Exhibit 10.3


 


Confidential


 


 


SUBSCRIPTION AGREEMENT


 


Star Peak Energy Transition Corp.


1603 Orrington Avenue, 13th Floor


Evanston, Illinois 60201


 


Ladies and Gentlemen:


 


In connection with
the proposed business combination (the “Transaction”) between Star Peak Energy Transition Corp., a Delaware
corporation (including any successor thereto pursuant to the terms of the Transaction Agreement, “STPK”), and
Stem, Inc., a Delaware corporation (“Stem”), pursuant to a business combination agreement (the “Transaction
Agreement”) to be entered into among Stem, STPK and a newly formed entity formed
for the purpose of consummating the Transaction (the “Company”), STPK is seeking commitments from interested
investors to purchase shares of Class A Common Stock, par value $0.0001 per share (the “Shares”), of STPK,
for a purchase price of $10.00 per share. The aggregate purchase price to be paid by the undersigned (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, the Investor and STPK agree as follows:


 


1.            Subscription.
The Investor hereby irrevocably subscribes for and agrees to purchase from STPK such number of Shares as is set forth on the signature
page of this Subscription Agreement on the terms provided for herein. Notwithstanding the foregoing or anything to the contrary
in Section 9 below, in the event that the Closing Date (as defined below) shall not have occurred by the Outside Date
(as defined in the Transaction Agreement) this Subscription Agreement shall be void and of no further effect and any monies paid
by the Investor to STPK in connection herewith shall immediately be returned to the Investor.


 


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  promptly following the consummation
of the Transaction. Upon (i) satisfaction or waiver of the conditions set forth in Section 3 below and (ii) delivery
of written notice from (or on behalf of) STPK to the Investor (the “Closing Notice”), that STPK reasonably
expects the closing of the Transaction to occur on a specified date that is not less than four (4) business days after the
date on which the Closing Notice is delivered to the Investor (the “Closing Date”), the Investor shall deliver
to STPK, two (2) business days prior to the Closing Date, the Subscription Amount by wire transfer of United States dollars
in immediately available funds to the account(s) specified by STPK in the Closing Notice, to be held in escrow until the
Closing. On the Closing Date, STPK shall issue the Shares to the Investor and subsequently cause the Shares to be registered in
book entry form in the name of the Investor on STPK’s share register, and the Subscription Amount shall be released from
escrow automatically and without further action by STPK or the Investor. This Subscription Agreement shall terminate and be of
no further force or effect, without any liability to either party hereto, if STPK notifies the Investor in writing that it has
abandoned its plans to move forward with the Transaction and/or terminates the Investor’s obligations without the delivery
of the Shares having occurred. In the event that the consummation of the Transaction does not occur within one (1) business
day after the anticipated Closing Date specified in the Closing Notice, STPK shall promptly (but in no event later than two (2) business
days after the anticipated Closing Date specified in the Closing Notice) return the funds so delivered by the Investor to STPK
by wire transfer in immediately available funds to the account specified by the Investor. For purposes of this Subscription Agreement,
 “business day” shall mean any day other than (a) any Saturday or Sunday or (b) any other day on which banks
located in New York, New York are required or authorized by applicable law to be closed for business.


 






    	 		 



     


    

 


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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)            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


 


(ii)            all
conditions precedent to the closing of the Transaction set forth in Article 6 of the Transaction Agreement and including
the approval of STPK’s stockholders and regulatory approvals, if any, shall have been satisfied (as determined by the parties
to the Transaction Agreement and other than those conditions which, by their nature, are to be satisfied at the closing of the
Transaction) or waived.


