#1PROTERRA Revolutionizing Commercial Vehicle Electrification January 2021 ARCLIGHT CLEAN TRANSITION PROTERRA POWERED ERRA QO *** TO OF PROTERRA ZX5 DUOPOWER TECHNOLOGY BATTERY ELECTRIC ZERO EMISSIONS ALL THE POWER PROTERRA#2INTRODUCTION PROTERRA Disclaimer This presentation (together with oral statements made in connection herewith, the "Presentation") is for informational purposes only to assist interested parties in making their own evaluation with respect to the proposed business combination (the "Business Combination") between ArcLight Clean Transition Corp. ("ArcLight") and Proterra Inc. ("Proterra" or the "Company"). By accepting this Presentation, you acknowledge and agree that all of the information contained herein or disclosed orally during this Presentation is confidential, that you will not distribute, reproduce, disclose or use such information for any purpose other than for the purpose of your firm's participation in the potential financing, that you will not distribute, reproduce, disclosure or use such information in any way detrimental to Proterra or Arclight, and that you will return to Arclight and Proterra, delete or destroy this Presentation upon request. Further, by accepting this Presentation, the recipient agrees to maintain all such information in strict confidence, including in strict accordance with any other contractual obligations applicable to the recipient and all applicable laws. You are also being advised that the United States securities laws restrict persons with material non-public information about a company obtained directly or indirectly from that company from purchasing or selling securities of such company, or from communicating such information to any other person under circumstances in which it is reasonably foreseeable that such person is likely to purchase or sell such securities on the basis of such information. The information contained herein does not purport to be all-inclusive and none of ArcLight, the Company or Morgan Stanley & Co. LLC, Barclays Capital, Inc., and BofA Securities, Inc. (the "Placement Agents") nor any of their respective subsidiaries, stockholders, shareholders, affiliates, representatives, control persons, partners, directors, officers, employees, advisers or agents make any representation or warranty, express or implied, as to the accuracy, completeness or reliability of the information contained in this Presentation. You should consult your own counsel and tax and financial advisors as to legal and related matters concerning the matters described herein, and, by accepting this Presentation, you confirm that you are not relying upon the information contained herein to make any decision. The recipient shall not rely upon any statement, representation or warranty made by any other person, firm or corporation (including, without limitation, the Placement Agents or any of their respective affiliates or control persons, officers, directors and employees) in making its investment or decision to invest in the Company. To the fullest extent permitted by law, in no circumstances will ArcLight, the Company, or any of their respective subsidiaries, stockholders, shareholders, affiliates, representatives, control persons, partners, directors, officers, employees, advisers or agents be responsible or liable for any direct, indirect or consequential loss or loss of profit arising from the use of this Presentation, its contents, its omissions, reliance on the information contained within it, or on opinions communicated in relation thereto or otherwise arising in connection therewith. In addition, this Presentation does not purport to be all-inclusive or to contain all of the information that may be required to make a full analysis of the Company, the potential financing or the Business Combination. The general explanations included in this Presentation cannot address, and are not intended to address, your specific investment objectives, financial situations or financial needs. Use of Data Certain information contained in this Presentation relates to or is based on studies, publications, surveys and the Company's own internal estimates and research. In addition, all of the market data included in this Presentation involves a number of assumptions and limitations, and there can be no guarantee as to the accuracy or reliability of such assumptions; neither the Company, ArcLight, the Placement Agents nor their representatives or affiliates assumes any responsibility for updating this Presentation based on facts learned following its use. Finally, while the Company believes its internal research is reliable, such research has not been verified by any independent source and none of ArcLight, the Company or the Placement Agents, nor any of their respective affiliates nor any of its or their control persons, officers, directors, employees or representatives make any representation or warranty with respect to the accuracy of such information. Forward-Looking Statements Certain statements in this Presentation may be considered forward-looking statements. Forward-looking statements generally relate to future events or ArcLight's or the Company's future financial or other performance metrics. For example (and without limitation), statements concerning the following include forward-looking statements: summary financial forecast; projections of operating performance, revenues, gross margin, expenses, capital expenditures, total cost of goods sold, gross (loss) profit; estimates and projections regarding future manufacturing capacity; projections and estimates of market opportunity and market share; future profitability; the Company's business plan; market acceptance of the Company's offerings, the Company's ability to further attract, retain, and expand its customer base; the Company's ability to timely and effectively scale its production and manufacturing processes; the Company's ability to develop new products and services and bring them to market in a timely manner; the Company's expectations concerning relationships with strategic partners, suppliers, and other third parties; the Company's ability to maintain, protect, and enhance its intellectual property; future acquisitions, ventures or investments in companies or products, services, or technologies; the Company's ability to attract and retain qualified employees; continuation of favorable regulations and government incentives affecting the markets in which the Company operates; the proceeds of the Business Combination and the Company's expected cash runway; and the potential effects of the Business Combination on Arclight and the Company. In some cases, you can identify forward-looking statements by terminology such as "believe," "may," "will," "potentially," "estimate," "continue," "anticipate," "intend," "could," "would," "project," "target," "plan," "expect," or the negatives of these terms or variations of them or similar terminology. Such forward-looking statements are subject to risks, uncertainties, and other factors which could cause actual results to differ materially from those expressed or implied by such forward looking statements. These forward-looking statements are based upon estimates and assumptions that, while considered reasonable by ArcLight and its management, and the Company and its management, as the case may be, are inherently uncertain and subject to material change. New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and uncertainties. Factors that may cause actual results to differ materially from current expectations include, but are not limited to, various factors beyond management's control, including general economic conditions and other risks, uncertainties and factors set forth in the section entitled "Risk Factors" and "Cautionary Note Regarding Forward-Looking Statements" in ArcLight's final prospectus relating to its initial public offering, dated September 22, 2020, and other filings with the Securities and Exchange Commission (SEC), as well as factors associated with companies, such as the Company, that are engaged in commercial electric vehicle technology, including anticipated trends, growth rates, and challenges in those businesses and in the markets in which they operate; macroeconomic conditions related to the global COVID-19 pandemic; trends with respect to government funding for public transit; the willingness of corporate and other public transportation providers to adopt and fund the purchase of electric vehicles