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© 2022. IEA. All Rights Reserved. 2 This presentation contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”) and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). The forward-looking statements can be identified by the use of forward- looking terminology including “may,” “should,” “likely,” “will,” “believe,” “expect,” “anticipate,” “estimate,” “forecast,” “seek,” “target,” “continue,” “plan,” “intend,” “project,” or other similar words. Other than statements of historical fact included in this Annual Report, all statements regarding expectations for future financial performance, business strategies, expectations for our business, future operations, financial position, estimated revenues and losses, projected costs, prospects, plans, objectives and beliefs of management are forward-looking statements. These forward-looking statements are based on information available as of the date of this Annual Report and our management’s current expectations, forecasts and assumptions, and involve a number of judgments, risks and uncertainties. Although we believe that the expectations reflected in such forward- looking statements are reasonable, we cannot give any assurance that such expectations will prove correct. Forward-looking statements should not be relied upon as representing our views as of any subsequent date. As a result of a number of known and unknown risks and uncertainties, our actual results or performance may be materially different from those expressed or implied by these forward-looking statements. Some factors that could cause actual results to differ include: • potential risks and uncertainties relating to COVID-19 (including new and emerging strains and variants), including the geographic spread, the severity of the disease, the scope and duration of the COVID-19 pandemic, actions that may be taken by governmental authorities to contain the COVID-19 pandemic or to mitigate its impact, and the potential negative impacts of COVID-19 on permitting and project construction cycles, the U.S. economy and financial markets; • supply chain and labor market disruptions; • availability of commercially reasonable and accessible sources of liquidity and bonding; • our ability to generate cash flow and liquidity to fund operations; • the timing and extent of fluctuations in geographic, weather and operational factors affecting our customers, projects and the industries in which we operate; • our ability to identify acquisition candidates and integrate acquired businesses; • our ability to grow and manage growth profitably; • the possibility that we may be adversely affected by economic, business, and/or competitive factors; • market conditions, technological developments, regulatory changes or other governmental policy uncertainty that affects us or our customers; • our ability to manage projects effectively, as well as the ability to accurately estimate the costs associated with our fixed price and other contracts, including any material changes in estimates for completion of projects; • the effect on demand for our services and changes in the amount of capital expenditures by customers due to, among other things, economic conditions, commodity price fluctuations, the availability and cost of financing, and customer consolidation; • the ability of customers to terminate or reduce the amount of work on short or no notice; • customer disputes related to the performance of services; • disputes with, or failures of, subcontractors to deliver agreed-upon supplies or services in a timely fashion; • our ability to replace non-recurring projects with new projects; • the impact of U.S. federal, local, state, foreign or tax legislation and other regulations affecting the renewable energy industry and related projects and expenditures; • the effect of state and federal regulatory initiatives, including costs of compliance with existing and future safety and environmental requirements; • fluctuations in equipment, fuel, materials, labor and other costs; • our beliefs regarding the state of the renewable energy market generally; and • the “Risk Factors” described in the Annual Report, and in our quarterly reports, other public filings and press releases. We do not undertake any obligation to update forward-looking statements to reflect events or circumstances after the date they were made, whether as a result of new information, future events or otherwise, except as may be required under applicable securities laws. SAFE HARBOR STATEMENT

3 © 2022. IEA. All Rights Reserved. A MARKET LEADER IN THE RENEWABLE ENERGY TRANSITION Atlas Clean Energy Index Select ESG Index Memberships Infrastructure and Energy Alternatives (“IEA”) is a leading provider of renewable energy services and transportation construction solutions in the United States. REPORTABLE SEGMENTS RENEWABLES SPECIALTY CIVIL GROWING REVENUE STRONG BACKLOG IMPROVED BALANCE SHEET RENEWABLES FOCUSED STRONG GROWTH TRENDS INDUSTRY TAIL-WINDS LONG-STANDING CUSTOMER RELATIONSHIPS Nasdaq: IEA STOCK TICKER SYMBOL Revenue CAGR(2) 2018-LTM Q1 2022 37% Renewables Revenue % of LTM Q1 2022 71% $2.2 Total Revenue LTM Q1 2022 billion Adjusted EBITDA(1) LTM Q1 2022 million$114.6 (1) See appendix for Adjusted EBITDA reconciliation to net income. (2) Revenue CAGR from full year 2018 (IPO) to LTM Q1 2022.