 


b.            The
obligation of STPK to consummate the purchase and sale of the Shares at the Closing pursuant to this Subscription Agreement shall
be subject to the satisfaction or valid waiver by STPK of the additional conditions that:


 


(i)            all
representations and warranties of the Investor contained in this Subscription Agreement are true and correct in all material respects
at and as of the Closing Date, and consummation of the Closing shall constitute a reaffirmation by the Investor of each of the
representations, warranties, covenants and agreements of the Investor contained in this Subscription Agreement as of the Closing
Date; and


 


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


 





c.            The
obligation of the Investor to consummate the purchase and sale of the Shares at the Closing pursuant to this Subscription Agreement
shall be subject to the satisfaction or valid waiver by the Investor of the additional conditions that:


 


(i)            all
representations and warranties of STPK 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 or Material Adverse Effect (as defined below),
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 STPK of each of the representations, warranties, covenants and agreements of STPK contained
in this Subscription Agreement as of the Closing Date;


 


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


 


(iii)            no
suspension of the offering or sale of the Shares shall have been initiated or, to STPK’s knowledge, threatened by the Securities
and Exchange Commission (the “SEC”).


 


4.            Further
Assurances. At the Closing, STPK and the Investor 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.            STPK
Representations and Warranties. STPK represents and warrants to the Investor that:


 


a.            STPK
has been duly formed as a Delaware corporation and is validly existing as a corporation
in good standing under the laws of the State of Delaware, with corporate power 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.


 






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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 STPK’s certificate
of incorporation (as amended to the Closing Date).


 


c.            This
Subscription Agreement has been duly authorized, executed and delivered by STPK and, assuming that this Subscription Agreement
constitutes the valid and binding agreement of the Investor, this Subscription Agreement is enforceable against STPK 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
issuance and sale of the Shares and the compliance by STPK with all of the provisions of this Subscription Agreement and the consummation
of the transactions contemplated herein will not (i) 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 STPK or any of its subsidiaries pursuant to the terms of any indenture, mortgage, deed of trust,
loan agreement, lease, license or other agreement or instrument to which STPK or any of its subsidiaries is a party or by which
STPK or any of its subsidiaries is bound or to which any of the property or assets of STPK is subject that would reasonably be
expected to have a material adverse effect on the business, financial condition or results of operations of STPK and its subsidiaries,
taken as a whole (a “Material Adverse Effect”) or materially affect the legal authority of STPK 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 STPK; 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 STPK or any of its subsidiaries or
any of their respective 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 STPK to comply in all material respects with this Subscription Agreement.


 


e.            As
of the date hereof, STPK is not in default or violation (and no event has occurred which, with notice or the lapse of time or
both, would constitute a default or violation) of any term, condition or provision of (i) the organizational documents of
STPK, (ii) any loan or credit agreement, guarantee, note, bond, mortgage, indenture, lease or other agreement, permit, franchise
or license to which, as of the date of this Subscription Agreement, STPK is a party or by which STPK’s properties or assets
are bound or (iii) any statute or any judgment, order, rule or regulation of any court or governmental agency, taxing
authority or regulatory body, domestic or foreign, having jurisdiction over STPK or any of its properties, except, in the case
of clauses (ii) and (iii), for defaults or violations that would not be reasonably likely to have, individually or in the
aggregate, a Material Adverse Effect.


 


f.            STPK
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 STPK 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) those required
by the New York Stock Exchange, including with respect to obtaining approval of STPK’s stockholders; and (vi) any filing,
the failure of which to obtain would not be reasonably likely to have, individually or in the aggregate, a Material Adverse Effect.


 


g.            As
of the date of this Subscription Agreement, the authorized capital stock of STPK consists of (i) 1,000,000 shares of preferred
stock, par value $0.0001 per share (“Preferred Stock”) and (ii) 440,000,000 shares of common stock, par
value $0.0001 per share (the “Common Stock”), including (1) 400,000,000 shares of Class A Common Stock,
par value $0.0001 per share (“Class A Shares”) and (2) 40,000,000 shares of Class B Common Stock, par
value $0.0001 (“Class B Common Stock”). As of the date of this Subscription Agreement, (i) no shares of
Preferred Stock are issued and outstanding, (ii) 38,358,504 Class A Shares are issued and outstanding, (iii) 9,589,626
Class B Shares are issued and outstanding and (iv) 12,786,168 redeemable warrants and 7,181,134 private placement warrants
are outstanding. All (i) issued and outstanding Class A Shares and Class B Shares have been duly authorized and
validly issued, are fully paid and are non-assessable and are not subject to preemptive rights and (ii) outstanding warrants
have been duly authorized and validly issued, are fully paid and are not subject to preemptive rights. Except as set forth above
and pursuant to the Other Subscription Agreements (as defined below), the Transaction Agreement and the other agreements and arrangements
referred to therein or in the SEC Reports (as defined below), as of the date hereof, there are no outstanding options, warrants
or other rights to subscribe for, purchase or acquire from STPK any shares of Common Stock or other equity interests in STPK,
or securities convertible into or exchangeable or exercisable for such equity interests. As of the date hereof, other than STPK
Merger Sub Corp., STPK has no subsidiaries and does not own, directly or indirectly, interests or investments (whether equity
or debt) in any person, whether incorporated or unincorporated. There are no stockholder agreements, voting trusts or other agreements
or understandings to which STPK is a party or by which it is bound relating to the voting of any securities of STPK, other than
(A) as set forth in the SEC Reports and (B) as contemplated by the Transaction Agreement. Except as disclosed in the
SEC Reports, as of September 30, 2020, STPK had no outstanding indebtedness and will not have any outstanding long-term indebtedness
as of the Closing Date.






