#1Eos Energy Enterprises Strategic Outlook - Path to Profitability December 12, 2023 Eos. Positively ingenious. eos. TM#2Disclaimer 1 Forward-Looking Statements This presentation includes "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. The words "anticipate," "believe," "continue," "could," "estimate," "expect," "intends," "may," "might," "plan," "possible," "potential," "predict," "project," "should," "would" and similar expressions, as they relate to us, are intended to identify forward-looking statements. These statements appear in a number of places in this presentation and include statements regarding the intent, belief or current expectations of Eos Energy Enterprises, Inc. ("Eos"), including but not limited to statements regarding current expectations with respect to future results and outlook, statement regarding technology and system performance, statement regarding cost reduction initiatives, and market demand and trends, as well as statements regarding the conversion of backlog, LOI and pipeline to revenue, the completion timing for Project AMAZE, the tax credits available to our customers or to Eos pursuant to the Inflation Reduction Act, or regarding our ability to secure financing, including final approval of a loan from the Department of Energy LPO, or our anticipated use of proceeds from any loan facility provided by the US Department of Energy, statements that refer to, projections, forecasts, scenarios or other characterizations of future events or circumstances, including any underlying assumptions. Forward-looking statements are based on our management's beliefs, as well as assumptions made by, and information currently available to them. Because such statements are based on expectations as to future financial and operating results and are not statements of fact, actual results may differ materially from those projected. Factors which may cause actual results to differ materially from current expectations include, but are not limited to: changes adversely affecting the business in which we are engaged; our ability to forecast trends accurately; our ability to generate cash, service indebtedness and incur additional indebtedness; our ability to raise financing in the future; our customer's ability to secure project financing; the amount of final tax credits available to our customers or to Eos Energy Enterprises, Inc. pursuant to the Inflation Reduction Act; uncertainties around our ability to secure final approval of a loan from the Department of Energy, the Loan Programs Office in a timely manner or at all, or the timing of funding and the final size of any loan if approved; the possibility of a government shutdown while we negotiate loan financing documents with the U.S. Department of Energy Loan Programs Office or while we await notice of a decision regarding the issuance of a loan or an advance from the Department Energy Loan Programs Office; our ability to develop efficient manufacturing processes to scale and to forecast related costs and efficiencies accurately; fluctuations in our revenue and operating results; competition from existing or new competitors; the failure to convert firm order backlog and pipeline to revenue; risks associated with security breaches in our information technology systems; risks related to legal proceedings or claims; risks associated with evolving energy policies in the United States and other countries and the potential costs of regulatory compliance; risks associated with changes to U.S. trade environment; risks resulting from the impact of global pandemics, including the novel coronavirus, Covid-19; our ability to maintain the listing of our shares of common stock on NASDAQ; our ability to grow our business and manage growth profitably, maintain relationships with customers and suppliers and retain our management and key employees; risks related to adverse changes in general economic conditions, including inflationary pressures and increased interest rates; risk from supply chain disruptions and other impacts of geopolitical conflict; changes in applicable laws or regulations; and other risks and uncertainties indicated in the company's most recent annual report on Form 10-K and subsequent reports on Forms 10-Q and 8-K, including those under the