POWER OF ATTORNEY
WHEREAS, directors, certain officers, and beneficial owners of more than 10% of any equity
security of AMEREN CORPORATION, a Missouri corporation (herein referred to as the "Company"),
as well as certain directors and officers of Company subsidiaries, are required to file with the
Securities and Exchange Commission and the New York Stock Exchange, under Section 16 of the
Securities Exchange Act of 1934, as now and hereafter amended, statements regarding ownership and
change in ownership of equity securities of the Company (the "Reporting Forms"); and
WHEREAS, the undersigned holds a directorship, office or offices in the Company and/or
Company subsidiaries and is required to file such Reporting Forms.
NOW, THEREFORE, the undersigned hereby constitutes and appoints Gregory L. Nelson
and/or G. L. Waters and/or Ronald S. Gieseke and/or Craig W. Stensland and/or any individual who
hereafter holds the offices of Secretary or Assistant Secretary of the Company the true and lawful
attorneys-in-fact of the undersigned, for and in the name, place and stead of the undersigned, to affix
the name of the undersigned (including, without limitation, any electronic signature) to said Reporting
Forms and any amendments thereto, and, for the performance of the same acts, each with power to
appoint in their place and stead and as their substitute, one or more attorneys-in-fact for the
undersigned, with full power of revocation; hereby ratifying and confirming all that said attorneys-in-
fact may do by virtue hereof. The undersigned acknowledges that the foregoing attorney-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 16 of the Securities
Exchange Act of 1934. The undersigned further acknowledges that in whatever capacities she may
hold in the Company and/or its subsidiaries in the future, this Power of Attorney shall remain in full
force and effect until such time it would be revoked by the undersigned.
IN WITNESS WHEREOF, the undersigned has hereunto set her hand this _14th__ day of
October, 2011.
/s/ Catherine S. Brune
Catherine S. Brune
STATE OF MISSOURI )
) SS.
CITY OF ST. LOUIS )
On this __14th___ day of October, 2011, before me, the undersigned Notary Public in and for
said State, personally appeared Catherine S. Brune, known to me to be the person described in and who
executed the foregoing power of attorney and acknowledged to me that she executed the same as her
free act and deed for the purposes therein stated.
IN TESTIMONY WHEREOF, I have hereunto set my hand and affixed my official seal.
/s/ Sue E. Whitman
Sue E. Whitman - Notary Public
State of Missouri - St. Louis County
Commission #09777931
My Commission Expires: 04/28/2013