WEC Energy (WEC) 8-K Regulation FD Disclosure

March 2010 March 2010 March 2010 Exhibit 99.1

Cautionary Statement Regarding Forward-Looking Information Much of the information contained in this presentation is forward-looking information based upon management's current expectations and projections that involve risks and uncertainties. Forward-looking information includes, among other things, information concerning earnings per share, earnings per share growth, dividend payouts and dividend payout ratios, construction costs and capital expenditures, customer and economic growth, electric sales, rate base and the capital structure. Readers are cautioned not to place undue reliance on this forward-looking information. Forward-looking information is not a guarantee of future performance and actual results may differ materially from those set forth in the forward-looking information. In addition to the assumptions and other factors referred to in connection with the forward- looking information, including, without limitation, successful resolution of the Michigan retail rate case; rate recovery of any costs above the PSCW approved amount for the Oak Creek expansion; and continued growth in earnings from ATC, factors that could cause Wisconsin Energy's actual results to differ materially from those contemplated in any forward- looking information or otherwise affect our future results of operations and financial condition include, among others, the following: general economic conditions; business, competitive and regulatory conditions in the deregulating and consolidating energy industry, in general, and, in particular, in the company's service territories; timing, resolution and impact of pending and future rate cases and other regulatory decisions; availability of the company's generating facilities; changes in purchased power costs; changes in coal or natural gas prices and supply and transportation availability; the ability to recover fuel and purchased power costs; varying weather conditions; construction risks; obtaining necessary investment capital to implement the company's Power the Future program; adverse interpretation or enforcement of permit conditions by permitting agencies; equity and bond market fluctuations; the investment performance of the company's pension and other post-retirement benefit plans; the impact of recent and future federal, state and local legislative and regulatory changes; foreign, governmental, economic, political and currency risks; and other factors described under the heading "Factors Affecting Results, Liquidity and Capital Resources" in Management's Discussion and Analysis of Financial Condition and Results of Operations and under the headings "Cautionary Statement Regarding Forward-Looking Information" and "Risk Factors" contained in Wisconsin Energy's Form 10-K for the year ended December 31, 2009 and in subsequent reports filed with the Securities and Exchange Commission. Wisconsin Energy expressly disclaims any obligation to publicly update or revise any forward-looking information.

Key Areas to be Covered Overview of the Company Forecast of Electric Sales Rate Case Activity Renewables Strategy Update on Oak Creek Construction Earnings Outlook

Largest electric and gas company in Wisconsin 1.1 million electric customers 1.0 million natural gas customers Overview of Wisconsin Energy Retail Electric and Gas Utilities

Overview of Wisconsin Energy Power the Future Plan Power the Future We Power builds, finances, and owns four new generating units Two natural gas units - now complete Two coal units - one complete and another nearing completion Leased to and operated by Wisconsin Electric under 25 and 30 year leases

Overview of Wisconsin Energy Power the Future Plan Natural Gas Coal Capacity 1,090 MW 1 1,030 MW 1 Investment $664 million $2.0 billion 2 ROE 12.7% 12.7% Equity 53% 55% Initial Lease Term 25 Years 30 Years Actual & Targeted In-service Dates Unit 1 - July 16, 2005 Unit 2 - May 23, 2008 Unit 1 - February 2, 2010 Unit 2 - August 2010 Consolidated Net Income 2011 Estimate $38 million 3 $ 119 million 3 1All capacity and investment amounts reflect WEC ownership only. Demonstrated capacity for the natural gas units is 1,150MW - value shown in table is amount guaranteed in lease agreement. 2Assumes that the final cost of the Oak Creek project is 105% of the amount originally approved by the PSCW plus WEC's portion of the Bechtel settlement ($61 million). We believe these costs are recoverable, but recovery is subject to our final calculation of costs and to review and approval by the PSCW. 3Includes allocation of holding company debt.

Overview of Wisconsin Energy Wholesale Electric Transmission Wisconsin Energy owns 26.2% of American Transmission Company (ATC) In 2009, ATC contributed $35 million to our net income Represented 9.3% of consolidated earnings ATC's projected capital investment over the next ten years is $2.5 billion ATC rate base at year end 2009 was approximately $2.5 billion Regulated by the FERC for purposes of rates and returns 12.2% return on equity with true-up mechanism Transmission siting comes under state jurisdiction

Forecast of Electric Sales for 2010 2010 Forecast vs. 2009 Actual 2010 Forecast vs. 2009 Normalized Residential 4.2% - 0.2% Small C&I -2.4% - 3.0% Large C&I (ex. Mines) 2.1% 1.7% Total Large C&I 1.8% 1.6% Total Retail 1.2% - 0.4%

Rate Case Activity Wisconsin Jurisdiction Order was received for 2010 retail rate case on December 18, 2009 Allowed returns and equity ratios ROE Equity Wisconsin Electric 10.4% 48.5% to 53.5% Wisconsin Gas 10.5% 45.0% to 50.0% Combined rate base for utilities is projected to be $5.8 billion in 2010

