EX-24

                               POWER OF ATTORNEY

    KNOW ALL BY THESE PRESENTS, that the undersigned, hereby constitutes and
appoints each of Sean F. McClain, Kevin A. Van Asdalan and John Ciroli, signing
singly and with full power of substitution and resubstitution, the undersigned's
true and lawful attorney-in- fact to:

    (1)   execute for and on behalf of the undersigned, in the undersigned's
capacity as an executive officer, director or ten percent stockholder of Montauk
Renewables, Inc. (the "Company"), all forms the undersigned is required to file
with the Securities and Exchange Commission, including, without limitation,
Forms 3, 4 and 5, Schedules 13D and 13G, and Forms 144, including any amendments
thereto, in accordance with Section 13 or Section 16 of the Securities Exchange
Act of 1934 and the rules and regulations thereunder (the "Exchange Act"), and
Rule 144 under the Securities Act of 1933 ("Rule 144");

    2)   do and perform any and all acts for and on behalf of the undersigned
which may be necessary or desirable to complete and execute any such Form 3, 4
or 5, Schedule 13D or 13G, or Form 144, including any amendments thereto, and
timely file such form with the United States Securities and Exchange Commission
and any stock exchange or similar authority;

    (3)   obtain, as the undersigned's representative and on the undersigned's
behalf, information regarding transactions in the Company's equity securities
from any third party, including the Company and any brokers, dealers, employee
benefit plan administrators and trustees, and the undersigned hereby authorizes
any such third party to release any such information to the attorney-in-fact;
and

    (4)   take any other action of any type whatsoever in connection with the
foregoing which, in the opinion of such attorney-in-fact, may be of benefit to,
in the best interests of, or legally required by, the undersigned, it being
understood that the documents executed by such attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be in such form and shall
contain such terms and conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.

    The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney-in-fact, or such
attorney-in- fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this Power of Attorney and the rights and powers herein
granted.

    The undersigned acknowledges that the foregoing attorneys-in-fact, in
serving in such capacity at the request of the undersigned, are not assuming,
nor is the Company assuming, any of the undersigned's responsibilities to comply
with Section 13 or Section 16 of the Exchange Act. Neither the Company nor the
foregoing attorneys-in-fact assume any liability for the undersigned's
responsibility to comply with the requirements of Section 13 or Section 16 of
the Exchange Act or Rule 144, any liability of the undersigned for any failure
to comply with such requirements, or any liability of the undersigned for
disgorgement of profits under Section 16(b) of the Exchange Act.

    This Power of Attorney shall remain in full force and effect until the
ndersigned is no longer required to file Forms 3, 4 and 5, Schedules 13D and
13G, and Form 144 with respect to the undersigned's holdings of and transactions
in securities issued by the Company, unless earlier revoked by the undersigned
in a signed writing delivered to the foregoing attorneys-in-fact. This Power of
Attorney revokes all previous powers of attorney with respect to the subject
matter of this Power of Attorney.

    IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of this 4th day of February, 2022.


                                        JOHN A. COPELYN

                                        By:   /s/ John A. Copelyn
                                              ----------------------------------
                                              Name: John A. Copelyn

                                        CIRCUMFERENCE ENERGY HOLDINGS LP

                                        By: Circumference Energy Holdings GP,
                                        LLC, its General Partner

                                        By:   /s/ John A. Copelyn
                                              ----------------------------------
                                              Name: John A. Copelyn
                                              Title: Sole Manager and Chief
                                              Executive Officer

EX-99.1

                                                                   Exhibit 99.1

                               Joint Filing Agreement

        In accordance with Rule 13d-1(k) promulgated under the U.S. Securities
Exchange Act of 1934, as amended, the undersigned hereby agree to the joint
filing with all other reporting persons on behalf of each of them of all
filings on any Form 3, Form 4, Form 5 or a statement on Schedule 13D or
Schedule 13G, and any and all amendments thereto and any other document
relating thereto (collectively, the "Filings") required to be filed by them
pursuant to the U.S. Securities Exchange Act of 1934, as amended, with respect
to the shares of common stock, par value $0.01 per share, of Montauk
Renewables, Inc., a Delaware corporation, and that this Agreement may be
included as an Exhibit to all such Filings. This Agreement may be executed in
any number of counterparts, all of which taken together shall constitute one
and the same instrument.

        IN WITNESS WHEREOF, the undersigned hereby execute this Agreement as of
February 3, 2022.

                         JOHN A. COPELYN

                         By:   /s/ John A. Copelyn
                               -----------------------------------------------
                               Name: John A. Copelyn


                         CIRCUMFERENCE ENERGY HOLDINGS LP

                         By: Circumference Energy Holdings GP, LLC, its General
                         Partner

                         By:   /s/ John A. Copelyn
                               -----------------------------------------------
                               Name:  John A. Copelyn
                               Title: Sole Manager and Chief Executive Officer