Item 1. BUSINESS

A. GENERAL

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 electric and natural gas service to approximately 950,000 electric and approximately 410,000 natural gas customers in the Midwest through its two public utility subsidiaries, IPL and WPL. The primary first tier wholly-owned subsidiaries of Alliant Energy are: IPL, WPL, Resources and Corporate Services. 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 to retail customers in select markets in Iowa. IPL provides utility services to incorporated communities as directed by the 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 December 31, 2015, IPL supplied electric and natural gas service to approximately 489,000 and 225,000 retail customers, respectively, in Iowa. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa. IPL is also engaged in the generation and distribution of steam for two customers in Cedar Rapids, Iowa. In 2015, 2014 and 2013, 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 to retail customers in select markets in Wisconsin. WPL operates in municipalities pursuant to permits of indefinite duration and state statutes authorizing utility operation in areas annexed by a municipality. At December 31, 2015, WPL supplied electric and natural gas service to approximately 461,000 and 184,000 retail customers, respectively. WPL also sells electricity to wholesale customers in Wisconsin. In 2015, 2014 and 2013, WPL had no single customer for which electric, gas and/or other sales accounted for 10% or more of WPL’s consolidated revenues. WPL’s consolidated subsidiary, WPL Transco, holds Alliant Energy’s investment in ATC. Refer to Note 6(a) for further discussion of ATC.

3. RESOURCES - 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 “Information Relating to Non-regulated Operations” for additional details.

4. CORPORATE SERVICES - was incorporated in 1997 in Iowa. Corporate Services provides administrative services to Alliant Energy, IPL, WPL and Resources.

Refer to Note 17 for further discussion of business segments, which information is incorporated herein by reference.

B. INFORMATION RELATING TO ALLIANT ENERGY ON A CONSOLIDATED BASIS

1. EMPLOYEES - At December 31, 2015, 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	1,103			584			1,687			65	%
WPL	1,117			241			1,358			82	%
Corporate Services	26			886			912			3	%
Resources	88			25			113			78	%
	2,334			1,736			4,070			57	%

At December 31, 2015, Alliant Energy employees covered by collective bargaining agreements were as follows:

	Number of			Contract
	Employees			Expiration Date
IPL:
IBEW Local 204 (Cedar Rapids)	785			8/31/17
IBEW - Various	318			Various
	1,103
WPL - IBEW Local 965	1,117			5/31/19
Resources and Corporate Services - Various	114			Various
	2,334

2. CAPITAL EXPENDITURE AND INVESTMENT PLANS - Refer to “Liquidity and Capital Resources” in MDA for discussion of anticipated construction and acquisition expenditures for 2016 through 2019.

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.

FERC -

Public Utility Holding Company Act of 2005 - Alliant Energy is registered with FERC as a public utility holding company, pursuant to the Public Utility Holding Company Act of 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 the Public Utility Holding Company Act of 2005 for various matters including, but not limited to, affiliate transactions, public utility mergers, acquisitions and dispositions, and books, records and accounting requirements.

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

Federal Power Act - FERC also has jurisdiction, under the Federal Power Act, over certain electric utility facilities and operations, electric wholesale and transmission rates, dividend payments, issuance of IPL’s securities, and accounting practices of Corporate Services, IPL and WPL.

Electric Wholesale Rates - IPL and WPL have received wholesale electric market-based rate authority from FERC. Market-based rate authorization allows for wholesale sales of electricity within the MISO market and in transactions directly with third parties, based on the market value of the transactions. IPL and WPL also have FERC-approved cost-of-service based rates related to the provision of firm full- and partial-requirement wholesale electric sales. Both IPL’s and WPL’s wholesale cost-of-service tariffs are formula-based tariffs that allow for true-ups to actual costs, including fuel costs.

Electric 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 on the use of the ITC and ATC transmission systems, respectively. Due to the formula rates used by ITC and ATC to charge their customers and possible future changes to these rates, there is uncertainty regarding IPL’s and WPL’s future electric transmission service expense. Refer to “Other Future Considerations” in MDA for further discussion of electric transmission service expense.

Natural Gas Act - FERC regulates the transportation and sale for resale of natural gas in interstate commerce under the Natural Gas Act. Under the Natural Gas Act, FERC has authority over certain natural gas facilities and operations of IPL and WPL.

IUB - IPL is subject to regulation by the IUB for various matters including, but not limited to, retail utility rates and standards of service, accounting requirements, sales of assets with values that exceed 3% of IPL’s revenues, and approval of the location and construction of EGUs.

Retail Utility Base Rates - IPL files periodic requests with the IUB for retail rate changes. These filings are based on historical test periods. The historical test periods may be adjusted for certain known and measurable changes to capital investments, cost of capital and operating and maintenance expenses consistent with IUB rules and regulations. Interim retail rates can be placed in effect 10 days after the rate application filing, subject to refund, and must be based on previously established regulatory principles. The IUB must decide on requests for retail rate changes within 10 months of the date of the application for which changes are filed, or the interim rates granted become permanent.

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. Any over- or under-collection of commodity costs are revised monthly and automatically reflected in future billings to retail customers.

Retail Electric Transmission Cost Recovery Mechanism - Electric transmission service expense is billed to IPL’s retail electric customers through a transmission cost rider. This cost recovery mechanism provides for subsequent adjustments to electric rates charged to retail electric customers for changes in electric transmission service expense. Changes in the under-/over-collection of these costs are revised annually and reflected in future billings to customers. The transmission cost rider will remain in effect until the IUB’s final decision in IPL’s next retail electric base rate case, at which time the rider will continue in its current form, continue in a modified form or be terminated.

Energy Efficiency Cost Recovery Mechanism - In accordance with Iowa law, IPL is required to file an EEP every five years with the IUB. An EEP provides a utility’s plan and related budget to achieve specified levels of energy savings. IUB approval demonstrates that IPL’s EEP is reasonably expected to achieve cost-effective delivery of the energy efficiency programs. To the extent approved by the IUB, costs associated with executing the EEP are recovered from ratepayers through an additional tariff called an EECR factor. The EECR factors are revised annually and include a reconciliation to eliminate any over- or under-recovery of energy efficiency expense from prior periods.

Electric Generating Units - 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, EGU located in Iowa with 25 MW or more of capacity. IPL’s ownership and operation of EGUs (including those located outside the state of Iowa) to serve Iowa customers is subject to retail utility rate regulation by the IUB.

