Exhibit 10.1


 


Execution Version


 


FORM OF SUBSCRIPTION
AGREEMENT


 


ArcLight Clean Transition Corp.

200 Clarendon Street, 55th Floor

Boston, Massachusetts 02116


 


Ladies and Gentlemen:


 


This Subscription Agreement
(this “Subscription Agreement”) is being entered into as of the date set forth on the signature page hereto,
by and between ArcLight Clean Transition Corp., a Cayman Islands exempted company (“ArcLight”), and the undersigned
subscriber (the “Investor”), in connection with the Agreement and Plan of Merger, dated as of the date hereof
(as may be amended, supplemented or otherwise modified from time to time, the “Merger Agreement”), by and among
ArcLight, Proterra Inc., a Delaware corporation (the “Company”), and Phoenix Merger Sub, Inc., a Delaware corporation
(“Merger Sub”), pursuant to which, among other things, Merger Sub will merge with and into the Company, with
the Company as the surviving company in the merger and, after giving effect to such merger, becoming a subsidiary of ArcLight,
on the terms and subject to the conditions therein (such merger, the “Transaction”). In connection with
the Transaction, ArcLight is seeking commitments from interested investors to purchase, following the Domestication (as defined
below) and prior to the closing of the Transaction, shares of ArcLight’s common stock, par value $0.0001 per share (the “Shares”),
in a private placement for a purchase price of $10.00 per share (the “Per Share Purchase Price”). On or about
the date of this Subscription Agreement, ArcLight is entering into subscription agreements (the “Other Subscription Agreements”
and together with this Subscription Agreement, the “Subscription Agreements”) with certain other investors (the
“Other Investors” and together with the Investor, the “Investors”), severally and not jointly,
pursuant to which the Investors, severally and not jointly, have agreed to purchase on the closing date of the Transaction, inclusive
of the Shares subscribed for by the Investor, an aggregate amount of up to 41,500,000 Shares, at the Per Share Purchase Price.


 


Prior
to the closing of the Transaction (and as more fully described in the Merger Agreement), ArcLight will domesticate as a Delaware
corporation in accordance with Section 388 of the General Corporation Law of the State of Delaware and Part XII of
the Cayman Islands Companies Law (2020 Revision) (the “Domestication”). The aggregate purchase price to be paid
by the Investor for the subscribed Shares (as set forth on the signature page hereto) is referred to herein as the “Subscription
Amount.”


 


In connection therewith,
and in consideration of the foregoing and the mutual representations, warranties and covenants, and subject to the conditions,
set forth herein, and intending to be legally bound hereby, each of the Investor and ArcLight acknowledges and agrees as follows:


 


1. Subscription.
The Investor hereby subscribes for and agrees to purchase from ArcLight the number of Shares set forth on the signature page of
this Subscription Agreement on the terms and subject to the conditions provided for herein. The Investor acknowledges and agrees
that the Investor’s subscription for the Shares shall be deemed to be accepted by ArcLight only when this Subscription Agreement
is signed by a duly authorized person by or on behalf of ArcLight; ArcLight may do so in counterpart form. The Investor acknowledges
and agrees that, as a result of the Domestication, the Shares that will be issued pursuant hereto shall be shares of common stock
in a Delaware corporation (and not, for the avoidance of doubt, ordinary shares in a Cayman Islands exempted company).


 


2. Closing.
The closing of the sale of the Shares contemplated hereby (the “Closing”) is contingent upon the substantially
concurrent consummation of the Transaction. The Closing shall occur on the date of, and substantially concurrently with and conditioned
upon the effectiveness of, the Transaction. Upon (a) satisfaction or waiver of the conditions set forth in Section 3 below and
(b) delivery of written notice from (or on behalf of) ArcLight to the Investor (the “Closing Notice”), that
ArcLight reasonably expects all conditions to the closing of the Transaction to be satisfied or waived on a date that is not less
than five (5) business days from the date on which the Closing Notice is delivered to the Investor, the Investor shall deliver
to ArcLight, two (2) business days prior to the closing date specified in the Closing Notice (the “Closing Date”),
the Subscription Amount by wire transfer of United States dollars in immediately available funds to the account(s) specified by
ArcLight in the Closing Notice. On the Closing Date, ArcLight shall issue a number of Shares to the Investor set forth on the
signature page to this Subscription Agreement and subsequently cause such Shares to be registered in book entry form in the name
of the Investor on ArcLight’s share register; provided, however, that ArcLight’s obligation to issue
the Shares to the Investor is contingent upon ArcLight having received the Subscription Amount in full accordance with this Section
2. In the event that (i) the consummation of the Transaction does not occur within three (3) business days after the anticipated
Closing Date specified in the Closing Notice, unless otherwise agreed to in writing by ArcLight and the Investor, ArcLight shall
promptly (but in no event later than four (4) business days after the anticipated Closing Date specified in the Closing Notice)
return the Subscription Amount so delivered by the Investor to ArcLight by wire transfer in immediately available funds to the
account specified by the Investor, and any book entries shall be deemed cancelled. Notwithstanding such return or cancellation,
unless and until this Subscription Agreement is terminated in accordance with Section 8 herein, the Investor shall remain obligated
(A) to redeliver funds to ArcLight in escrow following ArcLight’s delivery to the Investor of a new Closing Notice and (B)
to consummate the Closing immediately prior to or substantially concurrently with the consummation of the Transaction. For purposes
of this Subscription Agreement, “business day” shall mean a day, other than a Saturday or Sunday, on which commercial
banks in New York, New York and Boston, Massachusetts are open for the general transaction of business.


 






     


     


    

 


3. Closing
Conditions.


 


a. The
obligation of the parties hereto to consummate the purchase and sale of the Shares pursuant to this Subscription Agreement is subject
to the following conditions:


 


(i) that
no applicable governmental authority shall have enacted, issued, promulgated, enforced or entered any judgment, order, law, rule
or regulation (whether temporary, preliminary or permanent) which is then in effect and has the effect of making consummation of
the transactions contemplated hereby illegal or otherwise restraining or prohibiting consummation of the transactions contemplated
hereby and no such governmental authority shall have instituted or threatened in writing a proceeding seeking to impose any such
restraint or prohibition;


 


(ii) the
Shares shall have been approved for listing on the Nasdaq Capital Market (“Nasdaq”), subject to official notice
of issuance; and


 


(iii) all
conditions precedent to the closing of the Transaction under the Merger Agreement shall have been satisfied (as determined by the
parties to the Merger Agreement and other than those conditions under the Merger Agreement which, by their nature, are to be satisfied
at the closing of the Transaction, including to the extent that any such condition is dependent upon the consummation of the purchase
and sale of the Shares pursuant to this Subscription Agreement) or waived.


 


b. The
obligation of ArcLight to consummate the issuance and sale of the Shares pursuant to this Subscription Agreement is subject to
the following conditions:


 


(i) that
all representations and warranties of the Investor contained in this Subscription Agreement shall be true and correct in all material
respects (other than representations and warranties that are qualified as to materiality, which representations and warranties
shall be true in all respects) at and as of the Closing Date (unless they specifically speak as of an earlier date, in which case
they shall be true and correct in all material respects (other than representations and warranties that are qualified as to materiality,
which representations and warranties shall be true in all respects) as of such date), and consummation of the Closing shall constitute
a reaffirmation by the Investor of each of the representations and warranties of the Investor contained in this Subscription Agreement
as of the Closing Date; and


 


(ii) that
as of the Closing Date the Investor shall have performed, satisfied and complied in all material respects with all agreements,
conditions and covenants required by this Subscription Agreement to have been performed, satisfied or complied with by it at or
prior to the Closing.


 






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c. The
obligation of the Investor to consummate the purchase of the Shares pursuant to this Subscription Agreement is subject to the following
additional conditions:


 


(i) all
representations and warranties of ArcLight contained in this Subscription Agreement shall be true and correct in all material respects
(other than representations and warranties that are qualified as to materiality, which representations and warranties shall be
true in all respects) at and as of the Closing Date, and consummation of the Closing shall constitute a reaffirmation by ArcLight
of each of the representations and warranties of ArcLight contained in this Subscription Agreement as of the Closing Date;


 


(ii) ArcLight
shall have performed, satisfied or complied in all material respects with all agreements, conditions and covenants required by
this Subscription Agreement to have been performed, satisfied or complied with by it at or prior to the Closing;


 


(iii) no
amendment, modification or waiver of the Merger Agreement shall have occurred that would reasonably be expected to materially and
adversely affect the economic benefits that the Investor would reasonably expect to receive under this Subscription Agreement.


