Exhibit 99.1

 November 2023  H2B2 Electrolysis Technologies  Investor Presentation 

 Disclaimer  This presentation has been prepared for use by H2B2 Electrolysis Technologies, Inc. (together with its subsidiaries and affiliates, the “Company”) and RMG Acquisition Corp. III (“RMG III”) in connection with their proposed business combination (the “Business Combination”). This presentation is intended to provide a general overview of the business and operations of the Company and does not purport to deal with all aspects and details in respect thereof. This presentation is being delivered for informational purposes only and is being provided to you solely in your capacity as a potential investor considering an investment in the Company or RMG III. The information contained in this presentation and any oral statements made in connection with this presentation are subject to change and do not purport to be all inclusive or to contain all the information that a person may desire in considering an investment in the Company or RMG III and is not intended to form the basis of any investment decision in RMG III or the Company. Neither RMG III nor the Company makes any representation or warranty, express or implied, as to the accuracy, completeness or reliability of the information contained in this presentation. Prospective investors should consult with their own legal, regulatory, tax, business, financial and accounting advisors concerning the matters described herein, and, by accepting this presentation, you confirm that you are not relying solely upon the information contained herein to make any investment decision and that you must make your own decisions and perform your own independent analysis of an investment in RMG III or the Company and the transactions contemplated in this presentation. The information contained in this presentation has not been verified or revised by the auditors of the Company or RMG III.  This presentation does not constitute or form part of, and should not be construed as, (i) an offer to sell or the solicitation of an offer to buy any security, commodity or instrument or related derivative, (ii) a solicitation of a proxy, consent, vote of approval or authorization in any jurisdiction with respect to any securities or the Business Combination or (iii) an offer or commitment to lend, syndicate or arrange a financing, underwrite or purchase or act as an agent or advisor or in any other capacity with respect to any transaction, or commit capital, or to participate in any trading strategies. There shall not be any sale of securities in any jurisdiction in which the offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. 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Investment in the securities described herein has not been approved or disapproved by the U.S. Securities and Exchange Commission (the "SEC"), or any other regulatory authority, nor has any authority passed judgment upon or endorsed the merits of any securities of RMG III or the Company or the accuracy or adequacy of the information contained herein. RMG III and the Company reserve the right to update or supplement the information provided in this presentation.  Additional Information and Where to Find It  In connection with the Business Combination, RMG III filed with the SEC a registration statement on Form S-4, which includes a preliminary proxy statement/prospectus (as amended from time to time, the “Proxy Statement/Prospectus”). A definitive proxy statement/prospectus will be mailed to RMG III’s shareholders as of a record date to be established for voting on the Business Combination and other matters as described in the Proxy Statement/Prospectus. The Proxy Statement/Prospectus will include information regarding the persons who may, under SEC rules, be deemed participants in the solicitation of proxies to RMG III’s shareholders in connection with the Business Combination. RMG III will also file other documents regarding the Business Combination with the SEC. Before making any voting or investment decision, investors and security holders of RMG III, as well as other interested persons, are urged to read the Proxy Statement/Prospectus, the definitive proxy statement/prospectus and all other relevant documents filed or that will be filed with the SEC in connection with the Business Combination, including any amendments or supplements to these documents, carefully and in their entirety because they will contain important information about the Business Combination, RMG III and the Company. Investors and security holders will be able to obtain free copies of the Proxy Statement/Prospectus and all other relevant documents filed or that will be filed with the SEC by RMG III through the website maintained by the SEC at www.sec.gov. In addition, the documents filed by RMG III may be obtained free of charge from RMG III’s website at www.rmgacquisition.com/rmgiii or by written request to RMG III at RMG Acquisition Corp. III, 57 Ocean, Suite 403, 5775 Collins Avenue, Miami Beach, Florida.  Participants in the Solicitation  RMG III, the Company and certain of their respective directors and officers may be deemed to be participants in the solicitation of proxies from RMG III’s shareholders in connection with the Business Combination. Information about RMG III’s directors and executive officers and their ownership of RMG III’s securities is set forth in RMG III’s filings with the SEC, including RMG III’s Annual Report on Form 10-K for the year ended December 31, 2022, which was filed with the SEC on April 18, 2023 and the Proxy Statement/Prospectus. Additional information regarding the interests of those persons and other persons who may be deemed participants in the Business Combination may be obtained by reading the Proxy Statement/Prospectus regarding the Business Combination. You may obtain free copies of these documents as described in the preceding paragraph.  Forward-Looking Statements  This presentation contains certain forward-looking statements within the meaning of the federal securities laws. Forward-looking statements are predictions, projections and other statements about future events that are based on current expectations and assumptions and, as a result, are subject to risks and uncertainties. All statements contained in this presentation that do not relate to matters of historical fact should be considered forward-looking statements. Forward-looking statements may include, but are not limited to, statements about the financial and business performance of the Company; the Company’s anticipated results from operations in future periods and the products and services offered by the Company, the markets in which it operates, the projects which it operates and its customers; and the Company’s projected future results (including EBITDA, cash flow, revenue and net income). In addition, any statements that refer to projections, forecasts or other characterizations of future events or circumstances, including any underlying assumptions, are forward-looking statements. In some cases, you can identify forward-looking statements by terms such as “may,” “will,” “should,” “would,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “projection,” “contemplate,” “believe,” “estimate,” “predict,” “potential”, “plan,” “pipeline,” or “continue” or the negative of these terms or other similar expressions, although not all forward-looking statements are identified by these terms or expressions and the absence of such words does not mean that a statement is not forward-looking.  Forward-looking statements speak only as of the date they are made. The Company’s management has based these forward-looking statements largely on their current estimates, assumptions, expectations and projections that, while considered reasonable by the Company and its management, are inherently uncertain. Assumptions and estimates of the Company’s future performance and the future performance of the industry in which the Company operates are necessarily subject to a high degree of uncertainty and risk due to a variety of factors. Forward-looking statements involve a number of risks and uncertainties, which include, but are not limited to, those described in the “Risk Factors” section of RMG III's registration statement on Form S-4, the Proxy Statement/Prospectus contained therein, RMG III’s Annual Report on Form 10-K, RMG III’s Quarterly Reports on Form 10-Q and other documents filed by the Company or RMG III from time to time with the SEC. The risks and uncertainties described in such filings as well as other factors may cause actual events, results or performance to be materially different from those contained in the forward-looking statements, the Company’s estimates and beliefs or the estimates prepared by independent parties, and the Company may not actually achieve the plans, intentions or expectations disclosed in the forward-looking statements, including but not limited to the matters referred to as part of the Company's pipeline and projections. You should review this presentation completely and with the understanding of the foregoing and should not place undue reliance on the forward-looking statements. Except as required by applicable law, RMG III and the Company assume no obligation and do not intend to update or revise any information contained herein, including any forward-looking statements, financial projections and estimates, whether as a result of any new information, future events, changed circumstances or otherwise. Neither RMG III nor the Company gives any assurance that either RMG III or the Company will achieve its expectations. All subsequent written and oral forward-looking statements concerning the matters addressed in this presentation and attributable to RMG III, the Company or any person acting on their behalf are expressly qualified in their entirety by the cautionary statements and disclaimer contained or referred to herein.  Use of Projections  This presentation contains financial projections for the Company, including with respect to the Company’s projected revenue. The financial and operation forecasts and projections contained herein represent certain estimates of the Company as of the date hereof and are included herein for illustrative purposes only. The Company’s independent auditors have not audited, examined, reviewed, compiled or performed any procedures with respect to the forecasts or projections and, accordingly, do not express an opinion or other form of assurance with respect thereto. These projections should not be relied upon as being necessarily indicative of future results. The assumptions and estimates underlying the projected information are inherently uncertain and are subject to a wide variety of significant business, economic and competitive risks and uncertainties that could cause actual results to differ materially from those contained in the projected information. Even if the assumptions and estimates are correct, projections are inherently uncertain due to a number of factors outside of the Company’s control. Accordingly, there can be no assurance that the projected results are indicative of the future performance of the Company, or that actual results will not differ materially from those presented in the projected information. Inclusion of the projected information in this presentation should not be regarded as a representation by any person that the results contained in the projected information will be achieved.  Intellectual Property  All rights to the trademarks, service marks, trade names, copyrights, logos and other intellectual property listed herein are the property of their respective owners and are used for reference purposes only. Such use should not be construed as and does not imply an affiliation with, or endorsement by the owners of such trademarks, service marks, trade names copyrights, logos and other intellectual property. Solely for convenience, trademarks and trade names referred to in this presentation may appear with the ® or TM symbols, but such references are not intended to indicate, in any way, that such names and logos are trademarks or registered trademarks of the Company.  Industry and Market Data  Unless otherwise indicated, information contained in this presentation concerning the Company's industry, competitive position and the markets in which it operates is based on information from independent industry and research organizations, other third-party sources and management estimates. Management estimates are derived from publicly available information released by independent industry analysts and other third-party sources and are based on assumptions made by RMG III or the Company upon reviewing such data, and RMG III or the Company's experience in, and knowledge of, such industry and markets, which RMG III and the Company believe to be reasonable. While RMG III and the Company believe that such third-party information is reliable, neither the Company nor RMG III has independently verified, and makes no representation as to the accuracy or completeness of, such third party information. In addition, projections, assumptions and estimates of the future performance of the industry in which the Company operates and the Company's future performance are necessarily subject to uncertainty and risk due to a variety of factors, including those described above. These and other factors could cause results to differ materially from those expressed in the estimates made by independent parties and by the Company or RMG III. Neither RMG III nor the Company, nor any of their respective affiliates, give any express or implied warranties with respect to the information included herein, including, but not limited to, any warranties regarding its accuracy or of merchantability or fitness for a particular purpose or use, and RMG III, the Company and their respective affiliates, expressly disclaim any responsibility or liability for direct, indirect, incidental, exemplary, compensatory, punitive, special, or consequential damages, costs, expenses, legal fees, or losses (including lost income or profits and opportunity costs) in connection with the use of the information herein.  2 

