UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K



x	ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, ~~2011~~ 2012



¨	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to

CommissionFile Number	Name of Registrant, State of Incorporation, Address of Principal Executive Offices and Telephone Number	IRS EmployerIdentification Number
1-9894	ALLIANT ENERGY CORPORATION	39-1380265	~~39-1380265~~
	(a Wisconsin corporation)
	4902 N. Biltmore Lane
	Madison, Wisconsin 53718
	Telephone (608)458-3311
	Telephone (608) 458-3311
0-4117-1	INTERSTATE POWER AND LIGHT COMPANY	42-0331370	~~42-0331370~~
	(an Iowa corporation)
	Alliant Energy Tower
	Cedar Rapids, Iowa 52401
	Telephone (319)786-4411
	Telephone (319) 786-4411
0-337	WISCONSIN POWER AND LIGHT COMPANY	39-0714890	~~39-0714890~~
	(a Wisconsin corporation)
	4902 N. Biltmore Lane
	Madison, Wisconsin 53718
	Telephone (608)458-3311
	Telephone (608) 458-3311

This combined Form 10-K is separately filed by Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company. Information contained in the Form 10-K relating to Interstate Power and Light Company and Wisconsin Power and Light Company is filed by each such registrant on its own behalf. Each of Interstate Power and Light Company and Wisconsin Power and Light Company makes no representation as to information relating to registrants other than itself.

Securities registered pursuant to Section 12 (b) of the Act:

	Title of Class	~~Title~~Name of ~~Class~~Each Exchange on Which Registered	~~Name of Each Exchange on Which Registered~~
Alliant Energy Corporation	Common Stock, $0.01 Par Value	~~Common~~New York Stock, ~~$0.01 Par Value~~Exchange	~~New York Stock Exchange~~
Alliant Energy Corporation	Common Share Purchase Rights	~~Common~~New ~~Share~~York ~~Purchase~~Stock ~~Rights~~Exchange	~~New York Stock Exchange~~
Interstate Power and Light Company	8.375% Series B Cumulative Preferred Stock, $0.01 Par Value	~~8.375%~~New ~~Series~~York ~~B Cumulative Preferred~~ Stock, ~~$0.01 Par Value~~Exchange	~~New York Stock Exchange~~
Wisconsin Power and Light Company	4.50% Preferred Stock, No Par Value	~~4.50%~~NYSE ~~Preferred~~Amex ~~Stock, No Par Value~~LLC	~~NYSE Amex LLC~~

Securities registered pursuant to Section 12 (g) of the Act: Wisconsin Power and Light Company Preferred Stock ~~(Accumulation without Par Value)~~

~~Indicate~~(Accumulation bywithout ~~check~~Par ~~mark if the registrants are well-known seasoned issuers, as defined in Rule 405 of the Securities Act. Yes x No ¨~~ Value)

Indicate by check mark if the registrants are ~~not~~well-known ~~required~~seasoned toissuers, ~~file~~as ~~reports~~defined ~~pursuant~~in toRule ~~Section 13~~405 ~~or Section 15(d)~~ of the Securities Act. ~~Yes ¨ No x~~

Indicate by check mark whether the registrants (1) have filed all reports required to be filed by Section 13 or 15 (d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrants were required to file such reports) and (2) have been subject to such filing requirements for the past 90 days. Yes x No ¨

Indicate by check mark ~~whether~~if the registrants ~~have~~are ~~submitted~~not ~~electronically and posted on their corporate Web site, if any, every Interactive Data File~~ required to befile ~~submitted~~reports ~~and posted~~ pursuant to ~~Rule~~Section ~~405~~13 ofor ~~Regulation~~Section ~~S-T~~ 15(~~§232.405~~d) of ~~this chapter) during~~ the ~~preceding 12 months (or for such shorter period that the registrants were required to submit and post such files)~~Act. ~~Yes x No ¨~~

~~Indicate by check mark if disclosure of delinquent filers pursuant to Item~~Yes 405 of Regulation S-K is not contained herein, and will not be contained, to the best of the registrants’ knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.¨ No x

Indicate by check mark whether the registrants ~~are~~(1) have ~~large~~filed ~~accelerated~~all ~~filers,~~reports ~~accelerated~~required ~~filers,~~to ~~non-accelerated~~be ~~filers,~~filed by Section 13 or ~~smaller~~15(d) ~~reporting companies.~~of ~~See~~the ~~definitions~~Securities Exchange Act of ~~“large~~1934 ~~accelerated~~during ~~filer,”~~the ~~“accelerated~~preceding ~~filer”~~12 ~~and~~months ~~“smaller~~(or ~~reporting~~for ~~company”~~such inshorter ~~Rule~~period ~~12b-~~that the registrants were required to file such reports) and (2) have ofbeen subject to such filing requirements for the ~~Exchange~~past ~~Act.~~90 days. Yes x No ¨

~~LargeAcceleratedFiler~~Indicate ~~AcceleratedFiler~~by ~~Non-acceleratedFiler~~check ~~SmallerReportingCompanyFiler~~mark ~~Alliant~~whether ~~Energy~~the ~~Corporation~~registrants xhave ~~Interstate~~submitted ~~Power~~electronically and ~~Light~~posted ~~Company~~on xtheir ~~Wisconsin~~corporate ~~Power~~Web site, if any, every Interactive Data File required to be submitted and ~~Light~~posted ~~Company~~pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrants were required to submit and post such files). Yes x No ¨

Indicate by ~~checkmark~~check ~~whether~~mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of the registrants’ ~~are~~knowledge, ~~shell~~in ~~companies~~definitive ~~(as~~proxy ~~defined~~or information statements incorporated by reference in ~~Rule~~Part ~~12b-2~~III of ~~the~~this ~~Exchange Act)~~Form 10-K or any amendment to this Form 10-K. ~~Yes ¨ No x~~ x

~~The~~Indicate ~~aggregate~~by ~~market~~check ~~value~~mark ofwhether the ~~voting~~registrants ~~and~~are large accelerated filers, accelerated filers, non-~~voting~~accelerated ~~common~~filers, ~~equity~~or ~~held~~smaller byreporting ~~nonaffiliates~~companies. See asthe definitions of ~~June 30~~“large accelerated filer,” ~~2011:~~“accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Alliant Energy Corporation	$	4.5 billion
Interstate Power and Light Company	$	—
Wisconsin Power and Light Company	$	—



	Large Accelerated Filer	Accelerated Filer	Non-accelerated Filer	Smaller Reporting Company Filer
Alliant Energy Corporation	x
Interstate Power and Light Company			x
Wisconsin Power and Light Company			x

~~Number~~Indicate ofby ~~shares~~check ~~outstanding~~mark ofwhether ~~each~~the ~~class~~registrants ofare ~~common~~shell ~~stock~~companies (as ofdefined ~~Jan.~~in ~~31,~~Rule ~~2012:~~12b-2 of the Exchange Act). Yes ¨ No x

The aggregate market value of the voting and non-voting common equity held by nonaffiliates as of June 30, 2012:

Alliant Energy Corporation	$5.0 billion	~~Common stock, $0.01 par value, 111,008,651 shares outstanding~~
Interstate Power and Light Company	$—	~~Common stock, $2.50 par value, 13,370,788 shares outstanding (all of which are owned beneficially and of record by Alliant Energy Corporation)~~
Wisconsin Power and Light Company	$—	~~Common stock, $5 par value, 13,236,601 shares outstanding (all of which are owned beneficially and of record by Alliant Energy Corporation)~~

~~DOCUMENTS~~Number ~~INCORPORATED~~of BYshares ~~REFERENCE~~outstanding of each class of common stock as of January 31, 2013:

Portions of the Proxy Statements relating to Alliant Energy Corporation’s and Wisconsin Power and Light Company’s 2012 Annual Meetings of Shareowners are, or will be upon filing with the Securities and Exchange Commission, incorporated by reference into Part III hereof.



Alliant Energy Corporation	Common stock, $0.01 par value, 110,990,924 shares outstanding

Interstate Power and Light Company	Common stock, $2.50 par value, 13,370,788 shares outstanding (all of which are owned beneficially and of record by Alliant Energy Corporation)

Wisconsin Power and Light Company	Common stock, $5 par value, 13,236,601 shares outstanding (all of which are owned beneficially and of record by Alliant Energy Corporation)

~~Table~~DOCUMENTS ofINCORPORATED ~~Contents~~BY REFERENCE

~~TABLE~~Portions OFof ~~CONTENTS~~the Proxy Statement relating to Alliant Energy Corporation’s 2013 Annual Meeting of Shareowners are, or will be upon filing with the Securities and Exchange Commission, incorporated by reference into Part III hereof.

			Page Number
Forward-looking Statements				1
Website Access to Reports				2
Part I	Item 1.	Business		3
		General		3
		Employees		3
		Regulation		4
		Electric Utility Operations		7
		Gas Utility Operations		17
		Steam Utility Operations		21
		Non-regulated Operations		21
	Item 1A.	Risk Factors		21
	Item 1B.	Unresolved Staff Comments		27
	Item 2.	Properties		27
	Item 3.	Legal Proceedings		29
	Item 4.	Mine Safety Disclosures		30
	Executive Officers of the Registrants			31
Part II	Item 5.	Market for Registrants’ Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities		32
	Item 6.	Selected Financial Data		33
	Item 7.	Management’s Discussion and Analysis of Financial Condition and Results of Operations		35
		Executive Summary		35
		Strategic Overview		39
		Rate Matters		46
		Environmental Matters		53
		Legislative Matters		61
		Alliant Energy’s Results of Operations		62
		IPL’s Results of Operations		71
		WPL’s Results of Operations		76
		Liquidity and Capital Resources		79
		Other Matters		91
		Market Risk Sensitive Instruments and Positions		91
		Critical Accounting Policies and Estimates		92
		Other Future Considerations		96
	Item 7A.	Quantitative and Qualitative Disclosures About Market Risk		99
	Item 8.	Financial Statements and Supplementary Data		99
		Alliant Energy Corporation
		Management’s Annual Report on Internal Control Over Financial Reporting		99
		Reports of Independent Registered Public Accounting Firm		100
		Consolidated Statements of Income		102
		Consolidated Balance Sheets		103
		Consolidated Statements of Cash Flows		105
		Consolidated Statements of Common Equity		106
		Consolidated Statements of Comprehensive Income		106
		Interstate Power and Light Company
		Management’s Annual Report on Internal Control Over Financial Reporting		107
		Report of Independent Registered Public Accounting Firm		108
		Consolidated Statements of Income		109
		Consolidated Balance Sheets		110
		Consolidated Statements of Cash Flows		112
		Consolidated Statements of Common Equity		113

Table of Contents

~~Table~~TABLE ofOF ~~Contents~~CONTENTS

					Page Number
				Wisconsin Power and Light Company
Forward-looking Statements					1
				Management’s Annual Report on Internal Control Over Financial Reporting		114
Website Access to Reports					2
				Report of Independent Registered Public Accounting Firm		115
Part I.	Item 1. Business				2
				Consolidated Statements of Income		116
		General			2
				Consolidated Balance Sheets		117
		Employees			3
				Consolidated Statements of Cash Flows		119
		Regulation			3
				Consolidated Statements of Common Equity		120
		Electric Utility Operations			7
				Combined Notes to Consolidated Financial Statements
		Gas Utility Operations			17
				1. Summary of Significant Accounting Policies		121
		Other Utility Operations - Steam			20
				2. Utility Rate Cases		136
		Non-regulated Operations			20
				3. Leases		138
	Item 1A. Risk Factors				20
				4. Receivables		139
	Item 1B. Unresolved Staff Comments				26
				5. Income Taxes		141
	Item 2. Properties				26
				6. Benefit Plans		147
	Item 3. Legal Proceedings				28
				7. Common Equity		164
	Item 4. Mine Safety Disclosures				29
				8. Redeemable Preferred Stock		165
	Executive Officers of the Registrants				29
				9. Debt		166
Part II.	Item 5. Market for Registrants’ Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities				30
				10. Investments		168
	Item 6. Selected Financial Data				31
				11. Fair Value Measurements		169
	Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations				32
				12. Derivative Instruments		172
		Executive Summary			33
				13. Commitments and Contingencies		174
		Strategic Overview			37
				14. Jointly-owned Electric Utility Plant		181
		Rate Matters			43
				15. Segments of Business		181
		Environmental Matters			48
				16. Goodwill and Other Intangible Assets		185
		Legislative Matters			55
				17. Selected Consolidated Quarterly Financial Data (Unaudited)		186
		Alliant Energy’s Results of Operations			56
				18. Discontinued Operations		187
		IPL’s Results of Operations			64
				19. Asset Retirement Obligations		187
		WPL’s Results of Operations			68
				20. Variable Interest Entities		188
		Liquidity and Capital Resources			71
				21. Related Parties		188
		Other Matters			80
				22. Earnings Per Share		189
			Market Risk Sensitive Instruments and Positions		80
		Item 9.		Changes in and Disagreements With Accountants on Accounting and Financial Disclosure		190
			Critical Accounting Policies and Estimates		81
		Item 9A.		Controls and Procedures		190
			Other Future Considerations		86
		Item 9B.		Other Information		190
	Item 7A. Quantitative and Qualitative Disclosures About Market Risk				88
Part III		Item 10.		Directors, Executive Officers and Corporate Governance		190
	Item 8. Financial Statements and Supplementary Data				89
		Item 11.		Executive Compensation		191
		Alliant Energy Corporation:
		Item 12.		Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters		191
			Management’s Annual Report on Internal Control Over Financial Reporting		89
		Item 13.		Certain Relationships and Related Transactions, and Director Independence		192
			Reports of Independent Registered Public Accounting Firm		90
		Item 14.		Principal Accounting Fees and Services		192
			Consolidated Statements of Income		92
Part IV		Item 15.		Exhibits, Financial Statement Schedules		193
			Consolidated Balance Sheets		93
Signatures						198
			Consolidated Statements of Cash Flows		95
			Consolidated Statements of Common Equity		96

Table of Contents

FORWARD-LOOKING STATEMENTS



				Page Number
		Interstate Power and Light Company:
			Management’s Annual Report on Internal Control Over Financial Reporting	97
			Report of Independent Registered Public Accounting Firm	98
			Consolidated Statements of Income	99
			Consolidated Balance Sheets	100
			Consolidated Statements of Cash Flows	102
			Consolidated Statements of Common Equity	103
		Wisconsin Power and Light Company:
			Management’s Annual Report on Internal Control Over Financial Reporting	104
			Report of Independent Registered Public Accounting Firm	105
			Consolidated Statements of Income	106
			Consolidated Balance Sheets	107
			Consolidated Statements of Cash Flows	109
			Consolidated Statements of Common Equity	110
		Combined Notes to Consolidated Financial Statements
			1. Summary of Significant Accounting Policies	111
			2. Utility Rate Cases	126
			3. Leases	128
			4. Receivables	129
			5. Income Taxes	131
			6. Benefit Plans	136
			7. Common Equity	153
			8. Redeemable Preferred Stock	155
			9. Debt	156
			10. Investments	158
			11. Fair Value Measurements	159
			12. Derivative Instruments	163
			13. Commitments and Contingencies	164
			14. Jointly-owned Electric Utility Plant	171
			15. Segments of Business	172
			16. Selected Consolidated Quarterly Financial Data (Unaudited)	175
			17. Discontinued Operations and Assets and Liabilities Held for Sale	176
			18. Asset Retirement Obligations	177
			19. Related Parties	177
			20. Earnings Per Share	178
	Item 9. Changes in and Disagreements With Accountants on Accounting and Financial Disclosure			178
	Item 9A. Controls and Procedures			178
	Item 9B. Other Information			178
Part III.	Item 10. Directors, Executive Officers and Corporate Governance			178
	Item 11. Executive Compensation			179
	Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters			179
	Item 13. Certain Relationships and Related Transactions, and Director Independence			180
	Item 14. Principal Accounting Fees and Services			180
Part IV.	Item 15. Exhibits, Financial Statement Schedules			181
Signatures				184

~~Statements~~Table ~~contained in this Annual Report on Form 10-K that are not~~ of historical fact are forward-looking statements intended to qualify for the safe harbors from liability established by the Private Securities Litigation Reform Act of 1995. These forward-looking statements can be identified as such because the statements include words such as “expect,” “anticipate,” “plan” or other words of similar import. Similarly, statements that describe future financial performance or plans or strategies are forward-looking statements. Such forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from those expressed in, or implied by, such statements. Some, but not all, of the risks and uncertainties of Alliant Energy Corporation (Alliant Energy), Interstate Power and Light Company (IPL) and Wisconsin Power and Light Company (WPL) include: Contents

•FORWARD-LOOKING ~~federal and state regulatory or governmental actions, including the impact of energy, tax, financial and health care legislation, and of regulatory agency orders;~~STATEMENTS

•Statements ~~IPL’s~~contained ~~and~~in ~~WPL’s~~this ~~ability~~Annual toReport ~~obtain~~on ~~adequate~~Form ~~and~~10-K ~~timely~~that ~~rate~~are ~~relief~~not of historical fact are forward-looking statements intended to ~~allow~~qualify for, ~~among~~the ~~other~~safe ~~things,~~harbors from liability established by the ~~recovery~~Private Securities Litigation Reform Act of ~~operating~~1995. These ~~costs,~~forward-looking ~~fuel~~statements ~~costs,~~can ~~transmission~~be ~~costs,~~identified ~~deferred~~as ~~expenditures~~such because the statements include words such as “expect,” ~~capital~~“anticipate,” ~~expenditures~~“plan” or other words of similar import. Similarly, ~~and~~statements ~~remaining~~that ~~costs~~describe ~~related~~future financial performance or plans or strategies are forward-looking statements. Such forward-looking statements are subject to ~~generating~~certain ~~units~~risks and uncertainties that ~~may~~could because ~~permanently~~actual ~~closed~~results to differ materially from those expressed in, ~~earning~~or ~~their~~implied ~~authorized~~by, ~~rates~~such statements. Some, but not all, of ~~return~~the risks and uncertainties of Alliant Energy Corporation (Alliant Energy), Interstate Power and ~~the~~Light ~~payments~~Company to(IPL) ~~their~~and ~~parent~~Wisconsin ofPower ~~expected~~and ~~levels~~Light ofCompany ~~dividends;~~(WPL) that could materially affect actual results include:

• federal and state regulatory or governmental actions, including the ~~ability~~impact toof ~~continue~~energy, ~~cost~~tax, ~~controls~~financial and ~~operational~~health ~~efficiencies~~care legislation, and of regulatory agency orders;

• ~~the~~IPL’s ~~impact~~and ~~of IPL~~WPL’s ~~retail~~ability ~~electric~~to ~~base~~obtain adequate and timely rate ~~freeze~~relief into ~~Iowa~~allow ~~through~~for, ~~2013~~among other things, the recovery of operating costs, fuel costs, transmission costs, deferred expenditures, capital expenditures, and remaining costs related to generating units that may be permanently closed, earning their authorized rates of return, and the payments to their parent of expected levels of dividends;

• the ~~state~~ability ofto ~~the~~continue ~~economy~~cost incontrols ~~IPL’s~~ and ~~WPL’s~~operational ~~service territories and resulting implications on sales, margins and ability to collect unpaid bills~~efficiencies;

• ~~developments~~the ~~that adversely~~ impact ~~Alliant Energy’s, IPL’s and WPL’s ability to implement their strategic plans, including unanticipated issues with Alliant Energy Resources, LLC’s (Resources’) construction~~ of ~~and selling price of the electricity output from its new 100 megawatt (MW) wind generating project, new emission control equipment for various coal-fired generating facilities of~~ IPL ~~and WPL, WPL~~’s ~~potential~~retail ~~purchase of the Riverside Energy Center (Riverside), IPL’s potential construction of a new natural gas-fired~~ electric ~~generating~~base ~~facility~~rate freeze in Iowa, ~~and~~through ~~the potential decommissioning of certain generating facilities of IPL and WPL~~2013;

• ~~weather~~the ~~effects~~impact onof ~~results~~WPL’s ofretail ~~utility~~electric ~~operations~~and gas base rate freeze in Wisconsin through 2014;

• ~~successful~~weather ~~resolution~~effects ofon ~~the~~results ~~pending~~of ~~challenge~~utility byoperations, ~~interveners~~including of the ~~approval~~impacts byof ~~the~~temperature ~~Public~~changes ~~Service~~and ~~Commission~~drought ofconditions ~~Wisconsin~~in ~~(PSCW)~~IPL’s ofand WPL’s ~~Bent~~service ~~Tree~~territories -on ~~Phase~~customers’ Idemand ~~wind~~for ~~project~~electricity and gas;

• ~~issues related to~~ the ~~availability~~state of ~~generating~~the ~~facilities~~economy ~~and~~in ~~the~~IPL’s ~~supply~~ and ~~delivery~~WPL’s ofservice ~~fuel~~territories and ~~purchased~~resulting ~~electricity~~implications ~~and~~on ~~price thereof~~sales, ~~including~~margins ~~the~~and ability to ~~recover~~collect ~~and~~unpaid ~~to retain the recovery of purchased power, fuel and fuel-related costs through rates in a timely manner~~bills;

• ~~the~~developments that adversely impact ~~that~~Alliant ~~fuel~~Energy’s, IPL’s and ~~fuel~~WPL’s ability to implement their strategic plan, including unanticipated issues with new emission controls equipment for various coal-~~related~~fired ~~prices~~electric ~~may~~generating ~~have~~facilities onof IPL’s and WPL, IPL’s ~~customers~~construction of its proposed natural gas-fired electric generating facility in Iowa, IPL’s ~~demand~~recently ~~for~~approved ~~utility~~purchased ~~services~~power agreement (PPA) with NextEra Energy Resources, LLC (NER), Alliant Energy Resources, LLC’s (Resources’) selling price of the electricity output from its new 100 megawatt (MW) Franklin County wind project, and the potential decommissioning of certain generating facilities of IPL and WPL;

• ~~the~~issues ~~ability~~related to ~~defend~~the ~~against~~availability ~~environmental~~of ~~claims~~generating ~~brought~~facilities byand ~~state~~the supply and ~~federal~~delivery ~~agencies,~~of ~~such~~fuel asand purchased electricity and the ~~United~~price ~~States~~thereof, ofincluding ~~America~~the ~~(U.S.)~~ability ~~Environmental~~to ~~Protection~~recover ~~Agency~~and ~~(EPA),~~to orretain ~~third~~the ~~parties~~recovery of purchased power, ~~such~~fuel asand ~~the~~fuel-related ~~Sierra~~costs ~~Club~~through rates in a timely manner;

• ~~issues~~the ~~associated~~impact ~~with~~that ~~environmental~~fuel ~~remediation~~and ~~efforts~~fuel-related ~~and~~prices ~~with~~may ~~environmental~~have ~~compliance~~on ~~generally,~~IPL’s ~~including~~and ~~changing~~WPL’s ~~environmental~~customers’ ~~laws~~demand ~~and~~for ~~regulations~~utility services;

• the ability to ~~recover~~defend ~~through~~against ~~rates~~environmental ~~all~~claims ~~environmental~~brought ~~compliance~~by state and ~~remediation~~federal ~~costs~~agencies, ~~including~~such ~~costs~~as ~~for~~the ~~projects~~United ~~put~~States onof ~~hold~~America ~~due~~(U.S.) toEnvironmental ~~uncertainty~~Protection ofAgency ~~future~~(EPA), ~~environmental~~or ~~laws~~third ~~and~~parties, ~~regulations~~such as the Sierra Club;

