Exhibit 23 INDEPENDENT AUDITORS' CONSENT We consent to the incorporation by reference in Registration Statement Nos. 333-46735 and 333-88306 of Alliant Energy Corporation on Forms S-8 of our report dated July 3, 2002, appearing in this Annual Report on Form 11-K of the Alliant Energy Corporation 401(k) Savings Plan for the year ended December 31, 2001. /s/ Deloitte & Touche LLP Deloitte & Touche LLP Milwaukee, Wisconsin July 9, 2002 21