 Executive summary  1 

 4  Today’s presenters  H2B2 Electrolysis Technologies  RMG Acquisition Corp. III  Bob Mancini  CEO and Director  Anselmo Andrade  CEO  Felipe Benjumea  CIO  Florencio Ferrera  COO  Javier Brey  CTO 

 H2B2 at a glance  A leading green hydrogen company with a unique positioning across the entire value chain, offering clients complete solutions   Operating KPIs Business model and major highlights   Source: Company information  (1) PEM: Proton Exchange Membrane; SOEC: Solid Oxide Exchange Cells; AEM: Anion Exchange Membrane  A technological leader in PEM, SOEC, and AEM with references worldwide  Demonstrated success with flagship project SoHyCal and ~2.8 GW in pipeline  Selected by the European Commission to develop PEM, SOEC & AEM technology under the Important Project of Common European Interest (IPCEI) program  Ability to retain minority stakes through construction and operations phase, showcasing commitment to clients  Ability to offer LTSAs, making projects financeable  Ability to integrate with renewables, offering clients full solutions  5  Green H2  Technology agnostic focused on PEM, SOEC and AEM electrolyzers(1)  5.6 GW  Total pipeline, of which ~73 MW is under construction or awarded  ~$35mm  awarded R&D grants from IDEA, CDTI, EU and IPCEI  driving R&D new electrolysis technology  ~200+  Green H2 projects identified in pipeline through 2024E  Electrolyzers  EPC  O&M  Investments and Asset Management  Development of Green Hydrogen Facilities  R&D 

