Powering BeyondWells Fargo Equity Investor Meetings

April 6 , 2018

Safe HarborThis presentation contains statements that may be considered forward looking statements, such as management’s expectations of financial objectives and projections, capital expenditures, earnings growth, plant retirements, rate base, and new generation plans. These statements speak of the Company’s plans, goals, beliefs, or expectations, refer to estimates or use similar terms. Actual results could differ materially, because the realization of those results is subject to many uncertainties including regulatory approvals and results, unanticipated construction costs or delays, economic conditions in our service territories, and other factors, some of which are discussed in more detail in the Company’s Form 10-K for the year ended December 31, 2017. All forward looking statements included in this presentation are based upon information presently available and the Company assumes no obligation to update any forward looking statements.

In addition, this presentation contains non-GAAP financial measures. The reconciliations between the non-GAAP and GAAP measures are provided in this presentation.

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Investment Considerations• Attractive total return

• Long term earnings growth rate of 5-7% using 2017 non-GAAP temperature normalized base of $1.99 per share. Projected 6% earnings growth for 2018.

• Target dividend payout of 60-70% of consolidated earnings. Forecasting a dividend of $1.34 per share for 2018, a 6% increase over 2017.

• Future strategic investments focused on electric and gas distribution, as well as renewable and gas generation

• Constructive regulatory environments

• Strong balance sheet and liquidity

• 99% of non-GAAP earnings from continuing operations generated by regulated operations in 2017

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Regulated Utility Profile2017 data IPL WPL Total

Electric Customers 490,595 471,526 962,121

Electric Retail Sales (000s MWh) 14,356 10,739 25,095

Electric Wholesale Sales (000s MWH) 1,338 2,301 3,639

Summer Peak Demand (MW) 2,968 2,476

Gas Customers 224,041 189,013 413,054

Gas Sales (000s Dths) 65,945 60,221 126,166

Operating Revenues (millions) $1,870 $1,473 $3,382

Service Territory Advantages• Favorable commission rankings• Economic diversity• High quality renewable resources• Access to ANR, Northern Border, and Northern Natural Gas pipelines• Access to Powder River Basin coal 

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Iowa“IPL”

Wisconsin“WPL”

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Benefits of Wind EnergyHELPS KEEP RATES LOW• Turbine cost has dropped ~ 40% in the last 10 years• Improvements in turbine technology maximize energy output• Generation production tax credits for 10 years• No associated fuel expense, helping provide cost stability• Reduced fuel, along with tax credits, offset capital recovery

STRENGTHENS OUR COMMUNITIES• Provides tax revenues to support local services• Creates jobs and helps grow local economies• Lease payments for land owners• Helps spur improvements to strengthen the power grid• Attracts companies focused on sustainability

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Wind Development ProgressRegulatory Approvals

Iowa (IPL) Wisconsin (WPL)

RPU I: IUB approval for up to 500 MW in 2016

RPU II: filed additional IUB request in August 2017 for up to 500 MW

Plan to request construction authority from the PSCW for up to 150 MW of wind

* NCF = Net Capacity Factor for 2017, for developed sites

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Location Size (MW) NCF * In‐Service

Cedar Ridge 68 MW 30% 2008

Forward Energy 55 MW (of 129) 30% 2008

Whispering Willow East / Franklin County 300 MW 36% 2009 / 2012

Bent Tree 200 MW 32% 2011

Upland Prairie up to 300 MW 44‐46% 2019

English Farms up to 170 MW 42‐44% 2019

Whispering Willow Expansion up to 200 MW 47‐49% 2020

Alliant Energy Solar

Dubuque:Utility‐scale Solar

Indian CreekNature Center:Partnership and

Community Driven

Rock River PPA:  Environmental mitigation

Madison HQ:  Research and Education

Over 8.5MW in Operation Future DevelopmentProjects in Capital Expenditure Plan:• Marshalltown: 1.5 MW offset plant auxiliary power• West Riverside: 2.0 MW offset plant auxiliary power

Considerations for additional solar investments:• Site solar assets where they provide grid benefits (defer

Transmission and Distribution investment, address congestion issues, provide non-wires alternative, etc.)