Gas Pipeline Projects - IPL must obtain a pipeline permit from the IUB related to the siting of utility gas pipelines in Iowa that will be operated at a pressure over 150 pounds per square inch and will transport gas from a gathering or storage facility to a distribution system or single, large volume customer.

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

Electric Generating Unit Environmental Controls Projects - IPL is required to submit an updated EPB biennially to the IUB setting out a multi-year plan and budget for managing regulated emissions from its coal-fired EGUs in a cost-effective manner. IPL must simultaneously submit this plan and budget to the Iowa DNR for a determination of whether the plan and budget meet state environmental requirements for regulated emissions. The reasonable costs associated with implementing the approved plan are expected to be included in IPL’s future retail electric rates.

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 EGUs and certain other additions and extensions to facilities.

Retail Utility Base Rates - WPL files periodic requests with the PSCW for retail rate 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 retail base rate cases in approximately 10 months and has the ability to approve interim retail rate relief, subject to refund, if necessary. Currently, WPL is required to defer a portion of its earnings if its annual regulatory return on common equity exceeds certain levels and is allowed to request a change in retail base rates if its annual return on common equity falls below a certain level.

Retail Commodity Cost Recovery Mechanisms -

Electric - WPL’s retail electric base rates include estimates of annual fuel-related costs anticipated during the forward-looking test period. During each 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 retail electric customers that are outside the approved ranges. Deferrals of under-collections are reduced to the extent actual return on common equity earned by WPL during the fuel cost plan year exceeds the applicable 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.

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 are revised monthly and automatically reflected in future billings to retail customers.

Retail Electric Transmission Cost Recovery - WPL’s retail electric base rates include estimates of electric transmission service expense anticipated during the forward-looking test period. A majority of WPL’s electric transmission service expense is currently subject to a reconciliation of such estimated amounts to actual costs incurred with any difference deferred for inclusion in future base rate changes.

Energy Efficiency Cost Recovery - WPL contributes a certain percentage of its annual utility revenues to help fund Focus on Energy, Wisconsin’s state-wide 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 a future base rate proceeding.

New Electric Generating Units - A CA application is required to be filed with the PSCW for construction approval of any new EGU with a capacity of less than 100 MW and a project cost of $10 million or more. WPL must obtain a CPCN from the PSCW in order to construct a new EGU in Wisconsin with a capacity of 100 MW or more. In addition, WPL’s ownership and operation of EGUs (including those located outside the state of Wisconsin) to serve Wisconsin customers is subject to retail utility rate regulation by the PSCW.

Electric Generating Unit Upgrades - A CA application is required to be filed with the PSCW for construction approval of any additions to EGUs, including environmental controls projects. The current PSCW rules require a CA application for such projects with an estimated project cost of $10 million or more.

Electric Distribution Projects - A CA application is required to be filed with the PSCW for construction approval of electric distribution projects with an estimated project cost of $10 million or more.

Gas Distribution Projects - A CA application is required to be filed with the PSCW for construction approval of gas projects with an estimated project cost of $2.5 million or more and at any time that WPL requests to extend gas service to a new portion of its service territory.

Advance Rate-making Principles - Wisconsin law provides Wisconsin utilities with the opportunity to request rate-making principles prior to the purchase or construction of any nuclear or fossil-fueled EGU 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 law. WPL can proceed with an approved project under traditional rate-making terms or accept authorized rate-making principles under Wisconsin law.

MPUC - IPL is subject to limited regulation by the MPUC related to its operations in Minnesota for various matters including, but not limited to, approval of the location and construction of EGUs located in Minnesota with a capacity in excess of 50 MW. Refer to Note 3 for discussion of IPL’s sales of its Minnesota electric and natural gas distribution assets in 2015.

Environmental - Extensive environmental laws and regulations are applicable as a result of current and past operations. The environmental laws and regulations relate to the protection of the environment and health and safety matters, including those governing air emissions; water discharges; the management, storage and disposal of hazardous materials; and the clean-up of contaminated sites, including former MGP sites.

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.

Federal, state and local permits are regularly obtained to assure compliance with environmental laws and regulations. Costs associated with such compliance have increased in recent years and are expected to continue to increase in the future. Prudently incurred compliance and remediation costs for IPL and WPL are anticipated to be recoverable, in whole or part, through future rate case proceedings. Refer to “Environmental Matters” in MDA and Note 16(e) for further discussion of electric and gas environmental matters, including current or proposed environmental regulations. Refer to “Strategic Overview” in MDA for details of future environmental compliance plans to adhere to applicable environmental requirements.

Refer to Notes 1(b), 1(g), 2 and 16(e) and “Rate Matters” and “Environmental 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

Alliant 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 and the unallocated portions of the utility business. IPL’s and WPL’s operating revenues and operating income (loss) for these three utility business segments were as follows:

	2015												2014												2013
	IPL						WPL						IPL						WPL						IPL						WPL
	Revenue			Income			Revenue			Income			Revenue			Income			Revenue			Income			Revenue			Income			Revenue			Income
Electric	85	%		91	%		88	%		96	%		81	%		80	%		84	%		92	%		82	%		82	%		85	%		92	%
Gas	12	%		7	%		12	%		5	%		16	%		12	%		15	%		9	%		15	%		14	%		14	%		9	%
Other	3	%		2	%		—	%		(1	%)		3	%		8	%		1	%		(1	%)		3	%		4	%		1	%		(1	%)
	100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%

1. ELECTRIC UTILITY OPERATIONS

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 retail electric service in Iowa and WPL providing retail and wholesale electric service in Wisconsin. IPL also sells electricity to wholesale customers in Minnesota, Illinois and Iowa. In 2015, IPL completed the sale of its Minnesota electric distribution assets. Refer to Note 3 for further discussion of the sale. Refer to the “Electric Operating Information” tables for additional details regarding electric utility operations.

Jurisdictions - The percentage of regulated electric utility revenues were as follows:

	IPL									WPL
	2015			2014			2013			2015			2014			2013
IUB	93	%		93	%		93	%		—	%		—	%		—	%
PSCW	—	%		—	%		—	%		87	%		86	%		85	%
MPUC	3	%		5	%		5	%		—	%		—	%		—	%
FERC	4	%		2	%		2	%		13	%		14	%		15	%
	100	%		100	%		100	%		100	%		100	%		100	%

Customers - The number of electric customers at December 31, 2015 was as follows:

	Retail			Wholesale			Other			Total
	Customers			Customers			Customers			Customers
IPL	488,582			8			1,042			489,632
WPL	461,466			21			1,859			463,346
	950,048			29			2,901			952,978

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 that include recovery of and a return on investments in electric infrastructure and other costs required to serve customers. Electric transmission service expense is billed to IPL’s Iowa retail electric customers through a transmission cost rider. IPL’s fuel-related 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 fuel-related costs, electric transmission service costs and other costs required to serve customers. Refer to Note 2 and “Rate Matters” in MDA for discussion of utility rate cases.