 


4. Further
Assurances. At the Closing, the parties hereto shall execute and deliver such additional documents and take such additional
actions as the parties reasonably may deem to be practical and necessary in order to consummate the subscription as contemplated
by this Subscription Agreement.


 


5. ArcLight
Representations and Warranties. ArcLight represents and warrants to the Investor that:


 


a. ArcLight
is an exempted company duly incorporated, validly existing and in good standing under the laws of the Cayman Islands (to the extent
such concept exists in such jurisdiction). ArcLight has all power (corporate or otherwise) and authority to own, lease and operate
its properties and conduct its business as presently conducted and to enter into, deliver and perform its obligations under this
Subscription Agreement. As of the Closing Date, following the Domestication, ArcLight will be duly incorporated, validly existing
as a corporation and in good standing under the laws of the State of Delaware.


 


b. As
of the Closing Date, the Shares will be duly authorized and, when issued and delivered to the Investor against full payment therefor
in accordance with the terms of this Subscription Agreement, the Shares will be validly issued, fully paid and non-assessable and
will not have been issued in violation of or subject to any preemptive or similar rights created under ArcLight’s certificate
of incorporation or bylaws (each as amended to the Closing Date), by contract or under the General Corporation Law of the State
of Delaware.


 


c. This
Subscription Agreement has been duly authorized, executed and delivered by ArcLight and, assuming that this Subscription Agreement
constitutes the valid and binding agreement of the Investor, this Subscription Agreement is enforceable against ArcLight in accordance
with its terms, except as may be limited or otherwise affected by (i) bankruptcy, insolvency, fraudulent conveyance, reorganization,
moratorium or other laws relating to or affecting the rights of creditors generally, or (ii) principles of equity, whether considered
at law or equity.


 


d. The
execution and delivery of, and the performance of the transactions contemplated by, this Subscription Agreement, including the
issuance and sale of the Shares hereunder, and the compliance by ArcLight with all of the provisions of this Subscription Agreement
and the consummation of the transactions contemplated herein will not conflict with or result in a breach or violation of any of
the terms or provisions of, or constitute a default under, or result in the creation or imposition of any lien, charge or encumbrance
upon any of the property or assets of ArcLight or any of its subsidiaries pursuant to the terms of (i) any indenture, mortgage,
deed of trust, loan agreement, lease, license or other agreement or instrument to which ArcLight or any of its subsidiaries is
a party or by which ArcLight or any of its subsidiaries is bound or to which any of the property or assets of ArcLight is subject
that would reasonably be expected to have a material adverse effect on the business, properties, assets, liabilities, financial
condition or results of operations of ArcLight and its subsidiaries, taken as a whole (a “Material Adverse Effect”)
or materially affect the validity of the Shares or the legal authority of ArcLight to comply in all material respects with the
terms of this Subscription Agreement; (ii) result in any violation of the provisions of the organizational documents of ArcLight
or its subsidiaries; or (iii) result in any violation of any statute or any judgment, order, rule or regulation of any court or
governmental agency or body, domestic or foreign, having jurisdiction over ArcLight or its subsidiaries or any of their properties
that would reasonably be expected to have a Material Adverse Effect or materially affect the validity of the Shares or the legal
authority of ArcLight to comply in all material respects with this Subscription Agreement.


 






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e. As
of their respective dates, the SEC Reports required to be filed by ArcLight with the SEC complied in all material respects with
the applicable requirements of the Securities Act of 1933, as amended (the “Securities Act”), and the Securities
Exchange Act of 1934, as amended (the “Exchange Act”), and the rules and regulations of the SEC promulgated
thereunder, and none of the SEC Reports, when filed, contained any untrue statement of a material fact or omitted to state a material
fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances under
which they were made, not misleading. The financial statements of ArcLight included in the SEC Reports comply in all material respects
with applicable accounting requirements and the rules and regulations of the SEC with respect thereto as in effect at the time
of filing and fairly present in all material respects the financial position of ArcLight as of and for the dates thereof and the
results of operations and cash flows for the periods then ended, subject, in the case of unaudited statements, to normal, year-end
audit adjustments. A copy of each SEC Report is available to the Investor via the SEC’s EDGAR system. There are no outstanding
or unresolved comments in comment letters received by ArcLight from the staff of the Division of Corporation Finance of the SEC
with respect to any of the SEC Reports.


 


f. ArcLight
is not required to obtain any consent, waiver, authorization or order of, give any notice to, or make any filing or registration
with, any court or other federal, state, local or other governmental authority, self-regulatory organization or other person in
connection with the execution, delivery and performance by ArcLight of this Subscription Agreement (including, without limitation,
the issuance of the Shares), other than (i) filings with the SEC, (ii) filings required by applicable state securities laws, (iii)
filings required in accordance with Section 13 of this Subscription Agreement, (iv) filings required by the Nasdaq, including with
respect to obtaining approval of ArcLight’s shareholders, and (v) filings that the failure of which to obtain would not be
reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect.


 


g. Except
for such matters as have not had and would not be reasonably likely to have, individually or in the aggregate, a Material Adverse
Effect, as of the date hereof, there is no (i) action, suit, claim or other proceeding, in each case by or before any governmental
authority pending, or, to the knowledge of ArcLight, threatened against ArcLight or (ii) judgment, decree, injunction, ruling or
order of any governmental entity or arbitrator outstanding against ArcLight. ArcLight is in compliance with all applicable laws,
except where such non-compliance would not reasonably be expected to have a Material Adverse Effect.


 


h. As
of the date of this Subscription Agreement, the authorized capital stock of ArcLight consists of (i) 500,000,000 Class A ordinary
shares, (ii) 50,000,000 Class B ordinary shares and (iii) 5,000,000 preference shares, each with a par value of $0.0001 per share.
As of the date of this Subscription Agreement, (A) 27,750,000 Class A ordinary shares of ArcLight are issued and outstanding, (B)
6,937,500 Class B ordinary shares of ArcLight are issued and outstanding, (C) 21,425,000 warrants to purchase Class A ordinary
shares of ArcLight are issued and outstanding, and (D) no preference shares are issued and outstanding. All (1) issued and outstanding
Class A ordinary shares and Class B ordinary shares of ArcLight have been duly authorized and validly issued, are fully paid and
are nonassessable and are not subject to preemptive rights and (2) outstanding warrants have been duly authorized and validly issued
and are not subject to preemptive rights. Except as set forth above and pursuant to the Other Subscription Agreements, the Merger
Agreement and the other agreements and arrangements referred to therein or in the SEC Reports, as of the date hereof, there are
no outstanding options, warrants or other rights to subscribe for, purchase or acquire from ArcLight any Class A ordinary shares,
Class B ordinary shares or other equity interests in ArcLight, or securities convertible into or exchangeable or exercisable for
such equity interests. As of the date hereof, ArcLight has no subsidiaries, other than Merger Sub, and does not own, directly or
indirectly, interests or investments (whether equity or debt) in any person, whether incorporated or unincorporated. There are
no shareholder agreements, voting trusts or other agreements or understandings to which ArcLight is a party or by which it is bound
relating to the voting of any securities of ArcLight, other than (1) as set forth in the SEC Reports and (2) as contemplated by
the Merger Agreement.


 


i. As
of the date hereof, the issued and outstanding Shares of ArcLight are registered pursuant to Section 12(b) of the Exchange Act,
and are listed for trading on Nasdaq under the symbol “ACTC” (it being understood that the trading symbol will be changed
in connection with the Transaction). Except as disclosed in the reports (the “SEC Reports”) required to be filed
by ArcLight with the SEC, as of the date hereof, there is no suit, action, proceeding or investigation pending or, to the knowledge
of ArcLight, threatened against ArcLight by Nasdaq or the SEC, respectively, to prohibit or terminate the listing of ArcLight’s
Shares on Nasdaq or to deregister the Shares under the Exchange Act. ArcLight has taken no action that is designed to terminate
the registration of the Shares under the Exchange Act.