for mass transit; expected adoption of electrification technologies for commercial vehicles; the size and growth of the market for alternative energy vehicles in general and medium- and heavy-duty electric vehicles, including transit buses and other commercial vehicles, in particular, the effects of increased competition; the ability to stay in compliance with laws and regulations that currently apply or become applicable to the commercial electric vehicle technology business and government contractors; the failure to realize the anticipated benefits of the Business Combination; the amount of redemption requests made by ArcLight's public stockholders; the ability of the issuer that results from the Business Combination to issue equity or equity-linked securities or obtain debt financing in connection with the Business Combination or in the future. Nothing in this Presentation should be regarded as a representation by any person that the forward-looking statements set forth herein will be achieved or that any of the contemplated results of such forward-looking statements will be achieved. You should not place undue reliance on forward-looking statements in this Presentation, which speak only as of the date they are made and are qualified in their entirety by reference to the cautionary statements herein. Neither ArcLight nor the Company undertakes any duty to update these forward-looking statements. Use of Projections This Presentation contains projected financial information with respect to Proterra. Such projected financial information constitutes forward-looking information, and is for illustrative purposes only and should not be relied upon as necessarily being indicative of future results. The assumptions and estimates underlying such financial forecast information are inherently uncertain and are subject to a wide variety of significant business, economic, competitive and other risks and uncertainties that could cause actual results to differ materially from those contained in the prospective financial information. See "Forward-Looking Statements" paragraph above. Actual results may differ materially from the results contemplated by the financial forecast information contained in this Presentation, and the inclusion of such information in this Presentation should not be regarded as a representation by any person that the results reflected in such forecasts will be achieved. January 2021 2#3INTRODUCTION Disclaimer (Cont'd) PROTERRA Use of Projections (Cont'd) Neither ArcLight's nor the Company's independent auditors have audited, reviewed, compiled or performed any procedures with respect to the projections for the purpose of their inclusion in this Presentation, and accordingly, neither of them expressed an opinion or provided any other form of assurance with respect thereto for the purpose of this Presentation. In preparing and making certain forward-looking statements contained in this presentation, Proterra and ArcLight made a number of economic, market and operational assumptions. Notably, statements regarding the Company's 2025 vision, and summary financial forecast are, without limitation, subject to material assumptions regarding the Company's ability to economically manufacture and distribute its products at scale and meet its customers' business needs, the Company's ability to successfully execute its growth strategy, the Company's ability to maintain required strategic supply arrangements, rates of adoption of battery electric vehicles by customers in the markets in which the Company operates, and continuation of favorable regulations and government incentives affecting the markets in which the Company operates. The Company cautions that its assumptions may not materialize and that current economic conditions render such assumptions, although believed reasonable at the time they were made, subject to greater uncertainty. Additional Information In connection with the proposed Business Combination, ArcLight intends to file with the SEC a registration statement on Form S-4 containing a preliminary proxy statement/prospectus of ArcLight, and after the registration statement is declared effective, ArcLight will mail a definitive proxy statement/prospectus relating to the proposed Business Combination to its shareholders. This Presentation does not contain all the information that should be considered concerning the proposed Business Combination and is not intended to form the basis of any investment decision or any other decision in respect of the Business Combination. ArcLight's shareholders and other interested persons are advised to read, when available, the preliminary proxy statement/prospectus and the amendments thereto and the definitive proxy statement/prospectus and other documents filed in connection with the proposed Business Combination, as these materials will contain important information about the Company, ArcLight and the Business Combination. When available, the definitive proxy statement/prospectus and other relevant materials for the proposed Business Combination will be mailed to shareholders of ArcLight as of a record date to be established for voting on the proposed Business Combination. Shareholders will also be able to obtain copies of the preliminary proxy statement/prospectus, the definitive proxy statement/prospectus and other documents filed with the SEC, without charge, once available, at the SEC's website at www.sec.gov, or by directing a request to: ArcLight Clean Transition Corp., 200 Clarendon Street, 55th Floor, Boston, MA 02116. Financial Information The financial information and data contained in this Presentation is unaudited and does not conform to Regulation S-X promulgated under the Securities Act of 1933, as amended (the "Securities Act"). Accordingly, such information and data may not be included in, may be adjusted in or may be presented differently in, the registration statement to be filed by ArcLight and Proterra with the SEC. Participants in the Solicitation ArcLight, the Company and their respective directors and executive officers may be deemed participants in the solicitation of proxies from ArcLight's shareholders with respect to the proposed Business Combination. A list of the names of ArcLight's directors and executive officers and a description of their interests in ArcLight is contained in ArcLight's final prospectus relating to its initial public offering, dated September 22, 2020, which was filed with the SEC and is available free of charge at the SEC's web site at www.sec.gov, or by directing a request to ArcLight Clean Transition Corp., 200 Clarendon Street, 55th Floor, Boston, MA 02116. Additional information regarding the interests of the participants in the solicitation of proxies from ArcLight's shareholders with respect to the proposed Business Combination will be contained in the proxy statement/prospectus for the proposed Business Combination when available. No Offer or Solicitation This Presentation shall not constitute a "solicitation" as defined in Section 14 of the Securities Exchange Act of 1934, as amended. This Presentation does not constitute an offer, or a solicitation of an offer, to buy or sell any securities, investment or other specific product, or a solicitation of any vote or approval, nor shall there be any sale of securities, investment or other specific product in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. Any offering of securities (the "Securities") will not be registered under the Securities Act, and will be offered as a private placement to a limited number of "qualified institutional buyers" (as defined in Rule 144A under the Securities Act) or institutional "accredited investors" (within the meaning of Rule 501(a) under the Securities Act) and "Institutional Accounts" as defined in FINRA Rule 4512(c). Accordingly, the Securities must continue to be held unless a subsequent disposition is exempt from the registration requirements of the Securities Act. Investors should consult with their counsel as to the applicable requirements for a purchaser to avail itself of any exemption under the Securities Act. The transfer of the Securities may also be subject to conditions set forth in an agreement under which they are to be issued. Investors should be aware that they might be required to bear the final risk of their investment for an indefinite period of time. Neither the Company nor ArcLight is making an offer of the Securities in any state where the offer is not