the parties hereto with respect to the subject matter hereof.

 

    13

     

    

 

(c)
The indemnification, hold harmless, exoneration and advancement of expenses rights provided by or granted pursuant to this Agreement
shall be binding upon and be enforceable by the parties hereto and their respective successors and assigns (including any direct or
indirect successor by purchase, merger, consolidation or otherwise to all or substantially all of the business or assets of the
Company), shall continue as to an Indemnitees who has ceased to be a director, officer, employee or agent of the Company or a
director, officer, trustee, general partner, manager, managing member, fiduciary, employee or agent of any other Enterprise at the
Company’s request, and shall inure to the benefit of Indemnitees and his or her spouse, assigns, heirs, devisees, executors
and administrators and other legal representatives.

 

(d) The
Company shall require and cause any successor (whether direct or indirect by purchase, merger, consolidation or otherwise) to all, substantially
all or a substantial part, of the business and/or assets of the Company, by written agreement in form and substance satisfactory to the
Indemnitees, expressly to assume and agree to perform this Agreement in the same manner and to the same extent that the Company would
be required to perform if no such succession had taken place.

 

(e) The
Company and Indemnitees agree herein that a monetary remedy for breach of this Agreement, at some later date, may be inadequate, impracticable
and difficult of proof, and further agree that such breach may cause Indemnitees irreparable harm. Accordingly, the parties hereto agree
that Indemnitees may enforce this Agreement by seeking, among other things, injunctive relief and/or specific performance hereof, without
any necessity of showing actual damage or irreparable harm and that by seeking injunctive relief and/or specific performance, Indemnitees
shall not be precluded from seeking or obtaining any other relief to which he or she may be entitled. The Company and Indemnitees further
agree that Indemnitees shall be entitled to such specific performance and injunctive relief, including temporary restraining orders,
preliminary injunctions and permanent injunctions, without the necessity of posting bonds or other undertakings in connection therewith.
The Company acknowledges that in the absence of a waiver, a bond or undertaking may be required of Indemnitees by the Delaware Court,
and the Company hereby waives any such requirement of such a bond or undertaking.

 

		20.	MODIFICATION
                                            AND WAIVER. No supplement, modification or amendment of this Agreement shall be binding
                                            unless executed in writing by the parties hereto. No waiver of any of the provisions of this
                                            Agreement shall be deemed or shall constitute a waiver of any other provisions of this Agreement
                                            nor shall any waiver constitute a continuing waiver.

 

		21.	NOTICES.
                                            All notices, requests, demands and other communications under this Agreement shall be in
                                            writing and shall be deemed to have been duly given (i) if delivered by hand and receipted
                                            for by the party to whom said notice or other communication shall have been directed, or
                                            (ii) if mailed by certified or registered mail with postage prepaid, on the third (3rd) business
                                            day after the date on which it is so mailed:

 

(a) If
to Indemnitees, at the address indicated on the signature page of this Agreement, or such other address as Indemnitees shall provide
in writing to the Company.

 

 (b) If to the Company, to:

 

CleanTech
Acquisition Corp.

207 West 25th Street, 9th Floor

New York, NY 10001

Attn:
Eli Spiro, Chief Executive Officer

 

or
to any other address as may have been furnished to Indemnitees in writing by the Company.

 

    14

     

    

 

		22.	APPLICABLE
                                            LAW AND CONSENT TO JURISDICTION. This Agreement and the legal relations among the parties
                                            shall be governed by, and construed and enforced in accordance with, the laws of the State
                                            of Delaware, without regard to its conflict of laws rules. Except with respect to any arbitration
                                            commenced by Indemnitees pursuant to Section 14(a) of this Agreement, the Company and Indemnitees
                                            hereby irrevocably and unconditionally: (a) agree that any action or proceeding arising out
                                            of or in connection with this Agreement shall be brought only in the Delaware Court and not
                                            in any other state or federal court in the United States of America or any court in any other
                                            country; (b) consent to submit to the exclusive jurisdiction of the Delaware Court for purposes
                                            of any action or proceeding arising out of or in connection with this Agreement; (c) waive
                                            any objection to the laying of venue of any such action or proceeding in the Delaware Court;
                                            and (d) waive, and agree not to plead or to make, any claim that any such action or proceeding
                                            brought in the Delaware Court has been brought in an improper or inconvenient forum, or is
                                            subject (in whole or in part) to a jury trial.