 






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j. Assuming
the accuracy of the Investor’s and Other Investors’ representations and warranties set forth in Section 6 of this Subscription
Agreement, (i) no registration under the Securities Act is required for the offer and sale of the Shares by ArcLight to the Investor
under this Subscription Agreement, (ii) the Shares were not offered by any form of general solicitation or general advertising
and (iii) the Shares are not being offered in a manner involving a public offering under, or in a distribution in violation of,
the Securities Act or any state securities laws.


 


k. Other
than the Other Subscription Agreements, the Merger Agreement and any other agreement contemplated by the Merger Agreement, ArcLight
has not entered into any side letter or similar agreement with any investor in connection with such investor’s direct or
indirect investment in ArcLight or with any other investor (other than with respect to terms particular to the regulatory requirements
of such subscriber or its affiliates or related funds). No Other Subscription Agreement includes terms and conditions that are
materially more advantageous to any Other Investor than the Investor hereunder (other than terms particular to the regulatory requirements
of such subscriber or its affiliates or related funds), and such Other Subscription Agreements have not been amended or modified
in any material respect following the date of this Subscription Agreement to include any such terms and conditions.


 


l. Other
than fees payable to the Placement Agents (as defined below), ArcLight has not entered into any agreement or arrangement entitling
any agent, broker, investment banker, financial advisor or other person to any broker’s or finder’s fee or any other
commission or similar fee in connection with the transactions contemplated by this Subscription Agreement for which the undersigned
could become liable. Other than the Placement Agents (as defined below), ArcLight is not aware of any person that has been or will
be paid (directly or indirectly) remuneration for solicitation of purchasers in connection with the sale of any Shares.


 


6. Investor
Representations and Warranties. The Investor represents and warrants to ArcLight that:


 


a. The
Investor (i) is a “qualified institutional buyer” (as defined in Rule 144A under the Securities Act) or an institutional
“accredited investor” (within the meaning of Rule 501(a) under the Securities Act), in each case, satisfying the applicable
requirements set forth on Schedule A, (ii) is acquiring the Shares only for his, her or its own account and not for the
account of others, or if the Investor is subscribing for the Shares as a fiduciary or agent for one or more investor accounts,
the Investor has full investment discretion with respect to each such account, and the full power and authority to make the acknowledgements,
representations and agreements herein on behalf of each owner of each such account, and (iii) is not acquiring the Shares with
a view to, or for offer or sale in connection with, any distribution thereof in violation of the Securities Act (and shall provide
the requested information set forth on Schedule A). The Investor is not an entity formed for the specific purpose of acquiring
the Shares.


 


b. The
Investor acknowledges and agrees that the Shares are being offered in a transaction not involving any public offering within the
meaning of the Securities Act and that the Shares have not been registered under the Securities Act. The Investor acknowledges
and agrees that the Shares may not be offered, resold, transferred, pledged or otherwise disposed of by the Investor absent an
effective registration statement under the Securities Act except (i) to ArcLight or a subsidiary thereof, (ii) to non-U.S. persons
pursuant to offers and sales that occur outside the United States within the meaning of Regulation S under the Securities Act or
(iii) pursuant to another applicable exemption from the registration requirements of the Securities Act, and in each of clauses
(i) and (iii) in accordance with any applicable securities laws of the states and other jurisdictions of the United States, and
that any certificates representing the Shares shall contain a restrictive legend to such effect. The Investor acknowledges and
agrees that the Shares will be subject to the foregoing transfer restrictions and, as a result of these transfer restrictions,
the Investor may not be able to readily offer, resell, transfer, pledge or otherwise dispose of the Shares and may be required
to bear the financial risk of an investment in the Shares for an indefinite period of time. The Investor acknowledges and agrees
that the Shares will not be eligible for offer, resale, transfer, pledge or disposition pursuant to Rule 144 promulgated under
the Securities Act until at least one year from the Closing Date. The Investor acknowledges and agrees that it has been advised
to consult legal counsel prior to making any offer, resale, transfer, pledge or disposition of any of the Shares.


 






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c. The
Investor acknowledges and agrees that the Investor is purchasing the Shares from ArcLight. The Investor further acknowledges that
there have been no representations, warranties, covenants and agreements made to the Investor by or on behalf of ArcLight, the
Company, any of their respective affiliates or any control persons, officers, directors, employees, partners, agents or representatives
of any of the foregoing or any other person or entity, expressly or by implication, other than those representations, warranties,
covenants and agreements of ArcLight expressly set forth in Section 5 of this Subscription Agreement.


 


d. Either
(1) the Investor’s acquisition and holding of the Shares will not constitute or result in a non-exempt prohibited transaction
under Section 406 of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), Section 4975
of the Internal Revenue Code of 1986, as amended, or any applicable similar law or (2) the Investor is not a Benefit Plan Investor
as contemplated by ERISA.


 


e. The
Investor acknowledges and agrees that the Investor has received and has had an adequate opportunity to review such information
as the Investor deems necessary in order to make an investment decision with respect to the Shares, including, with respect to
ArcLight, the Transaction and the business of the Company and its subsidiaries. Without limiting the generality of the foregoing,
the Investor acknowledges that he, she or it has reviewed the SEC Reports. The Investor acknowledges and agrees that the Investor
and the Investor’s professional advisor(s), if any, have had the full opportunity to ask such questions, receive such answers
and obtain such information as the Investor and such Investor’s professional advisor(s), if any, have deemed necessary to
make an investment decision with respect to the Shares. The Investor further acknowledges that the information provided to the
Investor may change and ArcLight is under no obligation to inform the Investor regarding any such changes, except to the extent
such changes would reasonably be expected to cause the failure of ArcLight to satisfy a condition to the Investor’s obligations
at the Closing set forth in Section 3(c).


 


f. The
Investor became aware of this offering of the Shares solely by means of direct contact between the Investor and ArcLight, the Company
or a representative of ArcLight or the Company (including the Placement Agents), and the Shares were offered to the Investor solely
by direct contact between the Investor and ArcLight, the Company or a representative of ArcLight or the Company. The Investor did
not become aware of this offering of the Shares, nor were the Shares offered to the Investor, by any other means. The Investor
acknowledges that the Shares (i) were not offered by any form of general solicitation or general advertising and (ii) are not being
offered in a manner involving a public offering under, or in a distribution in violation of, the Securities Act, or any state securities
laws. The Investor acknowledges that it is not relying upon, and has not relied upon, any statement, representation or warranty
made by any person, firm or corporation (including, without limitation, ArcLight, the Company, the Placement Agents, any of their
respective affiliates or any control persons, officers, directors, employees, partners, agents or representatives of any of the
foregoing), other than the representations and warranties of ArcLight contained in Section 5 of this Subscription Agreement, in
making its investment or decision to invest in ArcLight.


 


g. The
Investor acknowledges that it is aware that there are substantial risks incident to the purchase and ownership of the Shares, including
those set forth in ArcLight’s filings with the SEC. The Investor has such knowledge and experience in financial and business
matters as to be capable of evaluating the merits and risks of an investment in the Shares, and the Investor has sought such accounting,
legal and tax advice as the Investor has considered necessary to make an informed investment decision.


 


h. Alone,
or together with any professional advisor(s), the Investor has adequately analyzed and fully considered the risks of an investment
in the Shares and determined that the Shares are a suitable investment for the Investor and that the Investor is able at this time
and in the foreseeable future to bear the economic risk of a total loss of the Investor’s investment in ArcLight. The Investor
acknowledges specifically that a possibility of total loss exists.


 


i. In
making its decision to purchase the Shares, the Investor has relied solely upon independent investigation made by the Investor.
Without limiting the generality of the foregoing, the Investor has not relied on any statements or other information provided by
or on behalf of the Placement Agents or any of their affiliates or any control persons, officers, directors, employees, partners,
agents or representatives of any of the foregoing concerning ArcLight, the Company, the Transaction, the Merger Agreement, this
Subscription Agreement or the transactions contemplated hereby or thereby, the Shares or the offer and sale of the Shares.


 






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j. The
Investor acknowledges and agrees that no federal or state agency has passed upon or endorsed the merits of the offering of the
Shares or made any findings or determination as to the fairness of this investment.