heading "Risk Factors" therein, and other factors identified in Eos's prior and future SEC filings with the SEC, available at www.sec.gov. Eos cautions that the foregoing list of factors is not exclusive and not to place undue reliance upon any forward-looking statements, which speak only as of the date made. Eos does not undertake or accept any obligation to release publicly any updates or revisions to any forward-looking statements to reflect any change in its expectations or any change in events, conditions or circumstances on which any such statement is based. Industry and Market Data In this presentation, we rely on and refer to information and statistics regarding market participants in the sectors in which Eos competes and other industry data. We obtained this information and statistics from third party sources, including reports by market research firms and company filings. We have not independently verified the accuracy or completeness of, and disclaim and liability with respect to, such third-party sources and the data therein that have been included in this presentation. Trademarks This presentation may contain trademarks, service marks, trade names and copyrights of other companies, which are the property of their respective owners. Solely for convenience, some of the trademarks, service marks, trade names and copyrights referred to in this presentation may be listed without the TM, SMⒸ or ® symbols, but Eos will assert, the fullest extent under applicable law, the rights of the applicable owners, if any, to these trademarks, service marks, trade names and copyrights. Znyth, Eos Znyth, and Eos Z3 are trademarks of Eos Energy Technology Holdings, LLC, wholly owned subsidiary of Eos Energy Enterprises, Inc Key Metrics Backlog. Our backlog represents the amount of revenue that we expect to realize from existing agreements with our customers for the sale of our battery energy storage systems and performance of services. The backlog is calculated by adding new orders in the current fiscal period to the backlog as of the end of the prior fiscal period and then subtracting the shipments in the current fiscal period. If the amount of an order is modified or cancelled, we adjust orders in the current period and our backlog accordingly, but do not retroactively adjust previously published backlogs. We believe that the backlog is a useful indicator regarding the future revenue of our Company. Pipeline. Our pipeline represents projects for which we have submitted technical proposals or non-binding quotes plus customers with letters of intent ("LOI") or firm commitments. Pipeline does not include lead generation projects. Booked Orders. Booked orders are orders where we have legally binding agreements with a Purchase Order ("PO") or Master Supply Agreement ("MSA") executed by both parties.#3Today's Agenda 1 Strategic Framework 2 Differentiated Technology 3 Building Commercial Momentum 4 Path to Profitability 2 J2 C 9.. eos#4Today's Presenters 3 Joe Mastrangelo Chief Executive Officer 6 years at Eos 31 years of experience Francis Richey SVP Research & Development 9 years at Eos 15 years of experience Pranesh Rao SVP Systems Engineering 1+ year at Eos 25 y years of experience Daniel Chang VP Product Management 1+ year at Eos 19 years of experience Nathan Kroeker Chief Financial Officer 1 year at Eos 26 years of experience Marshall Chapin Chief Customer Officer 1 year at Eos 30 years of experience Andy Meserve VP Business Development 1+ year at Eos 21 years of experience Jude Lepri VP FP&A 1+ year at Eos 18 years of experience Broad & Deep Domain Expertise B BLACK & VEATCH ◆ MACQUARIE SYSO A123 SYSTEMS Ner CATERPILLARⓇ spark 'energy enel x SUNCAT B.Basler Electric (USS) United States Steel GE eos#5Strategic Framework Path to Profitability A grid scale stationary storage company 4 How We'll Win 510-650 GWh TAM by 2030¹ 30% - 70% increase vs. 2021 projections Higher Demand Larger Projects Longer Duration 599 Product Differentiation Why We'll Grow System Simplicity Capital Efficient Mfg. Capacity (1) Total Addressable Market (TAM): Geographies are US, EU/UK, India, Australia/New Zealand TAM Source: Third Party Independent Research for Energy Storage Market Update TELY Digital Capabilities Low Product Cost Entitlement