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h.            As
of the date hereof, STPK has not received any written communication from a governmental entity that alleges that STPK is not in
compliance with or is in default or violation of any applicable law, except where such non-compliance, default or violation would
not, individually or in the aggregate, be reasonably likely to have a Material Adverse Effect.


 


i.            Assuming
the accuracy of Investor’s representations and warranties set forth in Section 6 of this Subscription Agreement, no
registration under the Securities Act (as defined below) is required for the offer and sale of the Shares by STPK to Investor
in the manner contemplated by this Subscription Agreement.


 


j.            Neither
STPK nor any person acting on its behalf has engaged or will engage in any form of general solicitation or general advertising
(within the meaning of Regulation D of the Securities Act) in connection with any offer or sale of the Shares.


 


k.            Other
than the subscription agreements entered into on or about the date hereof (the “Other Subscription Agreements”)
with certain other investors (the “Other Investors”), STPK has not entered into any side letter or similar
agreement with any Other Investor in connection with such Other Investor’s direct or indirect investment in STPK (other
than other than any side letter or similar agreement relating to the transfer to any investor of (i) securities of STPK by
existing securityholders of STPK, which may be effectuated as a forfeiture to STPK and reissuance, or (ii) securities to
be issued to the direct or indirect securityholders of the Company pursuant to the Transaction Agreement). No Other Subscription
Agreement includes terms and conditions that are materially more advantageous to any such Other Investor than the Investor hereunder,
and such Other Subscription Agreements have not been amended or modified in any material respect following the date of this Subscription
Agreement.


 


l.            As
of their respective filing dates, all reports required to be filed by STPK with the SEC (the “SEC Reports”)
complied in all material respects with the applicable requirements of the Exchange Act, and the rules and regulations of
the SEC promulgated thereunder. The financial statements of STPK 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 STPK 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 STPK from the staff of the Division of Corporation Finance of the SEC with
respect to any of the SEC Reports.


 


m.            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) investigation, action, suit, claim or other proceeding, in each case by or
before any governmental authority pending, or, to the knowledge of STPK, threatened against STPK or (ii) judgment, decree,
injunction, ruling or order of any governmental entity outstanding against STPK.


 


n.            Neither
STPK nor any of its subsidiaries has taken any steps to seek protection pursuant to any law or statute relating to bankruptcy,
insolvency, reorganization, receivership, liquidation, administration or winding up or failed to pay its debts when due, nor does
STPK or any subsidiary have any knowledge or reason to believe that any of their respective creditors intend to initiate involuntary
bankruptcy proceedings or seek to commence an administration.






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





 


a.            The
Investor (i) is a “qualified institutional buyer” (as defined in Rule 144A under the Securities Act of 1933,
as amended (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, and an “Institutional Account” as defined in FINRA Rule 4512(c) (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 on Schedule A). The Investor is
not an entity formed for the specific purpose of acquiring the Shares.