• Provide customers the opportunity to host our solar at their facility (under development as a product offering)

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Gas Generation Investments Drive Growth –Compliment Renewables

WPL’s West Riverside Energy Center Need resulting from planned coal and gas retirements and modest load growth An approximate 730 MW combined-cycle natural gas facility WPL’s share of estimated cost is $640 million for facility, excluding transmission

network upgrades and allowance for funds used during construction (AFUDC) Approved by Public Service Commission of Wisconsin (PSCW) in May 2016 AECOM selected as engineering, procurement and construction contractor GE Frame 7FA.05 combustion turbines In-service by early 2020

WPL will provide book-value purchase options for partial ownership of the facility.

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Utilities and electric cooperatives Purchase option amount Option timingAdams‐Columbia Electric Cooperative (ACEC)Rock Energy Cooperative (REC)Central Wisconsin Electric Cooperative (CWEC)

approximately 65 megawatts Options exercised January 2018

Wisconsin Public Service Corporation (WPS) up to 200 megawatts 2020 ‐ 2024Madison Gas and Electric Company (MGE) up to 50 megawatts 2020 ‐ 2025

Electric Distribution StrategyGrid Enhancements and Customer Need

• Distributed Generation/Renewable integration• Integrate planning with generation and transmission• Increase remote monitoring and control• Eliminate lower voltage systems• Resiliency improvements (incl. underground/hardening)• Enhanced communication network• Increased data and analytics• Utility as “trusted advisor” for technical solutions• Advanced metering infrastructure in Iowa

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Natural Gas StrategyReliability and Customer Growth

• Preparing for expected PHMSA rules‒ Modifying existing pipes for enhanced inspection and verification

requirements‒ Replacing and making modifications to aging gas transmission lines

• Increasing remote monitoring • Replacing distribution line made of certain material through

the Integrity Management program• Add capacity to areas of growth potential• Modify tariffs to promote growth • Utility as “trusted advisor” for natural gas solutions• Advanced metering infrastructure in Iowa

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Capital Expenditures2018 – 2021 Capital Expenditures

$5.4 Billion

OtherGas

Distribution

ElectricDistribution

OtherGeneration

WestRiverside

RenewableProjects

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$-

$0.5

$1.0

$1.5

$2.0

2018 2019 2020 2021

$1.7 $1.7

$1.0 $1.0

(In billions)

Estimated Capital Expenditures Post 2021(2022-2026 estimated capital expenditures, excluding AFUDC)

$5.0 billionElectric Distribution

New Generation

Generation Improvements

and Maintenance

GasDistribution

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2017 2018 2019 2020

Rate Base Growth Drives Earnings Growth

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DilutionRising Interest Expense

Regulatory Lag

5-7% projected 

Earnings per Share 

growth rate through 2021

Financing Investments

Up to $700 million of debt at IPL (refinancing $350 million)

Up to $1 billion of debt at AEF with AEC guarantee (refinancing $595 million LTD and ~$300 million commercial paper)

Up to $200 million of common equity through an at-the-market offering (ATM) Program and the Shareowner Direct Plan.

Interest Rates of 2018 Maturities IPL - $100 million of 5.875% Senior Debentures IPL - $250 million of 7.25% Senior Debentures AEF - $500 million variable rate term loan, ~2% at 12/31/2017 AEF - $95 million variable rate term loan, ~2% at 12/31/2017

2018 FinancingsLong-term Debt Maturities

(in millions)

$- $100 $200 $300 $400 $500 $600 $700 $800 $900

$1,000

2018 2019 2020 2021 2022

IPL WPL SERVCO AEF

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Key Regulatory InitiativesInterstate Power and Light Estimated Key Dates

Iowa Utilities Board

• Decision regarding Retail Electric Base Rate Review – Test Year 2016 (RPU‐2017‐0001)