Profitable Growth ↑ eos#6A Secular Shift in the Energy Industry -$125B-$160B potential energy storage market by 2030 Opportunity 5 Focus Target 2026 Cumulative Capacity 290 - 340 160-200 70-80 8 Expected capacity represents ~4% of US storage market Market Type (GWh) Targeted geographies all durations 1,2 (1) Storage system average usage short: 0-2 hrs, intraday: 4-12 hrs and inter-day 24+ hrs (2) Target geographies are US, EU/UK, India, Australia/New Zealand (3) Eos current opportunity pipeline (GWh) as of 11/30/23 Source: Third Party Independent Research for Energy Storage Market Update, BNEF - US all durations ¹ US intraday¹ Eos position 2030 Cumulative Capacity 510 - 650 270-400 130-160 Today's current opportunity 3 48³ pipeline 12 - 18% of US storage market, with future upside eos.#7Strategic Framework A Disciplined & Iterative Capacity Expansion Strategy Strong performance vs. select peer group Highest revenue delivered 6 Highest revenue to capex ratio USA manufacturing provides PTC benefits 3 Year Capex¹ 2 Year Revenue² Revenue / Capex Production Plans Company A Company B -$364 $0 0% Paused European facility construction (1) Numbers include 2021, 2022, & 9-months YTD 2023 Property, Plant, and Equipment from public company 10Qs (2) Numbers include 2022 & 9-months of 2023 revenue from public company 10Qs -$113 ~$7 6% Developing Asia mfg. capacity Company C -$21 -$6 27% "Add additional capacity late in 2024" Company D -$471 -$25 5% Paused US facility construction Eos -$57 -$28 49% Gen 2.3 to Z3 Project AMAZE eos#8Strategic Framework Project AMAZE Capacity Expansion Plan Update Forecasted spend currently below budget with focus on accelerating implementation plan 7 ACRO MADE INU.S.A. A Faster Line Implementation + Additional controls engineering resources - $500K + Prototype work-hold, part presentation, and dunnage Deliver Under Budget + Higher line capacity at same capex spend + + Expected ~60 – 70% line 1 shakedown costs vs. plan De-risk Line Implementation FAT at ACRO to lower execution risks + SAT acceleration incentives in place eos.#9Strategic Framework Eos Product Evolution Continued technology improvement driving lower levelized cost of storage (LCOS) Gluing Bonding Performance Metric Non-Flammable Mfg. Cycle Time Energy Density (Wh/L) Round Trip Efficiency (RTE) 8 Self Discharge 20 Year Degradation No Calendar Aging Bolting Gen 1 3 hours 40 65 - 70% 3% per hour 14 - 17% Gen 2 2 hours 50 70 - 75% ~ 2% per hour 14 - 17% Gen 2.3 1.5 hours 85 75% - 78% < 2% per hour 12 - 14% Assembly Eos Z3 < 3 minutes 120 75 - 82% < 1% per hour 9 - 12% Z3 vs. Gen 1 120x 3x +10-12 pts +66% +5 pts eos#109 67C0020 Differentiated Technology Francis Richey SVP Research & Development 9 years at Eos 15 years of experience Daniel Chang VP Product Management 1+ year at Eos 19 years of experience Pranesh Rao SVP Systems Engineering 1+ year at Eos 25 years of experience eos#11Differentiated Technology A Simpler Product Design New configuration utilizing widely available and proven components A Zinc-Based Aqueous Electrolyte Static Battery 10 3 1 3 2 Zinc-bromide High-performance aqueous electrolyte Conductive Plastic Non-degradable bipolar electrodes Graphite felt Non-degradable bipolar electrodes Plastic Fully-sealed polymer frames ZnBr₂ In Use Since 2013 In Use Since 2019 In Use since 2015 In Use Since 2019 Battery grade purified zinc bromide solution Graphite and HDPE composite produced in pellet form and extruded into sheet Graphitized polyacrylonitrile Carbon fiber precursor HDPE High Density polyethylene ● Other Uses ● Flame retardants Mining Fracking Antistatic & electronics Fuel cell Filtration & packaging • Automotive Aerospace Automotive Electronics Construction 100% recyclable components eos.