permitted. NEITHER THE SEC NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED OF THE SECURITIES OR DETERMINED IF THIS PRESENTATION IS TRUTHFUL OR COMPLETE. Trademarks and Trade Names Proterra and ArcLight own or have rights to various trademarks, service marks and trade names that they use in connection with the operation of their respective businesses. This Presentation also contains trademarks, service marks and trade names of third parties, which are the property of their respective owners. The use or display of third parties' trademarks, service marks, trade names or products in this Presentation is not intended to, and does not imply, a relationship with the Company or ArcLight, or an endorsement or sponsorship by or of the Company or ArcLight. Solely for convenience, the trademarks, service marks and trade names referred to in this Presentation may appear with the Ⓡ, TM or SM symbols, but such references are not intended to indicate, in any way, that the Company or ArcLight will not assert, to the fullest extent under applicable law, their rights or the right of the applicable licensor to these trademarks, service marks and trade names. Summary of Contracts Insofar as this Presentation contains summaries of existing agreements and documents, such summaries are qualified in their entirety by reference to the agreements and documents being summarized. No Obligation This Presentation does not create any obligation on the part of either the Company, ArcLight or the recipient to enter into any further agreement or arrangement. Unless and until a definitive agreement has been fully executed and delivered, no contract or agreement providing for a transaction will be deemed to exist and none of the Company, ArcLight or the recipient will be under any legal obligation of any kind whatsoever. Accordingly, this Presentation is not intended to create for any party a right of specific performance or a right to seek any payment or damages for failure, for any reason, to complete the proposed transaction contemplated herein. 3 January 2021#4INTRODUCTION Our Mission Advancing Electric Vehicle Technology to Deliver the World's Best Performing Commercial Vehicles TT Innovation DNA January 2021 Significant TAM 43 Differentiated Technology Profitable Growth Financial Profile Real-World Validation 6 PROTERRA POWERED C P G PROTARRA G PROTERRA 4#5INTRODUCTION Proterra and ArcLight Combination to Create Publicly Listed, Commercial Electric Vehicle Technology Leader Proterra Team Jack Allen Chairman and Chief Executive Officer NAVISTAR valspar January 2021 Dustin Grace Chief Technology Officer TESLA HONDA ArcLight Clean Transition Team Jake Erhard President, Chief Executive Officer and Director ARCLIGHT Schroders Amy Ard Chief Financial Officer AMG PCC Precision Castroants Com.pwc Aaron Chew VP, Investor Relations TESLA SolarCity Marco Gatti Chief Financial Officer ARCLIGHT WARBURG PINCUS Transaction Overview Proterra to combine with ArcLight Clean Transition Corp. ("ArcLight"), a publicly listed special purpose acquisition company with ~$278MM cash currently held in trust and a focus on leading companies enabling the transition to a sustainable future Jake Erhard from ArcLight to join Proterra Board, adding substantial experience in transportation logistics, power and fueling infrastructure, and a focus on accelerating Proterra Energy business unit PROTERRA Transaction reflects a $1.6Bn enterprise value for Proterra Proterra to receive ~$648MM cash at closing based on the $415MM committed PIPE and current cash in trust levels Proceeds will be used to continue to fund R&D and capex investments in next-generation battery program to unlock commercial vehicle powertrain parity Existing Proterra shareholders to roll 100% of their stakes, expected to own ~69% of the pro forma company at closing Pro forma company well-positioned and well-capitalized $2.4Bn pro forma equity value 1 $1.6Bn pro forma enterprise value 3.6x 2022E revenue of $439MM 0.6x 2025E revenue of $2,566MM Strong balance sheet with ~$852MM of cash at close ² ● 1. Amounts presented on this slide assume (1) there are no redemptions from the trust account, (2) the holders of Proterra's 2020 Convertible Notes receive 30.3MM shares for the conversion in full of $200MM principal amount of their notes (interest calculations and conversion of same not included) and (3) $24MM of other liabilities. If not voluntarily converted at the time of the Closing of the business combination, the 2020 Convertible Notes will convert if Proterra's common stock price exceeds $9.89 per share for 20 consecutive trading days after at least six months following the closing of the business combination. Amounts also exclude (1) outstanding out-of-the-money equity awards and outstanding unvested equity awards rolling over in the transaction and (2) the impact of any equity awards issued at or after the closing of the business combination 2. Assumes Proterra receives $648MM of cash at closing Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections 5#6INTRODUCTION ArcLight Clean Transition Corp. Overview Positioned to Help Proterra Accelerate Commercial Vehicle Electrification Top-Tier Leadership January 2021 Daniel Revers Chairman and Founder, ArcLight Capital Partners Arno Harris Director Audrey Lee Director Steven Berkenfeld Director Brian Goncher Director ARCLIGHT John Hancock MOTORS AMS Azure Power CLEAN ENERGY for BIDEN CLEAN ENERGY for BIDEN 党心中 GRIDWORKS Deloitte. RECURRENT ENERGY sunrun BARCLAYS Brightcore Svante ZincFive M POWERHOUSE Silicon Valley Forum PROTERRA ArcLight Clean Transition Corp. Overview ArcLight Clean Transition Corp. is a SPAC listed on the Nasdaq Capital Market that priced its IPO on September 22, 2020 ArcLight management team and board of directors bring significant experience in: ✓ Transportation logistics ✓ Renewable infrastructure ✓ Power networks ✓ Batteries ✓ Electric vehicles Sponsored by an affiliate of ArcLight Capital Partners, a leading private equity firm focused on power and energy infrastructure, and partnered with CAMS, a leading provider of operational and asset management services for infrastructure assets ArcLight's Due Diligence on Proterra ArcLight Clean Transition Corp. due diligence on Proterra includes: ✓ In-depth strategy reviews of the company's strategy across each business unit ✓ Discussions with key customers ✓ Multiple site visits to the Burlingame and Los Angeles factories Independent view of Proterra's battery technology by The Battery Lab 6#7PROTERRA Proterra Overview Who We Are January 2021 d 7#8PROTERRA OVERVIEW Track Record of Enabling Commercial Vehicle Electrification 1 2 3 4 5 6 January 2021 Integrated Technology Ecosystem Proven, Real-World Validation Significant Addressable Market Today Strategic Partnerships with Near-Term Deliveries Real Revenue, Rapid Growth, Clear Visibility Premier Strategic and Financial Investors PROTERRA POWERED ~16MM Real-World Service Miles ~$260Bn+ Global Commercial Electric Vehicle Market 3 DAIMLER $193MM '20E Revenue Constellation. An Exelon Company EDISON INTERNATIONAL 1. Over 550 vehicles on the road and over 450 vehicles in backlog as of September 2020 2. 2012-2019 Proterra electric transit bus market share in North America; refer to Index on page 52 for additional information 3. Includes commercial vehicles and charging; refer to Index on page 52 for additional information 4. From 2010 to 2019; refer to Index on page 52 for additional information PROTERRA TRANSIT 1,000+ Vehicles ¹ ~85% Decline in Electric Battery Costs 4 VAN HOOL 68% '20E-'25E Revenue CAGR DAIMLER BMW i Ventures 50%+ Electric Transit Bus Market Share ² ~40% Lower Vehicle Operating Costs 5 BUSTECH FRANKLIN TEMPLETON $750MM+ Orders and Backlog 7 INVESTMENTS COWEN PROTERRA PROTERRA ENERGY™ FLEET SOLUTIONS 54MW Charging Installations 100% Zero Emissions by 2050 15 State Targets 6 optimal 25% '25E Gross Margin generation. KPCB KLEINER PERKINS CAUFIELD BYERS 5. Versus diesel; refer to Index on page 52 for additional information 6. Medium-duty and heavy-duty truck market; refer to Index on page 52 for additional information 7. As of September 2020; represents Proterra Transit backlog and Proterra Powered orders signed and under advanced negotiation Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections 8#9PROTERRA OVERVIEW Integrated Technology Ecosystem: Strong Network Effect. Our Businesses What We Do PROTERRA POWERED PROTERRA TRANSIT PROTERRA ENERGY FLEET SOLUTIONS January 2021 