 

		23.	IDENTICAL
                                            COUNTERPARTS. This Agreement may be executed in one or more counterparts, each of which
                                            shall for all purposes be deemed to be an original but all of which together shall constitute
                                            one and the same Agreement. Only one such counterpart signed by the party against whom enforceability
                                            is sought needs to be produced to evidence the existence of this Agreement.

 

		24.	MISCELLANEOUS.
                                            Use of the masculine pronoun shall be deemed to include usage of the feminine pronoun where
                                            appropriate. The headings of the paragraphs of this Agreement are inserted for convenience
                                            only and shall not be deemed to constitute part of this Agreement or to affect the construction
                                            thereof.

 

		25.	PERIOD
                                            OF LIMITATIONS. No legal action shall be brought and no cause of action shall be asserted
                                            by or in the right of the Company against Indemnitees, Indemnitees’s spouse, heirs,
                                            executors or personal or legal representatives after the expiration of two years from the
                                            date of accrual of such cause of action, and any claim or cause of action of the Company
                                            shall be extinguished and deemed released unless asserted by the timely filing of a legal
                                            action within such two-year period; provided, however, that if any shorter period of limitations
                                            is otherwise applicable to any such cause of action such shorter period shall govern.

 

		26.	ADDITIONAL
                                            ACTS. If, for the validation of any of the provisions in this Agreement any act, resolution,
                                            approval or other procedure is required, the Company undertakes to cause such act, resolution,
                                            approval or other procedure to be affected or adopted in a manner that will enable the Company
                                            to fulfill its obligations under this Agreement.

 

		27.	WAIVER
                                            OF CLAIMS TO TRUST ACCOUNT. Notwithstanding anything to the contrary contained herein,
                                            Indemnitees hereby agrees that he or she does not have any right, title, interest or claim
                                            of any kind (each, a “Claim”) in or to any monies in the trust
                                            account established in connection with the Company’s initial public offering for the
                                            benefit of the Company and holders of shares issued in such offering, and hereby waives any
                                            Claim he or she may have in the future as a result of, or arising out of, any services provided
                                            to the Company and will not seek recourse against such trust account for any reason whatsoever.
                                            For purposes of clarity, Indemnitees acknowledges and agrees that no monies held in the Trust
                                            Account may be used to indemnify Indemnitees for any purpose whatsoever.

 

		28.	MAINTENANCE
                                            OF INSURANCE. The Company shall use commercially reasonable efforts to obtain and maintain
                                            in effect during the entire period for which the Company is obligated to indemnify the Indemnitees
                                            under this Agreement, one or more policies of insurance with reputable insurance companies
                                            to provide the officers/directors of the Company with coverage for losses from wrongful acts
                                            and omissions and to ensure the Company’s performance of its indemnification obligations
                                            under this Agreement. The Indemnitees shall be covered by such policy or policies in accordance
                                            with its or their terms to the maximum extent of the coverage available for any such director
                                            or officer under such policy or policies. In all such insurance policies, the Indemnitees
                                            shall be named as an insured in such a manner as to provide the Indemnitees with the same
                                            rights and benefits as are accorded to the most favorably insured of the Company’s
                                            directors and officers.

 

(Signatures
follow.)

 

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IN
WITNESS WHEREOF, the parties hereto have caused this Agreement to be signed as of the day and year first above written.

 

	 	CLEANTECH ACQUISITION CORP.
	 	 	 	 