 Source: Company Information  6  H2B2 electrolysis technologies overview  A leading green hydrogen company providing end-to-end solutions, with a pipeline of over 200 projects  Founded in 2016, H2B2 designs, builds, and operates H2 production facilities, including the transport, storage and sale of green H2  H2B2 has a extraordinary development,  best-in-class management team, with experience in H2 and energy project that has been delivering outstanding  performance together for over 20 years  Global strategy, co-locating electrolyzer manufacturing facilities next to major customers  Existing 200MW manufacturing facilities in Sevilla (Spain) and potentially adding facilities in US, India,  Colombia, and Northern Spain  Under H2B2’s GreenH joint venture, they also have leased a manufacturing facility in India with an expected manufacturing capacity of 100 MW  Strategy built around 6 business units (Labs, Project Development, Electrolyzers, EPC, O&M, and Asset Management) offering integrated solutions  H2B2 utilizes proven PEM technology and is developing in-house, next generation SOEC and AEM stacks and electrolyzers  – H2B2 has the flexibility to integrate any third-party technologies, including alkaline at the EPC level  1  2  3  4  5 

 Source:, Company information  (1) BloombergNEF New Energy Outlook 2021; (2) The first 3MW (Phase I) is operational, with an additional 6MW (Phase II) under FID  Key investment highlights  A leader in green hydrogen across the entire value chain, backed by a highly experienced management team with successful project track record  Strategy developed and delivered by industry leading team  H2B2’s top management team has 150+ years of combined experience in the H2 sector  60+ employees covering R&D, manufacturing, EPC and O&M across the US, Europe, LatAm and India  6  Green H2 expected to drive the decarbonization of the global economy  The green hydrogen energy market has potential to reach ~$10 trillion value by 2030(1)  United States’ IRA direct incentives and EU’s Green Industrial Plan are making large projects viable  1  100% owner of SoHyCal, one of the largest green H2 electrolysis plants in the US  Large 9MW(2) green H2 off-grid plant directly supply hydrogen refueling stations in California  Ability to provide full production guarantees for SoHyCal, facilitating long-term offtake agreements  5  H2B2, a leading global platform in the green H2 space  End-to-end value chain expertise: R&D, proprietary electrolyzer tech, project lifecycle, manufacturing, EPC, O&M, and green H2 production, storage, delivery  2  Patented and proprietary electrolyzer technology  Currently utilizing proven PEM technology in the supply of its manufactured electrolyzers  Developing next generation technologies (AEM & SOEC)  4  Client-centric business model  One-stop-shop approach with tailor-made and scalable solutions, offering development/design, EPC, electrolyzers, offtake agreements, financing and O&M services  3  7 

 8  Overview of RMG III management team  Founder and CEO of Riverside Management Group  Former CEO of Horsehead Industries (renamed American Zinc Recycling), the Largest Zinc Recycler and Producer in the U.S  Co-Founder of Mohegan Energy, Leading Capital Formation for the Acquisition of Met Resources  D. James Carpenter • Founding Investor & Board Member of Allied Resource Corp.  Chairman of the Board  Robert S. Mancini  CEO and Director  Former Partner, Founder & Co-Head of Power Investment Business at Carlyle (NASDAQ:CG)  Former Managing Director of Goldman Sachs (NYSE:GS)  Co-Founder & Head of Power Investment Business, Founder & Head of Commodities Principal Investment Business at Goldman Sachs (NYSE:GS)  Former Chairman & CEO of Cogentrix Energy  Philip Kassin  President, COO and Director  Former Senior Managing Director of Evercore (NYSE:EVR)  Former Head of M&A & Financing at Access Industries  Former Board Member and Chairman of the Finance & Investment Committee at LyondellBasell (NYSE:LYB)  Senior Investment Banking Roles at Morgan Stanley, Goldman Sachs, Merrill Lynch and AIG  Wesley Sima  CFO  Former Chief Financial Officer of RMG Acquisition Corp. II  Former Vice President of M-III Partners and M-III Acquisition Corp. (acquisition of IEA)  Former member of ING Capital LLC’s Natural Resource Project Finance, Corporate Finance and Advisory deal teams in New York City  Formerly a member of both the finance and corporate development teams at Entegra Power Group, formerly an independent power producer and owner/operator of multiple natural gas related assets, based in Tampa, FL  RMG Acquisition Corp. III Overview  RMG Acquisition Corp. III (“RMG III”) is a NASDAQ listed SPAC which completed its $483mm IPO on February 9, 2021  RMG III management team has significant public company board experience (NYSE, NASDAQ, and TSX)  The team successfully consummated SPAC transactions for RMG Acquisition Corp I and RMG Acquisition Corp II  Supported by Riverside Management Group, a leading merchant bank with ~25 years of experience in M&A advisory and principal investing  Previous Experience  Highly Experienced RMG III Management Team 