4 © 2022. IEA. All Rights Reserved. LEADERSHIP POSITIONS EXPANDING LEADERSHIP IN KEY RENEWABLE MARKETS IEA ranks on the 2021 Engineering News-Record Top 400 Contractors and Sourcebook List #2 WIND #8 SOLAR #4 POWER #17 RAIL #5 MINING #18 HIGHWAYS #39 TRANSPORTATION #48 TOP 400

5 © 2022. IEA. All Rights Reserved. RENEWABLE ENERGY DEVELOPMENT HOW IEA ADDS VALUE TO THE PROCESS Customers Renewable EPC Construction Services Illustrative EPC Services Engineering Procurement / Construction • Geotechnical • Preliminary & Detail • Engineering Management • Surveying & Permitting • Engineered Equipment Procurement • Public/Private Roads • WTG Foundations, Offloading, Erection & Installation • Medium Voltage U/G System • High Voltage Substation + Transmission Line • Repowering Illustrative Services • Development • Financing • Procurement and scheduling of key components (panels, blades, and turbines) • Operations IEA Risk Profile Short duration contracts Typical renewable project lasts 12-18 months after Notice to Proceed (NTP) Limited price risk IEA procures critical materials after receiving the NTP to limit price fluctuations from our bid estimate No large contract risk (1) IEA’s wind and solar projects are similar in size with no large contract risk 73% 27% Wind Solar Average Project Size: $50-60mm Illustrative customer base (1) Renewable revenue split based on LTM Q1 2022 results.

6 © 2022. IEA. All Rights Reserved. Constructed over 24.4 GW of wind and solar projects that annually offset 7.3 MILLION HOMES POWERED ANNUALLY 7.1 MILLION VEHICLE EMISSIONS CUT ANNUALLY CO2 – 32.8 million MT | NOx – 17.9 MT | SO2 – 19.5 MT | PM2.5 – 2.2 MT 1) Homes powered per year based on the GW installed compared to the average annual electricity consumption in the US per household, then further adjusted for industry average capacity factors. 2) Passenger vehicle equivalent based on CO2 emissions data using the EPA Greenhouse Gas Equivalencies Calculator. 3) Annual offsets estimated based on the emissions avoided by generating electricity with wind projects and solar PV with cumulative capacity equivalent to IEA’s cumulative installations of renewable energy projects as follows: (i) CO2, sulfur dioxide, nitrogen oxides, and particulate matter from national emission factors in EPA AVERT 2019 calculator; and (ii) annual average capacity factors as provided by EPA AVERT and DC to AC conversion factor for solar PV. 24.4 GW of renewable energy built through 2021 255+ wind and solar projects completed 11,000+ wind turbines erected 40 states renewable energy projects completed in 40 states STRONG ESG PROFILE IEA’S CONTRIBUTIONS TO DECARBONIZATION IN THE USA

7 © 2022. IEA. All Rights Reserved. REPORTING SEGMENTS IEA SEGMENT PROFILES RENEWABLES SPECIALTY CIVIL Wind Solar Power Delivery LTM Financial Performance (Q1-2022) $1.52 Total Revenue billion $130.8 Gross Margin $ million Long-Term Target Gross Margin % 10-12% 8.6% Gross Margin % Heavy Civil Rail Environmental LTM Financial Performance (Q1-2022) $637.7 Total Revenue million $62.6 Gross Margin $ million Long-Term Target Gross Margin % 8-10% 9.8% Gross Margin %Total Backlog $2.08billion $861.2 Total Backlog million

© 2022. IEA. All Rights Reserved. 8 Focused Renewable Exposure 70%+ of IEA’s business comes directly from Wind and Solar construction and services. LTM Revenue from renewables totals over $1.5 billion. Renewables Cost Less than Traditional Power Sources Renewables are the lowest cost form of new generation without incentives. The Levelized Cost of Energy from Wind and Solar is up to 40%-60% lower than the lowest conventional form of power.(1) Renewables are the Preferred Choice of Developers Approximately 90% of all new electrical generation capacity added in the U.S. in 2021 was wind, solar, and other renewable sources.(2) Legislation Provides Upside to Current Forecasts Analysis of the impact from potential legislation shows massive upside. Over the next decade utility-scale solar would see an uplift of 86% from current forecasts with an ITC extension.(2) New Wind Services Business Gaining Traction Expanding addressable market to include maintenance with new Wind Services business Environmental Work Strong Area For Growth Growing coal ash remediation business highlighted by increasing Environmental Remediation revenue (up 134% y/y in Q1-2022) KEY INVESTMENT HIGHLIGHTS EXCITING OPPORTUNITY IN ENERGY TRANSFORMATION (1) Lazard - Levelized Cost of Energy Analysis Version 15.0, Oct 2021. (2) Wood Mackenzie, “US Solar Market Insight: 2021 Year in Review” Mar 2022.

