ALLIANT ENERGY EXCESS RETIREMENT PLAN

Exhibit 10.1

ALLIANT ENERGY EXCESS RETIREMENT PLAN

(As Amended and Restated Effective December 31, 2008)

Table of Contents

Page

ARTICLE 1

BACKGROUND AND APPLICABILITY

The Plan is designed to attract, retain and motivate key executives and employees by providing competitive retirement benefits. It compensates Participants for the loss in benefits payable from the Qualified Plans resulting from the application of Sections 401(a)(17) and 415 of the Code and from the exclusion of elective nonqualified deferred compensation from the definition of “compensation” used for determining benefits under the Qualified Plans. The Plan was originally effective August 1, 1998 in the form of the Alliant Energy Excess Plan and is maintained on a calendar year basis.

This restatement is intended to reflect the requirements of Section 409A of the Code and the shift in accruals from the Qualified DB Plan to the Qualified DC Plan. None of the revisions shall apply to any Participant in the Plan who terminated employment on or before December 31, 2004, who shall be subject to the terms of the Alliant Energy Excess Plan as then in existence.

ARTICLE 2

DEFINITIONS

When the following words or phrases are used herein, they shall have the meanings set forth below unless otherwise specifically provided:

2.1            Affiliate . A business organization that is under common control with the Company, as determined under Sections 414(b) and (c) of the Code.

2.2            Beneficiary . For Participants subject to Section 5.2 with respect to their payment of benefits, the applicable beneficiary under the Supplemental Retirement Agreement. For all other Participants, the beneficiary of the Participant’s ER Tier Contributions Account under the Alliant Energy Corporation 401(k) Savings Plan.

2.3            Benefit Restrictions . Any or all of Section 401(a)(17) of the Code, Section 415 of the Code, and the exclusion from the applicable definition of “compensation” of elective deferrals under the Alliant Energy Deferred Compensation Plan or its predecessors (i.e., the Alliant Energy Key Employee Deferred Compensation Plan, the Wisconsin Power & Light Company Deferred Compensation Plans and the IES Utilities Key Employee Deferred Compensation Plan).

2.5            Company . Alliant Energy Corporate Services, Inc., and any successor or successors thereto.

2.6            Employer . The Company, Alliant Energy Corporation, and each Affiliate of the Company with at least one employee who is a Participant.

2.7            ERISA . The Employee Retirement Income Security Act of 1974, as from time to time amended.

2.8            Participant . Any employee of the Company or an Affiliate (i) who either was a “Participant” in the Qualified DB Plan on or after January 1, 1999 or was allocated a contribution to the ER Tier Contribution Account in the Qualified DC Plan on or after January 1, 2006 and (ii) whose benefits under one or both of the Qualified Plans for which they satisfy the requirement in (i) above are in fact limited from what they would otherwise be due to the application of any or all of the Benefit Restrictions. Notwithstanding the foregoing, an employee in a collective bargaining unit with which the Company or an Affiliate has a bargaining agreement shall not be eligible to participate in the Plan unless, and then only to the extent, such bargaining agreement specifically provides. Participant who ceases to be an employee shall remain a Participant as long as benefits are payable to such individual from the Plan.

2.9            Plan . The Alliant Energy Excess Retirement Plan, as set forth herein, and as from time to time amended.

2.10          Plan Administrator . The Compensation and Personnel Committee of the Board of Directors of Alliant Energy Corporation.

2.11          Qualified DB Plan . The Alliant Energy Cash Balance Pension Plan.

2.12           Qualified DC Plan . The Company Basic Contributions provision of the Alliant Energy Corporation 401(k) Savings Plan or any successor thereof resulting in contributions to the Participant’s ER Tier Contributions Account in such plan (but not any other portion of the Alliant Energy Corporation 401(k) Savings Plan such as Company Matching Contributions or Deferred Cash Contributions).