 Source: Company information  (1) SoHyCal Phase I has an electrolysis capacity of 1,290 kg per day of hydrogen, and once Phase II is completed, SoHyCal is expected to have an electrolysis capacity of 3,000 kg or more of hydrogen per day; (2) Important Projects of Common European Interest; (3) Hydrogen Refueling Stations  Proven track-record throughout the years in the H2 space  Since its foundation in 2016, H2B2 has proven its execution capabilities, successfully developing multiple H2 projects  9  2020  Divestment of Giner ELX (current Plug Power) for  ~$14.3mm, allowing H2B2 to focus on the development of SOEC-AEM  technologies  2017  Contract with CEPSA, for the supply of a PEM electrolyzer, to produce ultra-pure H2  Corporate milestones  Commercial milestones  2016  H2B2 Electrolysis Technologies is founded with the mission to design, build and operate H2 production facilities, including the transport and sale of hydrogen  Opening of offices in Spain and California  2021  $10mm capital raise, to reinforce growth and strengthen R&D capabilities  2022  JV with GRIL to develop hydrogen projects in India  EU selected H2B2 as an  IPCEI(2) and awarded  €25mm in grants  H2B2 was selected among 80 companies as Ecopetrol’s tech partner  2018  Electrolyzer supplied to CEU University, one of the leading Spanish universities, for investigation uses in domestic clean heat  2019  Involved in an EU-led trigeneration project seeking to improve energy efficiency through H2  Unit supplied to VTT; a leading research laboratory  2020  Supply contract of 2 PEM electrolyzers to be applied in a CCPP in the UAE  2021  Supply of an HRS(3), including H2 production to FM Logistic  Construction start of SoHyCal plant, a world pioneer green H2 production plant in California (expected 3Tn/day, 100% renewable)  2022  Supply of electrolyzers to Serveo (1MW), GP Joule (10MW), and Ecopetrol, among others  Development of a H2 self-supply energy system for a hospital in the Netherlands  2023  Electrolyzer supply contracts with Puerto de Vigo (1MW) and Redexis (2.5MW)  Selected bidder for an 18MW project in Norway and a 30MW project in the US  MoU signed with Enel  1 MW electrolyzer and train HRS under construction in India  2017  Strategic investment (25% stake) in Giner ELX, developer and manufacturer of PEM stacks technology  2018  The California Energy Commission awarded H2B2 a  1.29Tn/day(1) hydrogen plant (SoHyCal)  1MW PEM stack tested in NREL  2023  Signed a business combination agreement with RMG III with the intention of becoming listed on the NASDAQ 

 Green hydrogen plant in Rørvik  Norway  18 MW  Selected bidder (cooperation period)  Maritime fuel  India  1 MW, 420 kg / day HRS  Under Construction  Mobility  Highlighted projects  H2B2 has a highly visible project pipeline with several projects under construction or executable in the near-term  Green hydrogen plant in California (SoHyCal)  Source: Company information  (1) 3MW in Phase I (operational as of September 2023), and additional 6MW in Phase II  HRS and Electrolyzer in India  United States  9 MW(1)  Phase I: Operational  Phase II: Under FID  Mobility  Green hydrogen plant in California  United States  30 MW  Selected bidder Mobility  10  Hydrogenation Plant for Biofuel Production in Italy  Italy  3 MW  Selected bidder Industrial  Electrolyzer for Mobility in Spain  Spain  2.5 MW  Under Construction Mobility  California Energy Commission  Medha  GreenStat & NTE  Dynamis Energy  Greenswitch  Redexis 

 Source: Company information, ARUP  Electrolysis technologies  Technology agnostic with focus on technologies best suited for renewables  Electrolyzer Technology Overview  Most mature technology, used over the past ~30 years  The hydrogen evolution reaction takes place in a liquid alkaline electrolyte solution  Growing technology, usually developed with a renewable energy installation  Employs a conductive membrane that encapsulates the electrolyte and separate the gases  Runs in regenerative mode to achieve the electrolysis of water  Takes place at high temperatures, using steam allows for a superior kinetics performance  Less mature technology with a high potential  It integrates a solid, non-porous polymer electrolyte to enhance the kinetics  Pros  Most mature and commercially available technology  Ability to run at high pressure  Relatively easy to manufacture  Lower Capex per MW relative to PEM  Can be connected to renewable energy sources (PV, wind)  Fast start-up, shutdown  More efficient at a high current density  Higher purity H2 gas than alkaline  High conversion efficiency (up to 25% less electrical energy consumption)  Can be used with high-temperature heat sources  Ability to operate at high current densities  Fast start-up, shutdown  Use of non-precious-metal catalysts reduces cell cost  Ability to run at different pressure   Requires high input of electrical energy  × Relatively low current density  × High maintenance costs  × Not appropriate for operation using transient power sources   Requires high input of electrical energy and a power source   High system costs due to platinum- based family catalysts and a proton exchange membrane   High system cost   Need for constant operation   Long start-up and break-in times   Requires high input of electrical energy   Stability problems  Technology Readiness Level (TRL)  Cons  Commercialization phase  Commercialization phase  R&D phase  R&D phase  Solid Oxide  (SOEC)  Anion Exchange Membrane  (AEM)  Alkaline Water Electrolysis  (AWE)  Proton Exchange Membrane  (PEM)  Diversified supplier base  (Plug Power, Hystar, Bosch, Schaeffler)  In-house  In-house  In-house  In-house  In-house  Stack Supply  Electrolyzer Supply  11 

 Source: Company information  SoHyCal, one of the largest operating green hydrogen plants in the US  H2B2’s flagship project is a successful example of an operational, off-grid project, key for the energy transition  Location  California, US  Sponsor  California Energy Commission  Installed capacity  Phase I: 3 MW Phase II: 6 MW Total: 9 MW  Completion status Phase I: Operational Phase II: Under FID  Green H2 capacity  Phase I: 1,290 kg / day Phase II: >1,710 kg / day Total: >3,000 kg / day  Phase I Operational start date  September 2023  Understanding SoHyCal’s importance  H2B2 has a “first mover advantage”, as it expects to lead the supply of renewable hydrogen to major offtakers present in the region to fill unmet demand  The project, 100% developed by H2B2, is serving as a blueprint for future projects involving connection with renewables, gas pipeline, permitting, hydrogen dispensing and transport, etc., giving a significant competitive advantage vs others who have yet to develop and deliver a completed project  To accelerate the development and deployment of renewable hydrogen in the U.S., the U.S. Department of Energy has reserved up to $1.2bn to invest into green H2 projects in California. H2B2’s SoHyCal project may be eligible for a portion of these funds  One of the largest operating off-grid renewable energy hydrogen projects in the United States, using a 15 MW PV plant and biogas fed engine, supplied by a co-located dairy farm  12 