Rate Case Activity Wisconsin Jurisdiction Electric fuel case was filed on February 19 Total jurisdictional increase of $60.5 million or 1.8 percent With a new fuel recovery rate in place annual under recovery is now expected to be $18 to $22 million An increase in natural gas prices as compared to the forecast included in the current fuel rate is a key driver for the increase Expect interim relief in late March with a final review later in the year

Rate Case Activity Michigan Jurisdiction Electric case filed July 3, 2009 Requested $42 million increase (33%) Self implemented $12 million in February Hearings now complete Requested return on equity and equity ratio range match Wisconsin filing Key drivers are Power the Future and transition from historical to forward test period Final order expected in July

Renewable Energy Opportunity Renewable Portfolio Standard 2001-03 Baseline 2010 2015 2020 2025 0.0227 0.0427 0.0827 0.1827 0.2327 Total Renewable Energy Requirement 2010 - 1.4 TWh 2015 - 2.5 TWh 2020 - 5.5 TWh 2025 - 7.3 TWh Required Percentage of Wisconsin Retail Sales Existing Requirement Proposed Requirement

Renewable Energy Opportunity Wind Projects Blue Sky Green Field Completed May 2008 145 MW, $295 million investment Glacier Hills PSCW approval received January 22, 2010 Wisconsin Electric has executed 50 MW of short term Power Purchase Agreements

Renewable Energy Opportunity Biomass and Solar Projects Biomass project Announced 50MW project on September 1 Plan on filing with PSCW in late March Expected investment of $250 million with a target in-service date of 2013 12.5 MW of solar projects Expected investment of $85 to $90 million Targeting 2013 in-service date for initial projects We expect to need additional renewable capacity to meet the 2015 requirement If all of this came from wind projects, it would require almost 500MW All of these projects are subject to PSCW review and approval

Update on Oak Creek Expansion Oak Creek Unit 2 Bechtel is targeting in-service for the end of August Guaranteed in-service date is November 28 Bechtel had sought $517 million plus schedule relief of seven months for Unit 1 and four months for Unit 2 All claims in arbitration with Bechtel have been settled Settlement includes $72 million payment to Bechtel $10 million of this was paid in 2009 We are responsible for 85% of these amounts

Projected Earnings Base in 2011 Electric and Gas Utilities $2.61 Power the Future - - Includes allocation of approximately $375 million of 6.25% rate holding company debt $1.33 Wholesale Electric Transmission - - 26.2% Investment in ATC $0.33 Unallocated holding company debt ($0.27) $4.00

Projected Capital Expenditures 2007 2008 2009 2010E 2011E 2012E Utility 539 606 550 805 1000 804 We Power/Other 671 530 268 146 18 31 1210 1136 818 951 1018 835

Retail Electric and Gas Utilities Expected Earnings Key Assumptions Retail rate base of $5.3 billion in 2009 Expected to grow to $5.8 billion in 2010 and $6.7 billion in 2011 Utilities are projected to contribute at least $2.61 per share to EPS in 2011 Glacier Hills project assumed to cost $367 million - exclusive of AFUDC and reimbursable transmission-and be brought into service in 2011 Projected renewable spending in 2011 and 2012 includes $35 and $145 million, respectively for projects that are to be identified 2010E 2011E 2012E Base 406 436 445 Renewable 97 393 290 Environmental 302 171 69 Breakdown of Utility Capital Expenditures $805 $1,000 $804

Power the Future Expected Earnings 2009 2010 2011 Port Washington #1 & #2 32 32 32 Oak Creek #1 10 62 70 Oak Creek #2 10 31 Key Assumptions Oak Creek #2 in service end of August 2010 - one month change results in +/- 2 cents per share in 2010 Cost estimate of $2 billion for WEC's ownership of the coal units - - 105% of approved amount plus Bechtel settlement Free cash flow of $209 million in 2011 - after capex and debt repayment at We Power level Earnings contribution expected to grow somewhat over time as debt repayment occurs Earnings per Share Contribution Consolidated Basis $1.04 $1.33 $0.42 *Includes allocation of holding company interest. Capitalized interest benefit not included.

Wholesale Electric Transmission Expected Earnings 2010E 2011E ATC 220 273 WEC portion (26.2%) 58 72 Key Assumptions ATC expected to average $250 million annual capital expenditures over the next ten years Implies average $30 million effective annual rate base growth for WEC Expect a $0.33 contribution to EPS in 2011 Excludes potential transmission projects for renewables or other regional overlay Projected Capital Expenditures

Financing and Dividend Policy Capital Structure Goals Reach and maintain 55% debt to capital by the end of 2013 Assumes half of hybrid securities are treated as common equity Current Dividend Policy Target a dividend payout ratio of 40-45 percent of earnings this year as well as 2011 Target 45-50 percent of earnings starting in 2012 Do not expect to issue any additional shares

2009 2010 2011 1.35 1.6 1.8 $1.60 to $1.80 Projected Growth in Earnings and Dividends 2009 2010 2011 3.2 3.65 4 Earnings per Share Dividends per Share $3.65 to $3.75

Solid utility franchises with strong projected growth in rate base Power the Future program almost complete - highly visible earnings and strong cash flow Investment in American Transmission Company provides an additional regulated growth opportunity Positioned to deliver among the best risk-adjusted returns in the industry Key Takeaways on Wisconsin Energy