(a)       Separation from Service means a Participant’s termination of employment or, if the Participant continues to provide services following such termination, such later date as is considered a separation from service from the Company and its 409A affiliates within the meaning of Section 409A of the Code. Specifically, if a Participant continues to provide services to the Company or a 409A affiliate in a different capacity (i.e., a former employee becomes a director or an independent contractor or a former director becomes an employee or an independent contractor), such shift in status is not automatically a Separation from Service, subject to Treas. Reg. section 1.409A-1(h)(5) among other provisions.

(b)       For purposes of the Plan, a Participant’s termination of employment shall occur when the Company and the Participant reasonably anticipate that no further services will be performed by the Participant for the Company and its 409A affiliates (whether as an employee, a director or an independent contractor) or that the level of bona fide services the Participant will perform after such date will permanently decrease to no more than 20% of the average level of bona fide services performed by the Participant (whether as an employee, director or independent contractor) for the Company and its 409A affiliates over the immediately preceding 36-month period (or such lesser period of services). Notwithstanding the foregoing, if a Participant takes a leave of absence for purposes of military leave, sick leave or other bona fide leave of absence, the Participant will not be deemed to have incurred a termination of employment for the first 6 months of the leave of absence, or if longer, for so long as the Participant’s right to reemployment is provided either by statute or by contract; provided that if the leave of absence is due to a medically determinable physical or mental impairment that can be expected to result in death or last for a continuous period of not less than 6 months, where such impairment causes the Participant to be unable to perform the duties of his or her position of employment or any substantially similar position of employment, the leave may be extended for up to 29 months without causing a termination of employment.

(c)       For purposes of the Plan, the term “409A affiliate” means each entity that is required to be included in the Company’s controlled group of corporations within the meaning of Section 414(b) of the Code, or that is under common control with the Company within the meaning of Section 414(c) of the Code, provided, however, that the phrase “at least 50 percent” shall be used in place of the phrase “at least 80 percent” each place it appears therein or in the regulations thereunder.

ARTICLE 3

ADMINISTRATION

3.1            Powers and Duties . Full power and authority to construe, interpret, and administer this Plan is vested in the Plan Administrator. In particular, the Plan Administrator shall make each determination provided for in this Plan and may adopt such rules, regulations, and procedures, as it deems necessary or desirable to the efficient administration of the Plan. The Plan Administrator’s determinations need not be uniform, and may be made by it selectively among persons who may be eligible to participate in the Plan. The Plan Administrator shall have sole and exclusive discretion in the exercise of its powers and duties hereunder, and all determinations made by the Plan Administrator shall be final, conclusive, and binding unless they are found by a court of competent jurisdiction to have been arbitrary and capricious.

3.2            Delegation . The Plan Administrator may delegate part or all of its duties to any person or persons, and may from time to time revoke such authority and delegate it to another person or persons. Each such delegation to a person who is not an employee of the Company or an Affiliate will be in writing, and a copy will be furnished to the person to whom the duty is delegated, who will file a written acceptance with the Plan Administrator. Any delegate’s duty will terminate upon revocation of such authority by the Plan Administrator, upon withdrawal of such person’s acceptance or, in the case of a delegate who is an employee of the Company or an Affiliate, upon the termination of such employment. Any person to whom administrative duties are delegated may, unless the delegation provides otherwise, similarly delegate part or all of such duties to another person.

ARTICLE 4

AMOUNT OF BENEFITS AND VESTING

4.1            Participant’s Benefit . A Participant’s aggregate benefit from the Plan shall be the sum of the Participant’s benefit under Section 4.2 related to the Qualified DB Plan, if any, and the Participant’s benefit under Section 4.3 related to the Qualified DC Plan, if any. In any event, the Participant’s benefit shall be subject to the vesting provisions in Section 4.4.

4.2            Qualified DB Plan Benefit . The applicable benefit related to the Qualified DB Plan shall equal the excess, if any, of (a) over (b) as of the Participant’s Separation from Service, stated in a lump sum amount, where:

(a)       equals the t