• ~~impacts~~issues ofassociated ~~future~~with ~~tax~~environmental ~~benefits~~remediation ~~from~~efforts ~~deductions for repairs expenditures~~ and ~~mixed~~with ~~service~~environmental ~~costs~~compliance ~~and~~generally, ~~temporary~~including ~~differences~~changing ~~from~~environmental ~~historical~~laws ~~tax~~and ~~benefits~~regulations ~~from~~and ~~such~~litigation ~~deductions~~associated ~~that~~with ~~are~~changing ~~reversing~~environmental ~~into~~laws ~~income~~and ~~tax expense in future periods~~regulations;

• the ability to ~~find~~recover athrough ~~purchaser~~rates ~~for~~all ~~RMT,~~environmental ~~Inc.~~compliance ~~(RMT)~~and remediation costs, toincluding ~~successfully~~costs ~~negotiate~~for aprojects ~~purchase~~put ~~agreement~~on ~~and~~hold due to ~~close~~uncertainty ~~the~~of ~~sale~~future ofenvironmental ~~RMT~~laws and regulations;

• ~~continued access to~~ the ~~capital~~direct ~~markets~~or onindirect ~~competitive~~effects ~~terms~~resulting ~~and~~from ~~rates~~terrorist incidents, ~~and~~including ~~the~~cyber ~~actions~~terrorism, ofor ~~credit~~responses ~~rating~~to ~~agencies~~such incidents;

• ~~inflation~~impacts of future tax benefits from deductions for repairs expenditures and ~~interest~~mixed service costs and temporary differences from historical tax benefits from such deductions that are included in rates when the differences reverse in future periods;

• ~~changes~~any tomaterial ~~the~~post-closing ~~creditworthiness~~adjustments ofrelated ~~counterparties~~to ~~with~~any ~~which~~past ~~Alliant~~asset ~~Energy~~divestitures, ~~IPL and WPL have contractual arrangements,~~ including ~~participants in~~ the ~~energy~~sale ~~markets~~of ~~and~~RMT, ~~fuel~~Inc. ~~suppliers and transporters~~(RMT);

1• continued access to the capital markets on competitive terms and rates, and the actions of credit rating agencies;

~~Table~~• ofinflation ~~Contents~~and interest rates;

• ~~issues~~changes ~~related~~ to ~~electric~~the ~~transmission,~~creditworthiness ~~including~~of ~~operating~~counterparties inwith ~~Regional~~which ~~Transmission~~Alliant ~~Organization~~Energy, ~~(RTO)~~IPL ~~energy~~ and ~~ancillary~~WPL ~~services~~have ~~markets~~contractual arrangements, ~~the~~including ~~impacts~~participants ofin ~~potential~~the ~~future~~energy ~~billing~~markets ~~adjustments~~ and ~~cost~~fuel ~~allocation~~suppliers ~~changes from RTOs~~ and ~~recovery of costs incurred~~transporters;

• ~~unplanned~~issues ~~outages,~~related ~~transmission~~to ~~constraints~~electric ortransmission, ~~operational~~including ~~issues~~operating ~~impacting~~in ~~fossil~~Regional orTransmission ~~renewable~~Organization ~~generating~~(RTO) ~~facilities~~energy and ~~risks~~ancillary ~~related~~services tomarkets, ~~recovery~~the impacts of ~~resulting~~potential ~~incremental~~future ~~costs~~billing ~~through~~adjustments ~~rates~~and cost allocation changes from RTOs and recovery of costs incurred;

• ~~Alliant~~unplanned ~~Energy’s ability to successfully pursue appropriate appeals with respect to~~outages, ~~and~~transmission ~~any~~constraints ~~liabilities~~or ~~arising~~operational ~~out~~issues ~~of,~~impacting ~~the~~fossil ~~alleged~~or ~~violation~~renewable ofgenerating ~~the~~facilities ~~Employee~~and ~~Retirement~~risks ~~Income~~related ~~Security~~to ~~Act~~recovery of ~~1974~~resulting byincremental ~~Alliant~~costs ~~Energy’s~~through ~~Cash Balance Pension Plan~~rates;

• ~~current~~Alliant orEnergy’s ~~future~~ability ~~litigation~~to successfully pursue appropriate appeals with respect to, ~~regulatory~~and ~~investigations~~any liabilities arising out of, ~~proceedings~~the oralleged ~~inquiries~~violation of the Employee Retirement Income Security Act of 1974 (ERISA) by the Alliant Energy Cash Balance Pension Plan (Cash Balance Plan);

• ~~Alliant~~current ~~Energy’s~~or ~~ability~~future tolitigation, ~~sustain~~regulatory ~~its~~investigations, ~~dividend~~proceedings ~~payout~~or ~~ratio goal~~inquiries;

~~• employee workforce factors, including changes in key executives, collective bargaining agreements and negotiations, work stoppages or additional restructurings;~~1

•Table ~~impacts that storms or natural disasters in IPL’s and WPL’s service territories may have on their operations and recovery~~ of, ~~and rate relief for, costs associated with restoration activities;~~Contents

• ~~access~~Alliant Energy’s ability to ~~technological~~sustain ~~developments~~its dividend payout ratio goal;

• ~~any~~employee ~~material~~workforce ~~post-closing~~factors, ~~adjustments~~including ~~related~~changes toin ~~any~~key ~~past~~executives, ~~asset~~collective ~~divestitures~~bargaining agreements and negotiations, work stoppages or additional restructurings;

• ~~material~~impacts ~~changes~~that storms or natural disasters, including forest or prairie fires, in ~~retirement~~IPL’s and ~~benefit~~WPL’s ~~plan~~service territories may have on their operations and recovery of, and rate relief for, costs associated with restoration activities;

• ~~the~~access ~~impact~~to oftechnological ~~incentive compensation plans accruals~~developments;

• ~~the~~material ~~effect~~changes ofin ~~accounting~~retirement ~~pronouncements~~and ~~issued~~benefit ~~periodically~~plan ~~by standard-setting bodies~~costs;

• the impact of ~~changes~~performance-based tocompensation ~~government~~plans ~~incentive elections for wind projects~~accruals;

• the ~~impact~~effect of ~~adjustments~~accounting ~~made~~pronouncements toissued ~~deferred~~periodically ~~tax~~by ~~assets~~standard-setting ~~and liabilities from state apportionment assumptions~~bodies;

• the ~~ability~~impact toof ~~utilize~~changes ~~tax credits and net operating losses generated~~ to ~~date,~~government ~~and~~incentives ~~those~~for ~~that~~wind ~~may be generated in the future, before they expire~~projects;

• the ~~ability~~impact toof ~~successfully~~adjustments ~~complete~~made to deferred tax ~~audits~~assets and ~~appeals~~liabilities ~~with~~from nostate ~~material~~apportionment ~~impact on earnings and cash flows~~assumptions;

• the ~~direct~~ability orto ~~indirect~~utilize ~~effects~~tax ~~resulting~~credits ~~from~~and ~~terrorist~~net ~~incidents,~~operating ~~including~~losses ~~cyber~~generated ~~terrorism~~to date, orand ~~responses~~those tothat ~~such~~may ~~incidents;~~be ~~and~~generated in the future, before they expire;

• ~~factors~~the ~~listed~~ability into ~~Management’s~~successfully ~~Discussion~~complete ~~and~~tax ~~Analysis~~audits, ofchanges ~~Financial~~in ~~Condition~~tax accounting methods and ~~Results~~appeals ofwith ~~Operations~~no ~~(MDA)~~material ~~and~~impact inon ~~Item~~earnings 1Aand ~~Risk~~cash ~~Factors.~~flows; and

~~Alliant~~• ~~Energy,~~factors ~~IPL~~listed ~~and~~in ~~WPL~~Management’s ~~assume~~Discussion noand ~~obligation,~~Analysis ~~and~~of ~~disclaim~~Financial ~~any~~Condition ~~duty,~~and toResults ~~update~~of ~~the~~Operations ~~forward-looking~~(MDA) ~~statements~~and in ~~this Annual~~Item ~~Report~~1A onRisk ~~Form 10-K~~Factors.

~~WEBSITE~~Alliant ~~ACCESS~~Energy, TOIPL ~~REPORTS~~and WPL each assume no obligation, and disclaim any duty, to update the forward-looking statements in this Annual Report on Form 10-K.

~~Alliant~~WEBSITE ~~Energy~~ACCESS ~~makes~~TO its periodic and current reports, and amendments to those reports, available, free of charge, on its website at www.alliantenergy.com/investors on the same day as such material is electronically filed with, or furnished to, the Securities and Exchange Commission (SEC). Alliant Energy is not including the information contained on its website as a part of, or incorporating it by reference into, this Annual Report on Form 10-K. REPORTS

~~PART~~Alliant IEnergy makes its periodic and current reports, and amendments to those reports, available, free of charge, on its website at www.alliantenergy.com/investors on the same day as such material is electronically filed with, or furnished to, the Securities and Exchange Commission (SEC). Alliant Energy is not including the information contained on its website as a part of, or incorporating it by reference into, this Annual Report on Form 10-K.

~~This~~PART Annual Report on Form 10-K includes information relating to Alliant Energy, IPL and WPL (as well as Resources and Alliant Energy Corporate Services, Inc. (Corporate Services)). Where appropriate, information relating to a specific entity has been segregated and labeled as such. Unless otherwise noted, the information herein has been revised to exclude discontinued operations for all periods presented. I

2This Annual Report on Form 10-K includes information relating to Alliant Energy, IPL and WPL (as well as Resources and Alliant Energy Corporate Services, Inc. (Corporate Services)). Where appropriate, information relating to a specific entity has been segregated and labeled as such. Unless otherwise noted, the information herein has been revised to exclude discontinued operations for all periods presented.

~~Table~~ITEM of1. ~~Contents~~BUSINESS

~~ITEM 1~~A. ~~BUSINESS~~GENERAL

AAlliant Energy was incorporated in Wisconsin in 1981 and maintains its principal executive offices in Madison, Wisconsin. ~~GENERAL~~ Alliant Energy operates as a regulated investor-owned public utility holding company. Alliant Energy’s primary focus is to provide regulated electricity and natural gas service to approximately 1 million electric and approximately 415,000 natural gas customers in the Midwest through its two public utility subsidiaries. The primary first tier subsidiaries of Alliant Energy are: IPL, WPL, Resources and Corporate Services. An illustration of Alliant Energy’s first tier subsidiaries is shown below.

Alliant Energy was incorporated in Wisconsin in 1981 and maintains its principal executive offices in Madison, Wisconsin. Alliant Energy operates as a regulated investor-owned public utility holding company. Alliant Energy’s primary focus is to provide regulated electricity and natural gas service to approximately 1 million electric and approximately 414,000 natural gas customers in the Midwest through its two public utility subsidiaries. The primary first tier subsidiaries of Alliant Energy are: IPL, WPL, Resources ~~and~~ Corporate Services~~. An illustration of Alliant Energy’s first tier subsidiaries is shown below.~~

A brief description of the primary first tier subsidiaries of Alliant Energy is as follows:

1) IPL - was incorporated in 1925 in Iowa as Iowa Railway and Light Corporation. IPL is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas in selective markets in Iowa and southern Minnesota. In Iowa, IPL provides utility services to incorporated communities as directed by the Iowa Utilities Board (IUB) and utilizes non-exclusive franchises, which cover the use of public right-of-ways for utility facilities in incorporated communities for a maximum term of 25 years. At ~~Dec.~~ December 31, ~~2011~~2012, IPL supplied electric and gas service to ~~525~~526,~~770~~841 and 233,~~715~~ 820 retail customers, respectively. IPL is also engaged in the generation and distribution of steam for two customers in Cedar Rapids, Iowa. In ~~2011~~2012, ~~2010~~2011 and ~~2009~~2010, IPL had no single customer for which electric, gas, steam and/or other sales accounted for 10% or more of IPL’s consolidated revenues.

2) WPL - was incorporated in 1917 in Wisconsin as Eastern Wisconsin Electric Company. WPL is a public utility engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas in selective markets in southern and central Wisconsin. WPL operates in municipalities pursuant to permits of indefinite duration and state statutes authorizing utility operation in areas annexed by a municipality. At Dec. 31, 2011, WPL supplied electric and gas service to 456,637 and 179,945 retail customers, respectively. In 2011, 2010 and 2009, WPL had no single customer for which electric, gas and/or other sales accounted for 10% or more of WPL’s consolidated revenues. WPL Transco LLC is a wholly-owned subsidiary of WPL and holds WPL’s investment in the American Transmission Company LLC (ATC).

3)Table ~~RESOURCES~~of - was incorporated in 1988 in Wisconsin. In 2008, Resources was converted to a limited liability company. Alliant Energy’s non-regulated investments are organized under Resources. Refer to “D. Information Relating to Non-regulated Operations” for additional details. Contents

42) ~~CORPORATE~~WPL ~~SERVICES~~ - was incorporated in ~~1997~~1917 in ~~Iowa~~Wisconsin as Eastern Wisconsin Electric Company. WPL ~~Corporate~~is ~~Services~~a ~~provides~~public ~~administrative~~utility ~~services~~engaged principally in the generation and distribution of electricity and the distribution and transportation of natural gas in selective markets in southern and central Wisconsin. WPL operates in municipalities pursuant to ~~Alliant~~permits ~~Energy~~of indefinite duration and ~~its subsidiaries~~state statutes authorizing utility operation in areas annexed by a municipality. At December 31, 2012, WPL supplied electric and gas service to 458,180 and 181,028 retail customers, respectively. In 2012, 2011 and 2010, WPL had no single customer for which electric, gas and/or other sales accounted for 10% or more of WPL’s consolidated revenues. WPL Transco LLC is a wholly-owned subsidiary of WPL and holds WPL’s investment in the American Transmission Company LLC (ATC).

~~Refer~~3) toRESOURCES ~~Note~~- 15was ofincorporated ~~the~~in ~~“Combined~~1988 ~~Notes~~in toWisconsin. In ~~Consolidated~~2008, ~~Financial~~Resources ~~Statements”~~was ~~for~~converted ~~further~~to ~~discussion~~a oflimited ~~business segments,~~liability ~~which~~company. Alliant ~~information~~Energy’s isnon-regulated ~~incorporated~~investments ~~herein~~are byorganized ~~reference~~under Resources. Refer to “Information Relating to Non-regulated Operations” for additional details.

B4) CORPORATE SERVICES - was incorporated in 1997 in Iowa. Corporate ~~INFORMATION~~Services ~~RELATING~~provides TOadministrative ~~ALLIANT~~services ~~ENERGY~~to ONAlliant AEnergy ~~CONSOLIDATED~~and ~~BASIS~~ its subsidiaries.

1)Refer ~~EMPLOYEES~~to -Note At15 ~~Dec.~~of ~~31,~~the ~~2011,~~“Combined ~~Alliant~~Notes ~~Energy’s~~to ~~consolidated~~Consolidated ~~subsidiaries~~Financial ~~had~~Statements” ~~the~~for ~~following~~further ~~full- and~~discussion ~~part-time~~of ~~employees:~~business segments, which information is incorporated herein by reference.

	Number ofBargaining UnitEmployees		Number ofOtherEmployees		TotalNumber ofEmployees		Percentage of EmployeesCovered by CollectiveBargaining Agreements
IPL		1,121		531		1,652		68	%
WPL		1,073		235		1,308		82	%
Corporate Services		25		868		893		3	%
Resources:
RMT		—		296		296		—
Other		86		27		113		76	%
		2,305		1,957		4,262		54	%

B. INFORMATION RELATING TO ALLIANT ENERGY ON A CONSOLIDATED BASIS

31) EMPLOYEES - At December 31, 2012, Alliant Energy’s consolidated subsidiaries had the following full- and part-time employees:



	Number of	Number of	Total	Percentage of Employees
	Bargaining Unit	Other	Number of	Covered by Collective
	Employees	Employees	Employees	Bargaining Agreements
IPL	1,105	546	1,651	67	%
WPL	1,018	254	1,272	80	%
Corporate Services	26	817	843	3	%
Resources:
RMT (Alliant Energy sold RMT in January 2013)	—	175	175	—	%
Other	86	28	114	75	%
	2,235	1,820	4,055	55	%

At ~~Dec.~~ December 31, ~~2011~~2012, Alliant Energy employees covered by collective bargaining agreements were as follows:

		Number ofEmployees			ContractExpiration Date
	Number of			Contract
IPL:
	Employees			Expiration Date
International Brotherhood of Electrical Workers (IBEW) Local 949			220			9/30/12
IPL:
IBEW Local 204 (Dubuque)			87			9/30/12
International Brotherhood of Electrical Workers (IBEW) Local 204 (Emery)	13			4/30/13
IBEW Local 204 (Mason City)			42			9/30/12
IBEW Local 204 (Cedar Rapids)	726			8/31/13
IBEW Local 204 (Emery)			13			4/30/13
IBEW Local 1439	17			6/30/14
IBEW Local 204 (Cedar Rapids)			738			8/31/13
IBEW Local 949	219			9/30/15
IBEW Local 1439			16			6/30/14
IBEW Local 204 (Dubuque)	82			9/30/15
IBEW Local 1455			5			6/30/16
IBEW Local 204 (Mason City)	43			9/30/15
			1,121
IBEW Local 1455	5			6/30/16
WPL - IBEW Local 965			1,073			5/31/14
	1,105
Resources - Various			86			Various
WPL - IBEW Local 965	1,018			5/31/14
Corporate Services - IBEW Local 204			25			10/31/14
Resources - Various	86			Various
			2,305
Corporate Services - IBEW Local 204	26			10/31/14
	2,235

2) CAPITAL EXPENDITURE AND INVESTMENT PLANS - Refer to “Liquidity and Capital Resources - Cash Flows - Investing Activities - Construction and Acquisition Expenditures” in MDA for discussion of anticipated construction and acquisition expenditures for ~~2012~~2013 through ~~2015~~2016.

3) REGULATION - Alliant Energy, IPL and WPL are subject to regulation by various federal, state and local agencies. The following includes the primary regulations impacting Alliant Energy’s, IPL’s and WPL’s businesses.

~~Federal Energy Regulatory Commission (FERC) -~~ 3

~~Public~~Table ~~Utility Holding Company Act~~ of 2005 (PUHCA 2005) - Alliant Energy is registered with FERC as a public utility holding company, pursuant to PUHCA 2005, and is required to maintain certain records and to report certain transactions involving its public utilities, service company and other entities regulated by FERC. Corporate Services, IPL and WPL are subject to regulation by FERC under PUHCA 2005 for various matters including, but not limited to, affiliate transactions, public utility mergers, acquisitions and dispositions, and books and records requirements. Contents

~~Energy~~Federal ~~Policy Act - The~~ Energy ~~Policy~~Regulatory ~~Act~~Commission ~~requires creation of an Electric Reliability Organization~~ (~~ERO) to provide oversight by~~ FERC~~. FERC designated the North American Electric Reliability Corporation (NERC~~) ~~as the overarching ERO. The Midwest Reliability Organization (MRO), which is a regional member of NERC, has direct responsibility for mandatory electric reliability standards for IPL and WPL.~~ -

~~Federal~~Public ~~Power~~Utility Holding Company Act -of ~~FERC~~2005 ~~also~~(PUHCA ~~has~~2005) ~~jurisdiction,~~- ~~under~~Alliant ~~the~~Energy ~~Federal~~is ~~Power~~registered ~~Act,~~with ~~over~~FERC ~~certain~~as ~~electric~~a public utility ~~facilities~~holding ~~and operations~~company, ~~electric wholesale~~pursuant ~~and~~to ~~transmission~~PUHCA ~~rates~~2005, ~~dividend~~and ~~payments,~~is ~~issuance~~required ofto ~~securities~~maintain ~~(IPL~~certain records and ~~Corporate~~to ~~Services~~report ~~only)~~certain transactions involving its public utilities, service company and ~~accounting~~other ~~practices~~entities ofregulated by FERC. Corporate Services, IPL and WPL. are subject to regulation by FERC under PUHCA 2005 for various matters including, but not limited to, affiliate transactions, public utility mergers, acquisitions and dispositions, and books, records and accounting requirements.

~~Electric~~Energy ~~Wholesale~~Policy ~~Rates~~Act - ~~Corporate~~The ~~Services,~~Energy asPolicy ~~agent~~Act ~~for~~requires ~~both~~creation ~~IPL~~of ~~and~~an ~~WPL,~~Electric ~~has~~Reliability ~~received~~Organization ~~wholesale~~(ERO) ~~electric~~to ~~market-based~~provide ~~rate~~oversight ~~authority~~by ~~from~~ FERC. FERC ~~Market-based~~designated ~~rate authorization allows for wholesale sales of electricity within~~ the ~~Midwest~~North ~~Independent~~American ~~Transmission~~Electric ~~System~~Reliability ~~Operator~~Corporation (~~MISO~~NERC) ~~and~~as ~~PJM Interconnection, LLC (PJM) markets and in bilateral markets, based on~~ the ~~market~~overarching ~~value of the transactions~~ERO. The ~~IPL~~Midwest ~~and~~Reliability ~~WPL~~Organization ~~also~~(MRO), ~~have~~which ~~FERC-approved cost-of-service~~is ~~based~~a ~~rates~~regional ~~related~~member ~~to the provision~~ of ~~firm~~NERC, ~~full-~~has ~~and~~direct ~~partial-requirement~~responsibility ~~wholesale~~for mandatory electric ~~sales.~~reliability ~~Both~~standards for IPL’s and WPL~~’s wholesale cost-of-service tariffs are formula-based tariffs that allow for annual true-ups to actual costs, including fuel costs~~.

~~Electric~~Federal ~~Transmission~~Power ~~Rates~~Act - FERC ~~regulates~~also ~~the~~has ~~rates~~jurisdiction, ~~charged~~under ~~for~~the ~~electric~~Federal ~~transmission~~Power ~~facilities~~Act, ~~used in~~over ~~interstate~~certain ~~commerce. Neither IPL nor WPL own or operate~~ electric ~~transmission~~utility facilities; ~~however~~and operations, ~~both~~electric ~~IPL~~wholesale and ~~WPL pay for the use of the interstate electric~~ transmission ~~system based upon FERC-regulated~~ rates., ~~IPL~~dividend ~~relies~~payments, ~~primarily~~issuance ~~upon the use~~ of ~~the~~securities ~~ITC Midwest LLC~~ (~~ITC)~~IPL ~~transmission~~and ~~system.~~Corporate ~~WPL~~Services ~~relies~~only) ~~primarily~~and ~~upon~~accounting ~~the~~practices ~~use~~ of ~~the~~Corporate ~~ATC~~Services, ~~transmission~~IPL ~~system.~~and WPL.