	 	By:	/s/ Eli Spiro
	 	 	Name: 	Eli Spiro
	 	 	Title:	Chief Executive Officer
	 	 	 	 
	 	 	INDEMNITEES
	 	 	 	 
	 	 	/s/ Dan Reicher
	 		Dan Reicher
	 	 	 
	 	 	/s/ Alan Weiss
	 	 	Alan Weiss 
	 	 	 	 
	 	 	/s/ Douglas Cole
	 	 	Douglas Cole
	 	 	 	 
	 	 	/s/ Jonas Grossman
	 	 	Jonas Grossman
	 	 	 	 
	 	 	/s/ Britt Ide
	 	 	Britt Ide
	 	 	 	 
	 	 	/s/ Brendan Riley
	 	 	Brendan Riley
	 	 	 	 
	 	 	/s/ Bill Richardson
	 	 	Bill Richardson
	 	 	 	 
	 	 	/s/ Jon Najarian
	 	 	Jon Najarian
	 	 	 	 
	 	 	/s/ Ankur Dhanuka
	 	 	Ankur Dhanuka
	 	 	 	 
	 	 	/s/ Louis Buffalino
	 	 	Louis Buffalino
	 	 	 	 
	 	 	/s/ Richard Fitzgerald
	 	 	Richard Fitzgerald
	 	 	 	 
	 	 	/s/ Eli Spiro
	 	 	Eli Spiro

 

[Signature
Page to Indemnity Agreement]Exhibit 10.7

 

July 14, 2021

 

CleanTech Acquisition Corp.

207 West 25th Street, 9th Floor

New York, NY 10001

 

Ladies and Gentlemen:

 

CleanTech Acquisition
Corp. (the “Company”), a blank check company formed for the purpose of acquiring one or more businesses or entities (a “Business
Combination”), intends to register its securities under the Securities Act of 1933, as amended (“Securities Act”), in
connection with its initial public offering (“IPO”), pursuant to a registration statement on Form S- 1 (“Registration
Statement”).

 

The undersigned
hereby commits that it will purchase an aggregate of 6,500,000 warrants of the Company (“Private Warrants”), at a price of
$1.00 per warrant for an aggregate purchase price of $6,500,000 (the “Private Warrant Purchase Price”).

 

At least twenty-four
(24) hours prior to the effective date of the Registration Statement, the undersigned will cause the Private Warrant Purchase Price to
be delivered to Loeb & Loeb, LLP (“Loeb”), as escrow agent, by wire transfer as set forth in the instructions attached
as Exhibit A to hold in a non-interest bearing account until the Company consummates the IPO.

 

The consummation
of the purchase and issuance of the Private Warrants shall occur simultaneously with the consummation of the IPO. Simultaneously with
the consummation of the IPO, Continental shall deposit the Private Warrant Purchase Price, without interest or deduction, into the trust
fund (“Trust Fund”) established by the Company for the benefit of the Company’s public stockholders as described in
the Registration Statement.

 

Each of the Company
and the undersigned acknowledges and agrees that Loeb is serving hereunder solely as a convenience to the parties to facilitate the purchase
of the Private Warrants.

 

Additionally, the undersigned agrees:

 

		●	not to propose, or vote in favor of, an amendment to the Company’s Amended and Restated Certificate
of Incorporation that would affect the substance or timing of the Company’s obligation to redeem 100% of the Company’s shares
of Common Stock sold in the IPO if the Company does not complete an initial Business Combination within 12 months (or up to 18 months,
if the time to complete a Business Combination is extended as described in the prospectus) from the closing of the IPO, unless the Company
provides the holders of shares of Common Stock sold in the IPO with the opportunity to redeem their shares of Common Stock upon approval
of any such amendment at a per-share price, payable in cash, equal to the aggregate amount of the Trust Fund, including interest earned
on Trust Fund and not previously released to the Company
to pay the Company’s franchise and income taxes, divided by the number of then outstanding shares of Common Stock sold in the IPO;

 

     

     

    

 

		●	the undersigned will not participate in any liquidation distribution with respect to the Private Warrants
(but will participate in liquidation distributions with respect to any units or Common Stock purchased by the undersigned in the IPO or
in the open market) if the Company fails to consummate a Business Combination;

 