 Source: Company information, Ecopetrol, World Economic Forum, Government of Colombia  13  Leveraging partnerships to access global markets  H2B2 seeks to scale globally through strategic partnerships and joint ventures  H2B2 has been selected as technological partner by Ecopetrol in connection with its decarbonization strategy  Ecopetrol is the largest and primary petroleum company in Colombia and the second largest oil & gas company in Latin America  In May 2022, H2B2 was selected by Ecopetrol as technological partner to help the company in the decarbonization of its activities through green hydrogen facilities  – H2B2 was after a very competitive selection process that included 80+ companies from 16 countries  As part of the partnership, H2B2 will lead the construction of a manufacturing facility in Colombia to supply Ecopetrol’s South  American market, as well as provide maintenance services and HRS once completed   Ecopetrol: technological partner for decarbonization GreenH: JV to grow the hydrogen economy in Asia   In 2023, H2B2 launched GreenH, a joint venture with GR Promoter Group (“GR”) to develop the hydrogen economy in Asia  – GR is an India-based listed company, that develops, constructs and operates all types of infrastructure related projects (highways, power lines, substations, railways, multimodal logistic centers, etc.)  The JV is based in India, and H2B2 owns 50%  Through GreenH, H2B2 expects to manufacture electrolyzers and develop, construct, and operate green hydrogen generation plants for all sectors  GreenH expects to build and operate 10-500 MW green hydrogen production plants in key Asian countries  Under H2B2’s GreenH joint venture, they also have leased a manufacturing facility in India with an expected manufacturing capacity of 100 MW  Potentially provide O&M and associated services for these production plants  Key H2B2 responsibilities include the development and transfer of technology, supply of the stacks (PEM, SOEC and AEM) and ensuring projects are up to date with any technological upgrades 

 Industry overview  2  13 

 H  2  Introduction to green hydrogen  Hydrogen is broadly applicable to multiple end markets, and can be obtained as a gas through fossil fuels (Grey, Blue), nuclear power (Pink H2) or renewable sources (Green H2)  What is hydrogen?  Main types by source of energy utilized  Applications and end markets  Hydrogen (H ) is a clean, chemical energy carrier  2  alternative to methane (natural gas)  On the planet, vast numbers of hydrogen atoms are contained in water, plants, animals and humans  – It's the most abundant chemical element in the universe, contributing ~75% of total mass  – However, despite being present in nearly all molecules in living things, it’s very scarce as a gas (less than one part per million by volume)  Hydrogen can be produced from a variety of energy sources, such as natural gas, nuclear power, biogas and renewable power like solar and wind  Hydrogen can be obtained through a process called electrolysis, which consists of using electricity to split water into oxygen and hydrogen  H2O  Electrolysis  O2  Oxygen  Hydrogen H2  O2  H2  -  Grey hydrogen  Hydrogen produced from natural gas using steam methane reforming (SMR)  Natural gas  CO2  H2  Blue hydrogen  Grey hydrogen, but with carbon capture utilization and storage techniques applied  Green hydrogen  “Clean hydrogen,” generated from renewable energy, using water as a feedstock for electrolysis  Natural gas  H2  CO  2  Carbon capture (CCS)  O2  Water  H2  Renewable energy  Hydrogen H2  Mobility  Used as a substitute for fossil fuels in fuel cell cars, trucks, planes, trains, etc.  Heat and power  Power generation for grid, power buffering and heat for residential and industrial uses  Agriculture  Converted to ammonia and used in fertilizers and crop nutrients  Source: Hydrogen Council, US Department of Energy, McKinsey, Bloomberg  Industrial applications  Used for steel production, hydrocracking, hydrogenation and synthetic gas  Hydrogen is compressed and stored underground in tanks or caverns, to be used in the future  Seasonal storage  Pink hydrogen  Hydrogen produced using electrolysis powered by nuclear energy  O2  Water  Nuclear energy  13 

 Regulatory support schemes  Strong regulatory support worldwide (focus on H2B2’s core markets)  United States  Bipartisan Infrastructure Law includes $9.5bn for clean H2 initiatives ($8bn earmarked for Regional Clean H2 Hubs)  Inflation Reduction Act (IRA) provides green H2 with substantial investment or production tax credits  $3/kg green hydrogen tax credit supporting H2 production  Europe  REPowerEU sets a target of 10mm tons of domestic green H2 production and 10mm tons of imports by 2030  European Commission (EC) announced the creation of a €3bn European H2 bank in September 2022  EC has also proposed an upper subsidies capped at €4/kg for green hydrogen projects  Target of 50% of all H2 demand in industry from renewable origin by 2030  Latin America  Colombia: target of 1-3GW of electrolysis capacity (40% low-carbon) by 2030  Chile: 21% of its 2050 carbon neutrality target using green hydrogen (25GW by 2030)  Uruguay: target of 1mm tons per annum of green H2 production by 2040  India  Adopted net zero by 2070 in 2021  Committed to non-fossil energy capacity of 500GW by 2030  155GW new non-hydro capacity for green hydrogen production by 2030  25-year waiver on transmission charges for renewable power used by electrolyzers  Japan  In April 2023, the government of Japan published a draft to revise the Basic Hydrogen Strategy  The draft includes a target of 12mm tons hydrogen supply by 2040  The plan also mentions JPY 15tn government and private investments to drive the adoption of the hydrogen economy  Source: ARUP, Infrastructure Investment and Jobs Act Public Law No. 117-58, Inflation Reduction Act Public Law No. 117-169  16 

 Global electrolyzer market  Driven by tremendous hydrogen demand, the electrolyzer market is expected to experience solid growth over the next decade, with PEM gaining significant market share versus alkaline installations   Installed electrolyzer capacity (GW)    Annual electrolyzer capacity in Europe and North America (GW)    Annual electrolyzer installations by technology (GW)    Annual investment in electrolyzer deployment ($bn)   2  5  11  21  39  63  100  157  242  2022 2023E 2024E 2025E 2026E 2027E 2028E 2029E 2030E  1  2  5  9  13  16  21  27  36  2022 2023E 2024E 2025E 2026E 2027E 2028E 2029E 2030E  4  24  35  51  5  12  8  16  13  21  34  1  3  6  10  7  17  24  37  56  85  2022 2023E  2024E  2025E 2026E  Alkaline PEM  2027E 2028E 2029E 2030E  Total  82% CAGR  57% CAGR  2  3  7  11  18  27  1  3  3  5  4  6  7  7  0.3  0.7  2.5  5.5  8  11  17  25  34  2028E 2029E 2030E  Europe  2022 2023E 2024E 2025E 2026E 2027E  US + Canada  81% CAGR  74% CAGR  Source: BloombergNEF 2023  17 