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. Refer to “Strategic Overview” in MDA for discussion of recent agreements with certain of WPL’s electric wholesale customers related to its proposed Riverside expansion. Refer to “Other Future Considerations” in MDA for discussion of notifications provided to each of IPL and WPL to terminate certain of their wholesale power supply agreements. Refer to Note 3 for discussion of a wholesale power supply agreement between IPL and Southern Minnesota Energy Cooperative, which became effective upon the sale of IPL’s Minnesota electric distribution assets in 2015.

Seasonality - Electric sales are seasonal to some extent with the annual peak normally occurring in the summer months due to air conditioning requirements. Electric sales are also impacted to a certain extent in the winter months due to heating requirements. Maximum peak hour demands were as follows:

	2015								2014
	Summer Peak				Winter Peak				Summer Peak				Winter Peak
	MW		Date		MW		Date		MW		Date		MW		Date
Alliant Energy	5,385		July 13		4,668		January 7		5,426		July 22		4,803		January 6
IPL	3,005		July 13		2,531		January 7		2,840		September 4		2,601		January 6
WPL	2,564		August 14		2,153		January 7		2,594		July 22		2,202		January 6

Competition - Retail electric customers in Iowa and Wisconsin currently do not have the ability to choose their electric supplier, and IPL and WPL have obligations to serve all their retail electric customers. Although electric service in Iowa and Wisconsin is regulated, IPL and WPL still face competition from self-generation by large industrial customers, customer- and third party-owned generation (e.g. solar panels), alternative energy sources, and petitions to municipalize (Iowa) as well as service territory expansions by municipal utilities through annexations (Wisconsin). In addition, IPL’s and WPL’s wholesale customers may choose to purchase their electric energy and capacity needs from the MISO market, independent power producers or other utilities. However, IPL and WPL attempt to retain current customers and attract new customers into their service territories in an effort to keep energy rates low for all their customers.

Renewable Energy Standards - As discussed in greater detail below, the states in which IPL and WPL operate have RES, which establish the amount of energy electric utilities or service providers must supply from renewable resources.

IPL - The Iowa RES requires IPL to purchase or own 49.8 MW of nameplate capacity from alternate energy or small hydro facilities located in its Iowa service area. IPL primarily relies upon RECs generated from the wind projects it owns and renewable energy acquired under PPAs to meet such requirements. IPL currently exceeds the RES requirement.

WPL - The Wisconsin RES requires WPL to increase the portion of its 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 RES required a 6% increase above the benchmark by 2015. Based on this RES, WPL was required to supply a minimum of 9.28% of its total Wisconsin retail electric sales with renewable energy sources by 2015. WPL may reach the RES with renewable energy it generates, it acquires under PPAs or through the use of renewable resource credits. WPL met the 2015 requirements of the RES with its current renewable portfolio, which primarily consists of wind and hydro, as well as the use of excess renewable resource credits generated from previous years. A confirmation on WPL meeting the 2015 renewable requirements is expected from the PSCW in the second half of 2016.

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

Electric Supply - Alliant Energy, 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 has changed with WPL’s purchases of Wisconsin Electric Power Company’s 25% interest in Edgewater Unit 5 in 2011 and Riverside in 2012, the completion of wind projects including WPL’s Bent Tree wind farm in 2011, the expiration of WPL’s Kewaunee PPA in December 2013, IPL’s DAEC PPA for a term from February 2014 through December 2025, WPL’s 150 MW PPA for a term from January 2014 through December 2018, the switch from coal to natural gas as the fuel type at IPL’s M.L. Kapp Unit 2 in June 2015 and IPL’s and WPL’s retirement of various EGUs. Alliant Energy expects its mix of electric supply to change further in the next several years with IPL’s construction of Marshalltown, WPL’s proposed construction of the Riverside expansion, WPL’s retirement of Nelson Dewey Units 1 and 2 and Edgewater Unit 3 in December 2015, and the proposed retirement of additional EGUs. Generation plans are periodically updated to identify longer term electric supply resource needs. These long-term generation plans are intended to meet customer demand, reduce reliance on wholesale market purchases and mitigate the impacts of future EGU 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, retirement of EGUs, EGU outages, transmission system outages or extended periods of extreme weather conditions. Refer to the “Electric Operating Information” tables for a profile of the sources of electric supply used to meet customer demand from 2011 to 2015. Refer to “Strategic Overview” in MDA for details of future generation plans.

Sources of Electric Energy - Sources of electric energy were approximately as follows:

	2015									2014									2013
	IPL			WPL			Total			IPL			WPL			Total			IPL			WPL			Total
Internally generated coal-fired EGUs	38	%		46	%		42	%		43	%		47	%		45	%		41	%		56	%		48	%
Purchased power	46	%		28	%		37	%		47	%		33	%		40	%		49	%		29	%		40	%
Internally generated natural gas-fired EGUs	12	%		20	%		15	%		6	%		13	%		10	%		6	%		9	%		7	%
Internally generated wind farms	4	%		5	%		5	%		4	%		5	%		5	%		4	%		5	%		4	%
Other	—	%		1	%		1	%		—	%		2	%		—	%		—	%		1	%		1	%
	100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%		100	%

Electric Demand Planning Reserve Margin - IPL and WPL are required to maintain a planning reserve margin above their load at the time of the MISO-wide peak to ensure reliability of electric service to their customers. The required installed capacity reserve margin is 15.2% and the required unforced capacity reserve margin is 7.6% for the June 1, 2016 through May 31, 2017 MISO planning year. IPL and WPL currently have adequate capacity to meet the MISO planning reserve margin requirements for the June 1, 2016 through May 31, 2017 MISO planning year.

Generation - IPL and WPL own a portfolio of EGUs located in Iowa, Wisconsin and Minnesota with a diversified fuel mix including coal, natural gas and renewable resources. Refer to “Properties” in Item 2 for details of IPL’s and WPL’s EGUs.

