POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS,  that the undersigned does hereby
constitute and appoint each of  F. J. Buri, Joni Aeschbach, Karen E. Nelson
and Lori Matthews the true and lawful agents and attorneys-in-fact of the
undersigned, with respect to all matters arising in connection with the
undersigned?s reporting obligations under Section 16(a) of the Securities
Exchange Act of 1934 (the ?Exchange Act?) as amended, and related rules and
regulations, with full power and authority to execute and deliver for and on
behalf of the undersigned all Securities and Exchange Commission Forms 3, 4, 5
and other documents in connection therewith regarding Alliant Energy
Corporation, Interstate Power and Light Company, and Wisconsin Power and
Light Company securities, as each of said agents and attorneys-in-fact may
deem advisable.  The undersigned hereby gives each of said agents and
attorneys-in-fact full power and authority to act in the premises, and hereby
ratifies and confirms all that each of said agents and attorneys-in-fact may
do by virtue hereof.

The undersigned acknowledges that each attorney-in-fact, in serving in such
capacity at the request of the undersigned, is not assuming any of the
undersigned?s responsibilities to comply with the Exchange Act.  The
undersigned agrees to defend and hold harmless each attorney-in-fact from
and against any and all loss, damage or liability that such attorney-in-fact
may sustain as a result of any action taken in good faith hereunder.

This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file documents with respect to the
undersigned?s holdings of and transactions in securities issued by the Company,
unless earlier revoked by the undersigned in writing or by executing a new
Power of Attorney.

IN WITNESS WHEREOF, I have executed this Power of Attorney on this 13th day
of December, 2007.

					/s/ William D. Harvey
					William D. Harvey

Subscribed and sworn before me this
13th day of December, 2007.


/s/ F. J. Buri,
F. J. Buri
(Notary Public)

My Commission is permanent