 


b.            The
Investor understands 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 understands that the Shares
may not be resold, transferred, pledged or otherwise disposed of by the Investor absent an effective registration statement under
the Securities Act except (i) to STPK 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 cases (i) and (iii) in
accordance with any applicable securities laws of the states and other jurisdictions of the United States, and that any certificates
or book entry positions representing the Shares shall contain a restrictive legend to such effect; as a result the Investor may
not be able to readily resell 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 that the Shares will not immediately be eligible for resale pursuant to Rule 144
promulgated under the Securities Act. The Investor understands that it has been advised to consult legal counsel prior to making
any offer, resale, pledge or transfer of any of the Shares.


 


c.            The
Investor understands and agrees that the Investor is purchasing the Shares from STPK. The Investor further acknowledges that there
have been no representations, warranties, covenants and agreements made to the Investor by Stem, STPK, or their respective officers
or directors, expressly or by implication, other than those representations, warranties, covenants and agreements included in
this Subscription Agreement.


 


d.            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, Section 4975 of the Internal Revenue
Code of 1986, as amended, or any applicable similar law.


 


e.            The
Investor acknowledges and agrees that the Investor has received such information as the Investor deems necessary in order to make
an investment decision with respect to the Shares, including, with respect to the Company, STPK, the Transaction and the business
of Stem. Without limiting the generality of the foregoing, the Investor acknowledges that he, she or it has reviewed STPK’s
filings with the SEC. The Investor represents 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.


 


f.            The
Investor became aware of this offering of the Shares solely by means of direct contact between the Investor and STPK, the Company,
Stem or a representative of STPK, the Company or Stem or by means of contact from Goldman Sachs & Co. LLC, Credit Suisse
Securities (USA) LLC or any of their affiliates (the “Placement Agents”), and the Shares were offered to the
Investor solely by direct contact between the Investor and STPK, the Company, Stem or a representative of STPK, the Company or
Stem or by contact between the Investor and the Placement Agents. 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. 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 Company, STPK, Stem, the Placement Agents or their respective affiliates or any of its or
their control persons, officers, directors, employees or representatives), other than the representations and warranties of STPK
contained in Section 5 of this Subscription Agreement, in making its investment or decision to invest in STPK. The
Investor further acknowledges that the Placement Agents have not made, do not make and shall not be deemed to make any express
or implied representation or warranty with respect to STPK, the Company, Stem, this offering or the Transaction.






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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 STPK’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 STPK. 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
and STPK’s representations in Section 5. 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 of their control persons, officers, directors, employees or representatives concerning the Company, STPK, Stem, the Transaction,
the Transaction Agreement, the Subscription Agreement or the transactions contemplated hereby or thereby, the Shares or the offer
and sale of the Shares.


 


j.            The
Investor understands 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 has been duly formed or incorporated and is validly existing in good standing under the laws of its jurisdiction of incorporation
or formation, 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 charter 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 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, or (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.






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n.            No
disclosure or offering document has been prepared by the Placement Agents in connection with the offer and sale of the Shares.


 


o.            The
Placement Agents and each of their directors, officers, employees, representatives and controlling persons have made no independent
investigation with respect to STPK or the Shares or the accuracy, completeness or adequacy of any information supplied to the
Investor by STPK.


 


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.


 


q.            At
the Closing, the Investor will have sufficient funds to pay the Subscription Amount and consummate the purchase and sale of the
Shares when required pursuant to this Subscription Agreement.


 


7.            Registration
Rights


 