Nameplate Capacity - At December 31, the nameplate capacity of IPL’s and WPL’s EGUs by primary fuel type was as follows:

	2015																		2014
	IPL						WPL						Total						IPL						WPL						Total
	MWs			%			MWs			%			MWs			%			MWs			%			MWs			%			MWs			%
Natural gas	1,249			39	%		1,448			50	%		2,697			44	%		1,031			32	%		1,448			45	%		2,479			39	%
Coal	1,423			44	%		1,167			40	%		2,590			42	%		1,641			51	%		1,463			46	%		3,104			48	%
Oil	343			11	%		—			—	%		343			6	%		347			11	%		—			—	%		347			5	%
Wind	200			6	%		269			9	%		469			8	%		200			6	%		269			8	%		469			7	%
Hydro	—			—	%		41			1	%		41			—	%		—			—	%		41			1	%		41			1	%
Total	3,215			100	%		2,925			100	%		6,140			100	%		3,219			100	%		3,221			100	%		6,440			100	%

Fuel Costs - The average cost of delivered fuel per million British Thermal Units used for electric generation was as follows:

	IPL												WPL
	2015				2014				2013				2015				2014				2013
All fuels		$2.21				$2.50				$2.36				$2.67				$2.82				$2.52
Coal	1.94				2.05				1.99				2.49				2.22				2.21
Natural gas (a)	3.37				6.05				4.63				3.68				5.51				4.86

(a)	The average cost of natural gas includes commodity and transportation costs as well as realized gains and losses from swap and option contracts used to hedge the price of natural gas volumes expected to be used by IPL’s and WPL’s natural gas-fired EGUs.

Coal - Coal is a primary fuel source for internally generated electric supply. 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 EGUs for 2016 through 2018. As of December 31, 2015, existing contracts provide for a portfolio of coal supplies that cover approximately 79%, 55% and 33% of IPL’s and WPL’s estimated aggregate annual coal supply needs for 2016 through 2018, 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. Remaining coal requirements are expected to be met 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 IPL’s and WPL’s coal supply requirements. As of December 31, 2015, existing coal transportation agreements cover IPL’s and WPL’s estimated coal transportation needs for 2016 and 2017. In 2015 and 2016, two of Alliant Energy’s coal suppliers filed for restructuring under Chapter 11 of the U.S. Bankruptcy Code. There has been no significant impact to Alliant Energy, IPL and WPL as a result of these bankruptcy filings.

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 EGUs, 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 55 days for EGUs with year-round deliveries and 30 to 125 days (depending upon the time of year) for EGUs with seasonal deliveries. As of December 31, 2015, actual inventory days ranged from 29 to 92 days for EGUs with year-round deliveries and were 161 days for an EGU with seasonal deliveries. The EGU days on hand were computed based on actual tons of inventory divided by estimated average daily tons burned. Coal inventory levels have been impacted by lower natural gas prices, which makes natural gas-fired generation more economical compared to other fuel sources, such as coal. Coal inventory levels have also been impacted by lower electric demand due to milder temperatures in the fourth quarter of 2015.

Average delivered coal costs moderately declined during the last half of 2015 due to downward rail rate adjustments, lower rail fuel surcharges to historic low levels and lower spot market coal prices. However, average delivered coal costs are expected to slightly increase in the future due to price structures and adjustment provisions in existing coal contracts, in conjunction with expected rising market prices; rate structures and adjustment provisions in existing transportation contracts; and expected future coal and 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. Rate adjustment provisions in current rail transportation contracts are based on changes in the All Inclusive Index Less Fuel as published by the Association of American Railroads. These transportation contracts also contain fuel surcharges that are subject to change monthly based on changes in diesel fuel prices, which are currently at low levels. 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 SO2, NOx and mercury, along with other environmental limitations on EGUs, 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 to: the possible need for railroads to enhance and expand infrastructure, corresponding investments in locomotives and crews, 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. The 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 and strategic alignment of agreement expirations for negotiation purposes, Alliant Energy, IPL and WPL believe they are reasonably insulated against future higher coal transportation rates from the major railroads.

Natural Gas - Alliant Energy owns several larger natural gas-fired EGUs, including IPL’s Emery (603 MW), WPL’s Riverside (675 MW), WPL’s Neenah (371 MW) and Resources’ Sheboygan Falls (347 MW) facilities. WPL has exclusive rights to the output of Sheboygan Falls under an affiliated lease agreement. IPL and WPL also currently own several smaller natural gas-fired EGUs, including IPL’s M.L. Kapp Unit 2 (218 MW) for which the fuel type was switched from coal to natural gas in June 2015. These facilities help meet customer demand for electricity generally during peak hour demands and when natural gas prices are low enough to make natural gas-fired generation economical compared to other fuel sources, such as occurred in 2015. Alliant Energy manages the gas supply to these gas-fired EGUs and provides supply through a combination of third-party deliveries and pipeline transportation and storage contracts held by IPL and WPL. IPL and WPL have contracts to provide storage capacity, as well as firm pipeline transportation per day, as follows (in Dths):

	Storage			Firm Pipeline
	Capacity			Transportation
Riverside	2,500,000			80,000
Emery	1,250,000			60,000

In addition, IPL and WPL have each purchased 5,000 Dths per day of fixed price physical natural gas commodities for Emery and Riverside, respectively, for a five-year term from 2016 through 2020. These purchases represent less than 10% of the expected gas needs of these EGUs.

Refer to “Strategic Overview” in MDA for discussion of IPL’s construction of Marshalltown and WPL’s proposed construction of the Riverside expansion, both of which are natural gas-fired combined-cycle EGUs.

Wind - IPL’s 200 MW Whispering Willow - East wind farm in Franklin County, Iowa began generating electricity in 2009. WPL’s 68 MW Cedar Ridge wind farm in Fond du Lac County, Wisconsin began generating electricity in 2008. WPL’s 201 MW Bent Tree wind farm in Freeborn County, Minnesota began full generation of electricity in 2011. All or some of the renewable energy attributes associated with generation from these sources may be used in future years to comply with RES or other regulatory requirements, or sold to third parties in the form of RECs or other environmental commodities. Refer to “Properties” in Item 2 for the generating capacity of these wind farms.

Purchased Power - IPL and WPL periodically enter into PPAs and purchase electricity from wholesale energy markets to meet a portion of their customer demand for electricity. IPL’s most significant PPA is for the purchase of up to 431 MWs of capacity and the resulting energy from DAEC for a term from February 2014 through December 2025. WPL’s most significant PPA is for the purchase of 150 MWs of energy for a term from January 2014 through December 2018.