Leading electric powertrains North America's #1 electric transit bus OEM Fleet-level chargers and energy management What We Deliver BATTER E ESTR ELECTRIC Who We Serve Self-Reinforcing Model Commercial vehicle OEMs Transit agencies Commercial vehicle and transit fleet owners Why We Win Superior performance, lower cost PROTERRA ✓ Purpose-built vehicle platform Turnkey suite of hardware and software solutions Unique Portfolio of Solutions 9#10PROTERRA OVERVIEW Massive Commercial Vehicle Market Primed for Electrification $260 Billion Total Addressable Market Opportunity Ideal Characteristics... Large Fleets Cost-Driven Decisions High Mileage Low Fuel Economy Maintenance Intensive January 2021 Predictable Routes ...Increasing Demand for Sustainable Solutions... Governments Communities Companies 15 states targeting 100% zero-emission medium-duty and heavy-duty trucks by 2050 1 ~70% of consumers have changed their behavior out of concern for climate change 2 World's largest logistics players are targeting to electrify their fleets 1. Refer to Index on page 52 for additional information 2. Refer to Index on page 52 for additional information 3. From 2010 to 2019; refer to Index on page 52 for additional information 4. Versus diesel; refer to Index on page 52 for additional information Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections ...and Increasingly Compelling TCO ~85% PROTERRA ~40% Decline in electric battery costs since 2010 ³ Lower electric vehicle operating cost vs. diesel 4 10#11PROTERRA OVERVIEW Proterra Has Overcome Key Obstacles to Electrification Obstacle Cost Performance Safety Quality Charging Scale January 2021 What We Do Isn't Easy ✓ Highly competitive total cost of ownership ✓ Best-in-class battery system enables greater range and weight loads ✓ State-of-the-art testing, certification, and compliance programs ✓ ~16MM real world miles, long lifespan of 4,000+ cycles, and low maintenance ✓ End-to-end solutions with 54 MW installed at 450+ charge points Over a decade of experience with ~350k sq. ft. of advanced manufacturing capacity Integrated Platform Enabling Commercial Vehicle Electrification PROTERRA 11#12PROTERRA OVERVIEW Innovation DNA Meets Manufacturing Expertise Advanced R&D, 81 Patents, and Manufacturing Capabilities In-Place and At-Scale Established Footprint in Technology and Manufacturing Hubs Product Year Opened Los Angeles, CA Burlingame, CA Greenville, SC Since 2017 January 2021 Battery Bus Battery Bus 2020 2017 2017 2011 Max. Annual Capacity 1. Unit costs 675 MWh 280 Vehicles 345 MWh 400 Vehicles 86% Reduction in Battery Unit Cost Demonstrated Ability to Efficiently Scale Capacity BATTERY MANUFACTURING Los Angeles Battery Factory Case Study PROTERRA Rapid Deployment: Built in under 12 months ✓ Cost Effective: Sub-$20MM invested, 50K sq. ft.per GWh ✓ Automated: ~50% labor cost reduction Replicable: Template for co-location at customer sites 55% Reduction in Labor and Overhead ¹ 12#13PROTERRA OVERVIEW Producing the Vehicles of Tomorrow, Today Other Mobility Technology Players: PowerPoints and Prototypes Early Deployments in Fleets with 30.000-Trucks 2,000,000 miles driven over-the-road to date January 2021 ΑΓΓΙVAL Prototypes NIKOLA Prototypes 1 CANO 0- I Prototypes ⒸHYLIION Early Stage Deployments Proterra: Proven Products on the Road GH SCHOOL ● Going to School In Virginia Going to a Park in New York 841 KINGS PLACH COD 0019 ELECTRICUS ROTTERRA YAHOOL Commuting in San Francisco HO ENSSIONS ELECTRIC BUS PROTERRA Touring the Ski Slopes In Jackson Hole STARTS START BUS PROTERRA 2006 13#14PROTERRA OVERVIEW Proterra is Miles Ahead of the Competition Proterra has a Distinct First-Mover Advantage Multi-Million Real-World Miles Revenue (2020E) Production Track Record Manufacturing Capacity 1 Full Charging Solution 1 I January 2021 1 1 PROTERRA 16MM $193MM ~10 Years I I I I I 1 I I 1 I I 1 I I I I I I 1 I I I I I I I I ΑΓΓΙΛΕ X X X X X HYLIION X Minimal X X x NIKOLA X X X X X ROMEO POWER TECHNOLOGY x $11MM X 1. Status as of 1/1/2021 Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections Highly Valuable Learning Curve Advantage Field Data PROTERRA Technology Development Safety, Testing and Compliance Manufacturing Experience Customer Relationships Brand Credibility Incremental Units Sold Significant Time and Enormous Capital Investment Required for Competitors to Catch-Up...and Proterra is Moving Forward 14#15PROTERRA OVERVIEW Integrated Technology Ecosystem Complete, Purpose-Built Technology Platform January 2021 Heavy-Duty Battery Pack High energy density, low-cost, ruggedized High Efficiency Drivetrains 5x efficiency of diesel Best-in-class acceleration Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections Vehicle Integration End-to-end powertrain integration 111 Energy Solutions Fully-integrated charging solutions PROTERRA® APEX Apex Software PROTERRA Full-service fleet management platform Future A Vehicle-to-Grid Integrated utility-scale power ecosystem 15#16PROTERRA OVERVIEW PROTERRA POWERED PROTERRA January 2021 TRANSIT PROTERRA ENERGY™ FLEET SOLUTIONS Proterra Well-Positioned for ~$260 Billion TAM ~$225 Billion Global Commercial Vehicle Market 1 ~4.4 Million Vehicles 1 PROTERRA POWERED MOHRIFF PROTERRA DAIMLER TRANSIT DAIMLER VAN HOOL DIMPLA BUSTECE >optimal I Com Cocton Coraz Current Proterra Customers ~$37 Billion Global Commercial Vehicle Charging Investment ² 40 TWh Annual Energy Need by 2030+² PROTERRA ENERGY FLEET SOLUTIONS 1. Estimated 2023 addressable market and number of vehicles for long-haul, medium-duty, construction / mining and buses; refer to Index on page 52 for additional information 2. Estimated 2030 addressable market and energy need excluding passenger cars; refer to Index on page 52 for additional information Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections PROTERRA TM 16#17PROTERRA OVERVIEW PROTERRA POWERED Business Model End-to-End Powertrain Partnership Proterra Powered: Tailored Approach Through Partnership Model Proven Partnerships with Industry Leaders. PROTERRA Battery Partnership TRANSIT Energy System Integration Partnership January 2021 PROTERRA ENERGY LETO CONTEN Offering Provided to OEMs High Voltage Systems and Controls Battery System Drivetrain PROTERRA TRANSIT BUSTECH optimal Existing Customers and Applications ELECTRIC Transit Bus Transit Bus Shuttle Bus TEE DAIMLER CLOTHES DAIMLER COLMINTLINE C Class VAN HOOL School Bus Stepvan Coach Bus PROTERRA 1. Statistic specific to North America only 2. Annual vehicles across North American transit, school bus, shuttle bus, coach bus, step van and non-North American transit, refer to Index on page 52 for additional information Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections Manufacturer of 1 of 3 school buses on the road today ¹ North America's leading class 6-8 vocational brand Coach and bus leader with 10k+ on the road today 1 Established Partnerships Serve a Target Segment Market Opportunity of ~175,000 Annual Vehicles 2 17#18PROTERRA OVERVIEW PROTERRA POWERED PROTERRA Proterra Powered: Daimler Strategic Partnership World's Largest Commercial Vehicle Manufacturer is a Customer and Investor DAIMLER ● TRANSIT BUILT BUBEB Seven Iconic Commercial Vehicle Brands Under One Roof January 2021 PROTERRA ENERGY LETO CONTEN W WESTERN STAR Anchor investor in the current $415MM PIPE BAILARIA TRENE FREIGHTLINER BHARATBENZ World's largest commercial vehicle manufacturer with unmatched global scale ~$50 billion in annual revenue and ~520,000 annual vehicles sold 1 Meaningful Shareholder and Senior Executive Commitment In September 2018, Daimler Trucks & Buses co-led investment in Proterra SETRA FUSO Jochen Goetz Head of Finance & Controlling, Daimler Trucks & Buses Proterra Director 1. Fiscal Year 2019 2. Refer to Index on page 52 for additional information 3. Refer to Index on page 52 for additional information Sizable, Existing Commercial Agreements BUILT BUBEBL PROTERRA Deliveries expected to begin in 2021 ✓ Existing Industry Fleet in U.S.: 300,000+ vehicles 2 In production since 2Q 2020 ✓ Existing Industry Fleet in U.S.: 480,000+ vehicles ³ 18#19PROTERRA OVERVIEW PROTERRA POWERED PROTERRA Proterra Transit: North America's #1 Electric Transit Bus OEM Clear Leadership in Flagship Validation Market with 50%+ Market Share ¹ PROTERA ZXS OVER TECHNOLOGY BATER ELECTRIC PROTERRA TRANSIT TERO EMISSIONS ALL THE POWER PROTERRA ENERGY LETO CONTEN January 2021 ZX5 5th GENERATION CLEAN & QUIET Pei LONGEST RANGE PROTERRA Purpose-Built Electric Transit Bus Technology Platform Proven Validation Superior Performance Significant Savings 1. 