 


k. The
Investor, if not an individual, has been duly formed or incorporated and is validly existing and is in good standing under the
laws of its jurisdiction of formation or incorporation, with power and authority to enter into, deliver and perform its obligations
under this Subscription Agreement.


 


l. The
execution, delivery and performance by the Investor of this Subscription Agreement are within the powers of the Investor, have
been duly authorized and will not constitute or result in a breach or default under or conflict with any order, ruling or regulation
of any court or other tribunal or of any governmental commission or agency, or any agreement or other undertaking, to which the
Investor is a party or by which the Investor is bound, and, if the Investor is not an individual, will not violate any provisions
of the Investor’s organizational documents, including, without limitation, its incorporation or formation papers, bylaws,
indenture of trust or partnership or operating agreement, as may be applicable. The signature on this Subscription Agreement is
genuine, and the signatory, if the Investor is an individual, has legal competence and capacity to execute the same or, if the
Investor is not an individual, the signatory has been duly authorized to execute the same, and, assuming that this Subscription
Agreement constitutes the valid and binding agreement of ArcLight, this Subscription Agreement constitutes a legal, valid and binding
obligation of the Investor, enforceable against the Investor in accordance with its terms except as may be limited or otherwise
affected by (i) bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium or other laws relating to or affecting
the rights of creditors generally, and (ii) principles of equity, whether considered at law or equity.


 


m. The
Investor is not (i) a person or entity named on the List of Specially Designated Nationals and Blocked Persons administered by
the U.S. Treasury Department’s Office of Foreign Assets Control (“OFAC”) or in any Executive Order issued
by the President of the United States and administered by OFAC (“OFAC List”), or a person or entity prohibited
by any OFAC sanctions program, (ii) a Designated National as defined in the Cuban Assets Control Regulations, 31 C.F.R. Part 515,
or (iii) a non-U.S. shell bank or providing banking services indirectly to a non-U.S. shell bank. The Investor agrees to provide
law enforcement agencies, if requested thereby, such records as required by applicable law, provided that the Investor is
permitted to do so under applicable law. If the Investor is a financial institution subject to the Bank Secrecy Act (31 U.S.C.
Section 5311 et seq.) (the “BSA”), as amended by the USA PATRIOT Act of 2001 (the “PATRIOT Act”),
and its implementing regulations (collectively, the “BSA/PATRIOT Act”), the Investor maintains policies and
procedures reasonably designed to comply with applicable obligations under the BSA/PATRIOT Act. To the extent required, it maintains
policies and procedures reasonably designed for the screening of its investors against the OFAC sanctions programs, including the
OFAC List. To the extent required by applicable law, the Investor maintains policies and procedures reasonably designed to ensure
that the funds held by the Investor and used to purchase the Shares were legally derived.


 


n. The
Investor acknowledges that no disclosure or offering document has been prepared by Morgan Stanley & Co. LLC, Barclays Capital,
Inc., Citigroup Global Markets Inc. and BofA Securities, Inc. or any of their affiliates (the “Placement Agents”)
in connection with the offer and sale of the Shares.


 


o. Neither
the Placement Agents, nor any of their affiliates nor any control persons, officers, directors, employees, partners, agents or
representatives of any of the foregoing have made any independent investigation with respect to ArcLight, the Company or its subsidiaries
or any of their respective businesses, or the Shares or the accuracy, completeness or adequacy of any information supplied to the
Investor by ArcLight.


 


p. In
connection with the issue and purchase of the Shares, the Placement Agents have not acted as the Investor’s financial advisor
or fiduciary.


 






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q. The
Investor has or has commitments to have and, when required to deliver payment to ArcLight pursuant to Section 2 above, will have,
sufficient funds to pay the Subscription Amount and consummate the purchase and sale of the Shares pursuant to this Subscription
Agreement.


 


r. The
Investor acknowledges that the purchase and sale of Shares hereunder meets the exemptions from filing under FINRA Rule 5123(b)(1).


 


s. The
Investor acknowledges that the Placement Agents may have acquired, or during the term of the Shares may acquire, non-public information
with respect to ArcLight, which the Investor agrees need not be provided to it.


 


7. Registration
Rights.


 


a. In
the event that the Shares are not registered in connection with the consummation of the Transaction, ArcLight agrees that, within
twenty (20) business days after the consummation of the Transaction (the “Filing Deadline”), it will file with
the SEC (at the its sole cost and expense) a registration statement registering the offering of the resale of the Shares (the “Registration
Statement”), and it shall use its commercially reasonable efforts to have the Registration Statement declared effective
as soon as practicable after the filing thereof, but no later than the earlier of (i) sixty (60) calendar days after the filing
thereof (or ninety (90) calendar days after the filing thereof if the SEC notifies ArcLight that it will “review” the
Registration Statement) and (ii) ten (10) business days after ArcLight is notified (orally or in writing, whichever is earlier)
by the SEC that the Registration Statement will not be “reviewed” or will not be subject to further review (such date,
the “Effectiveness Date”). ArcLight agrees to cause such Registration Statement, or another shelf registration
statement that includes the Shares to be sold pursuant to this Subscription Agreement, to remain effective until the earliest of
(i) the third anniversary of the Closing, (ii) the date on which the Investor ceases to hold any Shares issued pursuant to this
Subscription Agreement, or (iii) on the first date on which the Investor is able to sell all of its Shares issued pursuant to this
Subscription Agreement (or shares received in exchange therefor) under Rule 144 of the Securities Act within 90 days without limitation
as to the amount of such securities that may be sold, provided that at such time ArcLight is in compliance with the current
public information requirement under Rule 144 and continues to be in compliance with such requirement (the earliest of (i)–(iii)
being the “Expiration”). The Investor agrees to disclose its ownership and any other information reasonably
requested to ArcLight upon request to assist it in making the determination described above. The Investor acknowledges and agrees
that ArcLight may suspend the use of any such registration statement if it determines that in order for such registration statement
not to contain a material misstatement or omission, an amendment thereto would be needed to include information that would at that
time not otherwise be required in a current, quarterly or annual report under the Exchange Act, provided that (A) ArcLight
shall not so delay filing or so suspend the use of the Registration Statement for a period of more than sixty (60) consecutive
days or more than a total of one hundred twenty (120) calendar days, in each case in any three hundred sixty (360) day period,
(B) ArcLight shall have a bona fide business purpose for not making such information public and (C) ArcLight shall use commercially
reasonable efforts to make such registration statement available for the sale by the Investor of such securities as soon as practicable
thereafter. ArcLight’s obligations to include the Shares issued pursuant to this Subscription Agreement (or shares issued
in exchange therefor) for resale in the Registration Statement are contingent upon the Investor furnishing in writing to ArcLight
such information regarding the Investor, the securities of ArcLight held by the Investor and the intended method of disposition
of such Shares, which shall be limited to non-underwritten public offerings, as shall be reasonably requested by ArcLight to effect
the registration of such Shares, and shall execute such documents in connection with such registration as ArcLight may reasonably
request that are customary of a selling stockholder in similar situations (collectively, the “Questionnaire”),
provided, however, that the Investor shall not in connection with the foregoing be required to execute any lock-up
or similar agreement or otherwise be subject to any contractual restriction on the ability to transfer the Shares. ArcLight will
provide a draft of the Registration Statement to the Investor for review at least two (2) business days in advance of filing the
Registration Statement. So long as the Investor delivers to ArcLight a completed Questionnaire (which shall include representations
and warranties as to relevant matters), the Investor shall not be identified as a statutory underwriter in the Registration Statement
unless in response to a comment or request from the staff of the SEC or another regulatory agency; provided, however,
that if the SEC requests that the Investor be identified as a statutory underwriter in the Registration Statement, the Investor
will have an opportunity to withdraw from the Registration Statement. For purposes of clarification, any failure by ArcLight to
file the Registration Statement by the Filing Deadline or to effect such Registration Statement by the Effectiveness Date shall
not otherwise relieve ArcLight of its obligations to file or effect the Registration Statement as set forth in this Section 7.