~~National~~Electric ~~Gas~~Wholesale ~~Act~~Rates - IPL and WPL have received wholesale electric market-based rate authority from FERC. Market-based ~~regulates~~rate authorization allows for wholesale sales of electricity within the ~~transportation~~Midwest Independent Transmission System Operator (MISO) and ~~sale~~PJM ~~for~~Interconnection, ~~resale~~LLC of(PJM) ~~natural~~markets ~~gas~~and in ~~interstate~~bilateral ~~commerce~~markets, ~~under~~based on the ~~Natural~~market ~~Gas~~value ~~Act.~~of ~~Under~~ the ~~Natural~~transactions. IPL ~~Gas~~and ~~Act,~~WPL also have FERC-approved ~~has~~cost-of-service ~~authority~~based ~~over~~rates ~~certain~~related ~~natural~~to ~~gas~~the ~~facilities~~provision of firm full- and ~~operations~~partial-requirement ofwholesale electric sales. Both IPL’s and WPL.’s wholesale cost-of-service tariffs are formula-based tariffs that allow for annual true-ups to actual costs, including fuel costs.

4Electric Transmission Rates - FERC regulates the rates charged for electric transmission facilities used in interstate commerce. Neither IPL nor WPL own or operate electric transmission facilities; however, both IPL and WPL pay for the use of the interstate electric transmission system based upon FERC-regulated rates. IPL and WPL rely primarily upon the use of the ITC Midwest LLC (ITC) and ATC transmission systems, respectively.

~~Table~~FERC is performing an investigation into Attachment “O” protocols under the MISO tariff, focusing on the areas of ~~Contents~~participation, transparency and challenge procedures. IPL filed comments related to ITC’s Attachment “O” protocols. IPL supports increasing the participation, transparency and challenge procedures related to Attachment “O.” ITC filed comments contrary to IPL’s position, alleging that the status quo affords IPL adequate information to challenge ITC’s rates. Refer to “Other Future Considerations” in MDA for discussion of IPL’s formal complaint filed with FERC in September 2012 alleging that ITC’s Attachment “FF” tariff is unjust, unreasonable and unduly discriminatory to IPL and its electric customers.

AsNatural ~~part~~Gas ofAct ~~routine~~- ~~procedures,~~FERC inregulates the ~~fourth~~transportation ~~quarter~~and ofsale ~~2011,~~for ~~FERC~~resale ~~commenced an audit~~ of ~~Alliant~~natural ~~Energy, including~~gas ~~its~~in ~~centralized~~interstate ~~service~~commerce ~~company~~under ~~(Corporate~~the ~~Services)~~Natural ~~and~~Gas ~~other affiliated companies~~Act. Under Athe ~~final~~Natural ~~report~~Gas isAct, ~~expected to be issued by~~ FERC inhas ~~late~~authority ~~2012~~over orcertain ~~early~~natural ~~2013.~~gas ~~Alliant~~facilities ~~Energy~~and ~~does~~operations ~~not~~of ~~believe~~IPL ~~that~~and ~~the final report will have any impact upon its financial condition or results of operations~~WPL.

Environmental - Alliant Energy, IPL and WPL are subject to extensive environmental requirements. The EPA administers certain federal regulatory programs and has delegated the administration of other environmental regulatory programs to the applicable state environmental agencies. In general, the state agencies have jurisdiction over air and water quality, hazardous substances management, transportation and clean-up, and solid waste management requirements. In certain cases, the state environmental agencies have delegated the administration of environmental programs to local agencies. Alliant Energy, IPL and WPL are subject to these environmental regulations as a result of their current and past operations.

IUB - IPL is subject to regulation by the IUB related to its operations in Iowa for various matters including, but not limited to, retail utility rates and standards of service, accounting requirements and approval of the location and construction of electric generating facilities. As part of the IUB’s February 2011 order related to IPL’s Iowa retail electric rate case (2009 test year), the IUB outlined plans for IPL’s management activities to be audited by a third party vendor. This audit commenced in the third quarter of 2011. A final report is expected to be issued by the third party vendor to the IUB in the second half of 2012. Alliant Energy and IPL do not currently believe that the final report will have any impact upon their financial condition or results of operations.

Retail Utility Base Rates - IPL files periodic requests with the IUB for retail rate ~~relief~~changes. These filings are based on historical test periods. The historical test periods may be adjusted for certain known and measurable ~~capital~~changes ~~additions~~to ~~placed~~capital ininvestments, ~~service~~cost ~~by IPL within nine months from the end~~ of ~~the~~capital ~~historical test period~~ and ~~certain known and measurable~~ operating and maintenance expenses ~~incurred~~consistent bywith ~~IPL~~IUB ~~within~~rules 12and ~~months of the commencement of the proceeding~~regulations. Interim retail rates can be placed in effect 10 days after the rate application filing, subject to refund, and must be based on past precedent. The IUB must decide on requests for retail rate ~~relief~~changes within 10 months of the date of the application for which ~~relief~~changes isare filed, or the interim rates granted become permanent. Refer to “Rate Matters” in MDA for details of a retail electric base rate freeze effective for IPL’s Iowa customers through 2013.

Retail Commodity Cost Recovery Mechanisms - IPL’s retail electric and natural gas tariffs contain automatic adjustment clauses for changes in prudently incurred commodity costs required to serve its retail customers in Iowa. Any over- or under-collection of commodity costs for each given month are automatically reflected in future billings to retail customers. 4

~~Retail~~Table Electric Transmission Cost Recovery Mechanism - Effective February 2011, electric transmission service expenses were removed from base rates and billed to IPL’s Iowa retail electric customers through the transmission cost rider. This new cost recovery mechanism provides for subsequent adjustments to electric rates charged to Iowa retail electric customers for changes in electric transmission service expenses. Any over- or under-collection of electric transmission costs for each given month are automatically reflected in future billings to retail customers. The transmission cost rider will remain in effect until the IUB’s decision in IPL’s next retail electric base rate case, whereby the rider will be revisited. Contents

~~Energy~~Retail ~~Efficiency~~Commodity Cost Recovery ~~(EECR)~~Mechanisms ~~Mechanism~~ - IPL’s retail electric and natural gas tariffs contain anautomatic ~~EECR~~adjustment ~~factor~~clauses tofor ~~recover~~changes in prudently incurred ~~energy~~commodity ~~efficiency~~ costs ~~incurred~~required onto ~~behalf~~serve ofits ~~IPL’s~~retail ~~Iowa~~ customers. ~~EECR~~in ~~factors~~Iowa. Any ~~are~~over- ~~revised~~or ~~annually,~~under-collection ~~subject~~of tocommodity ~~approval~~costs byfor ~~the~~each ~~IUB,~~given ~~and~~month ~~include~~are aautomatically ~~reconciliation~~reflected ~~to eliminate~~in ~~any~~future ~~over-~~billings orto ~~under-recovery~~retail ~~of energy efficiency expenses from prior periods~~customers.

~~New~~Retail Electric ~~Generating~~Transmission ~~Facilities~~Cost -Recovery ~~A Certificate~~Mechanism of- ~~Public~~Effective ~~Convenience~~February 2011, ~~Use~~electric ~~and~~transmission ~~Necessity~~service ~~(GCU~~expenses ~~Certificate)~~were ~~application~~removed isfrom ~~required~~base rates and billed to beIPL’s ~~filed~~Iowa ~~with~~retail electric customers through the ~~IUB~~transmission cost rider. This new cost recovery mechanism provides for ~~construction~~subsequent ~~approval~~adjustments ofto ~~any~~electric ~~new~~rates charged to Iowa retail electric ~~generating~~customers ~~facility~~for ~~located~~changes in ~~Iowa~~electric ~~with~~transmission 25service MWexpenses. Changes orin ~~more~~the under-/over-collection of ~~capacity~~these costs are reflected in future billings to customers. The transmission cost rider will remain in effect until the IUB’s decision in IPL’s next retail electric base rate case, at which time the rider will be revisited.

~~Advance~~Energy ~~Rate~~Efficiency ~~Making~~Cost ~~Principles~~Recovery -(EECR) ~~Iowa~~Mechanism ~~Code~~- ~~§476.53~~In ~~provides~~accordance with Iowa ~~utilities~~law, ~~with~~IPL ~~rate~~is ~~making~~required ~~principles~~to ~~prior~~file toan ~~making~~Energy ~~certain~~Efficiency ~~generation investments~~Plan in(EEP) ~~Iowa.~~every ~~Under~~five ~~Iowa~~years ~~Code~~with ~~§476~~the IUB.~~53,~~ An ~~IPL~~EEP ~~must~~provides ~~file~~a ~~for,~~utility’s plan and ~~the~~related ~~IUB~~budget ~~must~~to ~~render~~achieve aspecified ~~decision~~levels ~~on,~~of ~~rate~~energy ~~making~~savings. IUB ~~principles~~approval ~~for~~demonstrates ~~electric~~that ~~generating~~the ~~facilities~~IUB ~~located~~believes inthat ~~Iowa~~IPL’s ~~including~~EEP ~~new~~is ~~base-load~~reasonably ~~(primarily~~expected ~~defined~~to asachieve ~~nuclear or coal~~cost-~~fired~~effective ~~generation)~~delivery ~~facilities~~of ~~with~~the aenergy ~~capacity~~efficiency ofprograms. To ~~300~~the MWextent orapproved ~~more~~by the IUB, ~~combined-cycle~~costs ~~natural~~associated ~~gas-fired~~with ~~facilities~~executing ofthe ~~any~~EEP ~~size~~are ~~and~~recovered ~~renewable~~from ~~generating~~ratepayers ~~resources,~~through ~~such~~an asadditional ~~wind~~tariff ~~facilities,~~called ofan ~~any~~EECR ~~size~~factor. The ~~Upon~~EECR ~~approval~~factors ofare ~~rate~~revised ~~making~~annually ~~principles~~and byinclude ~~the IUB,~~a ~~IPL~~reconciliation ~~must~~to ~~either~~eliminate ~~build~~any ~~the~~over- ~~facility~~or under-recovery ~~the~~of ~~approved~~energy ~~rate~~efficiency ~~making~~expenses ~~principles,~~from orprior ~~not at all~~periods.

5Electric Generating Facilities - IPL must obtain a Certificate of Public Convenience, Use and Necessity (GCU Certificate) from the IUB in order to construct a new or significantly alter an existing electric generating facility located in Iowa with 25 MW or more of capacity.

~~Table~~Advance Rate-making Principles - Iowa Code §476.53 provides Iowa utilities with rate-making principles prior to making certain generation investments in Iowa. As a result, IPL must file for, and the IUB must render a decision on, rate-making principles for electric generating facilities located in Iowa, including new base-load (nuclear or coal-fired generation) facilities with a capacity of ~~Contents~~300 MW or more, combined-cycle natural gas-fired facilities of any size and renewable generating resources, such as wind facilities, of any size. Upon approval of rate-making principles by the IUB, IPL must either build the facility under the approved rate-making principles, or not at all.

Electric Generating Facility Emission ~~Control~~Controls Projects - IPL is required to submit an Emissions Plan and Budget (EPB) biennially to the IUB setting out a multi-year plan and budget for managing regulated emissions from its electric generating facilities in a cost-effective manner. IPL must simultaneously submit this plan and budget to the Iowa Department of Natural Resources for a determination of whether the plan and budget ~~meets~~meet state environmental requirements for regulated emissions. The reasonable costs associated with implementing the plan are expected to be included in IPL’s future retail electric rates.

Public Service Commission of Wisconsin (PSCW) - Alliant Energy is subject to regulation by the PSCW for the type and amount of Alliant Energy’s investments in non-utility businesses and other affiliated interest activities, among other matters. WPL is also subject to regulation by the PSCW related to its operations in Wisconsin for various matters including, but not limited to, retail utility rates and standards of service, accounting requirements, issuance and use of proceeds of securities, affiliate transactions, approval of the location and construction of electric generating facilities and certain other additions and extensions to facilities.

Retail Utility Base Rates - WPL files periodic requests with the PSCW for retail rate ~~relief~~changes. These filings are required to be based on forward-looking test periods. There is no statutory time limit for the PSCW to decide retail base rate requests. However, the PSCW attempts to process ~~base~~ retail base rate cases in approximately 10 months and has the ability to approve interim retail rate relief, subject to refund, if necessary. Refer to “Rate Matters” in MDA for details of a retail electric and gas base rate freeze effective for WPL’s customers during 2013 and 2014.

Retail Commodity Cost Recovery Mechanisms -

Electric - WPL’s retail electric base rates include estimates of annual fuel-related costs (fuel and purchased power energy costs) anticipated during the test period. During each ~~electric~~ retail electric rate proceeding or in a separate fuel cost plan approval proceeding, the PSCW sets fuel monitoring ranges based on the forecasted fuel-related costs used to determine rates in such proceeding. If WPL’s actual fuel-related costs fall outside these fuel monitoring ranges, WPL is authorized to defer the incremental over- or under-collection of fuel-related costs from ~~electric~~ retail electric customers that are outside the approved ranges. Deferral of under-collections are reduced to the extent actual return on common equity earned by WPL during the fuel cost plan year exceeds the ~~most~~applicable ~~recently~~ authorized return on common equity. Subject to review and approval by the PSCW, any deferred over- or under-collection of fuel-related costs for each year are reflected in future billings to retail customers. ~~This cost recovery mechanism became effective for WPL on Jan. 1, 2011.~~

Natural Gas - WPL’s retail natural gas tariffs contain an automatic adjustment clause for changes in prudently incurred natural gas costs required to serve its retail gas customers. Any over- or under-collection of natural gas costs for each given month are automatically reflected in future billings to retail customers. 5

~~EECR~~Table ~~Mechanism - WPL contributes a certain percentage~~ of its annual retail utility revenues to help fund Focus on Energy, Wisconsin’s statewide energy efficiency and renewable energy resource program. Estimated contributions to Focus on Energy, along with WPL-run energy efficiency program costs, are recovered from WPL’s retail customers through changes in base rates determined during periodic rate proceedings and include a reconciliation of such estimated amounts to actual costs incurred with any difference deferred for inclusion in future base rate changes. Contents

~~New~~Natural ~~Electric~~Gas ~~Generating Facilities~~ - AWPL’s ~~Certificate~~retail ofnatural ~~Authority~~gas ~~(CA)~~tariffs ~~application~~contain isan ~~required~~automatic toadjustment beclause ~~filed with the PSCW~~ for ~~construction~~changes ~~approval of~~in ~~any~~prudently ~~new~~incurred ~~electric~~natural ~~generating~~gas ~~facility~~costs ~~with a capacity of less than 100 MW. A Certificate of Public Convenience and Necessity application is~~ required to beserve ~~filed~~its ~~with~~retail ~~the~~gas ~~PSCW~~customers. Any ~~for~~over- ~~construction~~or ~~approval~~under-collection of ~~any~~natural ~~new~~gas ~~electric~~costs ~~generating~~for ~~facility~~each ~~with~~given ~~a capacity~~month ofare ~~100~~automatically MWreflected ~~or more built~~ in ~~Wisconsin.~~future Inbillings ~~addition, WPL’s ownership and operation of electric generating facilities (including those located outside the state of Wisconsin)~~ to ~~serve Wisconsin customers is subject to~~ retail ~~utility rate regulation by the PSCW~~customers.

~~Electric~~EECR ~~Generating~~Mechanism ~~Facility~~- ~~Upgrades~~WPL -contributes Aa CAcertain ~~application~~percentage isof ~~required~~its annual retail utility revenues to behelp ~~filed~~fund ~~with~~Focus ~~the~~on ~~PSCW~~Energy, ~~for construction~~Wisconsin’s ~~approval~~state-wide ofenergy ~~any~~efficiency ~~additions~~and renewable energy resource program. Estimated contributions to ~~electric~~Focus ~~generating~~on ~~facilities~~Energy, ~~including~~along ~~emission~~with ~~control~~WPL-run ~~projects~~energy ~~that~~efficiency ~~exceed~~program acosts, ~~certain~~are ~~threshold~~recovered ~~amount.~~from ~~The~~WPL’s ~~current~~retail ~~PSCW~~customers ~~rules~~through ~~require~~changes in base rates determined during periodic rate proceedings and include a CAreconciliation ~~for~~of ~~projects~~such estimated amounts to actual costs incurred with anany ~~estimated~~difference ~~cost~~deferred for inclusion in ~~excess~~future ofbase ~~approximately $8~~rate ~~million~~changes.

~~Advance~~New ~~Rate~~Electric ~~Making~~Generating ~~Principles~~Facilities - ~~Wisconsin~~A ~~Statute~~Certificate ~~§196.371~~of ~~provides~~Authority ~~Wisconsin~~(CA) ~~utilities~~application ~~with~~is ~~the~~required ~~opportunity~~ to ~~request~~ ~~rate~~be ~~making~~filed ~~principles~~with ~~prior to~~ the ~~purchase~~PSCW orfor construction approval of any ~~nuclear~~new ~~or fossil-fueled~~ electric generating facility orwith ~~renewable~~a ~~generating~~capacity ~~resource,~~of ~~such~~less asthan a100 ~~wind~~MW. WPL ~~facility,~~must ~~utilized~~obtain toa ~~serve~~GCU ~~Wisconsin~~Certificate ~~customers.~~from ~~WPL~~the isPSCW ~~not~~in ~~obligated~~ order to ~~file~~construct ~~for~~a ornew ~~accept~~electric ~~authorized~~generating ~~rate~~facility ~~making~~in ~~principles~~Wisconsin ~~under~~with ~~Wisconsin~~a ~~Statute~~capacity ~~§196~~of 100 MW or more.~~371.~~ In addition, WPL’s ~~can~~ownership ~~proceed~~and ~~with~~operation anof ~~approved~~electric ~~project~~generating ~~under~~facilities ~~traditional~~(including ~~rate~~those ~~making~~located ~~terms~~outside orthe ~~accept~~state ~~authorized~~of ~~rate~~Wisconsin) ~~making~~to ~~principles~~serve ~~under~~ Wisconsin ~~Statute §196.371.~~customers is subject to retail utility rate regulation by the PSCW.

~~Minnesota~~Electric ~~Public~~Generating ~~Utilities~~Facility ~~Commission~~Upgrades ~~(MPUC)~~ - ~~IPL~~A CA application is ~~subject~~required to ~~regulation~~be byfiled with the ~~MPUC~~PSCW ~~related to its operations in Minnesota~~ for ~~various~~construction ~~matters~~approval ~~including,~~of ~~but~~any ~~not~~additions ~~limited~~ to, ~~retail~~electric ~~utility~~generating ~~rates and standards of service~~facilities, ~~accounting~~including ~~requirements,~~emission ~~issuance~~controls ~~and~~projects ~~use of proceeds of securities~~ that ~~encumber~~exceed ~~property~~a incertain ~~Minnesota,~~threshold ~~affiliate transactions,~~amount. The ~~and~~current ~~approval~~PSCW ofrules ~~the~~require ~~location~~a ~~and~~CA ~~construction~~for ofprojects ~~electric generating facilities located in Minnesota~~ with aan ~~capacity~~estimated inproject ~~excess~~cost of 50$10 ~~MW.~~million or more.

6Advance Rate-making Principles - Wisconsin Statute §196.371 provides Wisconsin utilities with the opportunity to request rate-making principles prior to the purchase or construction of any nuclear or fossil-fueled electric generating facility or renewable generating resource, such as a wind facility, utilized to serve Wisconsin customers. WPL is not obligated to file for or accept authorized rate-making principles under Wisconsin Statute §196.371. WPL can proceed with an approved project under traditional rate-making terms or accept authorized rate-making principles under Wisconsin Statute §196.371.

~~Table~~Minnesota Public Utilities Commission (MPUC) - IPL is subject to regulation by the MPUC related to its operations in Minnesota for various matters including, but not limited to, retail utility rates and standards of ~~Contents~~service, accounting requirements, issuance and use of proceeds of securities that encumber property in Minnesota, affiliate transactions, and approval of the location and construction of electric generating facilities located in Minnesota with a capacity in excess of 50 MW.

Retail Utility Rates - Requests for retail rate ~~relief~~change can be based on either historical or projected data and interim retail rates are permitted. IPL ~~typically~~has ~~files~~historically ~~requests~~requested ~~for~~ retail rate relief based on historical test periods. The historical test periods may be adjusted for certain known and measurable capital additions placed in service by IPL and operating and maintenance expenses incurred by IPL within 12 months of the end of the test year. Unless otherwise ordered, the MPUC must reach a final decision within 10 months of filing for retail rate relief; however, the MPUC can extend the timing by 90 days.

Renewable Energy Cost Recovery Mechanism - In ~~November~~ 2011, IPL received an order from the MPUC approving the implementation of an automatic cost recovery rider on a temporary basis to recover costs associated with renewable generation. The renewable energy rider does not require a base rate case for annual revision of rates charged to IPL’s Minnesota retail electric customers, but requires that the renewable energy costs incurred be fully reconciled against the revenues collected for such costs. Initially, this would allow recovery of IPL’s Whispering Willow - East wind project located in Iowa. In ~~November~~ 2011, the MPUC deferred judgment on the prudence of the Whispering Willow - East wind project costs. The initial recovery amount of the project costs will be allowed through the temporary renewable energy rider at a levelized cost of $51 per megawatt-hour (MWh). In ~~The~~January ~~final~~2013, ~~recovery~~IPL ~~amount~~filed a request with the MPUC for full cost recovery of the Minnesota retail portion of IPL’s Whispering Willow - East wind project construction costs ~~will~~of beapproximately ~~addressed~~$30 inmillion. IPL expects to receive a ~~separate~~decision ~~proceeding~~from ~~that~~the isMPUC ~~expected~~in to2013 befor ~~completed~~the infinal ~~2012.~~recovery amount for such costs.

Refer to Notes 1(b), 1(h), 2 and 13(de) of the “Combined Notes to Consolidated Financial Statements,” and “Rate Matters,” “Environmental Matters” and “Legislative Matters” in MDA for additional information regarding regulation and utility rate matters.

4) STRATEGIC OVERVIEW - Refer to “Strategic Overview” in MDA for discussion of various strategic actions by Alliant Energy, IPL and WPL.

~~C. INFORMATION RELATING TO UTILITY OPERATIONS~~ 6

~~Alliant~~Table Energy’s utility business (IPL and WPL) has three segments: a) electric operations; b) gas operations; and c) other, which includes IPL’s steam operations, various other energy-related products and services, and the unallocated portions of ~~the utility business. In 2011, IPL’s and WPL’s operating revenues and operating income (loss) for these three utility business segments were as follows:~~ Contents

	IPL						WPL
	OperatingRevenues			OperatingIncome			OperatingRevenues			OperatingIncome (Loss)
Electric		81	%		87	%		86	%		94	%
Gas		16	%		10	%		14	%		10	%
Other		3	%		3	%		—			(4	%)
		100	%		100	%		100	%		100	%

C. INFORMATION RELATING TO UTILITY OPERATIONS

1Alliant Energy’s utility business (IPL and WPL) ~~ELECTRIC~~has ~~UTILITY~~three ~~OPERATIONS~~segments: a) electric operations; b) gas operations; and c) other, which includes IPL’s steam operations, various other energy-related products and services, and the unallocated portions of the utility business. In 2012, IPL’s and WPL’s operating revenues and operating income (loss) for these three utility business segments were as follows:

General - Electric utility operations represent the largest operating segment for Alliant Energy, IPL and WPL. Alliant Energy’s electric utility operations are located in the Midwest with IPL providing electric service in Iowa and southern Minnesota and WPL providing electric service in southern and central Wisconsin. Refer to the “Electric Operating Information” tables for additional details regarding electric utility operations.