9 © 2022. IEA. All Rights Reserved. U.S. electricity generation from selected fuels AEO 2022 reference case Billion kilowatthours 0 1,000 2,000 3,000 4,000 5,000 6,000 2010 2020 2030 2040 2050 2021 history projections natural gas renewables nuclear coal 40% 21% 19% 19% 36% 42% 11% 11% Source: US Energy Information Administration, Annual Energy Outlook 2022 (AEO2022) Key Takeaways EIA – Annual Energy Outlook 2021 ▪ Wind and Solar are projected to contribute 44% of total US electricity generation by 2050, up from 21% in 2021 ▪ Renewable technologies account for over 57% of the approximately 1,000 GW of cumulative capacity additions projected from 2021 to 2050 ▪ EIA’s 2021 reference case assumes 1) PTC phases out after 2024, 2) ITC, solar receives a 30% tax credit through 2024, 26% for 2024 and 2025 and phasing down to a non‐expiring credit of 10% starting in 2026. ▪ Implies further upside with possible extension of PTC and ITC Renewable technologies account for over 57% of the approximately 1,000 GW of cumulative capacity additions projected from 2021 to 2050 RENEWABLES OUTLOOK DECADES-LONG GROWTH OPPORTUNITY

10 © 2022. IEA. All Rights Reserved. CIVIL OUTLOOK “ONCE-IN-A-GENERATION” INVESTMENT IN INFRASTRUCTURE (1) ARTBA “Market Forecast 2021” 2021 (2) United States Environmental Protection Agency Fiscal Year 2020 Justification of Appropriation - Estimates for the Committee on Appropriations (3) Whitehouse.gov Bipartisan Infrastructure Deal (Infrastructure Investment and Jobs Act) Impact on Key IEA Civil Markets ARTBA Major Construction Markets(1) ARTBA 2020 Annual Spend Estimate(1) Infrastructure Deal Targeted Investments(3) Total Amount Funded(3) Public & Private Highway and Bridge Construction $155 billion Roads, bridges and major infrastructure projects $110 billion Subway and Light Rail Construction $11 billion Modernize public transit $39 billion Class I Railroads $13 billion Passenger and freight rail $66 billion Superfund approved budget (2) $1 billion Clean up Superfund and brownfield sites, reclaim abandoned mine land and cap orphaned gas wells $21 billion

11 © 2022. IEA. All Rights Reserved. CIVIL OUTLOOK LARGEST INCREASE IN FUNDING SINCE THE FEDERAL- AID HIGHWAY ACT OF 1956 (1) Source: ARTBA “$1 Trillion Infrastructure Bill Passes House, Heads to President for Enactment” Nov 5 2021 Bipartisan Infrastructure Deal (Infrastructure Investment and Jobs Act) Impact on Highway Funding

12 © 2022. IEA. All Rights Reserved. COAL ASH REMEDIATION OUTLOOK LARGE OPPORTUNITY WITH LONG-TERM CONTRACTS There are more than 1,000 coal ash impoundments and surface landfills (1) that require EPA-Mandated closure or remediation Coal ash remediation opportunity could be as much as $50 billion to $150 billion(2) The easy to remediate sites are typically closed first, leaving behind higher dollar projects. 10% 90% Closed or remediated Still require closure or remediation Source: (1) United States Environmental Protection Agency, FirmoGraphs LLC CCR Market Overview, and management estimates. (2) Estimated based on assumed average cost to remediate of $25 to $75 per metric ton, the upper end of the range is based on Duke Energy’s publicly announced remediation costs of $8 – $9 billion to close the utility’s 31 ash basins in North Carolina, which contain 120 million tons of CCRs, and 2.3 billion cubic yards of coal ash currently stockpiled in the U.S. according to FirmoGraphs LLC CCR Market Overview. In the Early StagesLarge Multi-Decade Opportunity coal ash impoundments and surface landfills1,000 2M estimated tons per siteX $25 to $75 estimated price per ton for remediationX = $50 to $150B TOTAL OPPORTUNITY