• File 2019‐2023 Energy Efficiency Plan (EEP‐2017‐002)

• Decision regarding Wind Expansion Advance Ratemaking Principles (RPU‐2017‐0002) Q1 2018

• File Retail Gas Base Rate Review – Test Year 2017 Q2 2018

• Decision regarding ratemaking treatment of the effect of the Tax Cut and Jobs Act of 2017 (INU‐2018‐0001) Q2 2018

Federal Energy Regulatory Commission (FERC)

• Decision regarding authorized return on equity (ROE) amounts for MISO transmission owners’ second complaint H1 2018

Wisconsin Power and Light

Public Service Commission of Wisconsin

• Decision regarding the purchase of an interest in Forward Wind Energy Center (5‐BS‐226)

• File for Wind Expansion Construction Authority  H1 2018

• File Retail Electric and Gas Rate Review – Test Periods 2019 and 2020 Q2 2018

• Decision regarding ratemaking treatment of the effect of the Tax Cut and Jobs Act of 2017 (05‐AF‐101) Q2 2018

FERC

• Decision regarding the purchase of an interest in Forward Wind Energy Center (FERC 203 filing)

• Decision regarding authorized ROE amounts for MISO transmission owners’ second complaint H1 2018

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Incremental Growth Opportunity - ATCATC’s Midwest Operations (16% equity ownership interest):• Projected capital expenditures of $3.6 to $4.4 billion over 10 years from 2016-2025

‒ Rate Base: 13-month average rate base approx. $3.3 billion‒ Capital structure: Hypothetical 50% equity component‒ Annual true-up mechanism for revenue requirement‒ Current return on construction work-in-progress

ATC’s Business Development (20% equity ownership interest):• ATC – Alaska Project – 6 munis or coops develop a Transco model for Alaska’s Railbelt

• Established 50/50 Joint Venture with Duke Energy in 2011 (Duke-ATC LLC or DATC)

$- $100 $200 $300 $400 $500 $600

2017 2018 2019 2020

ATC Midwest OperationsProjected Capital Expenditures

(in millions)

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Attractive Growth inEarnings, Dividends and Total Returns

Adjusted (non-GAAP temperature normalized)

Earnings per Sharefrom continuing operations

Dividends per Common Share

(a) Annual common stock dividend target. Payment of the quarterly dividends is subject to the actual dividend declaration by the Board of Directors.

$1.70  $1.79  $1.88 $1.99 

$2.11 

2014 2015 2016 2017 2018E

$1.02 $1.10 

$1.18 $1.26 

$1.34 

2014 2015 2016 2017 2018E

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$100

$150

$200

$250

2012 2013 2014 2015 2016 2017Alliant Energy Corporation (LNT)S&P 500 IndexEEI Utilities

Total Shareholder Return

Comparison of cumulative five-year total return when investing $100 on December 31, 2012

(a)

Charitable Contributions by Alliant and its employees

$7

Environmental, Social, Governance

million in 2017

Carbon Dioxide Emissions 2030 targeted reduction

40% from 2005 levels

Fossil Generation Water Withdrawals2030 targeted reduction

75% from 2005 levels

Gender Diversity in the boardroom

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Women 55%Board

Diversity

Renewable Investments

$2 billion 2016 - 2020

At end of 2017, achieved 30% At end of 2017, achieved 25%

Reconciliation between GAAP and Non-GAAP Measures

2014 2015 2016 2017GAAP EPS from continuing operations $1.74 $1.69 $1.65 $1.99

• Temperature impacts (0.04) 0.04 0.06

Non‐GAAP Adjustments:

• Losses from sales of Minnesota distribution assets 0.04

• Voluntary employee separation charges 0.02

• Valuation charge related to the Franklin County wind farm 0.23

• Tax Reform (0.08)

• Net write‐down of regulatory assets due to IPL electric rate review settlement 0.02

Non‐GAAP temperature normalized EPS from continuing operations $1.70 $1.79 $1.88 $1.99

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