	IPL				WPL
	Operating		Operating		Operating		Operating
	Revenues		Income		Revenues		Income (Loss)
Electric	83	%	83	%	88	%	91	%
Gas	14	%	12	%	12	%	10	%
Other	3	%	5	%	—	%	(1	%)
	100	%	100	%	100	%	100	%

~~Jurisdictions~~1) -ELECTRIC ~~Electric~~UTILITY ~~utility revenues by state were as follows (dollars in millions):~~ OPERATIONS

	2011					2010					2009
	Amount		Percent			Amount		Percent			Amount		Percent
IPL:
Iowa	$	1,327.2		50	%	$	1,386.0		52	%	$	1,242.3		50	%
Minnesota		81.1		3	%		78.3		3	%		73.3		3	%
Subtotal		1,408.3		53	%		1,464.3		55	%		1,315.6		53	%
WPL:
Wisconsin		1,227.5		47	%		1,209.9		45	%		1,160.3		47	%
	$	2,635.8		100	%	$	2,674.2		100	%	$	2,475.9		100	%

7Jurisdictions - Electric utility revenues by state were as follows (dollars in millions):



	2012				2011				2010
	Amount		Percent		Amount		Percent		Amount		Percent
IPL:
Iowa		$1,295.5	50	%		$1,327.2	50	%		$1,386.0	52	%
Minnesota	75.6		3	%	81.1		3	%	78.3		3	%
Subtotal	1,371.1		53	%	1,408.3		53	%	1,464.3		55	%
WPL:
Wisconsin	1,218.2		47	%	1,227.5		47	%	1,209.9		45	%
		$2,589.3	100	%		$2,635.8	100	%		$2,674.2	100	%

The percentage of electric utility revenues regulated by the IUB, PSCW, MPUC and FERC were as follows:

	IPL	~~IPL~~							WPL				~~WPL~~
		2011				2010			2009				2011				2010			2009
	2012			2011			2010		2012			2011			2010
IUB	92	%	90	%90	%		91	%	—	90%	%	—	%	—	—	%		—			—
PSCW	—	%	—	—	%		—	%	86	—%		85	%	85	%84	%		84	%		80	%
MPUC	5	%	6	%6	%		5	%	—	5%	%	—	%	—	—	%		—			—
FERC	3	%	4	%4	%		4	%	14	5%	%	15	%	15	%16	%		16	%		20	%
	100	%	~~100~~	%100	%		100	%	100	~~100~~%	%	100	%	~~100~~	%100	%		~~100~~	%		~~100~~	%

Customers - The number of electric customers and communities served at ~~Dec.~~ December 31, ~~2011~~2012 was as follows:

	Retail Customers	~~Retail Customers~~		Wholesale Customers	~~Wholesale Customers~~	Other Customers	~~Other~~Total Customers		Communities Served	~~Total Customers~~		~~Communities Served~~
IPL	526,841		~~525,770~~	8		91,373	528,222	~~1,372~~	752		~~527,151~~		~~752~~
WPL	458,180		~~456,637~~	21		212,245	460,446	~~2,236~~	606		~~458,894~~		~~606~~
			982,407			30		3,608			986,045		1,358
	985,021			29		3,618	988,668		1,358

IPL and WPL provide electric utility service to a diversified base of retail customers in several industries, with the largest concentrations in the food manufacturing, chemical (including ethanol) and paper industries. IPL’s retail customers in the above table are billed under base rates established by the IUB or MPUC that include recovery of and a return on investments in electric infrastructure and recovery of purchased electric capacity costs and other costs required to serve customers. Prior to 2011, electric transmission service expenses were recovered from IPL’s retail electric customers in Iowa through changes in base rates. Effective February 2011, electric transmission service expenses were removed from base rates and billed to IPL’s Iowa retail electric customers through a transmission cost rider. This new cost recovery mechanism provides for subsequent adjustments to electric rates charged to Iowa electric retail customers for changes in electric transmission service expenses. IPL’s electric production fuel and energy purchases costs are recovered pursuant to fuel adjustment clauses. WPL’s retail customers in the above table are billed under base rates established by the PSCW that include recovery of and a return on investments in electric infrastructure and recovery of electric production fuel and purchased energy costs, purchased electric capacity costs, electric transmission service costs and other costs required to serve customers. Effective Jan. 1, 2011, WPL defers electric production fuel and energy purchases costs that exceed or fall below established fuel monitoring ranges through a new electric fuel cost recovery mechanism. WPL’s recovery of deferred electric production fuel and energy purchases costs is restricted if it earns in excess of its authorized return on common equity. Refer to “Rate Matters” in MDA for discussion of a potential retail electric rate filing by WPL in 2012.

Wholesale customers in the above table, which primarily consist of municipalities and rural electric cooperatives, are billed under wholesale service agreements. These agreements include standardized pricing mechanisms that are detailed in tariffs approved by FERC through wholesale rate case proceedings. The tariffs include an annual true-up process for actual costs incurred. A significant majority of IPL’s and WPL’s wholesale service agreements have terms that end after 2017. 7

InTable ~~addition,~~of IPL and WPL have bulk power customers, included in “Other customers” in the above table, that are billed according to negotiated, long-term customer-specific contracts, pursuant to FERC-approved tariffs. Contents

~~Seasonality~~electric -capacity ~~Electric~~costs, ~~sales~~electric ~~are~~transmission ~~seasonal~~service costs and other costs required to ~~some extent~~serve ~~with~~customers. Effective ~~the~~January ~~annual~~1, ~~peak~~2011, ~~normally~~WPL ~~occurring~~defers electric production fuel and energy purchases costs that exceed or fall below established fuel monitoring ranges through a new electric fuel cost recovery mechanism. WPL’s recovery of deferred electric production fuel and energy purchases costs is restricted if it earns in ~~the~~excess ~~summer~~of ~~months~~its ~~due~~authorized toreturn ~~air~~on ~~conditioning~~common ~~requirements~~equity. Refer Into ~~2011,~~“Rate ~~the~~Matters” ~~maximum~~in ~~peak~~MDA ~~hour~~for ~~demands~~discussion ~~were~~of asrate ~~follows:~~filings by WPL in 2012.

Alliant Energy

IPL

WPL

5,734

3,131

2,761

Date

July 18

Aug. 2

July 20

~~Competition~~In ~~- Retail electric customers in Iowa~~addition, ~~Wisconsin and Minnesota currently do not have the ability to choose their electric supplier. However, IPL and~~ WPL ~~attempt~~has tobulk ~~attract~~power ~~new~~ customers, ~~into~~included ~~their service territories~~ in an“Other ~~effort~~customers” ~~to keep energy rates low for all. Although electric service~~ in ~~Iowa,~~the ~~Wisconsin~~above ~~and Minnesota is regulated~~table, ~~IPL~~that ~~and WPL~~are ~~still~~billed ~~face~~according ~~competition~~to ~~from~~negotiated, ~~self~~long-~~generation~~term bycustomer-specific ~~large industrial customers~~contracts, ~~alternative~~pursuant ~~energy sources, and petitions~~ to ~~municipalize (Iowa) as well as service territory expansions by municipal utilities through annexations (Wisconsin). Refer to “Rate Matters~~ FERC-approved ~~Other - Economic Development Program” in MDA for discussion of the PSCW’s approval of an economic development program to attract and retain industrial customers in WPL’s service territory~~tariffs.

8Seasonality - Electric sales are seasonal to some extent with the annual peak normally occurring in the summer months due to air conditioning requirements. In 2012, the maximum peak hour demands were as follows:



	Alliant Energy	IPL	WPL
MW	5,886	3,130	2,851
Date	July 25	July 25	July 5

~~Renewable~~Competition ~~Energy~~- ~~Standards~~Retail electric customers in Iowa, Wisconsin and Minnesota currently do not have the ability to choose their electric supplier. However, IPL and WPL attempt to attract new customers into their service territories in an effort to keep energy rates low for all. Although electric service in Iowa, Wisconsin and Minnesota is regulated, IPL and WPL still face competition from self-generation by large industrial customers, owners of distributed generation, alternative energy sources, and petitions to municipalize (~~RES~~Iowa) -as well as service territory expansions by municipal utilities through annexations (Wisconsin).

~~Iowa~~In -June ~~Electric~~2010, ~~utilities~~the inPSCW ~~Iowa~~issued ~~are~~an ~~required~~order toapproving ~~purchase~~an oreconomic ~~own~~development ~~their~~program ~~proportionate~~effective ~~share~~July of2010, ~~105~~which MWis ofintended ~~capacity~~to attract and ~~associated~~retain ~~energy~~industrial ~~from~~customers ~~alternate~~in WPL’s service territory. The program permits WPL to provide eligible industrial customers a discounted energy orrate ~~small~~based ~~hydro~~upon ~~facilities~~specifically-defined ~~located~~conditions in through December 2014. To be eligible for the ~~utilities’~~program, ~~service~~each ~~area.~~customer ~~IPL’s~~needs ~~proportionate~~to ~~share~~demonstrate that it is ~~approximately~~also 50eligible ~~MW.~~for Asdirect ofgovernmental ~~Dec.~~assistance 31through a local, ~~2011~~state or federal economic development program, ~~IPL~~in ~~had~~addition ~~met~~to ~~the~~other ~~requirements~~criteria. The discount amounts are limited to ensure recovery of ~~this~~marginal ~~renewable~~costs ~~energy~~and ~~standard~~will be decreased over time until a customer is paying the full tariff rate. Currently, there are three WPL customers utilizing the economic development program.

~~Wisconsin - A Wisconsin~~ Renewable ~~Portfolio~~Energy ~~Standard~~Standards (~~RPS~~RES) ~~was~~- ~~established~~As indiscussed ~~2006 that requires electric utilities~~ in ~~Wisconsin,~~greater ~~including~~detail ~~WPL~~below, ~~to increase~~ the ~~portion~~states ~~of their total Wisconsin retail electric sales supplied by renewable energy sources above a benchmark of average retail sales from renewables~~ in ~~2001,~~which ~~2002~~IPL and ~~2003.~~WPL ~~The~~operate ~~RPS~~have ~~required~~RES, awhich 2%establish ~~increase above~~ the ~~benchmark~~amount ~~by 2010 and will require a 6% increase above the benchmark by 2015. Based on this RPS, WPL was required to supply a minimum~~ of ~~5.28%~~energy ~~of its total Wisconsin retail~~ electric ~~sales with renewable energy sources by 2010 and will be required to increase this amount to 9.28% by 2015. Wisconsin~~ utilities ~~may~~ ~~reach the RPS with renewable energy generated by the utility, acquired under purchased power agreements (PPAs),~~ or ~~through~~service ~~the~~providers ~~use~~must ofsupply ~~renewable~~from ~~resource credits. WPL has met the 2010 requirements of this~~ renewable ~~energy standard and currently expects to meet the 2015 requirements of the RPS with its current wind generation and wind PPAs~~resources.

~~Minnesota~~IPL - AIPL ~~Minnesota~~allocates ~~RES~~its ~~was established~~portfolio inof ~~2007~~renewable ~~that~~energy ~~requires~~credits ~~electric~~(RECs) ~~utilities~~between ~~operating~~its inIowa and Minnesota, ~~including~~jurisdictions ~~IPL,~~based toon ~~supply~~ a ~~minimum~~load-ratio ~~level~~share. IPL ofhas ~~their~~excess ~~total~~RECs ~~Minnesota~~in ~~retail~~Iowa ~~electric~~and ~~sales~~a ~~with~~shortfall ~~renewable~~of ~~energy~~RECs ~~sources~~in ~~by certain future dates~~Minnesota. ~~Based on this RES~~ However, ~~IPL’s total~~the ~~Minnesota~~excess ~~retail~~RECs ~~electric~~in ~~sales~~Iowa ~~supplied~~are ~~with~~much ~~renewable~~larger ~~energy~~than ~~sources~~the ~~must~~Minnesota beshortfall atpartially ~~least~~due ~~12%~~to bythe ~~2012;~~relatively ~~17%~~small byamount ~~2016;~~of ~~20%~~IPL’s byload ~~2020;~~served ~~and 25% by 2025. Utilities~~ in Minnesota ~~may~~compared ~~meet~~to ~~the~~Iowa. IPL’s ~~requirements~~surplus of ~~the~~RECs ~~RES~~in ~~with~~Iowa ~~renewable~~could ~~energy~~be ~~generated~~used byto ~~the utility,~~meet ~~renewable energy acquired under PPAs or~~ the ~~use~~deficit of ~~renewable~~RECs ~~energy~~in ~~credits~~Minnesota. IPL ~~currently~~ expects to ~~satisfy~~meet ~~the~~both ~~2012~~its ~~requirements~~Iowa ofand ~~the~~Minnesota ~~RES~~renewable ~~with~~energy ~~its~~requirements ~~current~~on ~~wind~~a ~~generation~~system-wide ~~and~~basis ~~wind~~without ~~PPAs,~~the ~~and~~need ~~supplemented~~to aspurchase ~~needed~~additional ~~with renewable energy credits~~RECs.

~~Energy~~Iowa ~~Conservation~~ - IPL ~~and~~is ~~WPL~~required ~~continue~~ to ~~promote~~purchase ~~energy~~or ~~conservation,~~own ~~including~~50 ~~their~~MW ~~customers’~~of ~~ability~~capacity ~~to efficiently~~from ~~manage~~alternate ~~their~~ energy ~~use.~~or ~~Refer~~small tohydro ~~“Strategic~~facilities ~~Overview~~located ~~- Energy Efficiency Programs”~~ in ~~MDA~~its ~~for~~service ~~discussion~~area. IPL ofhas ~~current~~met ~~energy~~the ~~efficiency~~Iowa ~~programs~~requirement atthrough ~~IPL and WPL~~2012.

~~Electric~~Minnesota ~~Supply~~ - ~~Alliant~~A ~~Energy,~~Minnesota ~~IPL~~RES ~~and~~was ~~WPL~~established ~~have~~in ~~met~~2007 ~~historical~~that ~~customer~~requires ~~demand~~IPL ~~of electricity and expect~~ to ~~continue meeting future demand through internally generated electric~~ supply~~, electric~~ ~~supply~~a ~~from~~minimum ~~long-term~~level ~~PPAs~~of ~~and~~its ~~additional~~total ~~electric~~Minnesota ~~supply~~retail ~~purchases from wholesale energy markets. Alliant Energy’s mix of~~ electric ~~supply~~sales ~~experienced changes in recent years~~ with ~~WPL’s~~renewable ~~purchases~~energy ofsources ~~the~~by ~~Neenah~~certain ~~Energy~~future ~~Facility~~dates. Based ~~in 2009~~on ~~and~~this ~~Wisconsin Electric Power Company’s 25% interest in Edgewater Unit 5 in early 2011~~RES, ~~the completion of~~ IPL’s ~~Whispering~~total ~~Willow~~Minnesota -retail ~~East wind project in late 2009, the completion of WPL’s Bent Tree - Phase I wind project in early 2011, and IPL’s retirement of various~~ electric ~~generating~~sales ~~units~~supplied ~~in 2010. Alliant Energy expects its mix of electric supply to change further in the next several years~~ with ~~IPL’s~~renewable ~~potential~~energy ~~construction~~sources ofmust abe ~~new~~at ~~600~~least MW12% ~~natural~~by ~~gas-fired electric~~2012; ~~generating~~17% ~~facility~~by in2016; ~~Iowa,~~20% ~~WPL’s~~by ~~anticipated~~2020; ~~purchase of Riverside, the anticipated decision not to enter into long-term agreements related to IPL’s~~ and ~~WPL’s~~25% ~~existing~~by ~~nuclear PPAs, and the anticipated retirement of additional generating units~~2025. Utilities ~~Alliant~~in ~~Energy,~~Minnesota ~~IPL~~may ~~and WPL periodically update their generation plans to identify longer term generation needs. These long-term generation plans are intended to~~ meet ~~customer demand, reduce reliance on PPAs and wholesale market purchases and mitigate~~ the ~~impacts~~requirements of ~~future~~the ~~plant~~RES ~~retirements while maintaining compliance~~ with ~~long-term electric demand planning reserve margins, environmental requirements and~~ renewable energy ~~standards~~generated ~~established~~ by ~~regulators.~~ ~~Alliant~~the ~~Energy~~utility, ~~IPL~~renewable ~~and~~energy ~~WPL~~acquired ~~currently~~under ~~expect to meet utility customer demand in the future. However~~PPAs, ~~unanticipated regional~~ or ~~local reliability issues could still arise in~~ the ~~event~~use of ~~unexpected~~accumulated ~~delays in the construction of new generating and/~~or ~~transmission~~acquired ~~facilities, retirement of generating facilities, generating facility outages, transmission system outages or extended periods of extreme weather conditions~~RECs. IPL ~~Refer~~currently expects to ~~the~~satisfy ~~“Electric~~future ~~Operating~~Minnesota ~~Information” tables~~RES ~~for~~requirements awith ~~profile~~its ofcurrent ~~the~~wind ~~sources~~generation ofand ~~electric~~wind ~~supply~~PPAs, ~~used~~supplemented toas ~~meet~~needed ~~customer~~by ~~demand~~acquiring ~~for~~additional ~~Alliant~~RECs ~~Energy, IPL and WPL~~ from ~~2007~~its toIowa ~~2011.~~excess ~~Refer to “Strategic Overview - Generation Plans” in MDA for details of Alliant Energy’s, IPL’s and WPL’s future generation plans~~supply.

Electric Demand Planning Reserve Margin (PRM) - IPL and WPL are required to maintain a PRM above their projected annual peak demand forecast to help ensure reliability of electric service to their customers. WPL is required to maintain a 14.5% PRM for long-term planning (planning years two through 10) and a PRM established by MISO for short-term planning. PRM requirements for IPL follow MISO’s reserve requirements. IPL and WPL currently have adequate capacity to meet the MISO PRM requirements. 8

~~Generation~~Table ~~- IPL and WPL own a portfolio~~ of electric generating facilities located in Iowa, Wisconsin and Minnesota with a diversified fuel mix including coal, natural gas and renewable resources. Refer to Item 2 Properties for details of IPL’s and WPL’s electric generating stations. Contents

WPL - A Wisconsin Renewable Portfolio Standard (RPS) was established in 2006 that requires electric utilities in Wisconsin, including WPL, to increase the portion of their total Wisconsin retail electric sales supplied by renewable energy sources above a benchmark of average retail sales from renewables in 2001, 2002 and 2003. The RPS required a 2% increase above the benchmark by 2010 and will require a 6% increase above the benchmark by 2015. Based on this RPS, WPL was required to supply a minimum of 5.28% of its total Wisconsin retail electric sales with renewable energy sources by 2010 and will be required to increase this amount to 9.28% by 2015. Wisconsin utilities may reach the RPS with renewable energy generated by the utility, acquired under PPAs or through the use of renewable resource credits. WPL has met the 2010 requirements of this RPS and currently expects to meet the 2015 requirements of the RPS with its current wind generation and wind PPAs.

~~Table~~Energy Conservation - IPL and WPL continue to promote energy conservation, including their customers’ ability to efficiently manage their energy use. Refer to “Strategic Overview - Energy Efficiency Programs” in MDA for discussion of ~~Contents~~energy efficiency programs at IPL and WPL.

~~Generating~~Electric ~~Capacity~~Supply - ~~The~~Alliant ~~generating~~Energy, ~~capacity~~IPL and WPL have met historical customer demand of electricity and expect to continue meeting future demand through a mix of electric supply including internally generated electricity, PPAs and additional purchases from wholesale energy markets. Alliant Energy’s mix of electric supply experienced changes in recent years with WPL’s purchases of the Neenah Energy Facility in 2009, Wisconsin Electric Power Company’s 25% interest in Edgewater Unit 5 in early 2011 and the Riverside Energy Center (Riverside) in the fourth quarter of 2012, the completion of wind projects including IPL’s Whispering Willow - East wind project in late 2009 and WPL’s Bent Tree - Phase I wind project in early 2011, and IPL’s retirement of various electric generating ~~facilities~~ isunits. Alliant ~~based~~Energy ~~upon~~expects ~~MISO~~its mix of electric supply to change further in the next several years with IPL’s proposed construction of the Marshalltown Generating Station, the decision not to renew WPL’s existing nuclear PPA beyond its December 2013 expiration date, and the proposed retirement of additional generating units. Alliant Energy, IPL and WPL periodically update their generation plans to identify longer term electric supply resource ~~adequacy~~needs. These ~~process~~long-term generation plans are intended to meet customer demand, ~~which~~reduce ~~uses~~reliance on PPAs and wholesale market purchases and mitigate the ~~unforced~~impacts ~~capacity~~of future plant retirements while maintaining compliance with long-term electric demand planning reserve margins, environmental requirements and RES established by regulators. Alliant Energy, IPL and WPL currently expect to meet utility customer demand in the future. However, unanticipated regional or local reliability issues could still arise in the event of unexpected delays in the construction of new generating and/or transmission facilities., ~~The~~retirement of generating ~~capacity~~facilities, generating facility outages, transmission system outages or extended periods of extreme weather conditions. Refer to the “Electric Operating Information” tables for a profile of the ~~June~~sources ~~2011~~of electric supply used to ~~May~~meet customer demand for Alliant Energy, IPL and WPL from 2008 to 2012. Refer ~~planning~~to ~~period~~“Strategic byOverview ~~fuel~~- ~~type~~Generation Plans” in ~~MWs~~MDA ~~was~~for asdetails ~~follows:~~of Alliant Energy’s, IPL’s and WPL’s future generation plans.

	IPL		WPL		Total
Coal		1,392		1,332		2,724
Natural gas		779		613		1,392
Oil		277		—		277
Wind (a)		—		6		6
Hydro		—		24		24
Total		2,448		1,975		4,423

Electric Demand Planning Reserve Margin (PRM) - IPL and WPL are required to maintain a PRM above their load at the time of the MISO-wide peak to ensure reliability of electric service to their customers. The installed capacity reserve margin is 14.2% and the unforced capacity reserve margin is 6.2% for the June 1, 2013 through May 31, 2014 MISO planning year. IPL and WPL currently have adequate capacity to meet the MISO PRM requirements.

~~(a)~~Effective Asfor ofthe ~~Dec.~~June 1, 2013 through May 31, ~~2011~~2014 MISO planning year, ~~completed~~MISO ~~wind~~implemented ~~projects~~a ~~owned~~Local byResource ~~Alliant~~Zone ~~Energy~~(LRZ) ~~included~~concept. The ~~IPL’s~~purpose ~~200~~of MWthe ~~Whispering~~LRZ ~~Willow~~concept -is ~~East~~to ~~wind~~encourage ~~project~~adequate generating resources adjacent to load served by such generating resources. IPL is located in ~~Franklin~~LRZ ~~County~~No. 3, which covers the entire state of Iowa, ~~WPL’s~~and 68a MWportion ~~Cedar~~of ~~Ridge~~southern ~~wind~~Minnesota. WPL ~~project~~is located in ~~Fond~~LRZ duNo. ~~Lac County~~2, ~~Wisconsin~~which covers the southern and ~~WPL’s~~eastern ~~200~~portions MWof ~~Bent~~Wisconsin ~~Tree~~and -upper ~~Phase~~peninsula Iof ~~wind~~Michigan. Subject ~~project~~to incertain ~~Freeborn~~zonal ~~County~~transfer capacity limits, ~~Minnesota.~~load-serving ~~The~~utilities ~~amounts~~(including inIPL ~~the~~and ~~table~~WPL) ~~above~~are ~~represent~~permitted ~~0%,~~to 9%have ~~and~~generating 0%capacity located outside of their respective LRZs if they procure firm point-to-point transmission service to import the capacity offrom ~~IPL’s~~another ~~Whispering~~LRZ. If ~~Willow~~a utility chooses to import capacity from another LRZ without firm point-to-point ~~East~~transmission service, ~~WPL’s~~it ~~Cedar~~will ~~Ridge~~incur ~~and~~a ~~WPL’s~~zonal ~~Bent~~delivery ~~Tree~~charge. Neither -IPL ~~Phase~~or IWPL ~~wind~~have ~~projects,~~current ~~respectively,~~generating ~~based~~capacity ~~upon~~located ~~the~~outside ~~MISO~~of ~~resource~~their ~~adequacy~~respective ~~process,~~LRZs; ~~which~~therefore isthey ~~determined~~do ~~separately~~not ~~for~~expect ~~each~~to ~~wind~~be ~~site,~~subject ~~during~~to ~~the~~zonal ~~planning~~delivery ~~period~~charges ~~from~~during the June ~~2011~~1, to2013 through May ~~2012~~31, 2014 MISO planning year.