 






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b. Prior
to the Expiration, ArcLight shall advise the Investor within three (3) business days (at ArcLight’s expense): (i) when a
Registration Statement or any post-effective amendment thereto has become effective; (ii) of the issuance by the SEC of any stop
order suspending the effectiveness of any Registration Statement or the initiation of any proceedings for such purpose; (iii) of
the receipt by ArcLight of any notification with respect to the suspension of the qualification of the Shares included therein
for sale in any jurisdiction or the initiation or threatening of any proceeding for such purpose; and (iv) subject to the provisions
in this Subscription Agreement, of a suspension pursuant to Section 7(a) or the occurrence of any event that requires the making
of any changes in any Registration Statement or prospectus so that, as of such date, the statements therein are not misleading
and do not omit to state a material fact required to be stated therein or necessary to make the statements therein (in the case
of a prospectus, in the light of the circumstances under which they were made) not misleading (provided that any such notice pursuant
to this Section 7(b)(iv) shall solely provide that the use of the Registration Statement or prospectus has been suspended without
setting forth the reason for such suspension). ArcLight shall use its commercially reasonable efforts to obtain the withdrawal
of any order suspending the effectiveness of any Registration Statement as soon as reasonably practicable. Upon the occurrence
of any event contemplated in clauses (i) through (iv) above, except for such times as ArcLight is permitted hereunder to suspend,
and has suspended, the use of a prospectus forming part of a registration statement, ArcLight shall use its commercially reasonable
efforts to as soon as reasonably practicable prepare a post-effective amendment to such registration statement or a supplement
to the related prospectus, or file any other required document so that, as thereafter delivered to purchasers of the Shares included
therein, such prospectus will not include any untrue statement of a material fact or omit to state any material fact necessary
to make the statements therein, in the light of the circumstances under which they were made, not misleading. The Investor agrees
that it will immediately discontinue offers and sales of the Shares using a Registration Statement until the Investor receives
copies of a supplemental or amended prospectus that corrects the misstatement(s) or omission(s) referred to above in clause (iv)
and receives notice that any post-effective amendment has become effective or unless otherwise notified by ArcLight that it may
resume such offers and sales. If so directed by ArcLight, the Investor will deliver to ArcLight or, in the Investor’s sole
discretion destroy, all copies of the prospectus covering the Shares in the Investor’s possession; provided, however,
that this obligation to deliver or destroy all copies of the prospectus covering the Shares shall not apply (x) to the extent the
Investor is required to retain a copy of such prospectus in order to comply with applicable legal, regulatory, self-regulatory
or professional requirements or in accordance with a bona fide pre-existing document retention policy or (y) to copies stored electronically
on archival servers as a result of automatic data back-up.


 


c. Prior
to the Expiration, ArcLight will use commercially reasonable efforts to file all reports necessary to enable the undersigned to
resell the Shares pursuant to the Registration Statement. For as long as the Investor holds Shares, ArcLight will use commercially
reasonable efforts to file all reports necessary to enable the undersigned to resell the Shares pursuant to Rule 144 of the Securities
Act (when Rule 144 of the Securities Act becomes available to the Investor). In addition, in connection with any proposed sale,
assignment, transfer or other disposition of the Shares by the Investor pursuant to Rule 144, or pursuant to any other exemption
under the Securities Act, or in connection with a sale or transfer in the manner described in the Registration Statement such that
the Shares held by the Investor become freely tradable and upon compliance by the Investor with the requirements of this Subscription
Agreement, if requested by the Investor, ArcLight shall cause the Transfer Agent to remove any restrictive legends related to the
book entry account holding such Shares and make a new, unlegended entry for such book entry Shares sold or disposed of without
restrictive legends within two (2) trading days of any such request therefor from the Investor, provided that ArcLight and
the Transfer Agent have timely received from the Investor customary representations and other documentation reasonably acceptable
to ArcLight and the Transfer Agent in connection therewith.


 


d. Indemnification.


 


(i) ArcLight
agrees to indemnify and hold harmless, to the extent permitted by law, the Investor, its directors, and officers, employees, and
agents, and each person who controls the Investor (within the meaning of the Section 15 of the Securities Act or Section 20 of
the Exchange Act) and each affiliate of the Investor (within the meaning of Rule 405 under the Securities Act) from and against
any and all losses, claims, damages, liabilities and expenses (including, without limitation, any reasonable attorneys’ fees
and expenses incurred in connection with defending or investigating any such action or claim) caused by any untrue or alleged untrue
statement of material fact contained in any Registration Statement, prospectus included in any Registration Statement or preliminary
prospectus or any amendment thereof or supplement thereto or any omission or alleged omission of a material fact required to be
stated therein or necessary to make the statements therein not misleading, except insofar as and to the extent, but only to the
extent, the same are caused by or contained in any information furnished in writing to ArcLight by or on behalf of the Investor
expressly for use therein, including the contents of any Questionnaire.


 






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(ii) The
Investor agrees, severally and not jointly with any person that is a party to the Other Subscription Agreements, to indemnify and
hold harmless ArcLight, its directors and officers and agents and each person who controls ArcLight (within the meaning of Section
15 of the Securities Act and Section 20 of the Exchange Act) against any losses, claims, damages, liabilities and expenses (including,
without limitation, reasonable attorneys’ fees) resulting from any untrue statement of material fact contained in the Registration
Statement, prospectus or preliminary prospectus or any amendment thereof or supplement thereto or any omission of a material fact
required to be stated therein (in the case of any prospectus, or preliminary prospectus or supplement thereto, in light of the
circumstances under which they were made) or necessary to make the statements therein not misleading, but only to the extent that
such untrue statement or omission is contained in any information or affidavit so furnished in writing by the Investor (including
any Questionnaire furnished by the Investor) expressly for use therein. In no event shall the liability of the Investor be greater
in amount than the dollar amount of the net proceeds received by the Investor upon the sale of the Shares purchased pursuant to
this Subscription Agreement giving rise to such indemnification obligation.


 


(iii) Any
person entitled to indemnification hereunder shall (1) give prompt written notice to the indemnifying party of any claim with respect
to which it seeks indemnification (provided that the failure to give prompt notice shall not impair any person’s right to
indemnification hereunder to the extent such failure has not materially prejudiced the indemnifying party) and unless in such indemnified
party’s reasonable judgment a conflict of interest between such indemnified and indemnifying parties exists with respect
to such claim, permit such indemnifying party to assume the defense of such claim with counsel reasonably satisfactory to the indemnified
party. If such defense is assumed, the indemnifying party shall not be subject to any liability for any settlement made by the
indemnified party without its consent (but such consent shall not be unreasonably withheld, conditioned or delayed). An indemnifying
party who is not entitled to, or elects not to assume the defense of a claim shall not be obligated to pay the fees and expenses
of more than one counsel for all parties indemnified by such indemnifying party with respect to such claim, unless in the reasonable
judgment of legal counsel to any indemnified party a conflict of interest exists between such indemnified party and any other of
such indemnified parties with respect to such claim. No indemnifying party shall, without the consent of the indemnified party,
consent to the entry of any judgment or enter into any settlement which cannot be settled in all respects by the payment of money
(and such money is so paid by the indemnifying party pursuant to the terms of such settlement) or which settlement includes a statement
or admission of fault and culpability on the part of such indemnified party or which does not include as an unconditional term
thereof the giving by the claimant or plaintiff to such indemnified party of a release from all liability in respect to such claim
or litigation.


 


(iv) The
indemnification provided for under this Subscription Agreement shall remain in full force and effect regardless of any investigation
made by or on behalf of the indemnified party or any officer, director, employee, agent, affiliate or controlling person of such
indemnified party and shall survive the transfer of the Shares purchased pursuant to this Subscription Agreement.