a.            In
the event that the Shares are not registered in connection with the consummation of the Transaction, STPK agrees that, as soon
as reasonably practicable (but in any case no later than thirty (30) calendar days after the consummation of the Transaction),
it will file with the SEC (at its sole cost and expense) a registration statement registering such resale (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, in the event the SEC reviews and has written comments to the Registration
Statement, the ninetieth (90th) calendar day following the filing thereof) and
(ii) the tenth (10th) business day after the date STPK 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 ((i) and
(ii) collectively, the “Effectiveness Deadline”); provided, that if such falls on a Saturday, Sunday
or other day that the SEC is closed for business, the Effectiveness Deadline shall be extended to the next business day on which
the SEC is open for business. STPK will provide a draft of the Registration Statement to the undersigned for review at least two
(2) business days in advance of filing the Registration Statement. In no event shall the undersigned be identified as a statutory
underwriter in the Registration Statement unless requested by the SEC. Notwithstanding the foregoing, if the SEC prevents STPK
from including any or all of the shares proposed to be registered under the Registration Statement due to limitations on the use
of Rule 415 of the Securities Act for the resale of the Shares by the applicable stockholders or otherwise, such Registration
Statement shall register for resale such number of Shares which is equal to the maximum number of Shares as is permitted by the
SEC. In such event, the number of Shares to be registered for each selling shareholder named in the Registration Statement shall
be reduced pro rata among all such selling shareholders. STPK will use its commercially reasonable efforts to maintain the continuous
effectiveness of the Registration Statement until all such securities cease to be Registrable Securities (as defined below) or
such shorter period upon which all Investors with Registrable Securities included in such Registration Statement have notified
STPK that such Registrable Securities have actually been sold. STPK will use its commercially reasonable efforts to (i) cause
the removal of all restrictive legends from any Shares being sold under the Registration Statement or pursuant to Rule 144
under the Securities Act (“Rule 144”) at the time of sale of such Registrable Securities and, at the request
of an applicable holder, cause the removal of all restrictive legends from any Registrable Securities held by such an applicable
holder that may be sold by such an applicable holder without restriction under Rule 144, including without limitation, any
volume and manner of sale restrictions, and (ii) cause its legal counsel to deliver the necessary legal opinions, if any,
to the transfer agent in connection with the instruction under subclause (i) upon the receipt of such supporting documentation,
if any, as reasonably requested by such counsel. STPK will use commercially reasonable efforts to file all reports, and provide
all customary and reasonable cooperation, necessary to enable Investor to resell Registrable Securities pursuant to the Registration
Statement or Rule 144, as applicable, qualify the Registrable Securities for listing on the applicable stock exchange, update
or amend the Registration Statement as necessary to include Registrable Securities and provide customary notice to holders of
Registrable Securities. “Registrable Securities” shall mean, as of any date of determination, the Shares and
any other equity security of STPK issued or issuable with respect to the Shares by way of share split, dividend, distribution,
recapitalization, merger, exchange, replacement or similar event or otherwise. As to any particular Registrable Securities, once
issued, such securities shall cease to be Registrable Securities (i) when they are sold, transferred, disposed or exchanged
pursuant to an effective Registration Statement under the Securities Act, (ii) the earliest of (A) the fourth anniversary
of the Closing, (B) such time that such holder has disposed such securities pursuant to Rule 144 or (C) if Rule 144(i) is
no longer applicable to STPK or Rule 144(i)(2) is amended to remove the reporting requirement preceding a disposition
of securities, such time that such holder is able to dispose of all of its, his or her Registrable Securities pursuant to Rule 144
without any volume limitations thereunder, (iii) when such securities shall have ceased to be outstanding or (iv) when
such securities have been sold in a private transaction in which the transferor’s rights under this Section 7(a) are
not assigned to the transferee of such securities. The Investor agrees to disclose its ownership to STPK upon request to assist
it in making the determination described above. The Investor agrees that STPK may suspend the use of any such registration statement,
for a continuous period of up to 60 days not more than twice in any 12-month period, 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 of 1934, as amended
(the “Exchange Act”). STPK’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 STPK such information regarding the Investor, the securities of STPK held by the Investor and the intended method of
disposition of such Shares as shall be reasonably requested by STPK to effect the registration of such Shares, and shall execute
such documents in connection with such registration as STPK may reasonably request that are customary of a selling stockholder
in similar situations.






    7


     


    




 





Confidential


  


