Exhibit 3.4

AMENDED AND RESTATED

ARTICLES OF INCORPORATION

OF

WISCONSIN POWER AND LIGHT COMPANY

Pursuant to Section 180.1007(1) of the Wisconsin Business Corporation Law, these Amended and Restated Articles of Incorporation shall supersede and take the place of the Corporation’s existing Restated Articles of Organization and all prior amendments thereto.

ARTICLE I

The name of the Corporation is Wisconsin Power and Light Company.

ARTICLE II

The Corporation is incorporated under Chapter 180 of the Wisconsin Statutes. At the time of the adoption of these Amended and Restated Articles of Incorporation the Corporation’s registered agent and incorporator is F. J. Buri and the address of the Corporation’s registered agent and registered office is 4902 North Biltmore Lane, Madison, Wisconsin 53718.

ARTICLE III

Section 1. Authorized Capital Stock. The authorized capital stock of the Corporation shall consist of 34,000,000 shares, of which (i) 18,000,000 shall be designated “Common Stock” of the par value of $5.00 each; and (ii) 16,000,000 shares shall be designated “Preferred Stock” of no par value.

Section 2. Preferred Stock. Authority is hereby vested in the Board of Directors to divide the Preferred Stock into series and, within the limitations set forth in the Wisconsin Business Corporation Law, to fix and determine the relative rights and preferences of the shares of any series so established, including, without limitation:

1. The voting power, if any, of the Preferred Stock of such series.

2. The rate and time at which, and the terms and conditions on which, dividends on the Preferred Stock of such series may be paid.

3. The price at and the terms and conditions on which the shares of Preferred Stock of such series may be redeemed.

4. The right, if any, of holders of shares of Preferred Stock of such series to convert the same into, or exchange the same for, other classes of stock of the Corporation and the terms and conditions of such conversion or exchange.

Exhibit 3.4

5. The rights of the holders of shares of Preferred Stock of such series, including without limitation the amount payable on shares of such series, upon the voluntary or involuntary liquidation, dissolution or winding up of the Corporation.

6. Sinking fund provisions for the redemption or purchase of shares of Preferred Stock of such series.

In order to establish such series, the Board of Directors and the Corporation shall comply with the procedure therefor as provided in the Wisconsin Business Corporation Law. Upon such compliance, the resolution of the Board of Directors establishing and designating the series and fixing and determining the relative rights and preferences thereof shall become effective and shall constitute an amendment of these Amended and Restated Articles of Incorporation.

The rights of the Common Stock of the Corporation shall be subject to the relative rights and preferences of the Preferred Stock of each series as fixed herein and from time to time by the Board of Directors as aforesaid.

The shares of Preferred Stock may be issued for such consideration as shall be fixed from time to time by the Board of Directors.

Section 3. Distributions. After the requirements, if any, with respect to preferential dividends upon the Preferred Stock of all series thereof shall have been met and after the Corporation shall have complied with all requirements, if any, with respect to the setting aside of sums as a sinking fund or redemption or purchase account for the benefit of any series thereof, then, and not otherwise, the holders of Common Stock shall be entitled to receive such dividends as may be declared from time to time by the Board of Directors. After distribution in full of the preferential amounts, if any, to be distributed to the holders of all series of Preferred Stock then outstanding in the event of a voluntary or involuntary liquidation, dissolution or winding up on the Corporation and subject to any additional or special rights of the Preferred Stock as to the remaining assets of the Corporation for distribution, the holders of the Common Stock shall be entitled to receive the remaining assets of the Corporation available for distribution to its shareholders ratably in proportion to the number of shares of Common Stock held by them respectively.

Section 4: Voting Rights. Each holder of Common Stock shall have one vote in respect of each share of such stock held by such holder. Each holder of Preferred Stock shall have only such voting rights as are fixed for shares of each series by the Board of Directors pursuant to Section 2 of this Article III or are provided, to the extent applicable, by the Wisconsin Business Corporation Law.

Exhibit 3.4

ARTICLE IV

Section 1: Election of Directors. The number of directors constituting the Board of Directors shall be as fixed from time to time by the Bylaws of the Corporation, but the number so fixed shall not be less than seven (7). The directors of the Corporation shall be divided into three classes as nearly equal in number as possible, to serve for staggered three-years terms or until their respective successors are duly elected and qualified as provided for in the Bylaws of the Corporation. If, at any annual meeting of the shareholders, directors of more than one class are to be elected, each class of directors to be elected at such meeting shall be nominated and voted for in a separate election. Any vacancy occurring in the Board of Directors, including a vacancy created by an increase in the number of directors, shall be filled until the next succeeding annual meeting of shareholders by the majority vote of the directors then in office, even if less than a quorum.

ARTICLE V

Section 1: Liability. Personal liability of a director of the corporation shall be limited to the fullest extent permitted by the Wisconsin Business Corporation Law, as amended from time to time. Any repeal or modification of this section by the shareholders of the Corporation shall not adversely affect any right or protection of a director of the Corporation in respect of any act or omission occurring prior to the time of repeal or modification.

Section 2: Indemnification. The Corporation shall indemnify its directors, officers, employees and agents to the full extent permitted by the Wisconsin Business Corporation Law, as amended from time to time. The Corporation may purchase and maintain insurance on behalf of any person who is or was a director, officer, employee or agent of the Corporation, or is or was serving at the request of the Corporation as a director, officer, employee or agent or another corporation, partnership, joint venture, trust or other enterprise against any liability asserted against or incurred by such person in any such capacity or arising out of such person’s status as such, whether or not the Corporation would have the power to indemnify such person against such liability under the provisions of this section.

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