 






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(v) If
the indemnification provided under this Section 7(d) from the indemnifying party is unavailable or insufficient to hold harmless
an indemnified party in respect of any losses, claims, damages, liabilities and expenses referred to herein, then the indemnifying
party, in lieu of indemnifying the indemnified party, shall contribute to the amount paid or payable by the indemnified party as
a result of such losses, claims, damages, liabilities and expenses in such proportion as is appropriate to reflect the relative
fault of the indemnifying party and the indemnified party, as well as any other relevant equitable considerations. The relative
fault of the indemnifying party and indemnified party shall be determined by reference to, among other things, whether any action
in question, including any untrue or alleged untrue statement of a material fact or omission or alleged omission to state a material
fact, was made by, or relates to information supplied by, such indemnifying party or indemnified party, and the indemnifying party’s
and indemnified party’s relative intent, knowledge, access to information and opportunity to correct or prevent such action.
The amount paid or payable by a party as a result of the losses or other liabilities referred to above shall be deemed to include,
subject to the limitations set forth above, any legal or other fees, charges or expenses reasonably incurred by such party in connection
with any investigation or proceeding. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of
the Securities Act) shall be entitled to contribution pursuant to this Section 7(d) from any person who was not guilty of such
fraudulent misrepresentation. In no event shall the liability of the Investor be greater in amount than the dollar amount of the
net proceeds received by the Investor upon the sale of the Shares purchased pursuant to this Subscription Agreement giving rise
to such contribution obligation.


 


8. Termination.
This Subscription Agreement shall terminate and be void and of no further force and effect, and all rights and obligations of
the parties hereunder shall terminate without any further liability on the part of any party in respect thereof, upon the earlier
to occur of (a) such date and time as the Merger Agreement is terminated in accordance with its terms without being consummated,
(b) upon the mutual written agreement of each of the parties hereto to terminate this Subscription Agreement, (c) ArcLight’s
notification to the Investor in writing that it has abandoned its plans to move forward with the Transaction, (d) thirty (30)
days after the Termination Date (as defined in the Merger Agreement, as in effect as of the date hereof), if the Closing has not
occurred by such date, or (e) if any of the conditions to Closing set forth in Section 3 of this Subscription Agreement are not
satisfied or waived, or are not capable of being satisfied, on or prior to the Closing and, as a result thereof, the transactions
contemplated by this Subscription Agreement will not be and are not consummated at the Closing (the termination events described
in clauses (a)–(e) above, collectively, the “Termination Events”); provided that nothing herein
will relieve any party from liability for any willful breach hereof prior to the time of termination, and each party will be entitled
to any remedies at law or in equity to recover losses, liabilities or damages arising from any such willful breach. ArcLight shall
notify the Investor of the termination of the Merger Agreement promptly after the termination of such agreement. Upon the occurrence
of any Termination Event, this Subscription Agreement shall be void and of no further effect and any monies paid by the Investor
to ArcLight in connection herewith shall promptly (and in any event within one business day) following the Termination Event be
returned to the Investor.


 


9. Trust
Account Waiver. The Investor acknowledges that ArcLight is a blank check company with the powers and privileges to effect
a merger, asset acquisition, reorganization or similar business combination involving ArcLight and one or more businesses or assets.
The Investor further acknowledges that, as described in ArcLight’s prospectus relating to its initial public offering dated
September 22, 2020 (the “Prospectus”) available at www.sec.gov, substantially all of ArcLight’s assets
consist of the cash proceeds of ArcLight’s initial public offering and private placement of its securities, and substantially
all of those proceeds have been deposited in a trust account (the “Trust Account”) for the benefit of ArcLight,
its public shareholders and the underwriters of ArcLight’s initial public offering. Except with respect to interest earned
on the funds held in the Trust Account that may be released to ArcLight to pay its tax obligations, if any, the cash in the Trust
Account may be disbursed only for the purposes set forth in the Prospectus. For and in consideration of ArcLight entering into
this Subscription Agreement, the receipt and sufficiency of which are hereby acknowledged, the Investor hereby irrevocably waives
any and all right, title and interest, or any claim of any kind it has or may have in the future, in or to any monies held in
the Trust Account, and agrees not to seek recourse against the Trust Account as a result of, or arising out of, this Subscription
Agreement; provided, however, that nothing in this Section 9 shall be deemed to limit the Investor’s right,
title, interest or claim to any monies held in the Trust Account by virtue of its record or beneficial ownership of any equity
interests in ArcLight other than the Shares purchased by it pursuant to this Subscription Agreement, pursuant to a validly exercised
redemption right with respect to any such Class A ordinary shares, except to the extent that the Investor has otherwise agreed
with ArcLight to not exercise such redemption right.


 






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10. No
Short Sales. The Investor hereby agrees that, from the date of this Subscription Agreement until the Closing, none of the Investor,
its controlled affiliates, or any person or entity acting on behalf of the Investor or any of its controlled affiliates or pursuant
to any understanding with the Investor or any of its controlled affiliates will engage in any Short Sales with respect to securities
of ArcLight. For purposes of this Section 10, “Short Sales” shall include, without limitation, all “short sales”
as defined in Rule 200 promulgated under Regulation SHO under the Exchange Act, and all types of direct and indirect stock pledges
(other than pledges in the ordinary course of business as part of prime brokerage arrangements), forward sale contracts, options,
puts, calls, swaps and similar arrangements (including on a total return basis), and sales and other transactions through non-U.S.
broker dealers or foreign regulated brokers. Notwithstanding the foregoing, (i) nothing herein shall prohibit other entities under
common management with the Investor that have no knowledge of this Subscription Agreement or of the Investor’s participation
in the Transaction (including the Investor’s controlled affiliates and/or affiliates) from entering into any Short Sales
and (ii) in the case of an Investor that is a multi-managed investment vehicle whereby separate portfolio managers manage separate
portions of such Investor’s assets, and whereby none of the portfolio managers with respect to any such portion have knowledge
of the investment decisions made by the portfolio managers managing other portions of such Investor’s assets that have knowledge
of this Subscription Agreement, the covenant set forth above shall only apply with respect to the portion of assets managed by
the portfolio manager that made the investment decision to purchase the Shares covered by this Subscription Agreement.


 


11. Miscellaneous.


 


a. Neither
this Subscription Agreement nor any rights that may accrue to the Investor hereunder (other than the Shares acquired hereunder,
if any) may be transferred or assigned; provided that the Investor may assign its rights and obligations under this Subscription
Agreement to one or more of its affiliates prior to receipt of the Closing Notice (including other investment funds or accounts
managed or advised by the investment manager who acts on behalf of the Investor or an affiliate thereof); provided, further,
that no such assignment shall relieve the Investor of its obligations hereunder.


 


b. ArcLight
may request from the Investor such additional information as ArcLight may deem necessary to register the resale of the Shares and
evaluate the eligibility of the Investor to acquire the Shares, and the Investor shall provide such information as may reasonably
be requested, to the extent readily available and to the extent consistent with the Investor’s internal policies and procedures;
provided that ArcLight agrees to keep any such information provided by the Investor confidential except (i) as required
by the federal securities law or pursuant to other routine proceedings of regulatory authorities or (ii) to the extent such disclosure
is required by law, at the request of the staff of the SEC or regulatory agency or under the regulations of any national securities
exchange on which ArcLight’s securities are listed for trading. The Investor acknowledges that ArcLight may file a copy of
this Subscription Agreement that does not identify the Investor with the SEC as an exhibit to a periodic report or a registration
statement of ArcLight.


 


c. The
Investor acknowledges that ArcLight, the Placement Agents and, following the Closing, the Company, will rely on the acknowledgments,
understandings, agreements, representations and warranties contained in Section 6 of this Subscription Agreement. Prior to the
Closing, each party hereto agrees to promptly notify the other parties hereto and the Placement Agents if any of the acknowledgments,
understandings, agreements, representations and warranties set forth in Section 5 or Section 6 above, as applicable, are no longer
accurate in any material respect (other than those acknowledgments, understandings, agreements, representations and warranties
that are qualified as to materiality), in which case such party shall notify the other parties hereto and the Placement Agents
if they are no longer accurate in any respect. The Investor acknowledges and agrees that each purchase by the Investor of Shares
from ArcLight will constitute a reaffirmation of the acknowledgments, understandings, agreements, representations and warranties
herein (as modified by any such notice by the Investor as of the time of such purchase).


 


d. ArcLight,
the Company and the Placement Agents are each irrevocably authorized to produce this Subscription Agreement or a copy hereof to
any interested party in any administrative or legal proceeding or official inquiry with respect to the matters covered hereby;
provided, however, that the foregoing clause of this Section 11(d) shall not give the Company or the Placements Agent
any rights other than those expressly set forth herein.


 






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e. All
of the agreements, representations and warranties made by each party hereto in this Subscription Agreement shall survive the Closing.