#12Differentiated Technology Zinc Halide Battery Development History Simpler product with improved performance and lower total lifecycle costs MANIFOLD BLOCK ANOLYTE PUMP 11 ACCESS HOLES ANOLYTE RESERVOIR SIX BIPOLAR STACKS-80V CATHOLYTE RESERVOIR Figure 1-120-kWh Zinc-Bronine Battery X-201 Required separator OIL VALVE Carbon power cathode REVERSING VALVE FLOW METER Original Battery - 1983¹ Flow battery requiring pumps and tanks Bromide / Bromine redox CATHOLYTE PUMP Flow Battery System Conductive plastic current collectors Static Hybrid Battery Module Eos Z3 Battery - 2023 Static battery no pumps Eliminated separator Hybrid chloride / bromide redox Graphite felt cathode Conductive plastic current collectors (Titanium in Gen 2.3) ✓ Lower service costs ✓ ✓ Advantages Eliminated 3-4% pump aux load ✓ ✓ Increased performance Lower cost product 15% cell voltage improvement Lower cost raw materials ✓ Reduced degradation ✓ Wider operating temperature ranges ✓ Plastic processing improvements ✓ Improved ability to manufacture at scale (1) R. Bellows, H. Einstein, P. Grimes, E. Kantner, P. Malachesky, K. Newby, H. Tsien, A. Young Exxon Research and Engineering Company Advanced Energy Systems Laboratory Linden, NJ 07036 eos#13Differentiated Technology Driving Toward Higher Energy Density Multiple paths to improve Z3 energy density at lower cost Increased Cell Energy Same electrochemistry, improved materials 12 Reduced cathode felt fiber size Conductive plastic surface texturing Electrolyte additive elimination LENK SEI 10KV WD11mm 5945 Today 50-Qumi SEI 10k WD11mm5545 To Be ~10-15% improvement 500um Improved Module/Enclosure Energy Optimized internal space utilization Non-active components Discharge duration Enclosure packing density Discharge Energy (kWh) 5 10 Discharge Duration (Hours) ~5-10% improvement 15 eos.#14Differentiated Technology TM System Simplicity with Eos Z3™ Inline Energy Cube Designed to extend Eos value proposition for larger project installations 13 Cube-to-Cube connections Fully integrated auxiliary systems 4-corners or 6-points support flexibility Single point interconnection (Marshalling Box) eds eos HVDC +/- A A Connections Aux Fork truck bottom lift Comms Safety [0] 122 ✓ Simplified project design & development ✓ Rapid construction & commissioning ✓ Accelerated install to first energy discharge + + + Site Development & Engineering + Continuous in-line layout, improved site utilization + Simplified AC aux power feed, no HVAC / fire suppression + No concrete slab foundation, ~80% savings per installed cube ↓ ~19% Construction Cost Forklift no cranes External connections only Reduce skilled labor + + + Total Capital Cost Optimization Power cable runs 50% Site density 10% Industry std. inverters eos.#15Differentiated Technology Eos Digital Capability Roadmap Developing advanced control systems to enable larger installations with simpler system integration Integrated Eos Offering Customer Benefits Control Simplicity TADA Large Scale LDES Industry Challenges State of Charge 0000 14 VEGUMI System Balancing Auxiliary Systems Management 1555 G-Tek Custom Electronics Balance batteries precisely State of Charge State of Health Highly accurate Detailed condition of batteries battery capacity AI / ML Calculation engine J No HVAC No fire suppression Reduced Downtime 24/7 Increased reliability Easy EMS integration Increased Revenue Increased site energy Increased availability eos.#1615 Building Commercial Momentum Marshall Chapin Chief Customer Officer 1 year at Eos 30 years of experience Andy Meserve VP Business Development 1+ year at Eos 21 years of experience eos#17Building Commercial Momentum Inflection Point in the Energy Transition $12.9B opportunity pipeline¹ with higher LDES demand 16 Commercial Trends Deeper engagement post DOE LPO & Z3 Launch Opportunity Segmentation Avg. COD 4Q '27 1Q '26 3Q '25 Size > 1 GWh > 250 MWh < 250 MWh $ in billions Amount ~$8.7 -$3.7 ~$0.4 42% utility opportunity pipeline (1) As of 11/30/2023 (2) Average Selling Price (ASP) Note: Numbers may not add due to rounding eos Active Proposals ~54% Developed in 2023 COD Timing ~60% 2026 and beyond 2023 ASP² ~40% Higher than 2021 Discharge Duration ~64% > 6 hrs. of discharge eos#18Building Commercial Momentum How Does Eos Compete? IRR measures total project value across multiple performance parameters 17 System Sizing Operating Costs ITC 4-hour discharge -0.7% -1.0% +2.0% +0.2% +2.5% +0.3% +2.0% eos. +5% Capital Costs RTE Auxiliary Power Operational Flexibility Degradation Service osts Made in America 8-hour discharge -0.5% -0.9% +3.0% +0.4% +3.5% +0.5% +3.5% ● +9% ● ● Total IRR Delta* *All calculations are after tax, unlevered and derived on a 20-year project monetizing capacity and energy arbitrage ● Why it Matters? Higher EPC costs driven by larger footprint (civil works) RTE improves with longer duration discharge 90% lower than other technologies Dispatch flexibility to capture multiple revenue streams Low degradation and no system repowering No HVAC & fire system service Capturing IRA domestic content benefit eos.