~~Fuel~~Generation ~~Costs~~ - ~~The~~IPL ~~average~~and ~~cost~~WPL own a portfolio of ~~delivered~~electric generating facilities located in Iowa, Wisconsin and Minnesota with a diversified fuel ~~per~~mix ~~million~~including ~~British~~coal, ~~Thermal~~natural ~~Units~~gas ~~used~~and renewable resources. Refer to Item 2 Properties for ~~electric generation~~details ~~was~~of asIPL’s ~~follows:~~and WPL’s electric generating stations.

	IPL						WPL
	2011		2010		2009		2011		2010		2009
All fuels	$	2.18	$	2.17	$	2.29	$	2.28	$	2.17	$	2.13
Coal		1.86		1.73		1.56		2.22		2.06		2.02
Natural gas (a)		7.17		9.79		13.31		6.30		12.83		18.53

Generating Capacity - The generating capacity of IPL’s and WPL’s electric generating facilities is based upon MISO’s resource adequacy process, which uses the unforced capacity of the generating facilities. The generating capacity for the June 2012 to May 2013 planning period by fuel type in MWs was as follows:

(a) The average cost of natural gas includes commodity costs as well as gains and losses from swap contracts used to hedge the price of natural gas volumes expected to be used by Alliant Energy’s natural gas-fired electric generating facilities.9

~~Coal~~Table ~~- Coal is the primary fuel source for Alliant Energy’s, IPL’s and WPL’s internally generated electric supply and generally represents approximately 50% to 55%~~ of their total sources of electric energy. Alliant Energy, through Corporate Services as agent for IPL and WPL, has entered into contracts with different suppliers to help ensure that a specified supply of coal is available at known prices for IPL’s and WPL’s coal-fired generating facilities for 2012 and 2013. As of Dec. 31, 2011, existing contracts provide for a portfolio of coal supplies that cover approximately 80% and 50% of IPL’s and WPL’s estimated coal supply needs for 2012 and 2013, respectively. Alliant Energy, IPL and WPL believe this portfolio of coal supplies represents a reasonable balance between the risks of insufficient supplies and those associated with being unable to respond to future coal market changes. Alliant Energy, IPL and WPL expect to meet remaining coal requirements from either future contracts or purchases in the spot market. Alliant Energy, through its subsidiaries Corporate Services, IPL and WPL, also enters into various coal transportation agreements to meet its coal supply requirements. As of Dec. 31, 2011, existing coal transportation agreements cover approximately 100%, 50%, 50% and 15% of IPL’s estimated coal transportation needs for 2012 through 2015, respectively, and 100%, 100%, 100% and 30% of WPL’s estimated coal transportation needs for 2012 through 2015, respectively. Contents

Nearly all of the coal utilized by IPL and WPL is from the Wyoming Powder River Basin. A majority of this coal is transported by rail-car directly from Wyoming to IPL’s and WPL’s generating stations, with the remainder transported from Wyoming to the Mississippi River by rail-car and then via barges to the final destination. As protection against interruptions in coal deliveries, IPL and WPL strive to maintain average coal inventory supply targets of 25 to 50 days for generating stations with year-round deliveries and 30 to 150 days (depending upon the time of year) for generating stations with seasonal deliveries. Actual inventory averages for 2011 were 43 days for generating stations with year-round deliveries and 103 days for generating stations with seasonal deliveries. The average days on hand were computed based on actual tons of inventory divided by estimated average daily tons burned in 2011. Alliant Energy, IPL and WPL periodically test coal from sources other than the Wyoming Powder River Basin to determine which alternative sources of coal are most compatible with their generating stations. Access to alternative sources of coal is expected to provide Alliant Energy, IPL and WPL with further protection against interruptions and lessen their dependence on their primary coal source.



	IPL	WPL	Total
Coal	1,304	1,348	2,652
Natural gas (a)	820	1,183	2,003
Oil	242	—	242
Wind (b)	—	7	7
Total	2,366	2,538	4,904

10(a) In December 2012, WPL purchased Riverside, a 600 MW natural gas-fired electric generating facility. WPL was credited 572 MW of capacity for this facility during the period from February 2013 to May 2013 based upon the MISO resource adequacy process. WPL is utilizing 497 MW of the accredited capacity from Riverside to satisfy its PRM requirements and has sold 75 MW of the accredited capacity to a third-party with a PPA.

~~Table~~(b) As of ~~Contents~~December 31, 2012, completed wind projects owned by Alliant Energy’s regulated utilities included IPL’s 200 MW Whispering Willow - East wind project in Franklin County, Iowa, WPL’s 68 MW Cedar Ridge wind project in Fond du Lac County, Wisconsin and WPL’s 200 MW Bent Tree - Phase I wind project in Freeborn County, Minnesota. The amounts in the table above represent 0%, 10% and 0% of the capacity of IPL’s Whispering Willow - East, WPL’s Cedar Ridge and WPL’s Bent Tree - Phase I wind projects, respectively, based upon the MISO resource adequacy process, which is determined separately for each wind site, during the planning period from June 2012 to May 2013.

~~Average~~Fuel ~~delivered~~Costs fossil fuel costs are expected to increase in the future due to price structures and adjustment provisions in existing coal contracts, rate structures and adjustment provisions in existing transportation contracts, fuel-~~related~~ ~~surcharges~~The ~~incorporated~~average bycost ~~transportation carriers and expected future coal and transportation market trends. Existing coal commodity contracts with terms~~ of ~~greater~~delivered ~~than~~fuel ~~one~~per ~~year~~million ~~have~~British ~~fixed~~Thermal ~~future~~Units ~~year~~used ~~prices that generally reflect recent market trends. A few of Alliant Energy’s existing coal contracts have provisions~~ for ~~price~~electric ~~adjustments should~~generation ~~specific~~was ~~indices change. Rate adjustment provisions in older transportation contracts are primarily based on changes in the Rail Cost Adjustment Factor~~ as published by the U.S. Surface Transportation Board. Rate adjustment provisions in more recent transportation contracts are based on changes in the All Inclusive Index Less Fuel as published by the Association of American Railroads. These more recent transportation contracts also contain fuel surcharges that are subject to change monthly based on changes in diesel fuel prices. Other factors that may impact coal prices for future commitments are increasing costs for supplier mineral rights, increasing costs to mine the coal and changes in various associated laws and regulations. For example, emission restrictions related to sulfur dioxide (SO2), nitrogen oxide and mercury, along with other environmental limitations on generating stations, continue to increase and will likely limit the ability to obtain, and further increase the cost of, adequate coal supplies. Factors that may impact future transportation rates include, but are not limited tofollows: the need for railroads to enhance/expand infrastructure for demand growth, corresponding investments in locomotives and the desire to improve margins on coal movements commensurate with margins on non-coal movements.

Alliant Energy, IPL and WPL believe they are reasonably insulated against coal price volatility given their current coal procurement process, the specific coal market in their primary purchase region and regulatory cost-recovery mechanisms. Alliant Energy’s coal procurement process stresses periodic purchases, staggering of contract terms, stair-stepped levels of supply going forward for multiple years and supplier diversity. Similarly, given the term lengths of its transportation agreements, Alliant Energy, IPL and WPL believes they are reasonably insulated against future higher coal transportation rates from the major railroads.



	IPL						WPL
	2012		2011		2010		2012		2011		2010
All fuels		$2.26		$2.18		$2.17		$2.26		$2.28		$2.17
Coal	1.91		1.86		1.73		2.21		2.22		2.06
Natural gas (a)	3.79		7.17		9.79		3.21		6.30		12.83

~~Natural~~(a) ~~Gas~~The -average ~~Alliant~~cost ~~Energy~~of ~~owns several~~ natural gas~~-fired~~ ~~generating~~includes ~~facilities~~commodity ~~including~~and ~~IPL’s~~transportation ~~565~~costs MWas ~~Emery~~well ~~Generating~~as ~~Station,~~gains ~~WPL’s 300~~and MWlosses ~~Neenah~~from ~~Energy~~swap ~~Facility~~ and ~~Resources’~~option ~~300~~contracts MWused ~~Sheboygan Falls Energy Facility. WPL has exclusive rights~~ to hedge the ~~output~~price of the Sheboygan Falls Energy Facility under an affiliated lease agreement. These facilities help meet customer demand for electricity generally during peak hour demands. Internally generated electric supply from natural gas~~-fired~~ ~~generating~~volumes ~~facilities~~expected ~~generally~~to ~~represents~~be ~~less~~used ~~than~~by ~~5% of~~ Alliant Energy’s, ~~IPL’s~~natural ~~and~~gas-fired ~~WPL’s~~electric ~~total~~generating ~~sources of electric energy~~facilities.

Coal - Coal is the primary fuel source for Alliant Energy’s, ~~has~~IPL’s ~~responsibility~~and toWPL’s internally generated electric supply ~~natural~~and ~~gas~~represented approximately 40% to ~~the~~50% ~~generating~~of ~~facilities~~their ittotal ~~owns~~sources asof ~~well~~electric asenergy ~~Riverside~~in 2012. Alliant Energy, ~~which~~through Corporate Services as agent for IPL and WPL, has ~~rights~~ entered into contracts with different suppliers to ~~under~~help ensure that a ~~PPA.~~specified supply of coal is available at known prices for IPL’s and WPL’s ~~has~~coal-fired ~~contracted~~generating ~~with~~facilities ~~ANR~~for ~~Pipeline~~2013 ~~(ANR)~~through to2017. As of December 31, 2012, existing contracts provide ~~firm~~for ~~pipeline~~a ~~transportation~~portfolio of 60coal supplies that cover approximately 77%,~~000~~ ~~dekatherms~~44%, ~~(Dths)~~36%, ~~per~~9% ~~day~~and 7% of IPL’s and WPL’s estimated aggregate coal supply needs for ~~Riverside~~2013 through 2017, respectively. Alliant Energy, IPL and 2WPL believe this portfolio of coal supplies represents a reasonable balance between the risks of insufficient supplies and those associated with being unable to respond to future coal market changes. Alliant Energy, IPL and WPL expect to meet remaining coal requirements from either future term contracts or purchases in the spot market. Alliant Energy, through its subsidiaries Corporate Services, IPL and WPL, also enters into various coal transportation agreements to meet its coal supply requirements. As of December ~~million~~31, ~~Dths~~2012, existing coal transportation agreements cover approximately 100%, 95% and 14% of ~~storage~~IPL’s ~~capacity~~estimated coal transportation needs for 2013 through 2015, respectively, and 100%, 100% and 31% of WPL’s ~~natural~~estimated ~~gas-fired~~coal ~~generating facilities.~~transportation needs for 2013 through 2015, respectively.

~~Wind~~Nearly all of the coal utilized by IPL and WPL is from the Wyoming Powder River Basin. A majority of this coal is transported by rail-car directly from Wyoming to IPL’s ~~200~~and MWWPL’s ~~Whispering~~generating ~~Willow~~stations, with the remainder transported from Wyoming to the Mississippi River by rail-car ~~East~~and ~~wind~~then ~~project~~via barges to the final destination. As protection against interruptions in ~~Franklin~~coal ~~County~~deliveries, ~~Iowa~~IPL ~~began~~and WPL strive to maintain average coal inventory supply targets of 25 to 55 days for generating ~~electricity~~stations ~~in 2009.~~with ~~WPL’s~~year-round 68deliveries MWand ~~Cedar~~30 ~~Ridge~~to ~~wind~~150 ~~project~~days in(depending ~~Fond~~upon duthe ~~Lac~~time ~~County,~~of ~~Wisconsin~~year) ~~began~~for generating ~~electricity~~stations inwith ~~2008~~seasonal deliveries. Actual ~~WPL’s~~inventory ~~200~~averages MWfor ~~Bent~~2012 ~~Tree~~were -54 ~~Phase~~days Ifor ~~wind~~generating ~~project~~stations inwith ~~Freeborn~~year-round ~~County,~~deliveries ~~Minnesota~~and ~~began~~114 ~~full~~days ~~generation~~for ofgenerating ~~electricity~~stations inwith ~~early 2011~~seasonal deliveries. The ~~Internally~~average ~~generated~~days ~~electric~~on ~~supply~~hand ~~from~~were ~~wind~~computed ~~facilities~~based ~~generally~~on ~~represents~~actual ~~less~~tons ~~than~~of 5%inventory ofdivided by estimated average daily tons burned. Alliant Energy’s, IPL’s and WPL’s ~~total~~periodically ~~sources~~test ofcoal ~~electric~~from ~~energy.~~sources ~~All~~other orthan ~~some of~~ the ~~renewable~~Wyoming ~~energy~~Powder ~~attributes~~River ~~associated~~Basin ~~with generation~~to ~~from~~determine ~~these~~which alternative sources ~~may~~of becoal ~~used~~are inmost ~~future~~compatible ~~years~~with their generating stations. Access to ~~comply~~alternative ~~with~~sources ~~renewable~~of ~~energy~~coal ~~standards~~is orexpected ~~other~~to ~~regulatory~~provide ~~requirements~~Alliant Energy, orIPL ~~sold~~and toWPL ~~third~~with ~~parties~~further inprotection ~~the~~against ~~form~~interruptions ofand ~~renewable~~lessen ~~energy~~their ~~credits~~dependence oron ~~other~~their ~~environmental~~primary ~~commodities.~~coal source.

~~Purchased~~Average ~~Power~~delivered -fossil ~~IPL~~fuel ~~and~~costs ~~WPL~~are ~~enter~~expected ~~into PPAs and purchase electricity from wholesale energy markets~~ to ~~meet~~increase ain ~~portion~~the offuture ~~their~~due ~~customer demand for electricity. Purchased power represented approximately 40%~~ to ~~45%~~price ofstructures ~~Alliant Energy’s, IPL’s~~ and ~~WPL’s~~adjustment ~~total~~provisions ~~sources of electric energy~~ in ~~2011.~~existing ~~IPL’s~~coal ~~most significant PPA is with NextEra Energy~~contracts, ~~Inc.~~rate ~~for~~structures ~~the purchase of energy~~ and ~~capacity~~adjustment ~~from~~provisions ~~the~~in ~~Duane~~existing ~~Arnold~~transportation ~~Energy Center (DAEC) through February 2014. IPL currently believes it is unlikely that it will enter into any long-term agreement with NextEra Energy~~contracts, Inc. for the purchase of electricity generated by DAEC beyond the current DAEC PPA term. WPL’s most significant PPAs are with Dominion Resources, Inc. for the purchase of energy and capacity from the Kewaunee Nuclear Power Plant (Kewaunee) through December 2013 and with a subsidiary of Calpine Corporation for the purchase of energy and capacity from Riverside through May 2013. WPL currently believes it is unlikely that it will enter into any longfuel-~~term~~related ~~agreement~~surcharges with Dominion Resources, Inc. for the purchase of electricity generated by Kewaunee beyond the current Kewaunee PPA term. WPL currently anticipates it will acquire Riverside in late 2012 to replace the electricity output currently obtained from Riverside beyond the current Riverside PPA term.

11 10

Table of Contents

~~Refer~~incorporated toby ~~Note~~transportation ~~1(h)~~carriers ~~for~~and ~~discussion~~expected offuture ~~IPL’s~~coal and ~~WPL~~transportation market trends. Existing coal commodity contracts with terms of greater than one year have fixed future year prices that generally reflect recent market trends. One of Alliant Energy’s ~~rate~~existing ~~recovery~~coal contracts contain provisions for price adjustments should specific indices change beyond a certain threshold. Rate adjustment provisions in older transportation contracts are primarily based on changes in the Rail Cost Adjustment Factor as published by the U.S. Surface Transportation Board. Rate adjustment provisions in more recent transportation contracts are based on changes in the All Inclusive Index Less Fuel as published by the Association of ~~electric~~American ~~production~~Railroads. These more recent transportation contracts also contain fuel ~~and purchased~~surcharges ~~energy~~that ~~costs,~~are ~~Note~~subject ~~3(a)~~to change monthly based on changes in diesel fuel prices. Other factors that may impact coal prices for ~~details~~future ~~regarding~~commitments ~~PPAs~~are ~~accounted~~increasing costs for assupplier ~~operating~~mineral ~~leases~~rights, increasing costs to mine the coal and ~~Note~~changes 13in various associated laws and regulations. For example, emission restrictions related to sulfur dioxide (aSO2), ~~for~~nitrogen ~~details~~oxide (NOx) and mercury, along with other environmental limitations on ~~IPL’s~~generating stations, continue to increase and ~~WPL’s~~will likely limit the ability to obtain, and further increase the cost of, adequate coal supplies. Factors that may impact future transportation rates include, ~~natural~~but ~~gas~~are ~~and~~not ~~other~~limited ~~purchased~~to: ~~power~~the ~~commitments~~need for railroads to enhance/expand infrastructure for demand growth, corresponding investments in ~~the~~locomotives ~~“Combined~~and ~~Notes~~crews, and the desire to ~~Consolidated~~ ~~Financial~~improve ~~Statements.”~~margins on coal movements commensurate with margins on non-coal movements.

~~Electric~~Alliant ~~Transmission~~Energy, IPL and WPL believe they are reasonably insulated against coal price volatility given their current coal procurement process, the specific coal market in their primary purchase region and regulatory cost-recovery mechanisms. Alliant Energy’s coal procurement process stresses periodic purchases, staggering of contract terms, stair-stepped levels of supply going forward for multiple years and supplier diversity. Similarly, given the term lengths of their transportation agreements, Alliant Energy, IPL and WPL believes they are reasonably insulated against future higher coal transportation rates from the major railroads.

~~IPL~~Natural Gas - ~~IPL~~Alliant ~~completed~~Energy ~~the~~owns ~~sale~~several ofnatural ~~its~~gas-fired ~~electric~~generating ~~transmission~~facilities ~~assets~~including ~~located in Iowa, Minnesota and Illinois to ITC in 2007.~~ IPL’s ~~sold~~565 ~~its~~MW ~~electric~~Emery ~~transmission~~Generating ~~assets~~Station, inWPL’s ~~order~~300 toMW ~~monetize~~Neenah ~~the~~Energy ~~value of the assets to help fund future capital expenditures~~Facility, toWPL’s ~~capture~~600 ~~tax~~MW ~~benefits~~Riverside ~~under~~Generating ~~federal~~Station ~~tax~~and ~~policy~~Resources’ ~~that~~300 ~~allowed~~MW ~~deferral~~Sheboygan ofFalls ~~gains~~Energy onFacility. WPL ~~sales~~has ofexclusive ~~qualifying~~rights ~~electric transmission assets completed prior~~ to ~~Jan. 1, 2008 (based on regulations at~~ the ~~time~~ output of the ~~sale)~~Sheboygan ~~and~~Falls toEnergy ~~promote~~Facility ~~regional~~under ~~transmission~~an ~~expansion~~affiliated ~~that~~lease isagreement. These ~~expected~~facilities tohelp ~~improve~~meet ~~transmission~~customer ~~reliability~~demand ~~and~~for ~~access~~electricity ~~for~~generally ~~its~~during ~~customers~~peak inhour ~~Iowa~~demands and ~~Minnesota.~~when ~~ITC~~natural isgas anprices ~~independent~~are ~~for-profit,~~low ~~transmission-only~~enough ~~company~~to ~~and~~make isnatural ~~a transmission~~gas-~~owning~~fired ~~member~~generation ofeconomical ~~the~~compared ~~MISO~~to ~~RTO,~~other ~~MRO~~fuel ~~and Reliability First Corporation Regional Entities~~sources. Internally ~~ITC~~generated ~~has~~electric ~~transmission~~supply ~~interconnections~~from atnatural ~~various~~gas-fired ~~locations~~generating ~~with~~facilities ~~other~~represented ~~transmission~~less ~~owning~~than ~~utilities~~5% into ~~the~~10% ~~Midwest. These interconnections enhance the overall reliability~~ of ~~the~~Alliant Energy’s, IPL’s ~~delivery system~~ and ~~provide~~WPL’s ~~access~~total ~~to multiple~~ sources of ~~economic~~electric ~~and emergency~~ energy. ~~IPL~~in ~~currently receives substantially all its transmission services from ITC~~2012. Alliant ~~The~~Energy ~~annual~~manages ~~transmission~~the ~~service~~gas ~~rates~~supply ~~that~~to ~~ITC charge~~these ~~its~~gas-fired ~~customers~~generating isfacilities ~~calculated~~and ~~each~~provides ~~calendar~~supply ~~year~~through ~~using~~ a ~~FERC-approved~~combination ~~cost~~ of ~~service formula rate template referred to as Attachment “O.” Refer to “Other Matters~~ third-party ~~Other~~deliveries ~~Future~~and ~~Considerations~~pipeline -transportation ~~Electric~~and ~~Transmission~~storage ~~Service Charges”~~contracts inheld ~~MDA~~by ~~for additional information regarding transmission service charges from ITC. Refer to “Rate Matters - Recent Retail Base Rate Filings -~~ IPL’s ~~Iowa~~and ~~Retail Electric Rate Case (2009 Test Year)” for discussion of a new transmission cost rider for recovery of electric transmission service expenses approved by the IUB in January 2011~~WPL.