b.            STPK
shall, notwithstanding any termination of this Subscription Agreement, indemnify, defend and hold harmless Investor (to the extent
a seller under the Registration Statement), the officers, directors, trustees, agents, partners, members, managers, stockholders,
affiliates, employees and investment advisers of each of them, each person who controls Investor (within the meaning of Section 15
of the Securities Act or Section 20 of the Exchange Act) and the officers, directors, trustees, agents, partners, members,
managers, stockholders, affiliates, employees and investment advisers of each such controlling person, to the fullest extent permitted
by applicable law, from and against any and all losses, claims, damages, liabilities, costs (including, without limitation, reasonable
costs of preparation and investigation and reasonable attorneys’ fees) and expenses (collectively, “Losses”),
as incurred, that arise out of or are based upon any untrue or alleged untrue statement of a material fact contained in the Registration
Statement, any prospectus included in the Registration Statement or any form of prospectus or in any amendment or supplement thereto
or in any preliminary prospectus, or arising out of or relating to any omission or alleged omission to state a material fact required
to be stated therein or necessary to make the statements therein (in the case of any prospectus or form of prospectus or supplement
thereto, in light of the circumstances under which they were made) not misleading, except insofar as the same are caused by or
contained in any information furnished in writing to STPK by or on behalf of the Investor expressly for use therein.


 


c.            Investor
shall, severally and not jointly with any other Investor, indemnify and hold harmless STPK, its directors, officers, agents and
employees, each person who controls STPK (within the meaning of Section 15 of the Securities Act and Section 20 of the
Exchange Act), and the directors, officers, agents or employees of such controlling persons, to the fullest extent permitted by
applicable law, from and against all Losses, as incurred, arising out of or are based upon any untrue or alleged untrue statement
of a material fact contained in any Registration Statement, any prospectus included in the Registration Statement, or any form
of prospectus, or in any amendment or supplement thereto or in any preliminary prospectus, or arising out of or relating to any
omission or alleged omission of a material fact required to be stated therein or necessary to make the statements therein (in
the case of any prospectus, or any form of prospectus or supplement thereto, in light of the circumstances under which they were
made) not misleading to the extent, but only to the extent, that such untrue statements or omissions are based solely upon information
regarding Investor furnished in writing to STPK by Investor expressly for use therein. In no event shall the liability of Investor
be greater in amount than the dollar amount of the net proceeds received by Investor upon the sale of the Shares giving rise to
such indemnification obligation. Notwithstanding the forgoing, Investor’s indemnification obligations shall not apply
to amounts paid in settlement of any Losses or action if such settlement is effected without the prior written consent of Investor.






    8


     


    

 





Confidential


  


8.            Additional
Investor Agreement


 


a.            .
The Investor hereby agrees that, from the date of this Subscription Agreement, the Investor, its controlled affiliates, or any
person or entity acting on behalf of Investor or any of its controlled affiliates or pursuant to any understanding with Investor
or any of its controlled affiliates will not engage in any Short Sales with respect to securities of STPK prior to the Closing.
 “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). 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; (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 the portfolio managers have no knowledge of the investment decisions
made by the portfolio managers managing other portions of such Investor’s assets, this Section 8 shall only
apply with respect to the portion of assets managed by the portfolio manager that made the investment decision to purchase the
Subscription Amount covered by this Subscription Agreement and (iii) nothing herein shall prohibit the Investor from engaging
in derivative transactions of any kind, including, but not limited to, forward sale contracts, options, puts, calls, swaps and
similar arrangements (including on a total return basis), and sales and other transactions through U.S broker dealers or non-U.S.
broker dealers or foreign regulated brokers. STPK acknowledges and agrees that, notwithstanding anything herein to the contrary,
the Shares may be pledged by Investor in connection with a bona fide margin agreement, provided such pledge shall be (i) pursuant
to an available exemption from the registration requirements of the Securities Act or (ii) pursuant to, and in accordance
with, a registration statement that is effective under the Securities Act at the time of such pledge, and Investor effecting a
pledge of Shares shall not be required to provide STPK with any notice thereof; provided, however, that neither STPK or their
counsel shall be required to take any action (or refrain from taking any action) in connection with any such pledge, other than
providing any such lender of such margin agreement with an acknowledgment that the Shares are not subject to any contractual prohibition
on pledging or lock up, the form of such acknowledgment to be subject to review and comment by STPK in all respects.


 


9.            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 Transaction Agreement is terminated in accordance with its terms, (b) upon
the mutual written agreement of each of the parties hereto and Stem to terminate this Subscription Agreement, (c) STPK’s
notification to the Investor in writing that it has abandoned its plans to move forward with the Transaction and/or terminates
the Investor’s obligations with respect to the subscription without the delivery of the Shares having occurred, (d) the
Outside Date (as defined in the Transaction Agreement), 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; 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 breach. STPK shall notify the Investor of the termination of the
Transaction Agreement promptly after the termination of such agreement.