#1918 TOPULSTE W 4912 Path to Profitability Jude Lepri VP FP&A 1+ year at Eos 18 years of experience Nathan Kroeker Chief Financial Officer 1 year at Eos 26 years of experience eos#20Path to Profitability Z3 Cost Walk from Launch to Scale Cross functional Cost & Density Improvement Program (CDIP) 19 Overhead Direct Labor Materials 100% 31% 21% 48% Z3 Launch -4% + Alternative Materials + Increased Cell Energy + Higher Module & Enclosure Energy R&D -7% + System Energy Density + Digital Capabilities Engineering -25% + Strategic Agreements + Deflation + Insourcing + Volume Leverage + Manufacturing Automation + Improved Yield -44% -20% 1% 19% Z3 @ Scale Labor / OH Materials Supply Chain Operations Forecasted 18-month launch to scale roadmap delivering expected 80% $/kWh cost reduction eos#21Path to Profitability Infrastructure to Support Projected Growth Spend supports sales, research, product design, cost-out, and regulatory requirements Selling, General & Administration $53.0M Non-Cash Public Company Costs IT & All Other Outside Services 20 Payroll Rent & Utilities 12.1 6.5 4.4 6.1 21.5 2.4 FY 2023 Est Peer Group Benchmark ($ in Millions) Stock Compensation & Depreciation Audit Fees & SEC Counsel SOX Implementation D&O Insurance DOE Due Diligence, Capital Raising Costs ~20% Sales ~22% Supply Chain & Operations -29% Finance, Legal, Gov't Relations ~28% HR, IT, Executive 2023 9 Month YTD SG&A R&D Total SG&A / R&D Stock Comp² Company A 85,405 18,295 103,700 $ (7,859) 95,841 $ Non-Cash IT & All Other Outside Services Company B Materials Rent & Utilities Payroll Net SG&A / R&D $ (1) Numbers derived from 2023 public company 10Qs /ER's; Company A, B, C represented on page 6 (2) Stock comp includes G&A / R&D stock comp where defined; Company A represents total company stock comp, no breakout provided Note: Numbers may not add due to rounding 61,207 53,810 115,017 $ (52,472) 62,545 $ Research & Development $18.5M 2.0 1.1 1.5 Company C 3.6 9.1 1.1 FY 2023 Est 22,611 38,790 61,401 $ (6,795) 54,606 $ Eos Stock Compensation & Depreciation Intellectual Property and Patent Protection Z3 Prototype & Testing Alternate Materials for Cost Out -36% Research & Development -64% Product, System, Software Engineering 40,169 13,699 53,868 (9,624) 44,244 eos.#22● ● Path to Profitability Aligning Capacity with Potential Commercial Outcomes Backlog & Pipeline conversion rate & timing drives Project AMAZE implementation (Backlog as of 9/30/23 and Pipeline/LOI as of 11/30/23 - $B) Backlog / LOI Conversion Scenario 21 LOI Conversion Backlog $.075.10 2024 $.15.20 2025 $.40.45 2026 Assumes 75% backlog and 10% LOI to revenue conversion Backlog conversion timing aligned with current COD estimates Pipeline Conversion Scenarios 10% 15% 20% Backlog / LOI conversion Potential Revenue Scenarios Project AMAZE Timing Line 1 Line 2 Line 3 Line 4 $.075 $.08 $.10 2024 Note: The information presented above illustrates hypothetical scenarios for the conversion of backlog, LOI and pipeline to revenue, and is not a representation of management regarding actual conversion thereof. There can be no assurance that results in any future period will reflect the scenarios presented above and actual results could differ materially. $0.4 $0.6 $0.8 $0.15.20 2025 Navigating a Dynamic and Evolving Commercial Environment $1.0 $1.5 $2.0 $0.40.45 2026 eos#23Path to Profitability 2024 Strategic Outlook Recap Positioning to capture larger, longer duration energy storage opportunities 22 2030 TAM 510-650 GWh 30%-70% increase vs 2021 projections Z3 Cost-Out 80% 30% achieved 50% in progress Project AMAZE ✓ Budget Acceleration incentives in place Operating Expenses Flat Lowest in select peer group ● Capital Update Phase 1-State-of-the-art Line 1 Multiple opportunities available Pursuing structured debt and/or equity Phase 2 - Achieve Profitability Anticipated DOE loan closing and funding eos.#2423 eos WELD TEAM eas eos MAT es THANH Glasgad Upcoming Key Events Q4 Earnings Call Early March 2024 Investor Day Tentatively Q2 2024 eos