~~WPL~~Wind - ~~WPL transferred~~IPL’s ~~its~~200 ~~transmission~~MW ~~assets~~Whispering toWillow ~~ATC~~- inEast ~~2001~~wind inproject ~~exchange for an ownership interest~~ in ~~ATC.~~Franklin ~~As of Dec. 31~~County, ~~2011,~~Iowa ~~WPL~~began ~~held~~generating aelectricity ~~16% ownership interest~~ in ~~ATC with a carrying value of $239 million~~2009. WPL’s ~~currently~~68 ~~anticipates~~MW ~~making~~Cedar ~~capital contributions~~Ridge ofwind $7project ~~million, $4 million and $2 million to ATC~~ in ~~2012,~~Fond ~~2013~~du ~~and~~Lac ~~2014~~County, ~~respectively,~~Wisconsin tobegan ~~maintain~~generating ~~its~~electricity ~~current~~in ~~ownership percentage~~2008. ~~During 2011, ATC distributed to~~ WPL~~, in the form of dividends, $31 million or approximately 82% of WPL~~’s ~~equity~~200 ~~earnings~~MW ~~from~~Bent ~~ATC.~~Tree ~~Although~~- noPhase ~~assurance~~I ~~can~~wind beproject ~~given,~~in ~~WPL~~Freeborn ~~anticipates~~County, ~~ATC~~Minnesota ~~will~~began ~~continue~~full ageneration ~~dividend~~of ~~payout~~electricity ~~ratio close to this level~~ in ~~the~~early ~~future~~2011. Internally ~~ATC~~generated iselectric ansupply ~~independent~~from ~~for-profit,~~wind ~~transmission-only~~facilities ~~company~~represented ~~and~~less isthan ~~a transmission-owning~~5% ~~member~~ of ~~the~~Alliant ~~MISO RTO~~Energy’s, ~~MRO~~IPL’s and ~~Reliability~~WPL’s ~~First~~total ~~Corporation~~sources ~~Regional~~of ~~Entities.~~electric ~~ATC~~energy ~~has transmission interconnections with various other transmission owning utilities~~ in ~~the Midwest~~2012. All ~~These~~or ~~interconnections~~some ~~enhance the overall reliability~~ of the ~~WPL~~renewable ~~delivery~~energy ~~system~~attributes ~~and~~associated ~~provide~~with ~~access~~generation tofrom ~~multiple~~these sources ofmay ~~economic~~be ~~and~~used ~~emergency~~in ~~energy.~~future ~~WPL~~years ~~currently~~to ~~receives~~comply ~~substantially~~with ~~all~~RES ~~its~~or ~~transmission~~other ~~services~~regulatory ~~from~~requirements, ~~ATC.~~or ~~Refer~~sold to ~~Note~~third 21parties ofin the ~~“Combined~~form ~~Notes to Consolidated Financial Statements” for details~~ of ~~agreements~~RECs ~~between~~or ~~ATC~~other ~~and~~environmental ~~WPL~~commodities.

~~MISO~~Purchased ~~Markets~~Power - IPL and WPL ~~are~~periodically ~~members~~enter ofinto ~~MISO,~~PPAs ~~a FERC-approved~~and ~~RTO,~~purchase ~~which~~electricity isfrom ~~responsible~~wholesale ~~for~~energy ~~monitoring~~markets ~~and~~to ~~ensuring~~meet ~~equal~~a ~~access~~portion toof ~~the~~their ~~transmission~~customer ~~system~~demand infor ~~their~~electricity. Purchased ~~service~~power ~~territories.~~represented approximately 40% to 45% of Alliant Energy’s, IPL’s and WPL’s ~~participate~~total insources ~~the~~of ~~wholesale~~electric energy ~~and~~in ~~ancillary~~2012. IPL’s ~~services~~most ~~markets~~significant ~~operated~~PPA byis ~~MISO,~~with ~~which~~NER ~~are discussed~~for inthe ~~more~~purchase ~~detail~~of ~~below.~~energy ~~IPL~~ and ~~WPL~~capacity ~~are~~from ~~parties~~the toDuane aArnold ~~system~~Energy ~~coordination~~Center ~~and~~(DAEC) ~~operating~~through ~~agreement~~February ~~whereby~~2014. In ~~Corporate~~January ~~Services~~2013, ~~serves~~the asIUB ~~agent~~issued onan ~~behalf~~order ofallowing IPL ~~and~~to ~~WPL.~~proceed ~~The~~with ~~agreement~~a proposed DAEC PPA, which ~~has~~will ~~been~~provide ~~approved~~IPL or431 ~~reviewed~~MWs byof ~~FERC~~capacity and ~~all~~the ~~state regulatory~~resulting ~~bodies~~energy ~~having~~from ~~jurisdiction,~~DAEC ~~provides~~for a ~~contractual~~term ~~basis~~from ~~for~~the ~~coordinated~~expiration ~~planning,~~of ~~construction,~~the ~~operation~~existing ~~and~~PPA ~~maintenance~~in ofFebruary ~~the~~2014 ~~interconnected~~through ~~electric~~December ~~generation~~31, ~~systems~~2025. WPL’s ofmost ~~IPL~~significant ~~and~~PPA ~~WPL.~~is Aswith ~~agent~~Dominion ofResources, ~~the~~Inc. ~~agreement,~~(Dominion) ~~Corporate~~for ~~Services enters~~the ~~into~~purchase of energy, and capacity, ~~ancillary~~from ~~services,~~the ~~and~~Kewaunee ~~transmission~~Nuclear ~~service~~Power ~~sale~~Plant ~~and~~(Kewaunee) ~~purchase~~through ~~transactions~~December 2013. In ~~Corporate~~October ~~Services~~2012, ~~allocates~~Dominion ~~such~~announced ~~sales~~plans ~~and~~to ~~purchases~~shut ~~among~~down ~~IPL~~Kewaunee ~~and~~in the second quarter of 2013. WPL ~~based~~currently onexpects ~~information~~that ~~provided~~Dominion bywill ~~MISO~~provide WPL replacement energy and ~~procedures~~capacity ~~included~~under inthe terms of the ~~agreement.~~ ~~Refer~~Kewaunee toPPA ~~Note~~after 21the plant is shut down through the end of the ~~“Combined~~PPA ~~Notes~~term toin ~~Consolidated~~December ~~Financial~~2013. As ~~Statements”~~a ~~for~~result, ~~additional~~WPL ~~discussion~~currently ofexpects ~~these~~no ~~allocated~~material ~~amounts.~~changes to the expected energy and capacity payments under the PPA.

~~Wholesale~~Refer Energy Market - IPL and WPL began participation in the wholesale energy market operated by MISO in 2005. The market impacts the way IPL and WPL buy and sell wholesale electricity, obtain transmission services, schedule generation and ensure resource adequacy to ~~reliably~~Note ~~serve~~1(h) ~~load. In the market, IPL and WPL submit day-ahead and/or real-time bids and offers~~ for ~~energy~~discussion atof ~~locations across the MISO region. MISO evaluates~~ IPL’s~~, WPL’s~~ and ~~other market participants~~WPL’s ~~offers,~~rate ~~bids~~recovery ~~and~~of ~~energy~~electric ~~injections~~production ~~into,~~fuel and ~~withdrawals~~purchased ~~from,~~energy ~~the system to economically dispatch the entire MISO system on an hourly basis. MISO settles these hourly offers and bids based on locational marginal prices~~costs, ~~which~~Note ~~are~~3(a) ~~market-driven~~for ~~values~~details ~~based~~regarding onPPAs ~~the~~accounted ~~specific~~for ~~time~~as ~~and~~operating ~~location~~leases ~~of the purchase~~ and~~/or~~ ~~sale~~Note of13(b) ~~energy.~~for ~~The~~details market is intended to send price signals to stakeholders about where generation or transmission system expansion is needed. This market-based approach is expected to result in lower overall costs in areas with abundant transmission capacity. In addition, MISO may dispatch generators that support reliability needs, but that would not have operated based on ~~economic needs. In these cases, MISO~~IPL’s ~~settlement assures that these generators are made whole financially for their variable costs. IPL~~ and WPL ~~also periodically engage in related transactions in PJM~~’s ~~bid/offer-based~~coal, ~~wholesale energy~~natural ~~market,~~gas ~~which~~and ~~are~~other ~~accounted~~purchased ~~for~~power commitments in athe ~~similar~~“Combined ~~manner~~Notes asto ~~the~~Consolidated ~~MISO~~Financial ~~transactions~~Statements. ”

12 11

Table of Contents

~~Financial~~Electric Transmission ~~Rights (FTRs) and Auction Revenue Rights (ARRs)~~ - In areas of constrained transmission capacity, costs could be higher due to congestion and their impact on locational marginal prices. As part of the MISO market restructuring in 2005, physical transmission rights of IPL and WPL were replaced with FTRs. FTRs provide a hedge for congestion costs that occur in the MISO day-ahead energy market. Both IPL and WPL are allocated ARRs from MISO each year based on historical use of the transmission system. The revenue rights associated with these ARRs are used by IPL and WPL to acquire FTRs through the FTR auctions operated by MISO. IPL’s and WPL’s current FTRs acquired from ARRs extend through May 31, 2012. MISO re-allocates ARRs annually based on a fiscal year from June 1 through May 31. Based on the FTRs awarded to IPL and WPL to-date and future expected allocations of ARRs, along with the expected regulatory recovery treatment of MISO costs, the financial impacts associated with FTRs have not differed significantly from the financial impacts associated with physical transmission rights that existed prior to the MISO wholesale energy market.

~~Ancillary~~IPL ~~Services Market~~ - InIPL ~~2009,~~completed ~~MISO~~the ~~launched~~sale anof ~~ancillary~~its ~~services~~electric ~~market~~transmission assets located in Iowa, ~~which~~Minnesota ~~integrates~~and ~~the~~Illinois ~~procurement~~to ITC in 2007. ITC is an independent for-profit, transmission-only company and ~~use~~is a transmission-owning member of ~~regulation~~the MISO RTO, MRO and ~~contingency~~Reliability ~~reserves~~First ~~with~~Corporation ~~the~~Regional ~~existing~~Entities. IPL ~~wholesale~~currently ~~energy~~receives ~~market~~substantially ~~implemented~~all inits ~~2005~~transmission services from ITC. The ~~Regulation~~annual ~~reserves~~transmission ~~refer~~service torates ~~generation available~~that toITC ~~meet~~charges ~~the~~its ~~moment~~customers is calculated each calendar year using a FERC-~~to-moment~~approved ~~changes~~cost inof ~~generation~~service ~~that~~formula ~~are~~rate ~~necessary~~template referred to ~~meet~~as ~~changes~~Attachment in“O.” Refer ~~electricity~~to ~~demand.~~“Other ~~Contingency~~Future ~~reserves~~Considerations ~~refer~~- toElectric Transmission Service Charges” in MDA for additional ~~generation~~information orregarding ~~demand~~transmission ~~response~~service ~~resources,~~charges ~~either~~from onITC. Refer to “Rate Matters -~~line~~ orRecent ~~that~~Retail ~~can~~Base beRate ~~brought~~Filings on-~~line within~~ 10IPL’s ~~minutes,~~Iowa toRetail ~~meet~~Electric ~~certain~~Rate ~~major~~Case ~~events~~(2009 ~~such~~Test asYear)” ~~the~~in ~~loss~~MDA for discussion of a ~~large~~transmission ~~generating~~cost ~~unit~~rider orapproved by the IUB in January 2011 for recovery of IPL’s electric transmission ~~line.~~service expenses.

~~MISO~~WPL ~~and~~- ~~PJM~~WPL ~~Market~~transferred ~~Flow Corrections~~its -transmission Inassets ~~2009,~~to ~~MISO~~ATC ~~and~~in ~~PJM~~2001 ~~disclosed~~in exchange for an ~~error~~ownership interest in ~~the~~ATC. As ~~calculation~~ of ~~market~~December 31, ~~flow~~2012, ~~data~~WPL ~~between~~held ~~the~~a ~~two~~16% ~~independent~~ownership ~~system~~interest ~~operators~~in ~~that~~ATC ~~began~~with ina ~~2005.~~carrying ~~The~~value ~~error~~of ~~resulted~~$257 million. WPL’s investment in ~~incorrect~~ATC ~~payments~~generated ~~between~~equity ~~MISO~~income ~~and~~of ~~PJM~~$41 ~~during~~million ~~2005~~in ~~through 2009.~~2012 ~~Because~~for ~~IPL~~Alliant Energy and WPL. During ~~participated~~2012, inATC ~~both~~distributed to WPL, in the ~~MISO~~form ~~and~~of ~~PJM~~dividends, ~~markets~~$33 ~~during~~million ~~the~~or ~~period~~approximately 80% of ~~the~~WPL’s ~~error,~~equity ~~IPL~~earnings ~~and~~from ~~WPL~~ATC. Although ~~may~~no ~~have~~assurance ~~been~~can ~~entitled~~be togiven, ~~refunds~~WPL oranticipates ~~may~~ATC ~~have~~will ~~been~~continue ~~required~~a todividend ~~make~~payout ~~additional~~ratio ~~payments~~close to ~~MISO~~this ~~and/or~~level ~~PJM~~in the future. WPL Incurrently ~~2010,~~anticipates ~~MISO~~making ~~and~~capital ~~PJM filed~~contributions ~~complaints~~of ~~against~~$4 ~~each~~million, ~~other~~$2 ~~with~~million ~~FERC.~~and In$20 ~~January~~million ~~2011,~~to ~~MISO~~ATC ~~and~~in ~~PJM~~2013, ~~filed~~2014 aand ~~settlement~~2015, ~~which~~respectively, ~~was~~to ~~approved~~maintain byits ~~FERC~~current inownership ~~June~~percentage ~~2011.~~and ~~Under~~help ~~the~~fund ~~settlement,~~future ~~payments~~proposed ~~were~~transmission ~~not~~projects These ~~exchanged~~future ~~between~~proposed ~~MISO~~transmission ~~and~~projects ~~PJM,~~require ~~resulting~~approval infrom novarious ~~direct~~regulatory ~~financial~~agencies ~~impact~~ to ~~Alliant~~construct. Certain ~~Energy,~~of ~~IPL~~these orfuture ~~WPL.~~proposed ~~Instead,~~transmission ~~process~~projects ~~changes~~are ~~were~~currently ~~established,~~being ~~including~~challenged aby ~~baseline~~other ~~review~~utilities ofand ~~market~~other transmission-~~to-market~~only ~~processes~~companies ~~and~~who ~~accounting,~~have ~~establishment~~requested ofto own a ~~change~~portion ~~management~~of ~~process~~the ~~regarding~~future ~~the~~transmission ~~same~~projects ~~biennial~~proposed ~~review~~by ofATC. Alliant ~~process~~Energy ~~changes,~~ and ~~enhanced~~WPL ~~access~~are tocurrently ~~pertinent~~unable ~~data~~to ~~enabling~~determine ~~independent~~the ~~verification~~impact ofthese ~~calculations~~challenges ~~related~~may tohave ~~settlements.~~on ~~Future~~ATC’s ~~market-~~plans to~~-market~~ ~~billing~~construct ~~adjustment~~these ~~claims~~proposed ~~are~~transmission ~~limited~~projects toand ~~one~~the ~~year~~resulting ~~before~~impact ~~the~~on ~~error~~their isfuture ~~discovered~~capital ~~compared~~contributions to ~~the~~ATC ~~previous two-year~~and ~~limitation.~~equity earnings income and dividends received from ATC.

~~Electric~~ATC ~~Environmental~~is ~~Matters~~an -independent ~~Alliant Energy~~for-profit, ~~IPL~~transmission-only ~~and~~company ~~WPL are subject to extensive environmental laws~~ and ~~regulations~~is at a ~~federal,~~transmission-owning ~~state~~member ~~and local level relating to the protection~~ of the ~~environment~~MISO ~~and~~RTO, ~~health~~MRO and ~~safety~~Reliability ~~matters,~~First ~~including~~Corporation ~~those~~Regional ~~governing~~Entities. ATC ~~air~~has ~~emissions;~~transmission ~~water~~interconnections ~~discharges;~~with ~~the~~various ~~management,~~other ~~storage~~transmission ~~and~~owning ~~disposal~~utilities ofin ~~hazardous materials and~~ the ~~clean-up of contaminated sites~~Midwest. These ~~The~~interconnections ~~laws~~enhance ~~impacting Alliant Energy’s, IPL’s and WPL’s electric operations include, but are not limited to,~~ the ~~Safe~~overall ~~Drinking~~reliability ~~Water Act; Clean Water Act; Clean Air Act; National Environmental Policy Act~~ of ~~1969; Toxic Substances Control Act; Resource Conservation and Recovery Act; Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended by~~ the ~~Superfund~~WPL ~~Amendments~~delivery ~~and~~system ~~Reauthorization Act~~ and ~~Emergency Planning~~provide ~~and~~access ~~Community Right-~~to~~-Know~~ ~~Act~~multiple ofsources 1986; Endangered Species Act; Occupational Safety and Health Act; National Energy Policy Act, as amended; Federal Insecticide, Fungicide and Rodenticide Act; Hazardous Materials Transportation Act; Pollution Prevention Act; and Department of ~~Homeland~~economic ~~Security Appropriations Act, as well as similar state laws,~~ and ~~regulations~~emergency ~~promulgated thereunder~~energy. ~~Alliant Energy, IPL and~~ WPL ~~regularly~~currently ~~obtain~~receives ~~federal,~~substantially ~~state~~all ~~and~~its ~~local~~transmission ~~permits~~services tofrom ~~assure compliance with environmental protection laws and regulations~~ATC. The ~~Costs~~annual ~~associated~~transmission ~~with~~service ~~such~~rates ~~compliance~~that ~~have~~ATC ~~increased~~charges inits ~~recent~~customers ~~years and~~ are ~~expected~~calculated toeach ~~continue~~calendar toyear ~~increase~~using ina ~~the~~FERC-approved ~~future.~~cost ~~Alliant~~of ~~Energy,~~service ~~IPL~~formula ~~and WPL anticipate that prudently incurred compliance and remediation costs for IPL and WPL will be recoverable, in whole or part, through future~~ rate ~~case~~template ~~proceedings.~~referred ~~Refer~~ to ~~“Environmental~~as ~~Matters”~~Attachment ~~in MDA and Note 13(d) of the~~ “Combined Notes to Consolidated Financial Statements” for further discussion of electric environmental matters, including current or proposed environmental regulations under the Clean Air Interstate Rule, Cross-State Air Pollution Rule, Clean Air Visibility Rule, Utility Maximum Achievable Control Technology (MACT) Rule, Wisconsin State Mercury Rule, Wisconsin Reasonably Available Control Technology Rule, Industrial Boiler and Process Heater MACT Rule, Ozone National Ambient Air Quality Standard (NAAQS) Rule, Fine Particle NAAQS Rule, Nitrogen Dioxide NAAQS Rule, SO2 NAAQS Rule, Federal Clean Water Act including Section 316(b), Wisconsin and Iowa State Thermal Rules, Hydroelectric Fish Passages and Fish Protective Devices, Coal Combustion Residuals, Closed Ash Landfills, Polychlorinated Biphenyls and various legislation and EPA regulations to monitor and regulate the emission of Greenhouse Gases (GHG) including the Mandatory GHG Reporting Rule, the New Source Performance Standard for GHG Emissions from Electric Utilities and the GHG Tailoring RuleO. ” Refer to “~~Strategic~~Other ~~Overview~~Future Considerations - ~~Environmental~~Electric ~~Compliance~~Transmission ~~Plans~~Service Charges” in MDA for ~~details~~additional ofinformation ~~Alliant~~regarding ~~Energy’s,~~transmission ~~IPL’s~~service ~~and~~charges ~~WPL’s~~from ~~future environmental compliance plans to adhere to applicable environmental requirements~~ATC.

13In 2011, Duke Energy Corporation and ATC announced the creation of Duke-American Transmission Co. (DATC), a joint venture that is expected to build, own and operate new electric transmission infrastructure in North America. In 2011, DATC announced its first set of transmission projects, which include seven new transmission lines in five Midwestern states to be constructed over the next 10 years for an aggregate cost of approximately $4 billion. These transmission projects are subject to approval by various regulatory agencies. Alliant Energy and WPL are currently unable to determine what impacts the joint venture and transmission line projects noted above, if constructed, will have on their future equity income, distributions from ATC, capital contributions to ATC, or ownership in ATC.

~~Table~~Refer to Note 19 of ~~Contents~~the “Combined Notes to Consolidated Financial Statements” for details of agreements between ATC and WPL.

~~Alliant~~MISO ~~Energy~~Markets ~~Corporation~~- IPL and WPL are members of MISO, a FERC-approved RTO, which is responsible for monitoring and ensuring equal access to the transmission system in their service territories. IPL and WPL participate in the wholesale energy and ancillary services markets operated by MISO, which are discussed in more detail below. IPL and WPL are parties to a system coordination and operating agreement whereby Corporate Services serves as agent on behalf of IPL and WPL. The agreement, which has been approved or reviewed by FERC and all state regulatory bodies having jurisdiction, provides a contractual basis for coordinated planning, construction, operation and maintenance of the interconnected electric generation systems of IPL and WPL. As agent of the agreement, Corporate Services enters into energy, capacity, ancillary services, and transmission service sale and purchase transactions. Corporate Services allocates such sales and purchases among IPL and WPL based on information provided by MISO and procedures included in the agreement. Refer to Note 19 of the “Combined Notes to Consolidated Financial Statements” for additional discussion of these allocated amounts.

Electric Operating Information	2011		2010		2009		2008		2007
Operating Revenues (in millions):
Residential	$	985.8	$	1,001.5	$	868.6	$	844.7	$	847.5
Commercial		612.1		619.0		556.8		537.5		535.2
Industrial		748.9		762.8		710.7		734.7		731.9
Retail subtotal		2,346.8		2,383.3		2,136.1		2,116.9		2,114.6
Sales for resale:
Wholesale		189.8		196.8		190.1		201.9		179.8
Bulk power and other		52.2		44.1		98.3		31.1		56.7
Other (includes wheeling)		47.0		50.0		51.4		61.4		59.7
Total	$	2,635.8	$	2,674.2	$	2,475.9	$	2,411.3	$	2,410.8
Electric Sales (000s MWh):
Residential		7,740		7,836		7,532		7,664		7,753
Commercial		6,253		6,219		6,108		6,181		6,222
Industrial		11,504		11,213		10,948		12,490		12,692
Retail subtotal		25,497		25,268		24,588		26,335		26,667
Sales for resale:
Wholesale		3,372		3,325		3,251		3,813		3,547
Bulk power and other		1,757		1,378		2,583		983		2,550
Other		151		153		155		164		167
Total		30,777		30,124		30,577		31,295		32,931
Customers (End of Period):
Residential		842,780		841,726		840,927		840,644		840,122
Commercial		136,732		135,832		135,099		134,536		134,235
Industrial		2,895		2,875		2,881		2,934		2,964
Other		3,638		3,632		3,555		3,534		3,529
Total		986,045		984,065		982,462		981,648		980,850
Other Selected Electric Data:
Maximum peak hour demand (MW)		5,734		5,425		5,491		5,491		5,751
Cooling degree days (a):
Cedar Rapids, Iowa (IPL) (normal - 736)		887		923		406		583		846
Madison, Wisconsin (WPL) (normal - 614)		814		829		368		538		781
Sources of electric energy (000s MWh):
Coal		16,440		16,366		15,321		17,495		18,643
Purchased power:
Nuclear		5,483		5,667		5,428		5,465		5,103
Other (b)		7,529		7,514		9,542		7,866		8,298
Gas		588		633		661		1,037		1,894
Other (b)		1,413		820		402		245		309
Total		31,453		31,000		31,354		32,108		34,247
Revenue per kilowatt-hour (KWh) sold to retail customers (cents)		9.20		9.43		8.69		8.04		7.93

Wholesale Energy Market - IPL and WPL began participation in the wholesale energy market operated by MISO in 2005. The market dictates the process by which IPL and WPL buy and sell wholesale electricity, obtain transmission services, schedule generation and ensure resource adequacy to reliably serve load. In the market, IPL and WPL submit day-ahead and/

(a) Cooling degree days are calculated using a simple average of the high and low temperatures each day compared to a 65 degree base. Normal degree days are calculated using a rolling 20-year average of historical cooling degree days.12

~~(b)~~Table ~~All or some~~ of the renewable energy attributes associated with generation from these sources may be used in future years to comply with renewable energy standards or other regulatory requirements, or sold to third parties in the form of renewable energy credits or other environmental commodities.Contents

14or real-time bids and offers for energy. MISO evaluates IPL’s, WPL’s and other market participants’ offers, bids and energy injections into, and withdrawals from, the system to economically dispatch the entire MISO system on an hourly basis. MISO settles these hourly offers and bids based on locational marginal prices, which are market-driven values based on the specific time and location of the purchase and/or sale of energy. The market is intended to send price signals to stakeholders about where generation or transmission system expansion is needed. In addition, MISO may dispatch generators that support reliability needs, but that would not have operated based on economic needs. In these cases, MISO’s settlement assures that these generators are made whole financially for their variable costs. IPL and WPL also periodically engage in related transactions in PJM’s bid/offer-based wholesale energy market, which are accounted for in a similar manner as the MISO transactions.