© 2022. IEA. All Rights Reserved. 14 Record Revenue A record for first quarter with quarterly total revenue of $360 million, up 30% year-over-year, with record LTM total revenue of $2.2 billion Continued Strength in 2022 2022 forecasted to be another record year, Revenue expected to grow 15% and Adjusted EBITDA expected to increase 7% (at the midpoint of guidance) Record Solar Performance Record first quarter solar revenue of $126 million, up 275% year-over-year, with record LTM solar revenue of $406 million Strong Backlog Growth Backlog of $2.9 billion represents 10% year-over-year growth, NTM Backlog of $2.1 billion, up 13% year-over-year, providing strong visibility into 2022 BUSINESS HIGHLIGHTS–Q1 2022 SETTING UP FOR RECORD 2022 PERFORMANCE Solid Wind Performance Quarterly wind revenue of $118 million, in line with management expectations, with strong LTM wind revenue of over $1.1 billion (1) See appendix for Adjusted EBITDA reconciliation to net income. Record Environmental Performance Record first quarter environmental revenue of $48 million, up 134% year- over-year, with record LTM environmental revenue of $179 million

© 2022. IEA. All Rights Reserved. 15 STRONG BACKLOG –Q1 2022 EXCELLENT VISIBILITY FOR THE REMAINDER OF 2022 Next Twelve-Month Backlog ($mm) Total Backlog ($mm) ▪ Strong backlog in Q1-2022 of $2.9 billion • YoY increase of $0.3 billion (or +10%) ▪ Renewables Segment backlog of $2,085 million • YoY increase of $136 million (or +7%) ▪ Specialty Civil Segment backlog of $861 million • YoY increase of $134 million (or +18%) ▪ Next Twelve-Month Backlog of $2.1 billion • YoY increase of $233 million (or +13%) $2,116 $2,171 $2,070 $2,916 $2,676 $2,946 $0 $500 $1,000 $1,500 $2,000 $2,500 $3,000 $3,500 YE-2018 YE-2019 YE-2020 YE-2021 1Q-2021 1Q-2022 $1,173 $1,412 $1,629 $2,152 $1,852 $2,085 $0 $500 $1,000 $1,500 $2,000 $2,500 YE-2018 YE-2019 YE-2020 YE-2021 1Q-2021 1Q-2022

© 2022. IEA. All Rights Reserved. 16 SG&A Expense ($mm) Revenues ($mm) Adjusted EBITDA ($mm)(1) $3 -$17 1Q21 1Q22 $25 $35 1Q21 1Q22 Key Themes ▪ Record first quarter revenue of $360 million • Strong start to 2022 with increased full year revenue guidance ▪ Solid next-twelve-month backlog of $2.1 billion provides visibility for continued growth in 2022 ▪ Gross Margins lower than prior year ▪ Renewables down as a result of inflationary pressures on project costs ▪ Specialty Civil down as a result of inflationary pressures and increased close out costs related to a few heavy civil projects ▪ SG&A increased YoY, but more in line with our Q4-2021 run rate ▪ SG&A reflects our continued investment in people and IT infrastructure to support record 2022 guidance% Revenue 1.2% -4.8% (1) See appendix for Adjusted EBITDA reconciliation to net income. Gross Margin (%) 6.0% 1.1% 1Q21 1Q22 $276 $360 1Q21 1Q22 % Revenue 9.0% 9.7% RECORD PERFORMANCE –Q1 2022 STRONG REVENUE WITH LOWER GROSS MARGINS

© 2022. IEA. All Rights Reserved. 17 Key Takeaways ▪ Wind revenues in line with management expectations (down $29 million YoY, or 20%) ▪ Solar revenues up significantly YoY ($126 million vs $34 million the same period last year) • Fastest growing renewable business going forward ▪ Gross Margin % down as a result of inflationary pressures on project costs Key Takeaways ▪ Heavy Civil up 11% YoY due to increased activity ▪ Environmental up strongly YoY • Large, multi-year benefit from contract entered during Q3-2021 • Strong long-term outlook ▪ Rail down YoY • Continued COVID related slow- down and delays • Strong bidding environment provides improvement for balance of 2022 Gross Margin %: 4.5% 2.2% Revenue Gross Margins Re ne w ab le s Sp ec ia lty C iv il $4 $3 1Q21 1Q22 ($mm) Gross Margin %: 6.8% 0.5% $180 $244 1Q21 1Q22 $12 $1 1Q21 1Q22 $96 $117 1Q21 1Q22 SEGMENT RESULTS –Q1 2022 STRENGTH ACROSS BOTH RENEWABLES AND SPECIALTY CIVIL