 


10.            Trust
Account Waiver. The Investor acknowledges that STPK is a blank check company with the powers and privileges to effect a merger,
asset acquisition, reorganization or similar business combination involving STPK and one or more businesses or assets. The Investor
further acknowledges that, as described in STPK’s prospectus relating to its initial public offering dated August 17,
2020 (the “Prospectus”) available at www.sec.gov, substantially all of STPK’s assets consist of the cash
proceeds of STPK’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 STPK, its public shareholders
and the underwriter of STPK’s initial public offering. Except with respect to interest earned on the funds held in the Trust
Account that may be released to STPK 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 STPK 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 10 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 Shares other than the Shares purchased by it pursuant to
this Subscription Agreement, pursuant to a validly exercised redemption right with respect to any such Shares.






    9


     


    

 





Confidential


  


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 (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, that no such assignment shall relieve the
Investor of its obligations hereunder.


 


b.            STPK
may request from the Investor such additional information as STPK may deem necessary to evaluate the eligibility of the Investor
to acquire the Shares, and the Investor shall promptly provide such information as may reasonably be requested to the extent readily
available and to the extent consistent with its internal policies and procedures; provided, that, STPK agrees to keep any such
information provided by 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 STPK’s securities
are listed for trading. The Investor acknowledges and agrees that if it does not provide STPK with such requested information,
STPK may not be able to register the Investor's Shares for resale pursuant to Section 7 hereof. The Investor hereby agrees
that its identity and the Subscription Agreement, as well as the nature of the Investor’s obligations hereunder, may be
disclosed in any public announcement or disclosure required by the SEC and in any registration statement, proxy statement, consent
solicitation statement or any other SEC filing to be filed by STPK in connection with the issuance of shares contemplated by this
Subscription Agreement and/or the Transaction.


 


c.            The
Investor acknowledges that the STPK, the Company (following the Closing), Stem (following the Closing), the Placement Agents and others will rely on
the acknowledgments, understandings, agreements, representations and warranties contained in this Subscription Agreement.
Prior to the Closing, the Investor agrees to promptly notify STPK and the Placement Agents if any of the acknowledgments,
understandings, agreements, representations and warranties set forth in Section 6 above are no longer accurate in
any material respect (other than those acknowledgments, understandings, agreements, representations and warranties qualified
by materiality, in which case the Investor shall notify STPK and the Placement Agents if they are no longer accurate in all
respects). The Investor agrees that each purchase by the Investor of Shares from STPK 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. The Investor further acknowledges and agrees that Stem and the Placement Agent
shall be entitled to rely on the provisions of this Subscription Agreement of which Stem and the Placement Agent are each an
express third party beneficiary on the terms and subject to the conditions set forth herein.


 


d.            The
Company, Stem, STPK and the Placement Agents are each entitled to rely upon this Subscription Agreement and each is 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.


 


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 9 above)
except by an instrument in writing, signed by each of the parties hereto; provided, however, that no modification
or waiver by STPK of the provisions of this Subscription Agreement shall be effective without the prior written consent of
Stem (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). 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. Notwithstanding anything to the contrary
herein, Section 6, Section 11(c), Section 11(d), this Section 11(f) and Section 12
may not be modified, waived or terminated in a manner that is material and adverse to the Placement Agents without the written
consent of the Placement Agents.






    10


     


    

 





Confidential


  


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 9(b), Section 11(c), Section 11(d), Section 11(f) and
this Section 11(g) 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 with
right of enforcement 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.            The
parties hereto 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.


 


l.            Any
notice or communication required or permitted hereunder shall be in writing and either delivered personally, emailed or 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 (i) when so delivered personally, (ii) when sent, with no mail undeliverable or other rejection
notice, if sent by email, or (iii) three 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:


 


(i)            if
to Investor, to such address(es) or email address(es) set forth herein;


 


(ii)            if
to, prior to the Closing, STPK or the Company, to:


 


Star Peak Energy Transition Corp.