IPL’s DAEC PPA - In 2013, the IUB issued an order allowing IPL to proceed with a PPA for the purchase of capacity and energy generated by DAEC located near Palo, Iowa. The IUB also authorized IPL to recover the Iowa retail portion of the cost of the DAEC PPA from Iowa retail electric customers through the energy adjustment clause. The terms of the PPA provide IPL the right to the counterparty’s entire output quantities (70% of the total plant output) in exchange for payment from IPL to the counterparty based on the amount of MWhs received by IPL. Among the terms and conditions of the PPA are guarantees by the counterparty to provide minimum amounts of capacity and energy. The PPA also contains provisions for the replacement of energy from alternative sources under certain conditions as well as provisions that convey to IPL the potential environmental attributes associated with its portion of the output from DAEC.

Refer to Note 1(g) for discussion of IPL’s and WPL’s rate recovery of fuel-related costs and Note 16(b) for details on IPL’s and WPL’s coal, natural gas and other purchased power commitments.

Electric Transmission - IPL and WPL do not own electric transmission assets and currently receive substantially all their electric transmission services from ITC and ATC, respectively. ITC and ATC are independent for-profit, transmission-only companies and are transmission-owning members of the MISO Regional Transmission Organization, Midwest Reliability Organization and Reliability First Corporation Regional Entities. The annual transmission service rates that ITC and ATC charge their customers are calculated each calendar year using a FERC-approved cost of service formula rate template referred to as Attachment “O.” Refer to “Other Future Considerations” in MDA for additional information regarding transmission service charges from ITC and ATC. Refer to Note 1(g) for discussion of a transmission cost rider utilized by IPL for recovery of its electric transmission service expense, and discussion of WPL’s electric transmission service expense, which is recovered from its retail electric customers through changes in base rates determined during periodic rate proceedings. Note 1(g) also discusses escrow accounting treatment for electric transmission service expense, which WPL received as part of its approved retail electric rate case (2015/2016 Test Period) in July 2014 from the PSCW. Refer to Note 18 for details of agreements between ATC and WPL.

ATC - WPL Transco, which is partially owned by WPL and Resources’ subsidiary, ATI, has an ownership interest in ATC. WPL Transco’s capital contributions to ATC are currently funded by ATI, and are included in “Other” in the construction and acquisition expenditures table in “Liquidity and Capital Resources” in MDA. Alliant Energy currently anticipates that ATI will fund capital contributions of approximately $20 million, $21 million, $3 million and $0 to ATC in 2016, 2017, 2018 and 2019, respectively, to help fund future proposed transmission projects. These future proposed transmission projects require approval from various regulatory agencies to construct. Certain of these future proposed transmission projects are currently being challenged by other utilities and other transmission-only companies who have requested to own a portion of the future transmission projects proposed by ATC. Alliant Energy and WPL are currently unable to determine the impact these challenges may have on ATC’s plans to construct these proposed transmission projects and the resulting impact on ATI’s future capital contributions to ATC and WPL’s and ATI’s equity earnings income and dividends received from ATC. In addition, refer to “Other Future Considerations” in MDA for discussion of potential changes to ATC’s return on equity, which could result in Alliant Energy and WPL realizing lower equity income and dividends from ATC in the future.

In 2011, Duke Energy Corporation and ATC announced the creation of DATC, a joint venture that is expected to acquire, build, own and operate new electric transmission infrastructure in North America. DATC continues to evaluate new projects and opportunities, and participates in a competitive bidding process on projects it considers to be viable. DATC is continuing the design and development of a proposed transmission line that would deliver wind energy generated in eastern Wyoming to California and the southwestern U.S. This transmission line is currently estimated to cost approximately $2.5 billion to $3.5 billion. Alliant Energy and WPL are currently unable to determine what impacts DATC and the transmission line project noted above, if constructed, will have on their future equity income, dividends received from ATC, capital contributions to ATC, or ownership in ATC. The expenditures in the construction and acquisition expenditures table in “Liquidity and Capital Resources” in MDA do not include any capital contributions for potential DATC projects.

MISO Markets - IPL and WPL are members of MISO, a FERC-approved Regional Transmission Organization, 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. Corporate Services acts as agent on behalf of IPL and WPL pursuant to service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within the markets operated by MISO. Corporate Services assigns such sales and purchases between IPL and WPL based on statements received from MISO. Refer to Note 18 for additional discussion of these assigned amounts.

Wholesale Energy Market - IPL and WPL participate in the wholesale energy market operated by MISO. 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/or 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.

Ancillary Services Market - IPL and WPL also participate in MISO’s ancillary services market. The ancillary services market integrates the procurement and use of regulation and contingency reserves with the existing wholesale energy market. 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 EGU or transmission line.

Financial Transmission Rights and Auction Revenue Rights - In areas of constrained transmission capacity, costs could be higher due to congestion and its impact on locational marginal prices. 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, 2016.

Multi-value Projects - The MISO tariff identifies costs billed to IPL and WPL, including 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 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. The MISO tariff billed to IPL and WPL also includes costs related to other shared transmission projects, including projects designed to reduce market congestion, to provide interconnection to the transmission grid for new generation, and to ensure compliance with applicable reliability standards. The costs of these projects are primarily 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. Refer to “Other Future Considerations” in MDA for further discussion of MISO transmission charges billed to IPL and WPL.

Resource Adequacy - MISO conducts various studies regarding reliability of electric service to ensure its market participants have adequate resources, either owned or contracted, to meet MISO’s forecasted peak load obligations plus a reserve margin. Only accredited capacity assigned to EGUs from the MISO resource adequacy process is available to meet these requirements. To connect to the transmission system, MISO requires an EGU to obtain an interconnection agreement. In order for an EGU to receive accredited capacity, it must, among other requirements, satisfy all transmission requirements identified in its interconnection agreement prior to the MISO planning year. New EGUs like Marshalltown may not initially receive accredited capacity based on the inability to satisfy all identified transmission requirements. Therefore, accredited capacity may not be granted to such EGUs until all identified transmission requirements are resolved. As members of MISO, IPL and WPL must adhere to these resource adequacy protocols in executing their generation resource plans.