2012-2019 Proterra electric transit bus market share in North America; refer to Index on page 52 for additional information ● ● ● ● ● ● PROTERRA 50% Market Share 16 Million Real-World Service Miles 10+ Year Vehicle Service Track Record Successfully Completed 8 Altoona Tests Long Range High Fuel Efficiency Fastest Acceleration Greatest Horsepower Low Operating Costs High Uptime Zero Tailpipe Emissions 19#20PROTERRA OVERVIEW PROTERRA POWERED PROTERRA TRANSIT 2% PROTERRA ENERGY Proterra Transit: North American Bus Market is Rapidly Electrifying 130+ Communities in 43 States and Provinces Choose Proterra LETI CONTENS Projected to be 50% Electrified by 2025 1 % of Total North American Bus Market (Annual Sales) January 2021 '17-'25 CAGR: 50% 50% 2017 2018 2019 2020 2021 2022 2023 2024 2025 25K+ North American Buses Must be 100% Zero Emission by 2040² Zero Emission Buses Now 26% of Active Bid Universe 3 Proterra's Customers Operate Over 30% of the N.A. Transit Bus Fleet 4 Proterra Customer 550+ Vehicles on the Road $400MM Cumulative Sales PROTERRA 1. Refer to Index on page 52 for additional information 2. Reflects seven North American city and state mandates (California, NYC, Toronto, Chicago, Seattle, Minneapolis and Miami); refer to Index on page 52 for additional information 3. NFI Group's active North American transit bus bid universe; refer to Index on page 52 for additional information 4. Refer to Index on page 52 for additional information Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections 450+ Vehicles in Backlog 20#21PROTERRA OVERVIEW PROTERRA Zozo-Entimton BATTERY ELECTRICI POWERED SCHOOL BUS SIC Proterra Energy: Enabling the Electrification of Commercial Vehicles $37Bn of Annual Investment Expected in Global Charging Infrastructure by the End of the Decade 1 FLYSJC.COM TERRA January 2021 CON PROTERRA 60. PROTERRA V26 TRANSIT PROTERRA ENERGY™ FLEET SOLUTIONS Charging is Key to Electrify Commercial Vehicle Fleets... ...and Represents a Large, Underserved Market Hundreds of vehicles per depot, each requiring 75-300 kW of charging power High Power Needs Continuous Service Operational Constraints Peak power of up to ~30 MW per depot, multiples of typical interconnection Commercial vehicles operate every day, with consistently high charging needs 99%+ uptime is expected, reliability is a must even with untrained operators Must conform to existing high-density fleet yard layouts Must seamlessly integrate into normal-course operations Fleet Depots 1. Refer to Index on page 52 for additional information 2. Refer to Index on page 52 for additional information 3. Refer to Index on page 52 for additional information 4. Refer to Index on page 52 for additional information Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections En-Route Top-Ups Destination Charging ● PROTERRA Over 1.4MM vehicles managed by US fleet operators ² Focus: lowering TCO across vehicles and chargers Over 300,000 truck parking spaces across the U.S. ³ Focus: integration with existing infrastructure Significant Market Opportunity Requiring a Multidisciplinary Approach Over 250,000 warehouses in the U.S. 4 Focus: integration of charging with logistical activities 21#22PROTERRA OVERVIEW PROTERRA POWERED MIT IN SEMUILE WEDS K Proterra Energy: Integrated Fleet Charging Solutions 54 MW of Charging Infrastructure Installed at 450+ Charge Points Across North America PROTERRA CITU NE MODESTO January 2021 PROTERRA TRANSIT POWER CONTROL SYSTEM O PROTERRA PROTERRA ENERGY™ FLEET SOLUTIONS 21877 ● Engineered Planning Energy Sourcing Fleet modeling & planning Utility interface Turnkey infrastructure installation Project management EaaS financing & battery leasing Storage / Resiliency Charging Infrastructure High density behind-the-fence solutions Medium voltage interface Energy storage integration capability Exclusive partnership with: POWER ELECTRONICS Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections 4 Energy Management In-house SaaS platform Fleet monitoring ed V2G DERMS integration PROTERRA® APEX ● ● PROTERRA Reuse / Recycling 2nd life expansion attery fleet Actively working on recycling with reputable industry leaders 22#23PROTERRA OVERVIEW PROTERRA POWERED Home T Edmonton Transit Service Customer Perspective: Proterra Delivers Fully Integrated Solutions ETS Edmonton Transit System Electric Bus, Charging Infrastructure and Charge Management Software CO Edmonton PROTERRA Take Me TRANSIT January 2021 Edmantan PROTERRA ENERGY™ FLEET SOLUTIONS Deployment Proterra Transit: 40 electric transit buses ● ● ● Proterra Powered: 660 kWh batteries and DuoPower drivetrains Proterra Energy: 4.3 MW of charging hardware Customer Highlights ✓ Fully integrated charging solutions First-of-its-kind depot layout and software control systems Optimizes scheduling while lowering demand charges Dominion Energy® Batteries, Drivetrains, Vehicle Controls, and V2G Services TERRA OWER ONTROL YSTEM PROTERRA 60kW STROOL BUS POV CON SYS PROTERRA V2G Ase 60 POWER CONTE SYSTE PROTERRA 60 120 OH PROTERRA PROTERRA Deployment Proterra Powered: End-to-end electric powertrains for 50 Thomas-built school buses ● Proterra Powered: 220 kWh batteries, drivetrains and vehicle controls Proterra Energy: Charging infrastructure and V2G services Customer Highlights Dominion Energy is seeking state approval for additional 1,000+ electric school buses over next 5 years Bus batteries utilized as grid resource ✓ Provides backup power, stabilization and load shifting 23#24PROTERRA OVERVIEW Public Company-Ready Leadership Team and Board Leadership Team Jack Allen Chief Executive Officer Amy Ard Chief Financial Officer Dustin Grace Chief Technology Officer Josh Ensign Chief Operating Officer JoAnn Covington Chief Legal Officer Gareth Joyce President, Proterra Powered & Energy Rick Huibregtse Sr. VP, Engineering John Walsh Sr. VP of Sales January 2021 NAVISTAR valspar AMG TESLA PCC Precision Castparts Cera. pwc TESLA A DELTA Remy REV Vehicles for life HONDA Honeywell rocketfuel Mercedes-Benz DELPHI DAVEY COACH Board of Directors Jack Allen Chairman Ryan Popple Co-Founder & Executive Director Jake Erhard Director Nominee Jennifer Granholm Director Jochen Goetz Director Constance Skidmore Director Mike Smith Director Brook Porter Director Jeannine Sargent Director NAVISTAR valspar TESLA KPCB ARCLIGHT DAIMLER pwc G2VP flex PROTERRA Schroders Constellation 3 KLEIN ER BERKINIS CAURELD ER VOF ROS CAN KLEINER DER KONIS) CATFIELD SRYF IS KPCB ærlikon 24#25PROTERRA Proterra Technology Why We Win January 2021 To PROTERRA -POWERED 25#26PROTERRA TECHNOLOGY Proterra's Innovation DNA January 2021 O ROTERRA O PROTERRA Deep and Diversified Engineering Expertise Core engineering team has deep automotive battery engineering experience and dedication to first-principles engineering Expertise across multiple engineering disciplines: mechanical, electrical, chemical, software Strong Professional Backgrounds with Industry Leaders TESLA Premier and Innovative Product Development DNA PROTERRA HONDA BOSCH GM BATTERN ELECTRIC 81 Patents Across Our Integrated Technology Ecosystem 1. As of December 2020; key patent families are Battery Configuration and Energy Management, Powertrain and Vehicle Controls, Charging Interface and Methods, Composite Body and Vehicle Design, and Vehicle Controls PROTERRA 1 Bloomenergy® 26#27PROTERRA TECHNOLOGY Battery System: Vertically Integrated Development and Manufacturing Enhances Performance and Lowers Cost World-Class Cell Supply 3rd Party Cells Small Format Cylindrical Cells Long-term supply contract: ~2 GWh secured through '22 In-house cycle testing, safety testing, modeling, and algorithm development January 2021 Plan to co-invest in cell manufacturing capacity Deep Vertical Integration Approach ● Engineered, Validated and Manufactured by Proterra in California Module Highly Integrated Thermal and Structural Architecture Liquid cooled module beams make-up entirety of internal pack structure Capable of impact energy absorption Cell fusing & interconnection made via high-speed fiber laser processing 0 Ⓡ • ● Battery Pack Flexible Battery Management System Functional safety certified (ISO 26262) battery management system developed with strategic partner Flexible software and hardware architecture enables up to 1200 V strings Patented thermal event mitigation Ruggedized enclosure • Energy System Seamless Software Integration PROTERRA Internally-developed