© 2022. IEA. All Rights Reserved. 18 CAPITAL STRUCTURE KEY FIGURES POST REFINANCING • IEA successfully restructured our capital structure in Q3 2021 • Key activities included: • Equity Offering • Series A Preferred Conversion • Series B Preferred Payoff • High Yield Offering • Expanded Revolver • Total Liquidity of $161.4 million as of 1Q-22 • Current potential shares ~59.1 million (assuming conversion of all SPAC warrants, see appendix for details) • Potential shares ~55.2 million • SPAC warrants ~3.0 million • Anti dilution warrants ~0.9 million ($ in millions) Final Maturity Cost Balance as of 1Q-22 Cash and Equivalents 28.7$ Debt Revolving Credit Facility 8/17/2026 LIBOR + [2% to 3.5%] -$ Term Loan 8/15/2029 6.625% 300.0$ Finance Lease Obligations 5.17% 63.5$ Other Debt 3.0$ Total Debt 366.5$ Net Debt 337.8$ Revolver Availability, net of Letters of Credit 132.7$ Total Liquidity (as of 1Q-22) 161.4$

© 2022. IEA. All Rights Reserved. 19 2022 GUIDANCE AS OF MAY 9, 2022 ($ in Millions) Low High Revenue $2,300 $2,500 Net Income 45.0 51.0 Interest Expense, Net 25.0 26.0 Depreciation & Amortization 47.0 48.0 Expense for Income Taxes 18.0 19.0 EBITDA $135.0 $144.0 Non-Cash Stock Compensation Expense 5.0 6.0 Adjusted EBITDA $140.0 $150.0 • Increasing full year 2022 Revenue guidance • Maintaining full year 2022 Adjusted EBITDA guidance

© 2022. IEA. All Rights Reserved. 21 Dollars in thousands Last- Twelve- Month (LTM) 3-31-2022 Quarter Ended 3-31-2022 Quarter Ended 12-31-2021 Quarter Ended 9-30-2021 Quarter Ended 6-30-2021 Quarter Ended 3-31-2021 Net income (loss) $(90,366) $ (27,071) $ 31,655 $(99,649) $ 4,699 $(20,434) Interest expense 36,365 6,026 6,441 9,403 14,495 14,359 Provision (benefit) for income taxes 2,166 (11,424) 7,176 2,249 4,165 (2,392) Depreciation and amortization expense 48,566 12,286 12,672 12,577 11,031 10,799 EBITDA (3,269) (20,183) 57,944 (75,420) 34,390 2,332 Non-Cash stock compensation expense 6,264 1,630 1,182 1,526 1,926 727 Warrant liability fair value adjustment(1) 5,463 1,428 (12,881) 17,582 (666) 300 Transaction fees(2) 5,130 - 1 5,129 - - Loss on extinguishment of debt(3) 101,006 - - 101,006 - - Adjusted EBITDA $ 114,594 $ (17,125) $ 46,246 $ 49,823 $ 35,650 $ 3,359 1) Reflects an adjustment to the fair value of the Company’s Series B Preferred Stock - anti-dilution warrants and private merger warrant liability. The liabilities are fair value adjustments using different valuation methods. 2) Reflects the transaction fees associated with the debt transaction and new equity offering. 3) Reflects the loss incurred as a result of the extinguishment of the term loan and Series B Preferred Stock. ADJUSTED EBITDA

© 2022. IEA. All Rights Reserved. 22 Common shares in thousands Quarter Ended 3-31-2022 Shares outstanding 48,323 Prefunded warrants 4,327 Employee performance awards and others 2,597 Potential shares 55,247 SPAC warrants 2,981 Anti dilution warrants 907 After SPAC warrants exercise 59,135 SHARE RECONCILIATION Warrant repurchase update (1) Potential shares in thousands (2 : 1 warrant to common ratio) Quarter End 9-30-2021 Repurchased 4Q-2021 Year End 12-31-2021 Repurchased 1Q-2022 Quarter End 3-31-2022 SPAC warrants 8,463 (4,636) 3,827 (846) 2,981 Anti dilution warrants (2) 2,576 (1,411) 1,165 (258) 907 (1) On November 4, 2021, the Company’s Board of Directors authorized a repurchase program for the Company’s publicly traded warrants to purchase common stock, which trade on the Nasdaq under the symbol IEAWW. This repurchase program allows the Company to purchase up to $25.0 million of warrants, at prevailing prices, in open market or negotiated transactions, subjectto market conditions and other considerations, beginning November 11, 2021, and will end no later than the expiration of the warrants on March 26, 2023. As of March 31, 2022, the Company has repurchased 10,963,160 warrants. (2) With the purchase of SPAC warrants, anti dilution warrants are retired on a pro-rata basis.