Attachment Y Notices and System Support Resources - MISO requires its market participants (including IPL and WPL, among others) who own EGUs to submit an Attachment Y Notice if they plan to retire an EGU, reduce the capacity of an EGU or suspend all or a portion of the operations of an EGU for a period longer than two months. Upon receiving an Attachment Y Notice, MISO will conduct a study to determine whether all or a portion of the EGU’s capacity is necessary to maintain system reliability. If the EGU’s capacity is determined to be necessary to maintain system reliability, MISO designates the EGU as an SSR. When an EGU is required to continue to operate for system reliability, the market participant may enter into an SSR agreement and negotiate an annual revenue requirement with MISO. The annual revenue requirement for the SSR is subject to FERC approval and is assigned to load serving entities that benefit from the continued operations of the EGU. Alliant Energy, IPL and WPL are currently unable to estimate the amount of aggregate SSR charges that may be assigned to IPL and WPL as load serving entities. Alliant Energy, IPL and WPL are also currently unable to estimate the impacts of any potential SSR designations on EGUs they plan to retire or modify. Refer to “Strategic Overview” in MDA for discussion of EGUs that IPL and WPL currently plan to retire or modify, such as changing from coal-fired to an alternative fuel source, in the next few years. Refer to Note 2 for additional discussion of SSR costs.

Electric Environmental Matters - Refer to Note 16(e) and “Environmental Matters” in MDA for discussion of electric environmental matters, including current or proposed environmental regulations.

Electric Operating Information - Alliant Energy	2015				2014				2013				2012				2011
Operating Revenues (in millions) (a):
Residential		$983.0				$994.5				$1,009.1				$975.9				$985.8
Commercial	667.8				658.0				649.4				611.4				612.1
Industrial	823.3				799.0				765.4				741.8				748.9
Retail subtotal	2,474.1				2,451.5				2,423.9				2,329.1				2,346.8
Sales for resale:
Wholesale	221.0				206.6				195.4				187.6				189.8
Bulk power and other	28.5				2.9				17.7				23.8				52.2
Other	46.9				52.6				52.0				48.8				47.0
Total		$2,770.5				$2,713.6				$2,689.0				$2,589.3				$2,635.8
Electric Sales (000s MWh) (a):
Residential	7,271				7,697				7,824				7,679				7,740
Commercial	6,374				6,449				6,432				6,352				6,253
Industrial	11,735				11,821				11,471				11,555				11,504
Retail subtotal	25,380				25,967				25,727				25,586				25,497
Sales for resale:
Wholesale	3,614				3,586				3,564				3,317				3,372
Bulk power and other	1,228				335				763				1,303				1,757
Other	129				155				152				151				151
Total	30,351				30,043				30,206				30,357				30,777
Customers (End of Period) (a):
Residential	809,634				850,322				847,350				844,388				842,780
Commercial	137,870				139,138				138,520				137,791				136,732
Industrial	2,544				2,871				2,881				2,842				2,895
Other	2,930				3,662				3,657				3,647				3,638
Total	952,978				995,993				992,408				988,668				986,045
Other Selected Electric Data:
Maximum summer peak hour demand (MW)	5,385				5,426				5,820				5,886				5,734
Maximum winter peak hour demand (MW)	4,668				4,803				4,648				4,368				4,423
Cooling degree days (b):
Cedar Rapids, Iowa (IPL) (normal - 769)	732				670				884				1,052				887
Madison, Wisconsin (WPL) (normal - 663)	665				620				709				1,070				814
Sources of electric energy (000s MWh):
Coal	13,040				13,818				14,873				14,680				16,440
Purchased power:
Nuclear (c)	3,741				3,133				5,544				5,483				5,483
Wind (d)	1,190				1,252				1,201				1,188				1,285
Other (d)	6,675				8,074				5,541				7,053				6,244
Gas	4,738				2,971				2,224				1,285				588
Wind (d)	1,441				1,390				1,375				1,198				1,188
Other (d)	189				212				200				183				225
Total	31,014				30,850				30,958				31,070				31,453
Revenue per KWh sold to retail customers (cents)	9.75				9.44				9.42				9.10				9.20

(a)

In 2015, Alliant Energy sold its electric distribution assets in Minnesota to Southern Minnesota Energy Cooperative. At the date of the sale, Alliant Energy had approximately 42,000 electric retail customers in Minnesota. Prior to the asset sale, the electric sales to these retail customers are included in residential, commercial and industrial retail sales. Subsequent to the asset sale, the related electric sales are included in wholesale electric sales pursuant to a wholesale power supply agreement between IPL and Southern Minnesota Energy Cooperative, which is discussed in Note 3.

(b)	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. Refer to “Gas Utility Operations” below for details of heating degree days.

(c)	2013 MWhs include replacement energy provided under the Kewaunee PPA after Kewaunee was shut down in May 2013.

(d)	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.

Electric Operating Information - IPL	2015				2014				2013				2012				2011
Operating Revenues (in millions) (a):
Residential		$540.3				$556.4				$574.3				$529.9				$543.2
Commercial	416.3				410.2				409.6				365.3				366.0
Industrial	453.6				458.5				442.9				408.0				415.4
Retail subtotal	1,410.2				1,425.1				1,426.8				1,303.2				1,324.6
Sales for resale:
Wholesale	56.4				32.2				30.0				27.8				29.6
Bulk power and other	5.1				2.1				2.0				9.5				24.6
Other	32.1				33.9				33.0				30.6				29.5
Total		$1,503.8				$1,493.3				$1,491.8				$1,371.1				$1,408.3
Electric Sales (000s MWh) (a):
Residential	3,843				4,164				4,272				4,141				4,223
Commercial	4,059				4,099				4,118				4,045				3,953
Industrial	6,922				7,132				6,973				7,116				7,080
Retail subtotal	14,824				15,395				15,363				15,302				15,256
Sales for resale:
Wholesale	845				485				419				418				417
Bulk power and other	178				59				98				377				729
Other	67				81				80				81				84
Total	15,914				16,020				15,960				16,178				16,486
Customers (End of Period) (a):
Residential	406,028				445,483				444,905				443,802				443,358
Commercial	80,982				81,853				81,587				81,203				80,506
Industrial	1,572				1,856				1,863				1,836				1,906
Other	1,050				1,385				1,374				1,381				1,381
Total	489,632				530,577				529,729				528,222				527,151
Other Selected Electric Data:
Maximum summer peak hour demand (MW)	3,005				2,840				3,107				3,130				3,131
Maximum winter peak hour demand (MW)	2,531				2,601				2,528				2,404				2,454
Cooling degree days (b):
Cedar Rapids, Iowa (normal - 769)	732				670				884				1,052				887
Sources of electric energy (000s MWh):
Coal	6,263				7,092				6,705				7,302				8,456
Purchased power:
Nuclear	3,741				3,133				3,592				3,641				3,624
Wind (c)	757				798				768				743				661
Other (c)	3,015				3,802				3,766				3,237				3,094
Gas	1,874				1,069				920				1,081				532
Wind (c)	653				622				639				579				568
Other (c)	5				12				22				38				18
Total	16,308				16,528				16,412				16,621				16,953
Revenue per KWh sold to retail customers (cents)	9.51				9.26				9.29				8.52				8.68

(a)

In 2015, IPL sold its electric distribution assets in Minnesota to Southern Minnesota Energy Cooperative. At the date of the sale, IPL had approximately 42,000 electric retail customers in Minnesota. Prior to the asset sale, the electric sales to these retail customers are included in residential, commercial and industrial retail sales. Subsequent to the asset sale, the related electric sales are included in wholesale electric sales pursuant to a wholesale power supply agreement between IPL and Southern Minnesota Energy Cooperative, which is discussed in Note 3.