1603 Orrington Avenue, 13th Floor





Evanston, Illinois 60201





Attention:     Secretary





E-mail:         info@starpeakcorp.com


 


 


with a required copy to (which
copy shall not constitute notice):


 


Kirkland & Ellis LLP





609 Main Street





Houston, Texas 77002












    11


     


    




 





Confidential


 


Attention:     Matthew
R. Pacey, P.C.


William J.
Benitez, P.C.





Email:          matt.pacey@kirkland.com





      william.benitez@kirkland.com


 


m.            Each
party hereto shall pay all of its own expenses in connection with this Subscription Agreement and the transactions contemplated
herein except as otherwise set forth in this Subscription Agreement.


 


n.            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(n) OF THIS SUBSCRIPTION AGREEMENT OR IN SUCH OTHER MANNER AS MAY BE PERMITTED BY LAW SHALL
BE VALID AND SUFFICIENT SERVICE THEREOF.


 


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(n).


 


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, any of their affiliates or any of its or their control persons, officers, directors and employees), other
than the statements, representations and warranties of STPK expressly contained in Section 5 of this Subscription
Agreement, in making its investment or decision to invest in STPK. The Investor agrees that 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 respective controlling persons, officers, directors, partners, agents, or employees of any investor), (ii) the
Placement Agents, their affiliates or any of its or their control persons, officers, directors or employees, or (iii) any
other party to the Transaction Agreement, including any such party’s representatives, affiliates
or any of its or their control persons, officers, directors or employees, that is not a party hereto shall be liable to
the Investor, or to any other investor, pursuant to this Subscription Agreement or any other subscription agreement related to
the private placement of the Shares for any action heretofore or hereafter taken or omitted to be taken by any of them in connection
with the purchase of the Shares.






    12


     


    

 





Confidential






 


13.            Disclosure.
STPK 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 STPK 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 STPK, the Investor
shall not be in possession of any material, non-public information received from STPK or any of its officers, directors, or employees
or agents, and the Investor shall no longer be subject to any confidentiality or similar obligations under any current agreement,
whether written or oral, with STPK, the Placement Agent or any of their respective affiliates, relating to the transactions contemplated
by this Subscription Agreement. Notwithstanding anything in this Subscription Agreement to the contrary, STPK 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 STPK’s securities are listed for trading; provided, however, that STPK shall
provide Investor with prior written notice of such disclosure permitted under clauses (i) and (ii).





 


[SIGNATURE PAGES FOLLOW]






    13


     


    

 


 


 


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: ________, 2020
	 	 
	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 STPK in the Closing
Notice. To the extent the offering is oversubscribed, the number of Shares received may be less than the number of Shares subscribed
for.


 






    	 	14	 



     


    

 


IN WITNESS WHEREOF,
Star Peak Energy Transition Corp. has accepted this Subscription Agreement as of the date set forth below.


 


	 	Star
    Peak Energy Transition Corp.
	 	 
	 	By: 	 
	 	Name:	       
	 	Title:	 
	 	 
	Date:         ,
    2020	 



 






    	 	15	 



     


    

 


SCHEDULE A


 


ELIGIBILITY
REPRESENTATIONS OF THE INVESTOR


 


	A.	QUALIFIED INSTITUTIONAL BUYER STATUS
	 	(Please check the applicable subparagraphs):
	 	 


☐  We
are a “qualified institutional buyer” (as defined in Rule 144A under the Securities Act).


 


	B.	INSTITUTIONAL ACCREDITED INVESTOR STATUS


 


	 	(Please check the applicable subparagraphs):


 


	 	1.	☐  We are
    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 have marked
    and initialed the appropriate box on the following page indicating the provision under which we qualify as an “accredited
    investor.”


 


	 	2.    	☐  We are 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, 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.


 


	C.	FINRA INSTITUTIONAL ACCOUNT STATUS

        (Please check the applicable subparagraphs):



 


	 	1.	☐  We are
    an “institutional account” under FINRA Rule 4512(c).


 


	 	2.  	☐  We are not an “institutional account”
under FINRA Rule 4512(c).






    16


     


    

 


This page
should be completed by the Investor


and constitutes
a part of the Subscription Agreement.


 



    17