software, vehicle control unit, charge controller, and telemetry gateway Advanced system enables seamless integration of batteries and powertrains into partner vehicles Capable of over-the-air software flash updates 27#28PROTERRA TECHNOLOGY Battery System: Modular and Scalable for Many Commercial Vehicle Segments Multiple Widths and Heights KWh Battery System H Vehicle S SERIES January 2021 SERIES Versatile Design Elements Can Enable Applications Across Commercial Vehicle Market Scalable Lengths 113 .. Stackable Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections PROTERRA PROTERRA Configurable Voltage Module Battery Pack Voltage Options 17V / 25V / 35V / 50V Up to 1200V Up to 16 parallel strings 1,000 28#29PROTERRA TECHNOLOGY Battery System: State-of-the-Art Technology Designed to Excel in Medium and Heavy-Duty Vehicle Applications Proterra Battery Core Attributes Intelligent Battery Management System Gravimetric Energy Density Volumetric Energy Density Ruggedized, Commercial Grade Enclosure Functional Safety Certified Resiliency to Cell Defects and Failures Multi-Layered Passive and Active Safety Systems January 2021 Real-World Customer Benefit L Hundreds of sensors delivering continuous monitoring and diagnostics Extended range, higher cargo / occupant capacity, and increased vehicle efficiency Minimizes battery space requirements with packaging designed for safety Ballistic-grade materials designed to withstand the toughest conditions over vehicle lifecycle Redundant sensing and processing designed to ensure safe and reliable operation Long life span, intrinsically resistant to cell propagation State-of-the-art testing, certification & compliance programs PROTERRA PROTERRA POWERED 29#30PROTERRA TECHNOLOGY Battery System: Continuous Research and Development Excellence Next Generation Battery Targeting Commercial Vehicle Powertrain Cost Parity by Mid-Decade Confidential Next Generation 2022 5th Generation 2021 4th Generation 2017 3rd Generation January 2021 S Significant Increase in Scale to 5+ GWh SERIES H SERIES First to Market with NCM 811 18650 Cells Pursue Investment in Dedicated Domestic Cell Capacity 10% increase in Energy Density Higher Energy Density 2170 Cells New Core Single Module Architecture Vertical Integration of Sub-Components Flexible Module Platform (7 Variants) Ramp of Team Testing, and Integration Continued Module Design Enhancement Greater Scale and Continued Learning Curve 20%+ estimated cost reduction Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections Deepening of Vertical Integration of Electrical Components 20%+ estimated cost reduction PROTERRA 25%+ estimated cost reduction Battery Program Guiding Principles Increase Energy Density Lower Costs Further Advance Safety Leadership 30#31PROTERRA TECHNOLOGY Best-in-Class Integrated Drivetrains: Proven, Advanced Performance Purpose-Built to Optimize Torque and Efficiency Industry-Leading Drivetrain Capabilities Longest range with 5x the efficiency and 2x the acceleration of a diesel bus ✓Designed to outperform direct-drive systems in all conditions ✓ Dedicated team performs system integration, software & controls, testing & validation ✓ Next generation drivetrain unlocks new commercial vehicles. January 2021 Portfolio Serves Multiple Commercial Vehicle Applications Technology Proterra DuoPower eAxle Next Generation (In Development) Proterra ProDrive Confidential Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections Wheel Transmission Torque Dual 2-Speed 4-Speed 2-Speed 22,000 Nm 25,400 Nm 19,700 Nm Proterra is Well-Positioned with a Strong Portfolio of Multi-Speed Drivetrain Solutions PROTERRA Continuous Power 370 kW 200 kW 180 kW 31#32PROTERRA TECHNOLOGY Energy Solutions: Integrated Charging Applications for Fleets of All Sizes Universal Using Industry-Standard Connections Open Source Communications Protocol Unit Size Configuration Status January 2021 @ PROTERRA Overnight Charger 75 kW 150 kW Up to 4 vehicles Intelligent Smart-Charging Capable V2G Bi-directional Power Flow PROTERRA I Automatic Charger 250 kW 500 kW Up to 2 vehicles OPROTERRA I In Production 1 Remote PCS Can Be Up to 500 Feet from Dispenser Microgrid Ready Fleet Charger 1.5 MW Scalable up to 40 vehicles Fleet Charger Minimizes Footprint and Lowers Cost to the Customer PROTERRA Scalable & Adaptable Wall, Ceiling or Pedestal Installations Telematics Enabled ਦੇ PROTERRA Fleet Battery 1.5 MW 1st life or 2nd life In Development 32#33PROTERRA TECHNOLOGY Apex Software: Optimizes Fleet Ownership and Operation 99922339938 HVAC Defroster + BTM DC2 Power Steering 3.57 Actual Duration 58.6 January 2021 Monitoring & Analytics DFC1 Air Conditioner 2.000 8 1.000 500 0 ICHO Real Time Monitoring Speed (mph) 33 Milen Driven By Mash Fud Savings By Mands 2.500 1,000 Odometer: 21078 date date date date 2019-10-072019-10-07 2019-10-112019-10-12 Frequency #1 #Frequency 2 Frequency 3 Monthly Report Date Movitly Report Da Miles & kWh Used / Remaining Cabin Temp 64F Diagnostics & Analytics Outside Temp: 76F 7.65 Est Remaining Duration 153.01 P 100 90 80 70 80 50 40 30 20 10 D 8:25 PM EDT 8:55 PM EDT 9:25 PM EDT State of Change 9:55 PM EDT 10:25 PM EDT Odometer Bus Status 10:55 PM EDT Total 11:25 PM EDT Charged Charging Available to Charge Out of Service ● Companion out of S • Unavailable SESSION SUCCESS 0 0 10 0 17 11:55 PM EDT 20750 Total 20740 20730 20720 20710 20700 20090 Charger Status ● Charged Charging Available to Charge Out of Service • Companion out of S. Unavailable Historical Data & Analysis Carbon Credit Management 3,745 45% CH 1,685 W Power Monitoring 3000 2500 1000 rig 14:00 Bus Charging ● Status Avall ● Avall 15:00 Bus 16401 16404 M Vehicle-to-Grid 10/10 Condales Fed Deal 0 min U 16.00 ding 300, . 17:00 E Fork 15 c Bod 15 c 16.00 19:00 ESS O Plugged In2 Site Energy Management BIAY 20:00 u1,815 Status Avall Control Aval *** 1.000 2,290KW 21.00 Cuart Power Volge/Cumint Asiatic Cergy Man Avaa Power Vang ESS Central Start Charging Start Discharging Stop Charger Power Management & Configuration SURTE 002 SURTO 003 Cange 25 May 121 Sulege BMW ▸ 505529 780 Ready By Fackw P 150 kW 150 kW Charge Plan No Fas Found Ital Charge Phon Ital Charge Pan Smart Charging Energy Mgmt 4 B CHARGING DATA 200 341 11 141 130 100 40 60 Ready for Netedy Toppead Up Oot 1/10 7:00 PM 12:00 PM ic 8:00 PROTERRA Demand Lime 0 0 Die 10 -10-10 01-01- lala 09:00PM 100 GLA PO F 101 EU - 10-10-ie bici 10000 THO 01 01 &i= Miha dea 0 Marts 11:00 P Over-the-Air Updates Fleet Management 33#34PROTERRA TECHNOLOGY Vehicle-to-Grid Platform: Can Unlock New Revenue Opportunities BATTERY ELECTRIC Mobile Energy Storage PROTERRA January 2021 POWERED Vehicle Data (kWh, miles, SOH) Bi-Directional Power Flow (DC) PROTERRA® APEX CLOUD ENERGY MANAGEMENT Charge Session Metrics Command Charge/Discharge B PROTERRA Bi-Directional Charger PROTERRA ENERGY™ FLEET SOLUTIONS Command & Schedule Charge Session Metrics Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections Bi-Directional Power Flow (AC) PROTERRA 4 Distributed Energy Resource Management System A A Electrical Grid Initial Deployments in 2021 Dominion Energy Beverly, Massachusetts Proterra Vehicle-to-Grid Applications Can Transform Electric Vehicles Into Utility Grid Assets and Lower TCO ENERGY PROVIDER Data Energy 34#35PROTERRA Proterra Financials How We Grow January 2021 FAC SIC Lt FESIC.COM PROTERRA 35#36PROTERRA FINANCIALS Real Revenue, Rapid Growth, Clear Visibility 1. Strong revenue growth with expanding market opportunity 2. Large, near-term backlog creates financial performance visibility 3. Clear pathway to profitable growth 4. Transaction use of proceeds to accelerate growth strategy January 2021 PROTERRA 36#37PROTERRA FINANCIALS Commercial Vehicle Electrification Drives Substantial Revenue Growth $750MM+ of Orders and Backlog Creates Near-Term Financial Performance Visibility ¹ 1 Revenue $MM 123 2018A January 2021 181 2019A 193 2020E 246 2021E 439 2022E 838 2023E 1,449 2024E 1. As of September 2020; represents Proterra Transit backlog and Proterra Powered orders signed and under advanced negotiation Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections 2,566 2025E PROTERRA CAGR '20E-25E Total Proterra Powered & Energy Proterra Transit 68% 114% 39% 37#38PROTERRA FINANCIALS Gross Margin Positive Today with Proven Ability to Expand Margins ~26% Gross Margin Expansion in Under Three Years ¹... 1 86% reduction in battery cost / kWh 55% reduction in labor and overhead 2 47% reduction in freight cost per