 Source: Company information, ARUP  (1) Arup working under its capacity as vendor due diligence provider to H2B2 Electrolysis Technologies  H2B2 addresses challenges to development of green hydrogen  There has been industry-wide attrition in green hydrogen projects due to difficulties regarding securing external funding. H2B2 is positively situated to secure project financing where others are not.  Green hydrogen is a relatively expensive energy compared to many alternative energy sources. This can be a limiting factor for near-term demand and investment  Governments and regulatory bodies recognize the importance of hydrogen in the energy transition and have been increasing hydrogen-specific targets globally since 2016. These targets have been supported with regulatory incentives (e.g., US IRA, EU Green Industrial Plan, among others) that have made green hydrogen economically competitive  Regulation and government incentives  As the near- and medium-term demand grows rapidly due to regulatory drivers and improving economics, electrolyzer supply must increase commensurately to avoid industry wide shortages and project delays  Supply Chain Security  Securing an offtake agreement is key to obtaining funding for green hydrogen projects. Some past projects in the industry have stalled due difficulty securing offtake agreements to support project financing  Potential offtakers are concerned about investing projects where there is uncertainty regarding the consistent production of hydrogen, given the relatively new technology and largely unproven execution capabilities of most EPC providers  Most players are focused either on technology (electrolyzers) or EPC, creating a  technology gap/risk for financing institutions and offtakers  Execution Risk  H2B2 has the ability to provide production guarantees, which facilitates long-term offtake contracts. H2B2 is able to provide this due to its extensive project execution experience and vertical integration  H2B2 has the necessary capacity to complete the business plan. Electrolyzer technology agnosticism and current in- house supply further insulate H2B2 from supply chain risk  Green hydrogen production costs are expected to decline due to technological advancements and economies of scale. Further, Arup substantiated that H2B2 has potential to be a relatively low-cost provider of quality green hydrogen products(1)  Challenge  How H2B2 addresses  18 

 Business overview  3  H2B2 Manufacturing Facility  Sevilla Spain 

 Strategy developed and delivered by industry leading team  Management team with a solid track record and working together in hydrogen and renewables projects  Blanca Benjumea  CFO and HR manager  Founding member of H2B2  Last 5 years focused on hydrogen, holding top executive positions in H2B2  Past experience in public company auditing and strategic consulting at KPMG in Spain and New York  BSc in Business Administration from Fordham University in New York  Javier Brey  CTO  Founding member of H2B2  25+ years of experience in the H2 sector  Chairman of the Spanish Hydrogen Association since 2009  Former CEO of Abengoa Hydrogen  Former CEO of Hynergreen  PhD with thesis on Hydrogen Economy  Antonio Vázquez  Chairman  40+ years in management roles  Joined H2B2 in Dec-2022  Former chairman of listed- IAG (Iberia, British Airways)  Former Board Member of Telefónica Internacional and Aldeasa  Former CEO of listed-Altadis at the time of the ~$17 billion acquisition (enterprise value) by Imperial Tobacco  Anselmo Andrade  CEO  Founding member of H2B2  Last 7 years focused on hydrogen holding top executive positions in H2B2  Previously acted as CFO and Business Development Officer of H2B2  Past experience in strategic consulting  MSc in Finance from London School of Economics (LSE)  Felipe Benjumea  CIO  Founding member of H2B2  Last 7 years focused on hydrogen holding top executive positions in H2B2  Previously acted as Head of Investor Relations & Capital Markets  Past experience in corporate and investment banking  BSc in Business Administration from Saint Louis University  ~20 years working together and delivering outstanding performance  Florencio Ferrera  COO  27+ years in the energy sector across multiple EPC projects  Joined H2B2 in July 2021  Several senior positions in Abengoa (Energy Operations Director, Energy General Director and Project Manager)  África Castro Head of Business Development  Founding member of H2B2  20+ years dedicated to hydrogen  Vice-Chairman of the Spanish Hydrogen Technology Platform  Former Head of Business Dev. at Abengoa Hydrogen  Asdrúbal Lupi  Head of Engineering  35+ years of experience in infrastructure and power engineering  Joined H2B2 in December 2021 as Project Manager of SoHyCal  Power Plant I&C engineering at Abengoa Energy  José Luis Márquez Procurement Director & Construction Lead  Former CEO of Abeinsa (Abengoa) in the US  20+ years in EPC project management in the energy industry globally  Joined H2B2 in January 2023  Manuel Rodríguez Electrolyzers Business Unit Manager  Founding member of H2B2 as Project Engineer  Past experience as Engineer at Abengoa Hydrogen  Past experience as development and production manager  Antonio Zamora O&M Business Unit Manager  22+ years of experience in asset management of energy assets in multiple technologies  Joined H2B2 in October 2022  Industrial Technical Engineer specialized in Power Plants  Source: Company information  20 