(b)	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. Refer to “Gas Utility Operations” below for details of heating degree days.

(c)	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.

Electric Operating Information - WPL	2015				2014				2013				2012				2011
Operating Revenues (in millions):
Residential		$442.7				$438.1				$434.8				$446.0				$442.6
Commercial	251.5				247.8				239.8				246.1				246.1
Industrial	369.7				340.5				322.5				333.8				333.5
Retail subtotal	1,063.9				1,026.4				997.1				1,025.9				1,022.2
Sales for resale:
Wholesale	164.6				174.4				165.4				159.8				160.2
Bulk power and other	23.4				0.8				15.7				14.3				27.6
Other	14.8				18.7				19.0				18.2				17.5
Total		$1,266.7				$1,220.3				$1,197.2				$1,218.2				$1,227.5
Electric Sales (000s MWh):
Residential	3,428				3,533				3,552				3,538				3,517
Commercial	2,315				2,350				2,314				2,307				2,300
Industrial	4,813				4,689				4,498				4,439				4,424
Retail subtotal	10,556				10,572				10,364				10,284				10,241
Sales for resale:
Wholesale	2,769				3,101				3,145				2,899				2,955
Bulk power and other	1,050				276				665				926				1,028
Other	62				74				72				70				67
Total	14,437				14,023				14,246				14,179				14,291
Customers (End of Period):
Residential	403,606				404,839				402,445				400,586				399,422
Commercial	56,888				57,285				56,933				56,588				56,226
Industrial	972				1,015				1,018				1,006				989
Other	1,880				2,277				2,283				2,266				2,257
Total	463,346				465,416				462,679				460,446				458,894
Other Selected Electric Data:
Maximum summer peak hour demand (MW)	2,564				2,594				2,752				2,851				2,761
Maximum winter peak hour demand (MW)	2,153				2,202				2,120				1,964				1,991
Cooling degree days (a):
Madison, Wisconsin (normal - 663)	665				620				709				1,070				814
Sources of electric energy (000s MWh):
Coal	6,777				6,726				8,168				7,378				7,984
Purchased power:
Nuclear (b)	—				—				1,952				1,842				1,859
Wind (c)	433				454				433				445				624
Other (c)	3,660				4,272				1,775				3,816				3,150
Gas	2,864				1,902				1,304				204				56
Wind (c)	788				768				736				619				620
Other (c)	184				200				178				145				207
Total	14,706				14,322				14,546				14,449				14,500
Revenue per KWh sold to retail customers (cents)	10.08				9.71				9.62				9.98				9.98

(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. Refer to “Gas Utility Operations” below for details of heating degree days.

(b)	2013 MWhs include replacement energy provided under the Kewaunee PPA after Kewaunee was shut down in May 2013.

(c)	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.

2. GAS UTILITY OPERATIONS

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 WPL providing gas service in Wisconsin. In 2015, IPL completed the sale of its Minnesota natural gas distribution assets. Refer to Note 3 for further discussion of the sale. Refer to the “Gas Operating Information” tables for additional details regarding gas utility operations.

Customers - The number of gas customers at December 31, 2015 were as follows:

	Retail			Transportation /			Total
	Customers			Other Customers			Customers
IPL	224,914			376			225,290
WPL	184,491			251			184,742
	409,405			627			410,032

IPL’s and WPL’s retail gas customers in the above table are billed under base rates established by the IUB 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.

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 and inject it into underground storage fields, and remove it from storage fields in the winter to deliver to customers. The maximum daily winter peak demands were as follows:

	2015				2014
	Dth		Date		Dth		Date
IPL	267,314		January 7		296,190		January 6
WPL	209,289		January 7		234,837		January 6

Competition - Gas customers in Iowa and Wisconsin currently do not have the ability to choose their gas distributor, and IPL and WPL have obligations to serve all their gas customers. Federal and state regulatory policies are in place to bring 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. When natural gas service is available for a given area, customers in such area have generally selected natural gas over propane as a more cost competitive solution for their energy needs. Recently, lower natural gas prices compared to propane prices have resulted in increased customer requests to convert from propane to natural gas. Alliant Energy, IPL and WPL are also currently extending various gas distribution systems in their existing Iowa and Wisconsin service territories to serve new customer demand. Refer to “Strategic Overview” in MDA for further discussion of gas distribution systems.

Gas 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. Recently, IPL and WPL have each purchased 5,000 Dths per day of fixed price physical natural gas commodities for a five-year term from 2016 through 2020.

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. The tariffs for IPL’s and WPL’s retail gas customers provide for subsequent adjustments to their rates in the cost of gas sold. As a result, the decreased natural gas prices do not have a material impact on IPL’s or WPL’s gas margins, but result in lower customer bills.

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 NNG, ANR, NGPL and NBPL allow access to gas supplies located in the U.S. and Canada. Arrangements with FCS provide IPL with gas delivered directly to its service territory. In 2015, the maximum daily delivery capacity for IPL and WPL was as follows (in Dths):

	NNG			ANR			NGPL			FCS			NBPL			Total
IPL	170,142			48,000			76,673			5,000			4,126			303,941
WPL	91,056			167,467			—			—			—			258,523

Gas Demand Planning Reserve Margin - IPL and WPL are required to maintain adequate pipeline capacity to ensure they meet their customers’ maximum daily system demand requirements. Both IPL and WPL currently have planning reserve margins of 2% above their forecasted maximum daily system demand requirements from November 2015 through March 2016.

Refer to Note 1(g) for information relating to utility natural gas cost recovery mechanisms and Note 16(b) for discussion of natural gas commitments.

Gas Environmental Matters - Refer to Note 16(e) and “Environmental Matters” in MDA for discussion of gas environmental matters.