 


f. This
Subscription Agreement may not be modified, waived or terminated (other than pursuant to the terms of Section 8 above) except by
an instrument in writing, signed by each of the parties hereto, provided, however, that no modification or waiver
by ArcLight of the provisions of this Subscription Agreement shall be effective without the prior written consent of the Company
(other than modifications or waivers that are solely ministerial in nature or otherwise immaterial and do not affect any economic
or any other material term of this Subscription Agreement, provided that ArcLight provide the Company with prior written
notice thereof). No failure or delay of either party in exercising any right or remedy hereunder shall operate as a waiver thereof,
nor shall any single or partial exercise of any such right or power, or any abandonment or discontinuance of steps to enforce such
right or power, or any course of conduct, preclude any other or further exercise thereof or the exercise of any other right or
power. The rights and remedies of the parties hereunder are cumulative and are not exclusive of any rights or remedies that they
would otherwise have hereunder.


 


g. This
Subscription Agreement (including the schedule hereto) constitutes the entire agreement, and supersedes all other prior agreements,
understandings, representations and warranties, both written and oral, among the parties, with respect to the subject matter hereof.
Except as set forth in Section 7, Section 11(c), Section 11(d), this Section 11(g) and the last sentence of Section 11(l) with
respect to the persons specifically referenced therein, this Subscription Agreement shall not confer any rights or remedies upon
any person other than the parties hereto, and their respective successor and assigns, and the parties hereto acknowledge that such
persons so referenced are third party beneficiaries of this Subscription Agreement for the purposes of, and to the extent of, the
rights granted to them, if any, pursuant to the applicable provisions.


 


h. Except
as otherwise provided herein, this Subscription Agreement shall be binding upon, and inure to the benefit of the parties hereto
and their heirs, executors, administrators, successors, legal representatives, and permitted assigns, and the agreements, representations,
warranties, covenants and acknowledgments contained herein shall be deemed to be made by, and be binding upon, such heirs, executors,
administrators, successors, legal representatives and permitted assigns.


 


i. If
any provision of this Subscription Agreement shall be adjudicated by a court of competent jurisdiction to be invalid, illegal or
unenforceable, the validity, legality or enforceability of the remaining provisions of this Subscription Agreement shall not in
any way be affected or impaired thereby and shall continue in full force and effect.


 


j. This
Subscription Agreement may be executed in one or more counterparts (including by facsimile or electronic mail or in .pdf) and by
different parties in separate counterparts, with the same effect as if all parties hereto had signed the same document. All counterparts
so executed and delivered shall be construed together and shall constitute one and the same agreement.


 


k. Notwithstanding
anything in this Subscription Agreement to the contrary, ArcLight shall not publicly disclose the name of the Investor, its investment
advisor or any of their respective affiliates or advisers, or include the name of the Investor, its investment advisor or any of
their respective affiliates or advisers in any press release or in any filing with the SEC or any regulatory agency or trading
market, without the prior written consent of the Investor, except (i) as required by the federal securities law or pursuant to
other routine proceedings of regulatory authorities or (ii) to the extent such disclosure is required by law, at the request of
the staff of the SEC or regulatory agency or under the regulations of any national securities exchange on which ArcLight’s
securities are listed for trading; provided, however, that ArcLight shall provide to the Investor a copy of any proposed
disclosure under this Section 11(k) relating to the Investor in advance of any publication thereof and shall include such revisions
to such proposed disclosure as the Investor shall reasonably request.


 


l. The
parties hereto acknowledge and agree that irreparable damage would occur in the event that any of the provisions of this Subscription
Agreement were not performed in accordance with their specific terms or were otherwise breached. It is accordingly agreed that
the parties shall be entitled to an injunction or injunctions to prevent breaches of this Subscription Agreement, without posting
a bond or undertaking and without proof of damages, to enforce specifically the terms and provisions of this Subscription Agreement,
this being in addition to any other remedy to which such party is entitled at law, in equity, in contract, in tort or otherwise.
The parties hereto acknowledge and agree that the Company and the Placement Agents shall be entitled to rely on the provisions
of the Subscription Agreement of which the Company and the Placement Agents are each an express third party beneficiary, in each
case, on the terms and subject to the conditions set forth herein.


 






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m. If
any change in the number, type or classes of authorized shares of ArcLight (including the Shares), other than as contemplated by
the Merger Agreement or any agreement contemplated by the Merger Agreement, shall occur between the date hereof and immediately
prior to the Closing by reason of reclassification, recapitalization, stock split (including reverse stock split) or combination,
exchange or readjustment of shares, or any stock dividend, the number of Shares issued to the Investor shall be appropriately adjusted
to reflect such change.


 


n. This
Subscription Agreement shall be governed by and construed in accordance with the laws of the State of New York (regardless of the
laws that might otherwise govern under applicable principles of conflicts of laws thereof) as to all matters (including any action,
suit, litigation, arbitration, mediation, claim, charge, complaint, inquiry, proceeding, hearing, audit, investigation or reviews
by or before any governmental entity related hereto), including matters of validity, construction, effect, performance and remedies.


 


o. THE
PARTIES HERETO IRREVOCABLY SUBMIT TO THE EXCLUSIVE JURISDICTION OF THE UNITED STATES DISTRICT COURT FOR THE SOUTHERN DISTRICT OF
NEW YORK AND THE SUPREME COURT OF THE STATE OF NEW YORK SOLELY IN RESPECT OF THE INTERPRETATION AND ENFORCEMENT OF THE PROVISIONS
OF THIS SUBSCRIPTION AGREEMENT AND THE DOCUMENTS REFERRED TO IN THIS SUBSCRIPTION AGREEMENT AND IN RESPECT OF THE TRANSACTIONS
CONTEMPLATED HEREBY, AND HEREBY WAIVE, AND AGREE NOT TO ASSERT, AS A DEFENSE IN ANY ACTION, SUIT OR PROCEEDING FOR INTERPRETATION
OR ENFORCEMENT HEREOF OR ANY SUCH DOCUMENT THAT IS NOT SUBJECT THERETO OR THAT SUCH ACTION, SUIT OR PROCEEDING MAY NOT BE BROUGHT
OR IS NOT MAINTAINABLE IN SAID COURTS OR THAT VENUE THEREOF MAY NOT BE APPROPRIATE OR THAT THIS SUBSCRIPTION AGREEMENT OR ANY SUCH
DOCUMENT MAY NOT BE ENFORCED IN OR BY SUCH COURTS, AND THE PARTIES HERETO IRREVOCABLY AGREE THAT ALL CLAIMS WITH RESPECT TO SUCH
ACTION, SUIT OR PROCEEDING SHALL BE HEARD AND DETERMINED BY SUCH A NEW YORK STATE OR FEDERAL COURT. THE PARTIES HEREBY CONSENT
TO AND GRANT ANY SUCH COURT JURISDICTION OVER THE PERSON OF SUCH PARTIES AND OVER THE SUBJECT MATTER OF SUCH DISPUTE AND AGREE
THAT MAILING OF PROCESS OR OTHER PAPERS IN CONNECTION WITH SUCH ACTION, SUIT OR PROCEEDING IN THE MANNER PROVIDED IN THIS SECTION
11(o) OF THIS SUBSCRIPTION AGREEMENT OR IN SUCH OTHER MANNER AS MAY BE PERMITTED BY LAW SHALL BE VALID AND SUFFICIENT SERVICE THEREOF.


 


p. EACH
PARTY ACKNOWLEDGES AND AGREES THAT ANY CONTROVERSY WHICH MAY ARISE UNDER THIS SUBSCRIPTION AGREEMENT OR THE TRANSACTIONS CONTEMPLATED
HEREBY IS LIKELY TO INVOLVE COMPLICATED AND DIFFICULT ISSUES, AND THEREFORE EACH SUCH PARTY HEREBY IRREVOCABLY AND UNCONDITIONALLY
WAIVES ANY RIGHT SUCH PARTY MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY LITIGATION DIRECTLY OR INDIRECTLY ARISING OUT OF OR RELATING
TO THIS SUBSCRIPTION AGREEMENT OR THE TRANSACTIONS CONTEMPLATED BY THIS SUBSCRIPTION AGREEMENT. EACH PARTY CERTIFIES AND ACKNOWLEDGES
THAT (I) NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY
WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVER; (II) SUCH PARTY UNDERSTANDS AND HAS CONSIDERED THE
IMPLICATIONS OF THE FOREGOING WAIVER; (III) SUCH PARTY MAKES THE FOREGOING WAIVER VOLUNTARILY AND (IV) SUCH PARTY HAS BEEN INDUCED
TO ENTER INTO THIS SUBSCRIPTION AGREEMENT BY, AMONG OTHER THINGS, THE MUTUAL WAIVER AND CERTIFICATIONS IN THIS SECTION 11(p).