 Business model  Electrolyzers (Electrolyzers & Refueling Stations manufacturing)  EPC  (Construction & related services)  O&M  (O&M services)  Integrated product and services offering, with tailor-made solutions across the hydrogen value chain  H2B2 Business Model (full coverage of value chain)  across H value  2  chain)  R&D  (R&D  development  Development of Green Hydrogen Facilities (Project development services)  Investments and Asset Management  (Minority equity investments)  Present in some of the largest projects by installed capacity worldwide  Source: Company information  20  Hub-and-spoke manufacturing of PEM electrolyzers  Electrolyzers with top- tier technology  Several patents filed, and additional exclusive licensed patents already granted  Proven EPC capabilities  End-to-end solutions from power generation to dispensing/injection of green H2  Could offer different levels of guarantees to include coverage for costs, delays and/or potential performance variances  Technology agnostic, with the ability to integrate PEM, ALK, SOEC and AEM  Once a project is commissioned, H2B2 offers a variety of services for operations and maintenance to fit client requirements, including:  Preventive Maintenance  Long Term Service Agreement (LTSA)  Production guarantees  To keep minority equity stakes in project SPVs at financial close  Expected to generate sustainable dividends from these investments  Providing the services required to set up a green hydrogen production facility  Includes all pre- construction phase tasks: identifying opportunities, carrying out the feasibility analysis, permitting, ensuring offtake and sourcing of financing  Development of efficient and durable electrolysis technologies, allowing cost reductions in Capex and Opex for the production of green hydrogen  Partnered with leading research institutions and universities to support its R&D activities 

 Client-centric business model  Two differentiated, scalable business models providing bespoke services across the green hydrogen value chain  Conventional product  Integrated product  Self- developed  Third parties  Product  Business Model  Overview  Selected example  Equipment, plant and services provided to projects developed by third parties, including manufacturing, installation of electrolyzers and/or construction  Usually contracted through a competitive bidding process  R&D  Project Dev.  Electrol.  EPC  O&M  Asset Mgmt.  R&D  Project Dev.  Electrol.  EPC  O&M  Asset Mgmt.  R&D  Project Dev.  Electrol.  EPC  O&M  Asset Mgmt.  Projects developed by H2B2 and funded by third parties, where H2B2 can invest a minority stake  Sole developer or partner with other co- developers to create synergies  Focused in regulated markets (US & Europe)  H2B2 positions itself as a technological partner for a third party that is interested in developing green hydrogen projects  H2B2 to provide turnkey solutions for third party investors  The first 3 MW (Phase I) of SoHyCal in California is operational, with an additional 6 MW (Phase II) under FID  Technological partner for the supply of electrolyzers and refueling stations  Supply GP Joule with 10MW of electrolyzer capacity  GP Joule  Source: Company information  20  California Energy Commission  EcoPetrol 

 Business model | R&D  Under R&D, H2B2 is developing revolutionary technologies for PEM, AEM and SOEC electrolysis   Overview   H2B2 Labs is the business unit focused on R&D, and its fundamental objective is the development of more efficient and durable electrolysis technologies to allow a reduction in costs in both capital and operating expenditures in the production of hydrogen  H2B2’s R&D strategy is structured around the continuous improvement (efficiency and cost reduction) of PEM electrolyzers, and the development of SOEC and AEM technologies for stacks and electrolyzers  Partnering with leading institutions to develop particular parts of their SOEC and AEM electrolyzers, including CIEMAT and CSIC  H2B2 has licensing arrangements with third parties for patents related to electrolysis technologies, and has filed another 6 patents related to PEM Balance of Plant (BoP) and SOEC stacks  > 25 external collaborators for R&D within prominent institutions   R&D Grants    H2B2 objectives and cost down strategy   PEM  SOEC  AEM   Objectives    Cost-down strategy BoP simplification, improve heat and water management,  In-house design of purification systems, integration with batteries  Improvement of BoP for modular units. Development and BoP improvement of large facilities (>10MW)  Development of 100kW electrolyzers in the near-term, and up to 1MW in the medium- term  Development of 100kW electrolyzers in the near-term, and up to 1MW in the medium- term  Focused on dry membrane- electrode assembly manufacturing technique  Manufacture of ceramic electrolytes by 3D printing (increase stack energy density, and simplifies manufacturing)  ~$35mm  Awarded in R&D grants across 3 primary institutions (IPCEI(1), CDTI(2), IDAE(3))  IPCEI  CDTI  IDAE  Awarded by the IPCEI, an  Awarded through an R&D  Awarded to support R&D  EU subsidy program to  support program  from a program Spanish  support development and  sponsored by the Spanish  program which aims to  construction of  Ministry of Energy.  promote innovation and  manufacturing facilities for  technological development.  AEM and SOEC stacks.  Source: Company information  (1) Important Projects of Common European Interest; (2) Center for Technological Development and Innovation; (3) Institute for Energy Diversification and Saving  23 

 Source: Company information  Business model | Electrolyzers  Since 2016, H2B2 has manufactured and installed electrolyzers, with a unique product offering in the industry  Medium-scale  Capacity of 50-300 kW per container  Hydrogen production of 10-60 Nm3/h  Integrated within a container   Overview    Product portfolio    Highlighted projects   H2B2 is focused on the manufacturing, assembly and installation of electrolyzers and hydrogen refueling stations  H2B2 has two main types of electrolyzer solutions:  Containerized solutions for those units up to 15-20MW (“plug-and-play” electrolyzers)  Skid mounted solutions for those plants greater than 20 MW, skids are installed on-site and interconnected by H2B2  H2B2 has a wide range of electrolyzers under commercialization, with 1-4 stacks, with a total maximum output of approximately 1,726kg of green hydrogen per day  Apart from manufacturing and installation, this business unit also covers start up and testing works  H2B2 supplies electrolyzers with CE marking(1) and, if necessary, ETL stamp(2)  (priced separately), as well as required safety studies (HAZOP by default)  Leading renewables company  Supply of 5 EL400N units totaling 10MW capacity for HRS, producing 860 kg/day  Supporting Indian Railways’ carbon neutrality  Supply of 1MW EL200N electrolyzer and HRS  Leading gas distribution company  Supply of 2.5MW  electrolyzer to Redexis  Large-scale  Capacity of 0.5-5 MW per container  Hydrogen production of 100-1,000 Nm3/h  Integrated into 40ft containers  Large Scale Skid mounted solutions  For projects greater than 20 MW (e.g. 100MW), H2B2 can execute on-site installation of the electrolyzers  H2B2 Focus  GP Joule  24  (1) Conformité Européenne, meaning that have been assessed to meet high safety, health, and environmental protection requirements; (2) ETL Mark is proof of product  compliance to North American safety standards  Medha  Redexis 