~~Table~~Financial Transmission Rights (FTRs) and Auction Revenue Rights (ARRs) - In areas of ~~Contents~~constrained transmission capacity, costs could be higher due to congestion and its impact on locational marginal prices. As part of the MISO market restructuring in 2005, physical transmission rights of IPL and WPL were replaced with FTRs. FTRs provide a hedge for congestion costs that occur in the MISO day-ahead energy market. MISO allocates ARRs to IPL and WPL each year based on historical use of the transmission system. The revenue rights associated with the allocated ARRs are used by IPL and WPL to acquire FTRs through the FTR auctions operated by MISO. MISO allocates ARRs annually based on a fiscal year from June 1 through May 31. IPL’s and WPL’s current FTRs acquired from ARRs extend through May 31, 2013.

~~Interstate~~Ancillary ~~Power~~Services Market - IPL and ~~Light~~WPL ~~Company~~began participating in MISO’s ancillary services market that was launched in 2009. The ancillary services market integrates the procurement and use of regulation and contingency reserves with the existing wholesale energy market implemented in 2005. Regulation reserves refer to generation available to meet the moment-to-moment changes in generation that are necessary to meet changes in electricity demand. Contingency reserves refer to additional generation or demand response resources, either on-line or that can be brought on-line within 10 minutes, to meet certain major events such as the loss of a large generating unit or transmission line.

Electric Operating Information	2011		2010		2009		2008		2007
Operating Revenues (in millions):
Residential	$	543.2	$	561.9	$	478.9	$	455.2	$	451.2
Commercial		366.0		378.7		336.8		319.4		316.2
Industrial		415.4		441.9		412.5		407.0		402.0
Retail subtotal		1,324.6		1,382.5		1,228.2		1,181.6		1,169.4
Sales for resale:
Wholesale		29.6		29.8		23.5		23.4		21.3
Bulk power and other		24.6		23.5		37.3		21.1		42.2
Other (includes wheeling)		29.5		28.5		26.6		32.2		37.2
Total	$	1,408.3	$	1,464.3	$	1,315.6	$	1,258.3	$	1,270.1
Electric Sales (000s MWh):
Residential		4,223		4,295		4,113		4,218		4,204
Commercial		3,953		3,944		3,851		3,911		3,912
Industrial		7,080		6,961		6,829		7,742		7,750
Retail subtotal		15,256		15,200		14,793		15,871		15,866
Sales for resale:
Wholesale		417		425		403		449		406
Bulk power and other		729		683		901		682		1,581
Other		84		83		84		90		93
Total		16,486		16,391		16,181		17,092		17,946
Customers (End of Period):
Residential		443,358		443,694		443,615		443,589		444,974
Commercial		80,506		80,063		79,805		79,508		79,473
Industrial		1,906		1,900		1,914		1,939		1,954
Other		1,381		1,366		1,376		1,381		1,398
Total		527,151		527,023		526,710		526,417		527,799
Other Selected Electric Data:
Maximum peak hour demand (MW)		3,131		2,963		2,981		2,943		3,085
Cooling degree days (a):
Cedar Rapids, Iowa (normal - 736)		887		923		406		583		846
Sources of electric energy (000s MWh):
Coal		8,456		8,663		8,162		9,517		10,547
Purchased power:
Nuclear		3,624		3,623		3,577		3,619		3,066
Other (b)		3,755		3,620		4,315		3,154		3,101
Gas		532		578		636		983		1,778
Other (b)		586		375		58		23		127
Total		16,953		16,859		16,748		17,296		18,619
Revenue per KWh sold to retail customers (cents)		8.68		9.10		8.30		7.45		7.37

Multi-Value Projects (MVPs) - MISO tariffs billed to IPL and WPL include costs related to various shared transmission projects including MVPs. MVPs include new large scale transmission projects that enable the reliable and economic delivery of energy in support of documented energy policy mandates, reduce market congestion or provide economic value across multiple pricing zones within MISO. MVP costs are socialized across the entire MISO footprint based on energy usage of each MISO participant. MISO tariffs billed to IPL and WPL also include costs related to other shared transmission projects, including projects designed to reduce market congestion, provide interconnection service to the transmission grid for new generation, and to ensure compliance with applicable standards. The costs of these projects are allocated to MISO participants in a way that is commensurate with the benefit to the participants’ pricing zone. The MISO transmission charges billed to IPL and WPL are expected to increase in the future due to the increased number of shared transmission projects occurring in the MISO region.

Attachment Y Notices and System Support Resources (aSSR) ~~Cooling~~- ~~degree~~MISO ~~days~~requires ~~are~~its ~~calculated~~market ~~using~~participants (including IPL and WPL, among others) who own electric generating facilities to submit an Attachment Y Notice if they plan to retire a ~~simple~~facility ~~average~~or suspend operations of a facility for a period longer than two months. Pursuant to receiving an Attachment Y Notice, MISO will conduct a study to determine whether all or a portion of the ~~high~~facility’s ~~and~~capacity ~~low~~is ~~temperatures~~necessary to maintain system reliability. If the facility’s capacity is determined to be necessary to maintain system reliability, MISO designates the facility as an SSR. If the facility’s owner accepts the SSR designation, the facility’s owner negotiates with MISO an annual revenue requirement designed to cover the future costs of maintaining availability of the SSR. The annual revenue requirement determined for each ~~day~~SSR ~~compared~~is subject to FERC approval. The annual revenue requirement for the SSR is assigned to certain load serving entities based on a 65MISO ~~degree~~study. Alliant ~~base~~Energy, IPL and WPL are currently unable to estimate the amount of future SSR charges that may be assigned to IPL and WPL as load serving entities. Alliant ~~Normal~~Energy, ~~degree~~IPL ~~days~~and WPL are ~~calculated~~also ~~using~~currently aunable ~~rolling~~to 20estimate the impacts of any potential SSR designations on electric generating facilities they plan to retire. Refer to “Strategic Overview -~~year~~ ~~average~~Generation Plans” in MDA for discussion of ~~historical~~electric ~~cooling~~generating ~~degree~~facilities ~~days~~that IPL and WPL currently plan to retire.

~~(b)~~Electric ~~All~~Environmental orMatters ~~some~~- Alliant Energy, IPL and WPL are subject to extensive environmental laws and regulations at a federal, state and local level relating to the protection of the ~~renewable~~environment ~~energy~~and ~~attributes~~health ~~associated~~and ~~with~~safety ~~generation~~matters, ~~from~~including ~~these~~those ~~sources~~governing ~~may~~air beemissions; ~~used~~water indischarges; ~~future~~the ~~years~~management, tostorage ~~comply~~and ~~with~~disposal ~~renewable~~of ~~energy~~hazardous ~~standards~~materials; orand ~~other~~the ~~regulatory~~clean-up ~~requirements~~of contaminated sites. The laws impacting Alliant Energy’s, orIPL’s ~~sold~~and WPL’s electric operations include, but are not limited to, ~~third~~the ~~parties~~Safe inDrinking Water Act; Clean Water Act; Clean Air Act; National Environmental Policy Act of 1969; Toxic Substances Control Act; Resource Conservation and Recovery Act; Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended by the ~~form~~Superfund Amendments and Reauthorization Act and Emergency Planning and Community Right-to-Know Act of ~~renewable~~1986; ~~energy~~Endangered ~~credits~~Species orAct; ~~other~~Occupational ~~environmental~~Safety ~~commodities.~~and Health Act; National Energy Policy Act, as amended; Federal Insecticide, Fungicide and Rodenticide Act; Hazardous Materials Transportation Act;

15 13

Table of Contents

~~Wisconsin~~Pollution ~~Power~~Prevention Act; and ~~Light~~Department ~~Company~~of Homeland Security Appropriations Act, as well as similar state laws, and regulations promulgated thereunder. Alliant Energy, IPL and WPL regularly obtain federal, state and local permits to assure compliance with environmental protection laws and regulations. Costs associated with such compliance have increased in recent years and are expected to continue to increase in the future. Alliant Energy, IPL and WPL anticipate that prudently incurred compliance and remediation costs for IPL and WPL will be recoverable, in whole or part, through future rate case proceedings. Refer to “Environmental Matters” in MDA and Note 13(e) of the “Combined Notes to Consolidated Financial Statements” for further discussion of electric environmental matters, including current or proposed environmental regulations. Refer to “Strategic Overview - Environmental Compliance Plans” in MDA for details of Alliant Energy’s, IPL’s and WPL’s future environmental compliance plans to adhere to applicable environmental requirements.

Electric Operating Information	2011		2010		2009		2008		2007
Operating Revenues (in millions):
Residential	$	442.6	$	439.6	$	389.7	$	389.5	$	396.3
Commercial		246.1		240.3		220.0		218.1		219.0
Industrial		333.5		320.9		298.2		327.7		329.9
Retail subtotal		1,022.2		1,000.8		907.9		935.3		945.2
Sales for resale:
Wholesale		160.2		167.0		166.6		178.5		158.5
Bulk power and other		27.6		20.6		61.0		10.0		14.5
Other		17.5		21.5		24.8		29.2		22.5
Total	$	1,227.5	$	1,209.9	$	1,160.3	$	1,153.0	$	1,140.7
Electric Sales (000s MWh):
Residential		3,517		3,541		3,419		3,446		3,549
Commercial		2,300		2,275		2,257		2,270		2,310
Industrial		4,424		4,252		4,119		4,748		4,942
Retail subtotal		10,241		10,068		9,795		10,464		10,801
Sales for resale:
Wholesale		2,955		2,900		2,848		3,364		3,141
Bulk power and other		1,028		695		1,682		301		969
Other		67		70		71		74		74
Total		14,291		13,733		14,396		14,203		14,985
Customers (End of Period):
Residential		399,422		398,032		397,312		397,055		395,148
Commercial		56,226		55,769		55,294		55,028		54,762
Industrial		989		975		967		995		1,010
Other		2,257		2,266		2,179		2,153		2,131
Total		458,894		457,042		455,752		455,231		453,051
Other Selected Electric Data:
Maximum peak hour demand (MW)		2,761		2,654		2,558		2,583		2,816
Cooling degree days (a):
Madison, Wisconsin (normal - 614)		814		829		368		538		781
Sources of electric energy (000s MWh):
Coal		7,984		7,703		7,159		7,978		8,096
Purchased power:
Nuclear		1,859		2,044		1,851		1,846		2,037
Other (b)		3,774		3,894		5,227		4,712		5,197
Gas		56		55		25		54		116
Other (b)		827		445		344		222		182
Total		14,500		14,141		14,606		14,812		15,628
Revenue per KWh sold to retail customers (cents)		9.98		9.94		9.27		8.94		8.75

Alliant Energy Corporation



Electric Operating Information	2012		2011		2010		2009		2008
Operating Revenues (in millions):
Residential		$975.9		$985.8		$1,001.5		$868.6		$844.7
Commercial	611.4		612.1		619.0		556.8		537.5
Industrial	741.8		748.9		762.8		710.7		734.7
Retail subtotal	2,329.1		2,346.8		2,383.3		2,136.1		2,116.9
Sales for resale:
Wholesale	187.6		189.8		196.8		190.1		201.9
Bulk power and other	23.8		52.2		44.1		98.3		31.1
Other	48.8		47.0		50.0		51.4		61.4
Total		$2,589.3		$2,635.8		$2,674.2		$2,475.9		$2,411.3
Electric Sales (000s MWh):
Residential	7,679		7,740		7,836		7,532		7,664
Commercial	6,352		6,253		6,219		6,108		6,181
Industrial	11,555		11,504		11,213		10,948		12,490
Retail subtotal	25,586		25,497		25,268		24,588		26,335
Sales for resale:
Wholesale	3,317		3,372		3,325		3,251		3,813
Bulk power and other	1,303		1,757		1,378		2,583		983
Other	151		151		153		155		164
Total	30,357		30,777		30,124		30,577		31,295
Customers (End of Period):
Residential	844,388		842,780		841,726		840,927		840,644
Commercial	137,791		136,732		135,832		135,099		134,536
Industrial	2,842		2,895		2,875		2,881		2,934
Other	3,647		3,638		3,632		3,555		3,534
Total	988,668		986,045		984,065		982,462		981,648
Other Selected Electric Data:
Maximum peak hour demand (MW)	5,886		5,734		5,425		5,491		5,491
Cooling degree days (a):
Cedar Rapids, Iowa (IPL) (normal - 740)	1,052		887		923		406		583
Madison, Wisconsin (WPL) (normal - 625)	1,070		814		829		368		538
Sources of electric energy (000s MWh):
Coal	14,680		16,440		16,366		15,321		17,495
Purchased power:
Nuclear	5,483		5,483		5,667		5,428		5,465
Other (b)	8,241		7,529		7,514		9,542		7,866
Gas	1,285		588		633		661		1,037
Other (b)	1,381		1,413		820		402		245
Total	31,070		31,453		31,000		31,354		32,108
Revenue per kilowatt-hour (KWh) sold to retail customers (cents)	9.10		9.20		9.43		8.69		8.04

(ba) ~~All~~Cooling ordegree ~~some~~days ofare ~~the~~calculated ~~renewable~~using ~~energy~~a ~~attributes~~simple ~~associated~~average ~~with~~of ~~generation~~the ~~from~~high ~~these~~and ~~sources~~low ~~may~~temperatures beeach ~~used~~day incompared ~~future years~~ to ~~comply~~a ~~with~~65 ~~renewable~~degree ~~energy~~base. ~~standards~~Normal ordegree ~~other~~days ~~regulatory~~are ~~requirements,~~calculated orusing ~~sold~~a torolling ~~third~~20-year ~~parties~~average ~~in the form~~ of ~~renewable~~historical ~~energy~~cooling ~~credits~~degree ~~or other environmental commodities~~days.

16(b) All or some of the renewable energy attributes associated with generation from these sources may be used in future years to comply with renewable energy standards or other regulatory requirements, or sold to third-parties in the form of renewable energy credits or other environmental commodities.

~~Table of Contents~~14

2)Table ~~GAS~~of ~~UTILITY OPERATIONS~~ Contents

~~General~~Interstate -Power ~~Gas utility operations represent the second largest operating segment for Alliant Energy, IPL~~ and ~~WPL.~~Light Alliant Energy’s gas utility operations are located in the Midwest with IPL providing gas service in Iowa and southern Minnesota, and WPL providing gas service in southern and central Wisconsin. Refer to the “Gas Operating Information” tables for additional details regarding gas utility operations. Company

Jurisdictions - Gas utility revenues by state were as follows (dollars in millions):



Electric Operating Information	2012		2011		2010		2009		2008
Operating Revenues (in millions):
Residential		$529.9		$543.2		$561.9		$478.9		$455.2
Commercial	365.3		366.0		378.7		336.8		319.4
Industrial	408.0		415.4		441.9		412.5		407.0
Retail subtotal	1,303.2		1,324.6		1,382.5		1,228.2		1,181.6
Sales for resale:
Wholesale	27.8		29.6		29.8		23.5		23.4
Bulk power and other	9.5		24.6		23.5		37.3		21.1
Other	30.6		29.5		28.5		26.6		32.2
Total		$1,371.1		$1,408.3		$1,464.3		$1,315.6		$1,258.3
Electric Sales (000s MWh):
Residential	4,141		4,223		4,295		4,113		4,218
Commercial	4,045		3,953		3,944		3,851		3,911
Industrial	7,116		7,080		6,961		6,829		7,742
Retail subtotal	15,302		15,256		15,200		14,793		15,871
Sales for resale:
Wholesale	418		417		425		403		449
Bulk power and other	377		729		683		901		682
Other	81		84		83		84		90
Total	16,178		16,486		16,391		16,181		17,092
Customers (End of Period):
Residential	443,802		443,358		443,694		443,615		443,589
Commercial	81,203		80,506		80,063		79,805		79,508
Industrial	1,836		1,906		1,900		1,914		1,939
Other	1,381		1,381		1,366		1,376		1,381
Total	528,222		527,151		527,023		526,710		526,417
Other Selected Electric Data:
Maximum peak hour demand (MW)	3,130		3,131		2,963		2,981		2,943
Cooling degree days (a):
Cedar Rapids, Iowa (normal - 740)	1,052		887		923		406		583
Sources of electric energy (000s MWh):
Coal	7,302		8,456		8,663		8,162		9,517
Purchased power:
Nuclear	3,641		3,624		3,623		3,577		3,619
Other (b)	3,980		3,755		3,620		4,315		3,154
Gas	1,081		532		578		636		983
Other (b)	617		586		375		58		23
Total	16,621		16,953		16,859		16,748		17,296
Revenue per KWh sold to retail customers (cents)	8.52		8.68		9.10		8.30		7.45

	2011					2010					2009
	Amount		Percent			Amount		Percent			Amount		Percent
IPL:
Iowa	$	263.3		55	%	$	261.5		54	%	$	295.2		56	%
Minnesota		13.0		3	%		12.8		3	%		13.6		3	%
Subtotal		276.3		58	%		274.3		57	%		308.8		59	%
WPL:
Wisconsin		200.4		42	%		206.3		43	%		216.5		41	%
	$	476.7		100	%	$	480.6		100	%	$	525.3		100	%


(a)	Cooling degree days are calculated using a simple average of the high and low temperatures each day compared to a 65 degree base. Normal degree days are calculated using a rolling 20-year average of historical cooling degree days.

~~Customers~~(b) -All ~~The~~or ~~number~~some of ~~gas~~the ~~customers~~renewable ~~and~~energy ~~communities~~attributes ~~served~~associated atwith ~~Dec.~~generation 31from these sources may be used in future years to comply with renewable energy standards or other regulatory requirements, ~~2011~~or ~~were~~sold asto ~~follows:~~ third-parties in the form of renewable energy credits or other environmental commodities.

	RetailCustomers		Transportation /Other Customers		TotalCustomers		CommunitiesServed
IPL		233,715		273		233,988		243
WPL		179,945		227		180,172		239
		413,660		500		414,160		482

~~IPL’s~~Table ~~and WPL’s retail customers in the above table are billed under base rates established by the IUB, MPUC or PSCW that include recovery~~ of and a return on investments in gas infrastructure and recovery of costs required to serve customers. Commodity, storage and transportation costs incurred by IPL and WPL are recovered pursuant to natural gas cost recovery mechanisms. In addition to sales of natural gas to retail customers, IPL and WPL provide transportation service to commercial and industrial customers by moving customer-owned gas through Alliant Energy’s distribution systems to the customers’ meters. Revenues are collected for this service pursuant to transportation tariffs. Refer to “Rate Matters” in MDA for discussion of potential retail gas rate filings by IPL and WPL in 2012. Contents

~~Seasonality~~Wisconsin -Power ~~Gas sales follow a seasonal pattern with an annual base-load of gas~~ and aLight large heating peak occurring during the winter season. Natural gas obtained from producers, marketers and brokers, as well as gas in storage, is utilized to meet the peak heating season requirements. Storage contracts allow IPL and WPL to purchase gas in the summer, store the gas in underground storage fields and deliver it in the winter. Company

Competition - Federal and state regulatory policies are in place to bring more competition to the gas industry. While the gas utility distribution function is expected to remain a regulated function, sales of the natural gas commodity and related services are subject to competition from third parties. It remains uncertain if, and when, the current economic disincentives for smaller consumption customers to choose an alternative gas commodity supplier may be removed such that the utility business begins to face competition for the sale of gas to those customers.



Electric Operating Information	2012		2011		2010		2009		2008
Operating Revenues (in millions):
Residential		$446.0		$442.6		$439.6		$389.7		$389.5
Commercial	246.1		246.1		240.3		220.0		218.1
Industrial	333.8		333.5		320.9		298.2		327.7
Retail subtotal	1,025.9		1,022.2		1,000.8		907.9		935.3
Sales for resale:
Wholesale	159.8		160.2		167.0		166.6		178.5
Bulk power and other	14.3		27.6		20.6		61.0		10.0
Other	18.2		17.5		21.5		24.8		29.2
Total		$1,218.2		$1,227.5		$1,209.9		$1,160.3		$1,153.0
Electric Sales (000s MWh):
Residential	3,538		3,517		3,541		3,419		3,446
Commercial	2,307		2,300		2,275		2,257		2,270
Industrial	4,439		4,424		4,252		4,119		4,748
Retail subtotal	10,284		10,241		10,068		9,795		10,464
Sales for resale:
Wholesale	2,899		2,955		2,900		2,848		3,364
Bulk power and other	926		1,028		695		1,682		301
Other	70		67		70		71		74
Total	14,179		14,291		13,733		14,396		14,203
Customers (End of Period):
Residential	400,586		399,422		398,032		397,312		397,055
Commercial	56,588		56,226		55,769		55,294		55,028
Industrial	1,006		989		975		967		995
Other	2,266		2,257		2,266		2,179		2,153
Total	460,446		458,894		457,042		455,752		455,231
Other Selected Electric Data:
Maximum peak hour demand (MW)	2,851		2,761		2,654		2,558		2,583
Cooling degree days (a):
Madison, Wisconsin (normal - 625)	1,070		814		829		368		538
Sources of electric energy (000s MWh):
Coal	7,378		7,984		7,703		7,159		7,978
Purchased power:
Nuclear	1,842		1,859		2,044		1,851		1,846
Other (b)	4,261		3,774		3,894		5,227		4,712
Gas	204		56		55		25		54
Other (b)	764		827		445		344		222
Total	14,449		14,500		14,141		14,606		14,812
Revenue per KWh sold to retail customers (cents)	9.98		9.98		9.94		9.27		8.94

~~Gas~~(a) ~~Supply~~Cooling -degree ~~IPL~~days ~~and~~are ~~WPL~~calculated ~~maintain~~using ~~purchase~~a ~~agreements~~simple ~~with~~average ~~over 70 suppliers~~ of ~~natural gas from various gas producing regions of~~ the ~~U.S.~~high and ~~Canada.~~low ~~The~~temperatures ~~majority~~each ofday ~~the~~compared ~~gas~~to ~~supply~~a ~~contracts~~65 ~~are~~degree ~~for~~base. ~~terms~~Normal ofdegree ~~six~~days ~~months~~are orcalculated ~~less,~~using ~~with~~a ~~the~~rolling ~~remaining~~20-year ~~supply~~average ~~contracts~~of ~~having~~historical ~~terms~~cooling ~~through~~degree ~~March 2014~~days. ~~IPL’s and WPL’s gas supply commitments are primarily market-based.~~

~~Recently,~~(b) ~~natural~~All ~~gas~~or ~~prices~~some ~~have~~of ~~fallen~~the torenewable ~~levels~~energy ~~not~~attributes ~~seen~~associated inwith ageneration ~~decade.~~from ~~Prices~~these ~~have~~sources ~~fallen~~may ~~largely~~be ~~due~~used toin ~~surging~~future ~~supply~~years ~~caused~~to bycomply ~~shale~~with ~~gas production.~~renewable ~~Given~~energy ~~the~~standards ~~tariffs~~or ~~for~~other ~~IPL’s~~regulatory ~~and~~requirements, ~~WPL’s~~or ~~retail~~sold ~~gas customers provide for subsequent adjustments~~ to ~~their~~third-parties ~~rates~~ in the ~~cost~~form of ~~gas~~renewable ~~sold,~~energy ~~the~~credits ~~decreased~~or ~~natural~~other ~~gas~~environmental ~~prices do not have a material impact on their respective gas margins~~commodities.