 






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12. Non-Reliance
and Exculpation. The Investor acknowledges that it is not relying upon, and has not relied upon, any statement, representation
or warranty made by any person, firm or corporation (including, without limitation, the Placement Agents, the Company or any of
their respective affiliates or any control persons, officers, directors, employees, partners, agents or representatives of any
of the foregoing), other than the statements, representations and warranties of ArcLight expressly contained in Section 5 of this
Subscription Agreement, in making its investment or decision to invest in ArcLight. The Investor acknowledges and agrees that,
other than the statements, representations and warranties of ArcLight expressly contained in Section 5 of this Subscription Agreement,
none of (i) any other investor pursuant to this Subscription Agreement or any other subscription agreement related to the private
placement of the Shares (including the investor’s respective affiliates or any control persons, officers, directors, employees,
partners, agents or representatives of any of the foregoing), (ii) the Placement Agents, their affiliates or any control persons,
officers, directors, employees, partners, agents or representatives of any of the foregoing, or (iii) any other party to the Merger
Agreement (other than ArcLight) or any Non-Party Affiliate, shall have any liability to the Investor, or to any other investor,
pursuant to, arising out of or relating to this Subscription Agreement or any other subscription agreement related to the private
placement of the Shares, the negotiation hereof or thereof or its subject matter, or the transactions contemplated hereby or thereby,
including, without limitation, with respect to any action heretofore or hereafter taken or omitted to be taken by any of them
in connection with the purchase of the Shares or with respect to any claim (whether in tort, contract or otherwise) for breach
of this Subscription Agreement or in respect of any written or oral representations made or alleged to be made in connection herewith,
as expressly provided herein, or for any actual or alleged inaccuracies, misstatements or omissions with respect to any information
or materials of any kind furnished by ArcLight, the Company, the Placement Agents or any Non-Party Affiliate concerning ArcLight,
the Company, the Placement Agents, any of their controlled affiliates, this Subscription Agreement or the transactions contemplated
hereby. For purposes of this Subscription Agreement, “Non-Party Affiliates” means each former, current or future officer,
director, employee, partner, member, manager, direct or indirect equityholder or affiliate of ArcLight, the Company, the Placement
Agents or any of ArcLight’s, the Company’s or the Placement Agents’ controlled affiliates or any family member
of the foregoing.


 


13. Disclosure.
ArcLight shall, by 9:00 a.m., New York City time, on the first (1st) Business Day immediately following the date of this Subscription
Agreement, issue one or more press releases or file with the SEC a Current Report on Form 8-K (collectively, the “Disclosure
Document”) disclosing all material terms of the transactions contemplated hereby and by the Other Subscription Agreements,
the Transaction and any other material, nonpublic information that ArcLight or any of its representatives has provided to the Investor
at any time prior to the filing of the Disclosure Document. Upon the issuance of the Disclosure Document, to the actual knowledge
of ArcLight, the Investor shall not be in possession of any material, non-public information received from ArcLight or any of its
officers, directors, or employees or agents.


 


14. Notices.
Unless otherwise provided herein, any notice or communication required or permitted hereunder shall be in writing and either delivered
personally, emailed or telecopied, sent by overnight mail via a reputable overnight carrier, or sent by certified or registered
mail, postage prepaid, and shall be deemed to be given and received (a) when so delivered personally, (b) upon receipt of an appropriate
electronic answerback or confirmation when so delivered by telecopy (to such number specified below or another number or numbers
as such person may subsequently designate by notice given hereunder), (c) when sent, with no mail undeliverable or other rejection
notice, if sent by email, or (d) five (5) business days after the date of mailing to the address below or to such other address
or addresses as such person may hereafter designate by notice given hereunder to the address or addresses set forth on the signature
pages hereto.


 


[SIGNATURE PAGES
FOLLOW]


 






    15


     


    

 


IN WITNESS WHEREOF, the Investor has executed or caused this Subscription Agreement to be executed by its duly
authorized representative as of the date set forth below.


 


	Name of Investor:	 	State/Country of Formation or Domicile:
	 	 	 
	By:	 	 	 
	Name: 	 	 	 
	Title:	 	 	 
	 	 	 
	Name in which Shares are to be registered (if different):	 	Date: ________, 2021
	 	 	 
	Investor’s EIN:	 	 
	 	 	 
	Business Address-Street:	 	Mailing Address-Street (if different):
	 	 	 
	City, State, Zip:	 	City, State, Zip:
	 	 	 
	Attn:	                            	 	Attn:	                            
	 	 	 
	Telephone No.:	 	Telephone No.:
	 	 	 
	Facsimile No.:	 	Facsimile No.:
	 	 	 
	Number of Shares subscribed for:	 	 
	 	 	 
	Aggregate Subscription Amount: $	 	Price Per Share: $10.00
	 	 	 
	 	 	 



 


You must pay the Subscription
Amount by wire transfer of United States dollars in immediately available funds to the account specified by ArcLight in the Closing
Notice.


 


 


[Signature Page to Subscription Agreement]


 



     


     


    

 


IN WITNESS WHEREOF,
ArcLight has accepted this Subscription Agreement as of the date set forth below.


 


	 	ARCLIGHT CLEAN TRANSITION CORP.
	 	 
	 	By:	 
	 	Name: 	                                
	 	Title:	 



 


Date: January 11, 2021


 


 


[Signature Page to Subscription Agreement]


 



     


     


    

 


SCHEDULE A


 


ELIGIBILITY
REPRESENTATIONS OF THE INVESTOR


 


	A.	QUALIFIED INSTITUTIONAL BUYER STATUS


 


	 	(Please check if applicable):


 


☐ The
Investor is a “qualified institutional buyer” (as defined in Rule 144A under the Securities Act (a “QIB”)).


 


	B.	INSTITUTIONAL ACCREDITED INVESTOR STATUS


 


	 	(Please check the applicable subparagraphs, to the extent applicable):


 


	 	1.	☐ The Investor is an “accredited investor” (within the meaning of Rule 501(a) under the Securities Act or an entity in which all of the equity holders are accredited investors within the meaning of Rule 501(a) under the Securities Act), and has marked and initialed the appropriate box below indicating the provision under which the Investor qualifies as an “accredited investor.”


 


	 	2. ☐ The Investor is not a natural person.


 


Rule 501(a), in relevant part, states
that an “accredited investor” shall mean any person who comes within any of the below listed categories, or who the
issuer reasonably believes comes within any of the below listed categories, at the time of the sale of the securities to that person.
The Investor has indicated, by marking and initialing the appropriate box below, the provision(s) below which apply to the Investor
and under which the Investor accordingly qualifies as an “accredited investor.”


 


☐ Any
bank, registered broker or dealer, insurance company, registered investment company, business development company, or small business
investment company;


 


☐ Any
plan established and maintained by a state, its political subdivisions, or any agency or instrumentality of a state or its political
subdivisions for the benefit of its employees, if such plan has total assets in excess of $5,000,000;


 


☐ Any
employee benefit plan, within the meaning of the Employee Retirement Income Security Act of 1974, if a bank, insurance company,
or registered investment adviser makes the investment decisions, or if the plan has total assets in excess of $5,000,000;


 


☐ Any
organization described in Section 501(c)(3) of the Internal Revenue Code, corporation, Massachusetts or similar business trust,
or partnership, not formed for the specific purpose of acquiring the securities offered, with total assets in excess of $5,000,000;


 


☐ Any
trust with assets in excess of $5,000,000, not formed to acquire the securities offered, whose purchase is directed by a sophisticated
person; or


 


☐ Any
entity in which all of the equity owners are accredited investors meeting one or more of the above tests.


 


This page
should be completed by the Investor


and constitutes
a part of the Subscription Agreement.


 


 


[Schedule A to Subscription Agreement]