 Business model | EPC  H2B2 has full construction capabilities, from engineering to commissioning, including extensive experience in integration with renewable energy   Overview Main divisions within EPC    Illustrative H2B2 project timeline   H2B2 performs engineering, procurement, construction and commissioning  services required for the construction of hydrogen plants  Necessary capabilities to build tailor-made hydrogen plants in less than 20 months from engineering to commissioning  Main steps include Engineering, Procurement and Construction & Commissioning  Leading the construction of a green hydrogen plant in California (SoHyCal), and the electrical and mechanical installations of other projects  Extensive experience in the integration of renewable energy installations  (mainly PV and wind), being key in the construction of green hydrogen plants  Months  1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  Engineering  Procurement  Construction  Commissioning  H2B2 is capable of building a full hydrogen plant in 20 months, 10 if excluding engineering and procurement  Source: Company information  25  Engineering  Starts as soon as a project is awarded  Includes geotechnical testing, full permitting, areas classification, technical support, tabulations, etc.  If needed, H2B2 may collaborate with local engineering firms to ensure full code compliance  Procurement  Starts at the 2nd month of the project  Purchasing all material and equipment needed, including contract negotiations, in parallel with the engineering team  Building long-term relationships with key suppliers  Construction & Commissioning  On-site activities mainly targeted at the installation and construction of the plant, as well as the integration with third-party equipment  This stage includes performance tests until provisional acceptance and the plant reaches COD status  Division  Overview  Illustrative  Duration  ~12 months  ~13 months  ~10 months 

 Geographic commercial and manufacturing footprint  H2B2 is present in multiple countries, and with current or planned manufacturing facilities in Europe, America and Asia  Current manufacturing plant  Planned manufacturing plant  North America  Europe  Strategic partners  200  MW  Current manufacturing capacity  Market coverage of the plant  Latin America  Asia-Pacific  100  MW  Expected capacity for leased manufacturing facility, under GreenH Joint Venture  Strategic partners  Arches H2  California Energy Commission  Enel  Strategic partners  Ecopetrol  Strategic partners  GRIL  H2B2 Manufacturing Facility, Sevilla Spain  Source: Company information  25 

 Financials & pipeline  4  27 

 2023E 2024E 2025E  2023E-2025E revenue projections(1)  Strong growth supported by both highly visible pipeline and proven track record  H2B2 has a strong and achievable Business Plan, supported by specific identified opportunities and management’s proven track record of successful execution. Breakeven (at Adj. EBITDA level) will be achieved by 2025E  Revenue ($ millions)  $206.6  $78.6  $12.0  553% Growth  163% Growth  Source: Company Information  (1) Projections assume the SoHyCal project will be deconsolidated from H2B2 for accounting purposes in 2024  28 

 Summary financial projections(1)  Source: Company Information  (1) Projections assume the SoHyCal project will be deconsolidated from H2B2 for accounting purposes in 2024  28  310%+  Revenue CAGR generated primarily from projects under construction, awarded projects or projects currently in the pipeline  ~$35mm  Historical and projected grant funding for R&D to increase electrolyzer efficiency and breadth of product portfolio (next-generation SOEC  and AEM technologies)  ~45%  Of 2024 revenue expected to be generated from Integrated Products, providing a more fulsome / integrated suite of services for  clients  $m  2023E  2024E  2025E  Net Income (Loss)  ($20.9)  ($16.3)  $3.9  (+) Income tax expense  -  -  0.2  (+) Interest and other expense, net  -  0.1  0.3  (-) Other income  (0.7)  (1.7)  (2.9)  (+) Depreciation of long-lived assets  0.3  1.9  3.7  Adjusted EBITDA  ($21.2)  ($16.0)  $5.2  (+) Grant funding  7.2  10.2  11.5  (+) One-off expenses  6.2  -  -  (-) Dividends from Minority Interest Projects  -  -  0.1  Further Adjusted EBITDA  ($7.9)  ($5.8)  $16.7 

 H2B2’s robust pipeline(1)  Robust pipeline of ~5.6 GW of identified potential projects, of which ~73MW either under construction (~16 MW) or awarded pending FID (~57 MW)  Potential pipeline projects  Includes projects that have not been awarded yet but are at varying stages of the process, including those that (i) we have bids out for,  (ii) are at the budgetary or technological partner stage, (iii) are at the technical economical proposal or expected RFQ stage or (iv) are at the tender process or early development stage  Installed  ~5.5 GW  Potential pipeline projects  ~57 MW  Awarded projects  ~3 MW  Installed  ~16 MW  Under construction  ~5.6 GW  Pipeline + awarded + under construction + installed  ~76 MW  Award / Contracted / Installed  Under construction  Projects to be executed in 2023 & 2024  Source: Company Information  (1) Pipeline assumes the SoHyCal project will be deconsolidated from H2B2 for accounting purposes in 2024  30  Awarded projects  Projects awarded or named preferred bidder, subject to client obtaining financial close, including Phase II of SoHyCal  Dynamis Energy  NTE  California  Greenswitch Energy Commission  Medha  Serveo  Puerto de Vigo  GP Joule Redexis  California Energy Commission  Ecopetrol Cepsa Esenttia  FM  Logistics  VTT  Tecnicas Reunidas  PowiDian  Universitat De Valencia 

 Thank you  For Further Inquiries Please Contact  Investor Contacts:  Anselmo Andrade Fernandez de Mesa Chief Executive Officer anselmo.andrade@h2b2.es  Roberto Wilson Fernandez del Castillo Investor Relations roberto.wilson@h2b2.es