bus January 2021 Proven Ability to Reduce Costs ...with Roadmap to ~25% Gross Margins at Scale 4% Gross Margin 2020 YTD Redesign ● Battery pack Drive train +18% Manufacturing Efficiency 1. Proterra cost reductions since 2017 2. Unit costs Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections ● +24% Resource / Renegotiate ● Bill of Materials (21%) Price Reduction, Market Expansion Cells Vertical integration (non-cell battery components, harnesses) ● PROTERRA ● 25% Gross Margin 2025E Design for Manufacturability Automation of battery module and pack line Modularized design of products 38#39PROTERRA FINANCIALS Attractive and Credible Long Term Financial Model Fiscal Year Ended December 31, 2022E SMM Income Statement Items Transit Powered & Energy Total Proterra Revenue Growth % (-) Cost of Goods Sold Gross Profit Margin % (-) R&D (-) SG&A EBIT Margin % (+) D&A EBITDA Margin % Free Cash Flow Build EBITDA (-) Capex (-) Increases in WC Free Cash Flow January 2021 2020E 153 40 $193 6% (185) $8 4% (35) (54) ($81) NM 15 ($66) NM ($66) (18) (12) ($95) 2021E 189 57 $246 27% (235) $11 4% (44) (63) ($96) NM 15 ($82) NM ($82) (20) (18) ($120) 279 160 $439 79% (384) $55 13% (48) (66) ($59) NM 19 ($40) NM ($40) (60) (50) ($151) 2023E 492 346 $838 91% (708) $130 16% (50) (74) $6 1% 27 $33 4% $33 (110) (75) ($152) 2024E 640 809 $1,449 73% (1,159) $290 20% 1. 2020E-2025E CAGR Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections (53) (82) $154 11% 35 $190 13% $190 (55) (80) $55 2025E 784 1,782 $2,566 77% (1,924) $642 25% (56) (88) $499 19% 40 $539 21% $539 (40) (109) $390 PROTERRA 68% Revenue CAGR 1 25% Gross Margins at Scale ✓Significant Operating Leverage Attractive 20%+ EBITDA Margins Capital Efficiency, Disciplined Investment Ramping Cash Flow Generation 39#40PROTERRA FINANCIALS Use of Proceeds Expands Proterra's Moat and Accelerates Growth Investments in Next-Generation Battery Program Target Powertrain Parity Projected Use of Proceeds Strategic Priorities Research & Development Capital Investments Growth Capex Domestic Cell Capacity Co-Investment January 2021 $200MM $300MM $150MM - $225MM $100MM - $120MM ● ● ● Continue to optimize battery performance and costs Further develop drivetrain platform Fortify software and energy-as-a-service offerings Expand battery capacity to 5+ GWh Broaden vertical integration Co-locate factories at customers' sites Guarantee cell supply Lower cell prices Access to next-generation cell technology Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections PROTERRA 40#41January 2021 PROTERRA Clean, Quiet Transportation for All#42PROTERRA Transaction Summary January 2021 400 PROTERRA BATTERY 42#43TRANSACTION SUMMARY Detailed Transaction Overview $415 Million PIPE Key Transaction Terms Proterra and ArcLight entered into a business combination agreement on January 12, 2021 ● ● ArcLight currently has $278MM in cash held in trust account $1.6Bn pro forma enterprise value with strong balance sheet 3.6x 2022E Revenue of $439MM Earn-out of 2% of total shares outstanding at close issued to existing Proterra shareholders at illustrative pro forma share prices of $15.00 and an additional 2.5% at $20.00, $25.00 and $30.00 (or upon a change of control transaction at that valuation) 10% of ArcLight founder shares withheld at close subject to earn-out at $15.00 per share Pro Forma Ownership @ $10.00/Share ArcLight Public Shareholders ArcLight Founder Shares PIPE Investor Shares Existing Proterra Shareholders 1 Total January 2021 Shares (MM) 27.8 6.2 41.5 164.6 240.1 % 11.6% 2.6% 17.3% 68.6% 100.0% $MM $278 62 415 1,646 $2,401 Illustrative Pro Forma Valuation Share Price at Closing Pro Forma Shares Outstanding (MM) Equity Value Debt & Other Liabilities (Q3'20E) ¹ Existing Cash (Q3'20E) Plus: Cash to Balance Sheet Enterprise Value 2022E Revenue EV / 2022E Revenue Illustrative Sources and Uses Sources ArcLight Cash in Trust Committed PIPE Stock Consideration to Existing Shareholders ArcLight Founder Shares Total Sources Uses Cash to Balance Sheet Stock Consideration to Existing Shareholders Illustrative Fees & Expenses ArcLight Founder Shares Total Uses 1. Amounts presented on this slide assume (1) there are no redemptions from the trust account, (2) the holders of Proterra's 2020 Convertible Notes receive 30.3MM shares for the conversion in full of $200MM principal amount of their notes (interest calculations and conversion of same not included) and (3) $24MM of other liabilities. If not voluntarily converted at the time of the Closing of the business combination, the 2020 Convertible Notes will convert if Proterra's common stock price exceeds $9.89 per share for 20 consecutive trading days after at least six months following the closing of the business combination. Amounts also exclude (1) outstanding out-of-the-money equity awards and outstanding unvested equity awards rolling over in the transaction and (2) the impact of any equity awards issued at or after the closing of the business combination Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections PROTERRA $10.00 240.1 $2,401 51 (204) (648) $1,600 439 3.6x $MM $278 415 1,646 62 $2,401 $MM $648 1,646 45 62 $2,401 43#44TRANSACTION SUMMARY Differentiated Financial Profile Supports Attractive Valuation Favorable Comparisons vs. Broad Peer Landscape O PROTERRA ✓ Integrated Technology Ecosystem ✓ Real Revenue Today Higher Growth ✓Scaling Margins ✓ Risk-Adjusted Projections Compelling Valuation January 2021 Publicly-Traded Mobility Technology Leaders TESLA CATL BYD BALLARD NIO WORKHORSE PLUG POWER EVE 亿纬锂能 SAMSUNG SAMSUNG SDI Established players in the broader mobility technology space, with a focus on the electric vehicle ecosystem Leading OEMs, suppliers, and energy technology solution providers High-growth, profitable financial profiles Mobility Technology SPAC Transactions * ΑΓΓΙVAL 1 NIKOLA™ 1 - CANOO - 1 I ⒸHYLIION LORDSTOWN. PROTERRA ROMEO POWER TECHNOLOGY -chargepoin+ THE LION ELECTRIC CO ✪ XLFleet™ Recent mobility technology SPAC transactions most focused on the commercial vehicle electrification trend Disruptive growth business and financial profiles 44#45TRANSACTION SUMMARY Peer Median: 23% Higher Growth, Scaling Margins... Operational Benchmarking vs. Publicly-Traded Mobility Technology Leaders Revenue Growth 2020E2022E CAGR (%) ¹ 68% 51% 20E-20E- 22E 25E PROTERRA Peer Median: 37% Gross Margin 2022E (%) 1 16% 13% 20% 25% 22E 23E 24E 25E PROTERRA January 2021 82% 40% NIO NIO EVE亿纬锂能 39% PLUG POWER 37% P BALLARD 37% 35% CATL TESLA 27% 27% 25% 24% 23% 21% | | | | | | PLUG CATL EVE IZ BALLARD SAMSUNG SAMSUNG SDI TESLA POWER Source: Capital IQ, Company materials 1. Market data and Refinitiv median estimates from Capital IQ as of January 8, 2021 Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections 20% SAMSUNG SAMSUNG SDI 19% NIO 19% BYD 16% BYD PROTERRA NM WORKHORSE 13% WORKHORSE 45#46TRANSACTION SUMMARY ...at an Attractive Valuation Valuation Benchmarking vs. Publicly-Traded Mobility Technology Leaders Enterprise Value / Revenue 2021E/ 2022E (x) '21E Peer Median: 16.2x 6.5x '21E 3.6x '22E @ PROTERRA January 2021 '22E Peer Median: 10.3x 62.8x 43.8x PLUG POWER 54.5× 36.1x BALLARD 29.2x 12.8x WORKHORSE 21.2x 17.0x 16.2x 10.0x 13.5× Source: Capital IQ, Company materials 1. Market data and Refinitiv median estimates from Capital IQ as of January 8, 2021 Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections 10.3x 13.0x 9.9x TESLA NIO EVEZ CATL 3.7x 3.1x SAMSUNG SAMSUNG SDI PROTERRA 2021E¹ 3.3x 2022E¹ 2.9x BYD 46#47TRANSACTION SUMMARY 2020E Median: Favorable Valuation vs. Mobility Technology SPAC Transactions Especially Given Proterra's Revenue Scale Today vs. Low / No Revenue Businesses Lowest Enterprise Value Transaction Value / Current Trading ($Bn) 16.0 Transaction Median: 1.5 1.6 PROTERRA Highest Revenue 2020E/2021E ($MM) 246 193 PROTERRA Current Trading Median: 3.1 January 2021 2021E Median: 120 5.4 * ΑΓΓΙVAL 0 0 ΑΓΓΙVAL 12.3 2.4 3.3 -chargepoin+ N NIKOLA NIKOLA 135 198 3 6.7 0 150 29 4 4.1 1.5 THE LION ELECTRIC CO 204 THE LION ELECTRIC CO T I 1 CANO 0 1 0 I I 3.1 1.8 120 -CANOO- 3.0 1.0 LORDSTOWN. 