POWER OF ATTORNEY

     I, Stephen G. Shank, hereby authorize and designate each of Heidi M.
Wilson, Kristin A. Stokes, Amy M. Jensen, Amy C. Seidel, Nicole Kroetsch, and
Julie Regnier, signing singly, as my true and lawful attorney-in-fact to:

     (1) execute for and on my behalf, in my capacity as an officer and/or
director of Tennant Company (the "Company"), the Form ID and Forms 3, 4 and 5 in
accordance with Section 16(a) of the Securities Exchange Act of 1934 (the
"Exchange Act") and the rules and regulations promulgated thereunder;

     (2) do and perform any and all acts for and on my behalf which may be
necessary or desirable to complete and execute any such Form ID and Form 3, 4 or
5 and timely file such form with the Securities and Exchange Commission, any
stock exchange or similar authority, and the National Association of Securities
Dealers; and

     (3) take any other action of any type whatsoever in connection with the
foregoing which, in the opinion of such attorney-in-fact, may be to my benefit,
in my best interest, or legally required of me, it being understood that the
statements executed by such attorney-in-fact on my behalf 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.

     I hereby further grant 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 I might or could do if
personally present, with full power of substitutes 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. I hereby acknowledge that the foregoing attorneys-in-fact, in serving
in such capacity at my request, are not assuming, nor is the Company assuming,
any of my responsibilities to comply with Section 16 of the Exchange Act.

     This Power of Attorney shall remain in full force and effect until I am no
longer required to file Forms 3, 4 and 5 with respect to my holdings of and
transactions in securities issued by the Company, unless earlier revoked by me
in a signed writing delivered to the foregoing attorneys-in-fact.

     IN WITNESS WHEREOF, I have caused this Power of Attorney to be duly
executed as of this 10th day of June, 2010.


                                         /s/ Stephen G. Shank
                                         ------------------------
                                         Stephen G. Shank