Gas Operating Information - Alliant Energy	2015				2014				2013				2012				2011
Operating Revenues (in millions) (a):
Residential		$215.1				$287.5				$262.5				$224.3				$269.7
Commercial	120.5				172.8				150.3				124.3				155.1
Industrial	14.3				23.4				21.1				16.7				24.5
Retail subtotal	349.9				483.7				433.9				365.3				449.3
Transportation/other	31.3				33.8				30.9				31.0				27.4
Total		$381.2				$517.5				$464.8				$396.3				$476.7
Gas Sales (000s Dths) (a):
Residential	26,672				31,718				29,916				23,071				26,891
Commercial	18,966				23,301				21,892				17,115				19,271
Industrial	2,997				3,710				3,803				3,068				3,848
Retail subtotal	48,635				58,729				55,611				43,254				50,010
Transportation/other	74,162				64,717				60,261				57,532				52,210
Total	122,797				123,446				115,872				100,786				102,220
Retail Customers at End of Period (a):
Residential	364,415				373,319				370,895				368,708				367,497
Commercial	44,613				46,180				45,874				45,684				45,667
Industrial	377				428				441				456				496
Total	409,405				419,927				417,210				414,848				413,660
Other Selected Gas Data:
Heating degree days (b):
Cedar Rapids, Iowa (IPL) (normal - 6,756)	6,300				7,657				7,232				5,901				6,745
Madison, Wisconsin (WPL) (normal - 7,046)	6,667				7,884				7,627				5,964				6,992
Revenue per Dth sold to retail customers		$7.19				$8.24				$7.80				$8.45				$8.98
Purchased gas costs per Dth sold to retail customers		$4.40				$5.52				$4.90				$4.94				$5.88

(a)	In April 2015, Alliant Energy sold its natural gas distribution assets in Minnesota. At the date of the sale, Alliant Energy had approximately 11,000 gas retail customers in Minnesota.

(b)	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.

Gas Operating Information - IPL	2015				2014				2013				2012				2011
Operating Revenues (in millions) (a):
Residential		$120.0				$162.5				$152.8				$126.4				$155.2
Commercial	67.9				96.1				85.7				69.7				87.8
Industrial	10.5				17.4				16.1				12.8				19.0
Retail subtotal	198.4				276.0				254.6				208.9				262.0
Transportation/other	18.9				20.5				19.3				17.8				14.3
Total		$217.3				$296.5				$273.9				$226.7				$276.3
Gas Sales (000s Dths) (a):
Residential	14,472				17,839				16,975				12,955				15,660
Commercial	10,166				12,641				12,051				9,403				10,677
Industrial	2,239				2,804				2,931				2,435				3,023
Retail subtotal	26,877				33,284				31,957				24,793				29,360
Transportation/other	34,129				31,377				32,019				30,992				27,720
Total	61,006				64,661				63,976				55,785				57,080
Retail Customers at End of Period (a):
Residential	199,408				208,240				207,853				207,121				206,964
Commercial	25,289				26,530				26,460				26,439				26,455
Industrial	217				244				250				260				296
Total	224,914				235,014				234,563				233,820				233,715
Other Selected Gas Data:
Maximum daily winter peak demand (Dth)	267,314				296,190				262,076				233,456				264,252
Heating degree days (a):
Cedar Rapids, Iowa (normal - 6,756)	6,300				7,657				7,232				5,901				6,745
Revenue per Dth sold to retail customers		$7.38				$8.29				$7.97				$8.43				$8.92
Purchased gas cost per Dth sold to retail customers		$4.53				$5.54				$4.96				$4.92				$5.96

(a)	In April 2015, IPL sold its natural gas distribution assets in Minnesota. At the date of the sale, IPL had approximately 11,000 gas retail customers in Minnesota.

(b)	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.

Gas Operating Information - WPL	2015				2014				2013				2012				2011
Operating Revenues (in millions):
Residential		$95.1				$125.0				$109.7				$97.9				$114.5
Commercial	52.6				76.7				64.6				54.6				67.3
Industrial	3.8				6.0				5.0				3.9				5.5
Retail subtotal	151.5				207.7				179.3				156.4				187.3
Transportation/other	12.4				13.3				11.6				13.2				13.1
Total		$163.9				$221.0				$190.9				$169.6				$200.4
Gas Sales (000s Dths):
Residential	12,200				13,879				12,941				10,116				11,231
Commercial	8,800				10,660				9,841				7,712				8,594
Industrial	758				906				872				633				825
Retail subtotal	21,758				25,445				23,654				18,461				20,650
Transportation/other	40,033				33,340				28,242				26,540				24,490
Total	61,791				58,785				51,896				45,001				45,140
Retail Customers at End of Period:
Residential	165,007				165,079				163,042				161,587				160,533
Commercial	19,324				19,650				19,414				19,245				19,212
Industrial	160				184				191				196				200
Total	184,491				184,913				182,647				181,028				179,945
Other Selected Gas Data:
Maximum daily winter peak demand (Dth)	209,289				234,837				193,628				176,207				177,041
Heating degree days (a):
Madison, Wisconsin (normal - 7,046)	6,667				7,884				7,627				5,964				6,992
Revenue per Dth sold to retail customers		$6.96				$8.16				$7.58				$8.47				$9.07
Purchased gas cost per Dth sold to retail customers		$4.25				$5.48				$4.83				$4.97				$5.77

(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.

3. OTHER UTILITY OPERATIONS - STEAM - IPL’s Prairie Creek facility is the primary source of steam for IPL’s two high-pressure steam customers. IPL’s largest high-pressure steam customer accounts for approximately 90% of IPL’s steam revenues. This customer is under contract through 2025 for annual steam usage of at least 3.8 million Dths, with certain conditions. IPL’s other high-pressure steam customer is under contract through 2025 for annual steam usage of at least 0.3 million Dths, with certain conditions.

D. INFORMATION RELATING TO NON-REGULATED OPERATIONS

Resources manages a portfolio of wholly-owned subsidiaries and additional investments through the following distinct platforms:

Non-regulated Generation - owns Sheboygan Falls, a 347 MW, simple-cycle, natural gas-fired EGU near Sheboygan Falls, Wisconsin, which is leased to WPL for an initial period of 20 years ending in 2025, and the 99 MW Franklin County wind farm in Franklin County, Iowa.

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.

Other non-regulated investments - includes ATI’s partial ownership interest in WPL Transco, which holds Alliant Energy’s ownership interest in ATC, and several other modest investments.