		●	that the Private Warrants and underlying securities will not be transferable until 30 days after the consummation
of a Business Combination except (a) to officers or directors of the Company, any affiliates or family members of any of officers or directors
of the Company, any members of CleanTech Sponsor I LLC or CleanTech Investments, LLC, or any affiliates of CleanTech Sponsor I LLC or
CleanTech Investments, LLC; (b) in the case of an individual, by gift to a member of the individual’s immediate family or to a trust,
the beneficiary of which is a member of the individual’s immediate family, an affiliate of such person or to a charitable organization;
(c) in the case of an individual, by virtue of laws of descent and distribution upon death of the individual; (d) in the case of an individual,
pursuant to a qualified domestic relations order; (e) by private sales or transfers made in connection with the consummation of an initial
business combination at prices no greater than the price at which the shares or warrants were originally purchased; (f) in the event of
liquidation of the Company prior to the completion of its initial business combination; or (g) by virtue of the laws of Delaware or the
applicable limited liability company agreement upon dissolution of CleanTech Sponsor I LLC or CleanTech Investments, LLC, provided, however,
that in the case of clauses (a) through (e) or (g), these permitted transferees must enter into a written agreement agreeing to be bound
by these transfer restrictions and the other restrictions contained in the insider letter agreements with respect to such securities (including
provisions thereof relating to voting, the trust account and liquidation distributions) to be entered into by CleanTech Sponsor I LLC,
CleanTech Investments, LLC, and officers, directors and advisors of the Company; and

 

		●	the Private Warrants will include any additional terms or restrictions as is customary in other similarly
structured blank check company offerings or as may be reasonably required by the underwriters in the IPO in order to consummate the IPO,
each of which will be set forth in the Registration Statement.

 

The undersigned acknowledges
and agrees that the purchaser of the Private Warrants will execute agreements in form and substance typical for transactions of this nature
necessary to effectuate the foregoing agreements and obligations prior to the consummation of the IPO as are reasonably acceptable to
the undersigned, including but not limited to an insider letter.

 

The undersigned also
acknowledges to be bound by terms of the private warrants described in the warrant agreement between the Company and Continental Stock
Transfer & Trust Company that will be executed in connection with the Company’s IPO.

 

    2 

     

    

 

The undersigned hereby represents and warrants that:

 

		(a)	it has been advised that the Private Warrants have not been
registered under the Securities Act;

 

		(b)	it will be acquiring the Private Warrants for its account for
investment purposes only;

 

		(c)	it has no present intention of selling or otherwise disposing
of the Private Warrants in violation of the securities laws of the United States;

 

		(d)	it is an “accredited investor” as defined by Rule
501 of Regulation D promulgated under the Securities Act of 1933, as amended;

 

		(e)	it has had both the opportunity to ask questions and receive answers
from the officers and directors of the Company and all persons acting on its behalf concerning the terms and conditions of the offer
made hereunder;

 

		(f)	it is familiar with the proposed business, management, financial
condition and affairs of the Company;

 

		(g)	it has full power, authority and legal capacity to execute and
deliver this letter and any documents contemplated herein or needed to consummate the transactions contemplated in this letter; and

 

		(h)	this letter constitutes its legal, valid and binding obligation,
and is enforceable against it.

 

This letter agreement constitutes the entire
agreement between the undersigned and the Company with respect to the purchase of the Private Warrants, and supersedes all prior and
contemporaneous understandings, agreements, representations and warranties, both written and oral, with respect to the same.

 

    3 

     

    

 

	 	Very truly yours,
	 	 
	 	CLEANTECH SPONSOR I LLC
	 	 	 
	 	By:	/s/
    Eli Spiro
	 		Name: Eli Spiro 
	 		Title: Manager

 

	 	CLEANTECH INVESTMENTS, LLC
	 	 
	 	By:	/s/
    Jonas Grossman
	 	 	Name: Jonas Grossman
	 	 	Title: Managing Member

 

	Accepted and Agreed:	 
	 	 
	CLEANTECH ACQUISITION CORP.	 
	 	 
	By: 	/s/
    Eli Spiro	 
	 	Name: Eli Spiro	 
	 	Title:Chief Executive Officer	 

 

[Signature Page to Private Placement Warrant Subscription
Agreement]

 

     

     

    

 

Exhibit A

 

Wire Instructions

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00330-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00330-of-00352.parquet"}]]