17 16

Table of Contents

In providing gas commodity service to retail customers, Corporate Services administers a diversified portfolio of transportation and storage contracts on behalf of IPL and WPL. Transportation contracts with Northern Natural Gas Company (NNG2), ~~ANR,~~GAS ~~Natural~~UTILITY Gas Pipeline Co. of America (NGPL), Guardian Pipeline (Guardian) and Northern Border Pipeline (NBPL) allow access to gas supplies located in the U.S. and Canada. Arrangements with Firm Citygate Supplies (FCS) provide IPL with gas delivered directly to its service territory. In 2011, the maximum daily delivery capacity for IPL and WPL was as follows (in Dths): OPERATIONS

	NNG		ANR		NGPL		FCS		Guardian		NBPL		Total
IPL		191,969		43,180		42,618		11,500		—		9,085		298,352
WPL		76,056		167,467		—		—		10,000		—		253,523

General - Gas utility operations represent the second largest operating segment for Alliant Energy, IPL and WPL. Alliant Energy’s gas utility operations are located in the Midwest with IPL providing gas service in Iowa and southern Minnesota, and WPL providing gas service in southern and central Wisconsin. Refer to the “Gas Operating Information” tables for additional details regarding gas utility operations.

~~Refer~~Jurisdictions to- ~~Note~~Gas ~~1(h) for information relating to~~ utility ~~natural~~revenues ~~gas~~by ~~cost~~state ~~recovery~~were ~~mechanisms~~as ~~and~~follows ~~Note 13~~(a)dollars ~~for discussion of natural gas commitments~~ in ~~the “Combined Notes to Consolidated Financial Statements.”~~ millions):

Gas Environmental Matters - Alliant Energy is subject to extensive environmental laws and regulations at a federal, state and local level relating to the protection of the environment and health and safety matters, including remediation of former manufactured gas plant sites. The laws impacting Alliant Energy’s gas operations include, but are not limited to, the Safe Drinking Water Act; Clean Water Act; National Environmental Policy Act of 1969; Toxic Substances Control Act; Resource Conservation and Recovery Act; Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended by the Superfund Amendments and Reauthorization Act and Emergency Planning and Community Right-to-Know Act of 1986; Endangered Species Act; Occupational Safety and Health Act; National Energy Policy Act, as amended; Federal Insecticide, Fungicide and Rodenticide Act; Hazardous Materials Transportation Act; Pollution Prevention Act, and Department of Homeland Security Appropriations Act, as well as similar state laws, and regulations promulgated thereunder. Alliant Energy regularly obtains federal, state and local permits to assure compliance with environmental protection laws and regulations. Costs associated with such compliance have increased in recent years and are expected to continue to increase in the future. Alliant Energy anticipates that prudently incurred compliance and remediation costs for IPL and WPL will be recoverable, in whole or part, through future rate case proceedings. Refer to Note 13(d) of the “Combined Notes to Consolidated Financial Statements” for discussion of gas environmental matters. Refer to “Legislative Matters” in MDA for discussion of the Pipeline Safety, Regulatory Certainty and Job Creation Act of 2011, which was enacted in January 2012.



	2012				2011				2010
	Amount		Percent		Amount		Percent		Amount		Percent
IPL:
Iowa		$216.6	55	%		$263.3	55	%		$261.5	54	%
Minnesota	10.1		2	%	13.0		3	%	12.8		3	%
Subtotal	226.7		57	%	276.3		58	%	274.3		57	%
WPL:
Wisconsin	169.6		43	%	200.4		42	%	206.3		43	%
		$396.3	100	%		$476.7	100	%		$480.6	100	%

18Customers - The number of gas customers and communities served at December 31, 2012 were as follows:



	Retail	Transportation /	Total	Communities
	Customers	Other Customers	Customers	Served
IPL	233,820	334	234,154	243
WPL	181,028	240	181,268	239
	414,848	574	415,422	482

IPL’s and WPL’s retail gas customers in the above table are billed under base rates established by the IUB, MPUC or PSCW that include recovery of and a return on investments in gas infrastructure and recovery of costs required to serve customers. Commodity, storage and transportation costs incurred by IPL and WPL are recovered pursuant to natural gas cost recovery mechanisms. In addition to sales of natural gas to retail customers, IPL and WPL provide transportation service to commercial and industrial customers by moving customer-owned gas through Alliant Energy’s ~~Corporation~~distribution systems to the customers’ meters. Revenues are collected for this service pursuant to transportation tariffs. Refer to “Rate Matters” in MDA for discussion of IPL’s and WPL’s recent retail gas rate cases.

Gas Operating Information	2011		2010		2009		2008		2007
Operating Revenues (in millions):
Residential	$	269.7	$	273.7	$	290.8	$	385.0	$	348.6
Commercial		155.1		154.2		174.7		240.5		199.0
Industrial		24.5		27.3		30.7		51.1		39.4
Retail subtotal		449.3		455.2		496.2		676.6		587.0
Interdepartmental		1.1		1.5		4.9		7.8		17.4
Transportation/other		26.3		23.9		24.2		26.0		25.8
Total	$	476.7	$	480.6	$	525.3	$	710.4	$	630.2
Gas Sales (000s Dths):
Residential		26,891		27,128		27,711		30,630		28,137
Commercial		19,271		18,691		20,725		22,461		19,417
Industrial		3,848		4,158		4,558		5,558		4,694
Retail subtotal		50,010		49,977		52,994		58,649		52,248
Interdepartmental		887		887		938		1,373		2,591
Transportation/other		51,323		49,521		53,580		59,253		58,911
Total		102,220		100,385		107,512		119,275		113,750
Retail Customers at End of Period:
Residential		367,497		366,261		365,597		365,193		363,825
Commercial		45,667		45,552		45,641		45,413		45,374
Industrial		496		549		571		584		591
Total		413,660		412,362		411,809		411,190		409,790
Other Selected Gas Data:
Heating degree days (a):
Cedar Rapids, Iowa (IPL) (normal - 6,763)		6,745		6,868		7,074		7,636		6,815
Madison, Wisconsin (WPL) (normal - 7,083)		6,992		6,798		7,356		7,714		6,935
Revenue per Dth sold to retail customers	$	8.98	$	9.11	$	9.36	$	11.54	$	11.23
Purchased gas costs per Dth sold to retail customers	$	5.88	$	6.05	$	6.47	$	8.73	$	8.11

Seasonality - Gas sales follow a seasonal pattern with an annual base-load of gas and a large heating peak occurring during the winter season. Natural gas obtained from producers, marketers and brokers, as well as gas in storage, is utilized to meet the peak heating season requirements. Storage contracts allow IPL and WPL to purchase gas in the summer, store the gas in underground storage fields and deliver it in the winter.

~~(a)~~Competition ~~Heating~~- ~~degree~~Federal ~~days~~and state regulatory policies are ~~calculated~~in ~~using~~place to bring competition to the gas industry. While the gas utility distribution function is expected to remain a ~~simple~~regulated ~~average~~function, sales of the ~~high~~natural ~~and~~gas ~~low~~commodity ~~temperatures~~and ~~each~~related ~~day~~services ~~compared~~are subject to acompetition 65from ~~degree~~third ~~base~~parties. It ~~Normal~~remains ~~degree~~uncertain ~~days~~if, ~~are~~and ~~calculated~~when, ~~using~~the acurrent ~~rolling~~economic ~~20-year~~disincentives ~~average~~for smaller consumption customers to choose an alternative gas commodity supplier may be removed such that the utility business begins to face competition for the sale of ~~historical~~gas ~~heating~~to ~~degree~~those ~~days~~customers.

19Gas Supply - IPL and WPL maintain purchase agreements with over 70 suppliers of natural gas from various gas producing regions of the U.S. and Canada. The majority of the gas supply contracts are for terms of six months or less, with the remaining supply contracts having terms through March 2015. IPL’s and WPL’s gas supply commitments are primarily market-based.

~~Table~~In more recent years, natural gas prices have fallen to levels not seen in a decade. Prices have fallen largely due to surging supply caused by shale gas production. Given the tariffs for IPL’s and WPL’s retail gas customers provide for subsequent adjustments to their rates in the cost of ~~Contents~~gas sold, the decreased natural gas prices do not have a material impact on their respective gas margins.

~~Interstate~~In ~~Power~~providing gas commodity service to retail customers, Corporate Services administers a diversified portfolio of transportation and ~~Light~~storage contracts on behalf of IPL and WPL. Transportation contracts with Northern Natural Gas Company (NNG), ANR Pipeline (ANR), Natural Gas Pipeline Co. of America (NGPL), Guardian Pipeline (Guardian) and

Gas Operating Information	2011		2010		2009		2008		2007
Operating Revenues (in millions):
Residential	$	155.2	$	155.6	$	168.6	$	219.3	$	203.4
Commercial		87.8		88.4		100.8		137.3		115.0
Industrial		19.0		18.4		25.0		40.4		31.2
Retail subtotal		262.0		262.4		294.4		397.0		349.6
Interdepartmental		0.7		1.0		2.9		2.2		2.6
Transportation/other		13.6		10.9		11.5		11.2		12.3
Total	$	276.3	$	274.3	$	308.8	$	410.4	$	364.5
Gas Sales (000s Dths):
Residential		15,660		15,923		16,072		18,110		16,541
Commercial		10,677		10,596		11,451		13,099		11,080
Industrial		3,023		2,869		3,787		4,539		3,811
Retail subtotal		29,360		29,388		31,310		35,748		31,432
Interdepartmental		116		148		474		217		327
Transportation/other		27,604		27,923		29,924		34,776		34,433
Total		57,080		57,459		61,708		70,741		66,192
Retail Customers at End of Period:
Residential		206,964		206,979		206,937		206,866		206,873
Commercial		26,455		26,470		26,545		26,603		26,664
Industrial		296		343		359		367		366
Total		233,715		233,792		233,841		233,836		233,903
Other Selected Gas Data:
Heating degree days (a):
Cedar Rapids, Iowa (normal - 6,763)		6,745		6,868		7,074		7,636		6,815
Revenue per Dth sold to retail customers	$	8.92	$	8.93	$	9.40	$	11.11	$	11.12
Purchased gas cost per Dth sold to retail customers	$	5.96	$	6.05	$	6.61	$	8.50	$	8.38

~~Wisconsin~~Table ~~Power~~of ~~and Light Company~~ Contents

Gas Operating Information	2011		2010		2009		2008		2007
Operating Revenues (in millions):
Residential	$	114.5	$	118.1	$	122.2	$	165.7	$	145.2
Commercial		67.3		65.8		73.9		103.2		84.0
Industrial		5.5		8.9		5.7		10.7		8.2
Retail subtotal		187.3		192.8		201.8		279.6		237.4
Interdepartmental		0.4		0.5		2.0		5.6		14.8
Transportation/other		12.7		13.0		12.7		14.8		13.5
Total	$	200.4	$	206.3	$	216.5	$	300.0	$	265.7
Gas Sales (000s Dths):
Residential		11,231		11,205		11,639		12,520		11,596
Commercial		8,594		8,095		9,274		9,362		8,337
Industrial		825		1,289		771		1,019		883
Retail subtotal		20,650		20,589		21,684		22,901		20,816
Interdepartmental		771		739		464		1,156		2,264
Transportation/other		23,719		21,598		23,656		24,477		24,478
Total		45,140		42,926		45,804		48,534		47,558
Retail Customers at End of Period:
Residential		160,533		159,282		158,660		158,327		156,952
Commercial		19,212		19,082		19,096		18,810		18,710
Industrial		200		206		212		217		225
Total		179,945		178,570		177,968		177,354		175,887
Other Selected Gas Data:
Heating degree days (a):
Madison, Wisconsin (normal - 7,083)		6,992		6,798		7,356		7,714		6,935
Revenue per Dth sold to retail customers	$	9.07	$	9.36	$	9.31	$	12.21	$	11.40
Purchased gas cost per Dth sold to retail customers	$	5.77	$	6.06	$	6.28	$	9.08	$	7.70

Northern Border Pipeline (NBPL) allow access to gas supplies located in the U.S. and Canada. Arrangements with Firm Citygate Supplies (FCS) provide IPL with gas delivered directly to its service territory. In 2012, the maximum daily delivery capacity for IPL and WPL was as follows in dekatherms (Dths)):

(a) Heating degree days are calculated using a simple average of the high and low temperatures each day compared to a 65 degree base. Normal degree days are calculated using a rolling 20-year average of historical heating degree days.



	NNG	ANR	NGPL	FCS	Guardian	NBPL	Total
IPL	191,669	43,180	78,585	14,000	—	4,085	331,519
WPL	76,056	167,467	—	—	10,000	—	253,523

20Refer to Note 1(h) for information relating to utility natural gas cost recovery mechanisms and Note 13(b) for discussion of natural gas commitments in the “Combined Notes to Consolidated Financial Statements.”

~~Table~~Gas Environmental Matters - Alliant Energy is subject to extensive environmental laws and regulations at a federal, state and local level relating to the protection of ~~Contents~~the environment and health and safety matters, including remediation of former manufactured gas plant sites, as well as those governing air emissions, water discharges, and the management, storage and disposal of hazardous materials. The laws impacting Alliant Energy’s gas operations include, but are not limited to, the Safe Drinking Water Act; Clean Water Act; National Environmental Policy Act of 1969; Toxic Substances Control Act; Resource Conservation and Recovery Act; Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended by the Superfund Amendments and Reauthorization Act and Emergency Planning and Community Right-to-Know Act of 1986; Endangered Species Act; Occupational Safety and Health Act; National Energy Policy Act, as amended; Federal Insecticide, Fungicide and Rodenticide Act; Hazardous Materials Transportation Act; Pollution Prevention Act, and Department of Homeland Security Appropriations Act, as well as similar state laws, and regulations promulgated thereunder. Alliant Energy regularly obtains federal, state and local permits to assure compliance with environmental protection laws and regulations. Costs associated with such compliance have increased in recent years and are expected to continue to increase in the future. Alliant Energy anticipates that prudently incurred compliance and remediation costs for IPL and WPL will be recoverable, in whole or part, through future rate case proceedings. Refer to Note 13(e) of the “Combined Notes to Consolidated Financial Statements” for discussion of gas environmental matters.

Alliant Energy Corporation

3) STEAM UTILITY OPERATIONS - IPL has historically provided steam service to approximately 200 customers in Cedar Rapids, Iowa, who used high-pressure steam for production purposes or low-pressure steam for hot water and heat. Substantially all of the steam for these customers was generated by IPL’s Prairie Creek Generating Station (Prairie Creek) and Sixth Street Generating Station (Sixth Street) in Cedar Rapids prior to June 2008. In June 2008, Prairie Creek and Sixth Street were shutdown as a result of significant damage caused by severe flooding in downtown Cedar Rapids. Soon after the flood waters receded, IPL made necessary repairs to its steam distribution systems and established temporary steam generating systems (natural gas-fired package boilers and water treatment systems) to resume steam service for its customers. Following months of evaluations and discussions with its steam customers, IPL announced in 2009 its decision to discontinue providing temporary steam service to those steam customers located in downtown Cedar Rapids previously served by Sixth Street. IPL ceased low-pressure steam operations in downtown Cedar Rapids in December 2009 and high-pressure steam operations in downtown Cedar Rapids in the second quarter of 2010. Prairie Creek was returned to service in 2009 and is expected to be the primary source of steam for IPL’s remaining two high-pressure steam customers in the future.



Gas Operating Information	2012		2011		2010		2009		2008
Operating Revenues (in millions):
Residential		$224.3		$269.7		$273.7		$290.8		$385.0
Commercial	124.3		155.1		154.2		174.7		240.5
Industrial	16.7		24.5		27.3		30.7		51.1
Retail subtotal	365.3		449.3		455.2		496.2		676.6
Transportation/other	31.0		27.4		25.4		29.1		33.8
Total		$396.3		$476.7		$480.6		$525.3		$710.4
Gas Sales (000s Dths):
Residential	23,071		26,891		27,128		27,711		30,630
Commercial	17,115		19,271		18,691		20,725		22,461
Industrial	3,068		3,848		4,158		4,558		5,558
Retail subtotal	43,254		50,010		49,977		52,994		58,649
Transportation/other	57,532		52,210		50,408		54,518		60,626
Total	100,786		102,220		100,385		107,512		119,275
Retail Customers at End of Period:
Residential	368,708		367,497		366,261		365,597		365,193
Commercial	45,684		45,667		45,552		45,641		45,413
Industrial	456		496		549		571		584
Total	414,848		413,660		412,362		411,809		411,190
Other Selected Gas Data:
Heating degree days (a):
Cedar Rapids, Iowa (IPL) (normal - 6,794)	5,901		6,745		6,868		7,074		7,636
Madison, Wisconsin (WPL) (normal - 7,089)	5,964		6,992		6,798		7,356		7,714
Revenue per Dth sold to retail customers		$8.45		$8.98		$9.11		$9.36		$11.54
Purchased gas costs per Dth sold to retail customers		$4.94		$5.88		$6.05		$6.47		$8.73

~~IPL’s largest~~(a) ~~remaining~~Heating ~~high-pressure~~degree ~~steam~~days ~~customer~~are ~~accounts~~calculated ~~for~~using ~~approximately~~a ~~95%~~simple average of ~~IPL’s~~the ~~steam~~high ~~revenues.~~and ~~This~~low ~~customer~~temperatures iseach ~~under~~day ~~contract~~compared ~~through~~to ~~2025~~a ~~for~~65 ~~annual~~degree ~~steam usage of at least 3~~base.~~8 million~~ ~~Dths,~~Normal ~~with~~degree ~~certain~~days ~~conditions.~~are ~~IPL~~calculated ~~is currently~~using ~~negotiating~~ a 10rolling 20-year ~~contract~~average ~~with the other remaining high-pressure steam customer for annual steam usage~~ of athistorical ~~least~~heating ~~175,000~~degree ~~Dths, with certain conditions~~days.

~~D. INFORMATION RELATING TO NON-REGULATED OPERATIONS~~ 18

~~Resources~~Table ~~manages a portfolio~~ of ~~wholly-owned subsidiaries and additional investments through several distinct platforms: Transportation, RMT, Non-regulated Generation and other non-regulated investments.~~ Contents

Interstate Power and Light Company

Transportation - includes a short-line railway that provides freight service between Cedar Rapids, Iowa and Iowa City, Iowa; a barge terminal and hauling services on the Mississippi River; and other transfer and storage services.



Gas Operating Information	2012		2011		2010		2009		2008
Operating Revenues (in millions):
Residential		$126.4		$155.2		$155.6		$168.6		$219.3
Commercial	69.7		87.8		88.4		100.8		137.3
Industrial	12.8		19.0		18.4		25.0		40.4
Retail subtotal	208.9		262.0		262.4		294.4		397.0
Transportation/other	17.8		14.3		11.9		14.4		13.4
Total		$226.7		$276.3		$274.3		$308.8		$410.4
Gas Sales (000s Dths):
Residential	12,955		15,660		15,923		16,072		18,110
Commercial	9,403		10,677		10,596		11,451		13,099
Industrial	2,435		3,023		2,869		3,787		4,539
Retail subtotal	24,793		29,360		29,388		31,310		35,748
Transportation/other	30,992		27,720		28,071		30,398		34,993
Total	55,785		57,080		57,459		61,708		70,741
Retail Customers at End of Period:
Residential	207,121		206,964		206,979		206,937		206,866
Commercial	26,439		26,455		26,470		26,545		26,603
Industrial	260		296		343		359		367
Total	233,820		233,715		233,792		233,841		233,836
Other Selected Gas Data:
Heating degree days (a):
Cedar Rapids, Iowa (normal - 6,794)	5,901		6,745		6,868		7,074		7,636
Revenue per Dth sold to retail customers		$8.43		$8.92		$8.93		$9.40		$11.11
Purchased gas cost per Dth sold to retail customers		$4.92		$5.96		$6.05		$6.61		$8.50

~~RMT~~(a) -Heating ~~provides~~degree ~~renewable~~days ~~energy~~are ~~services~~calculated tousing ~~clients~~a ~~throughout~~simple ~~the~~average ~~U.S.,~~of ~~including~~the ~~facility~~high ~~siting,~~and ~~permitting,~~low ~~design,~~temperatures ~~procurement,~~each ~~construction~~day ~~and~~compared ~~high~~to ~~voltage~~a ~~connection~~65 ~~services~~degree ~~for~~base. ~~wind~~Normal ~~and solar~~degree ~~projects.~~days Inare ~~February~~calculated ~~2012,~~using ~~Alliant~~a ~~Energy~~rolling ~~announced~~20-year ~~plans~~average toof ~~sell~~historical ~~RMT~~heating indegree ~~2012~~days.

Wisconsin Power and Light Company

Non-regulated Generation - owns the 300 MW, simple-cycle, natural gas-fired Sheboygan Falls Energy Facility near Sheboygan Falls, Wisconsin, which is leased to WPL for an initial period of 20 years ending in 2025, and the 100 MW Franklin County wind project in Franklin County, Iowa that is currently under construction. The Franklin County wind project is expected to be placed in service by the end of 2012.



Gas Operating Information	2012		2011		2010		2009		2008
Operating Revenues (in millions):
Residential		$97.9		$114.5		$118.1		$122.2		$165.7
Commercial	54.6		67.3		65.8		73.9		103.2
Industrial	3.9		5.5		8.9		5.7		10.7
Retail subtotal	156.4		187.3		192.8		201.8		279.6
Transportation/other	13.2		13.1		13.5		14.7		20.4
Total		$169.6		$200.4		$206.3		$216.5		$300.0
Gas Sales (000s Dths):
Residential	10,116		11,231		11,205		11,639		12,520
Commercial	7,712		8,594		8,095		9,274		9,362
Industrial	633		825		1,289		771		1,019
Retail subtotal	18,461		20,650		20,589		21,684		22,901
Transportation/other	26,540		24,490		22,337		24,120		25,633
Total	45,001		45,140		42,926		45,804		48,534
Retail Customers at End of Period:
Residential	161,587		160,533		159,282		158,660		158,327
Commercial	19,245		19,212		19,082		19,096		18,810
Industrial	196		200		206		212		217
Total	181,028		179,945		178,570		177,968		177,354
Other Selected Gas Data:

Filing Compare · INTERSTATE POWER & LIGHT CO