118 LORDSTOWN. Transaction Value ¹ 2.7 1.1 XLFleet 21 -chargepoin+ NIKOLA Source: Company materials, Capital IQ 1. At announcement 2. Market data and Refinitiv median estimates from Capital IQ of January 8, 2021, for those companies that have not yet completed the deSPAC process, enterprise value calculated using market capitalization (equal to pro forma shares outstanding times SPAC's current share price) plus net debt as disclosed in transaction announcement materials 3. ChargePoint approximate calendar year (actual fiscal year ends January 31st) Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections 2020E Revenue ¹ 75 2.3 1.0 ROMEO POWER TECHNOLOGY 11 XLFleet 140 ROMEO POWER TECHNOLOGY PROTERRA Current Trading 2² 2.2 1.1 HYLIION 2021E Revenue ¹ 1 8 ⒸHYLIION 47#48TRANSACTION SUMMARY Conservative, Risk-Adjusted Projections... Revenue Growth Benchmarking High-Growth Technology Reference Peers and Mobility Technology SPAC Transactions Revenue rowth CAGR (%) ¹ 1 SPAC Median: 172% Base Year: 68% '20E Reference Median: 63% PROTERRA January 2021 Proterra's Projected Growth In-Line with Similar High-Growth Technology Precedents 61% TESLA '13-'18 Passenger Electric Vehicles 65% CATL '15-'19 Lithium-Ion Batteries 58% '20E 85% '22E -chargepoin+² LORDSTOWN. I 103% I '21E 1 -CANOO- 147% '22E HYLIION 172% '20E ROMEO POWER TECHNOLOGY High-Growth Technology Reference Peers 178% '21E 185% '20E PROTERRA 234% N NIKOLA™ XLFleet 4 '20E Mobility Technology SPAC Transactions 274% THE LION ELECTRIC CO Source: Company materials 1. Revenue growth CAGR calculated using the base year and the last year from each respective company's transaction announcement presentation, final year revenue based on 2024E for Arrival, Nikola, XL Fleet, Hyliion, Lion Electric, and Lordstown, 2025E for Proterra and Romeo Power, and 2026E for ChargePoint and Canoo 2. ChargePoint approximate calendar year (actual fiscal year ends January 31st) Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections '22E * ΑΓΓΙVAL 48#49TRANSACTION SUMMARY ...Yet Attractive Valuation Relative to Current Trading Levels Valuation Benchmarking vs. Mobility Technology SPAC Transactions Enterprise Value / 2022E Revenue At Announcement / Current Trading (x) Announcement Median: 3.9x 3.6x PROTERRA January 2021 Current Trading Median: 9.3x 35.5× 6.9x 27.4x 11.1x 2 -chargepoin+ ² NNIKOLA³ 3 15.9x 5.3x * ΑΓΓΙVAL 9.6x 3.9x XLFleet I 9.3x I 5.6x CANO0 6.4x 3.2x ⒸHYLIION 6.1x 2.3x At Announcement THE LION ELECTRIC CO 5.6x 2.4x ROMEO POWER TECHNOLOGY PROTERRA Source: Capital IQ, Company materials 1. Market data and Refinitiv median estimates from Capital IQ as of January 8, 2021; for those companies that have not yet completed the deSPAC process, enterprise value calculated using market capitalization (equal to pro forma shares outstanding times SPAC's current share price) plus net debt as disclosed in transaction announcement materials; all use at announcement 2022E revenue except Nikola 2. ChargePoint approximate calendar year (actual fiscal year ends January 31st) 3. Nikola current trading multiple based on 2022E Refinitiv median estimate revenue Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections Current Trading ¹ 1 1.7x 0.6x LORDSTOWN. 49#50TRANSACTION SUMMARY Compelling Valuation Across a Range of Comparisons Implied Enterprise Value $Bn January 2021 4.7 4.3 Publicly-Traded Mobility Technology Leaders 9.8 10.8x EV / 2022E Revenue 4.3 3.9 Mobility Technology SPAC Transactions ¹ 8.89.8x EV/2022E Revenue (Current Trading) Source: Capital IQ, Company materials 1. Includes ChargePoint, Nikola, Arrival, Canoo, Hyliion, XL Fleet, Romeo, Lion Electric and Lordstown Note: Refer to Disclaimer on pages 2 and 3 regarding forward-looking statements and use of projections 61% Discount 1.6 PROTERRA 65% Discount Proterra Valuation 50#51PROTERRA Index January 2021 PROUDLY BUILT IN THE USA PROTERRAC 51#52INDEX Index of Sources Page 8 2. Source: Federal Transit Administration's 2019 Annual Database Revenue Vehicle Inventory; share of electric buses ≥35-ft 3. 4. Based on $225Bn Global Commercial Vehicle Market and $37Bn Global Commercial Vehicle Charging Investment (see page 16 notes) 5. Source: Goldman Sachs "Outlook for Alternative Powertrain Technologies in Global Truck Markets" (October 2020) 2. Source: BloombergNEF "Battery Pack Prices Fall As Market Ramps Up With Market Average At $156/kWh In 2019" (December 2019); The percentage decline discussed in this footnote is expressed in real dollars 6. Source: California Air Resources Board "15 states and the District of Columbia join forces to accelerate bus and truck electrification" (July 2020 Press Release) Page 10 1. 4. Source: California Air Resources Board "15 states and the District of Columbia join forces to accelerate bus and truck electrification" (July 2020 Press Release) Source: Ipsos "Climate Change and Consumer Behavior" (December 2019); survey of 23k adults across 28 countries 3. Source: BloombergNEF "Battery Pack Prices Fall As Market Ramps Up With Market Average At $156/kWh In 2019" (December 2019); The percentage decline discussed in this footnote is expressed in real dollars Source: Goldman Sachs "Outlook for Alternative Powertrain Technologies in Glob Truck Markets" (October 2020) Page 16 1. Total Addressable Market is based on management estimates of the assumed price of an electric powertrain, and the number of vehicles per the following sources: LMC, "Global Commercial Vehicle Forecast World Query MHCV", Q3 2020; Freedonia, "Global Buses Industry Study 6th Edition", June 2019; Frost & Sullivan, "Global Electric Bus Market Opportunity Analysis, 2017- 2025", December 2018; Frost & Sullivan, "Global Earth Moving, Construction and Mining Equipment Market, Forecast to 2026", December 2017. Bloomberg NEF, "Charging Infrastructure Forecast Model (CIFM)", August 27, 2020. Estimates in 2023 are based on battery and drivetrain for all segments except North American transit, which includes assumed vehicle price 2. Source: BloombergNEF "Electric Vehicle Outlook 2020" Charging Infrastructure Forecast Model (August 2020) Page 17 2. Source: Freedonia, "Global Buses Industry Study 6th Edition", June 2019 (School bus, Coach bus, Non-North America transit bus numbers); Frost & Sullivan, "Global Electric Bus Market Opportunity Analysis, 2017- 2025", December 2018 (North America transit numbers); BUSRide "The Small & Midsize Bus Market in 2018 - Round Table" (October 2018) (North America shuttlebus numbers); Propane Education & Resource Council's Chief Business Development Officer Tucker Perkins quoted in LPGas Magazine "Industry Partners in place for propane to penetrate step-van market" (October 2014) (North America step van numbers) January 2021 Page 18 2. Source: Propane Education & Resource Council's Chief Business Development Officer Tucker Perkins quoted in LPGas Magazine "Industry Partners in place for propane to penetrate step-van market" (October 2014) Source: American School Bus Council (December 2020) 3. Page 19 1. Source: Federal Transit Administration's 2019 Annual Database Revenue Vehicle Inventory; share of electric buses ≥35-ft Page 20 2. 1. Source: Frost & Sullivan "Global Electric Bus Market Opportunity Analysis, 2017-2025" (December 2018) Source: California Air Resources Board "California transitioning to all-electric public bus fleet by 2040" (December 14, 2018), the City of Chicago Resolution R2019-157, King County, "Metro is transitioning to a zero- emissions bus fleet" (August 2019), Miami-Dade County Board of County Commissioners Resolution R-1034-18, Minnesota Metropolitan Council Transportation Committee "Bus Fleet Strategy" (December 10, 2018). Coalition for Clean Transportation, MTA 2020-2024 MTA Capital Program (September 2019), Toronto Transit Commission "TTC Green Initiatives" (December 2020), and Yale Environment 360, Yale School of the Environment (December 14, 2018) 3. PROTERRA 4. Source: NFI Group Company Materials (3Q 2020); represents NFI Group's North America transit bus active bid universe Source: Total North American Bus Fleet size reached through the addition of the United States total bus fleet size of 66,116 (American Public Transportation Association "2019 Public Transportation Fact Book," (2019)) to the Canadian total bus fleet size of 18,604 (Motor Carrier Passenger Council of Canada, "Labor Market Report 2019: Business and Financial" (2019) Page 21 1. Source: BloombergNEF "Electric Vehicle Outlook 2020" Charging Infrastructure Forecast Model (August 2020) 2. Source: FleetOwner "FleetOwner 500 Top Private Fleets" (April 15, 2019) 3. Source: US. Department of Transportation Federal Highway Administration, Office of Freight Management and Operations "Jason's Law Truck Parking Survey Results and Comparative Analysis" (April 2015) 4. Source: Wonder "US Warehouses and Distribution Hubs" (March 14, 2020) 52#53January 2021 PROTERRA