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Launch year
2021
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Region
Baltics
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Country
Estonia
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Our score
82.5
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Business category
Renewable energy
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Main industry
Renewable energy
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Tech layer
Deep Tech
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Category
CleanTech & Energy
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About the startup
Stargate Hydrogen was founded in 2021 in Tallinn, Estonia by CEO Marko Virkebau and CTO Dr. Rainer Küngas, a materials scientist with a PhD from the University of Pennsylvania, Fulbright Science & Technology Award, and a background spanning solid oxide fuel cells, high-temperature electrolysis, and lithium-ion batteries. Non-Executive Chairman Taavi Madiberk, founder of Skeleton Technologies, joined in 2024. The company's core innovation is a ceramic-based catalyst material that replaces precious metals in alkaline electrolysis, combined with a proprietary stack design inspired by lithium-ion battery development cycles, allowing for lower energy consumption, longer equipment lifespan, and a target levelised cost of €1 per kilogram of green hydrogen. Stargate operates two product lines: the Stellar Series stacks (0.5 MW, operating at 32 bar pressure) for system integrators, and the Gateway Series containerised turn-key systems (1-10 MW) for project developers. In June 2025, Stargate inaugurated its Tallinn factory, opened by the Prime Minister of Estonia, with an initial capacity of 140 MW/year and the potential to scale to 1 GW+ with modest additional investment. Production was fully booked through year-end 2025. In December 2025, Stargate's 1 MW system produced first hydrogen at Fortum's Kalla Test Centre in Finland. The company is one of the few electrolyser manufacturers with IPCEI (Important Project of Common European Interest) designation, and its technology has been independently validated by ZSW Stuttgart. Customers include Fortum, Utilitas, ABB, Rockfin, and OX2 across Europe, Turkey, and India, with a cooperation agreement signed with Saudi Arabia's RDI in September 2025 to explore regional headquarters in Riyadh. The team of 65+ people was recruited from Nel, Mitsubishi Heavy Industries, Gencell, ABB, McPhy, and Topsoe.
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Main NAICS code
333611 — Turbine and Turbine Generator Set Units Manufacturing
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Target market
Chemical, Energy, Transportation, Steel
/Business tags
Containerized Turn-key Electrolysers, Green Hydrogen Production, Energy Equipment, Engineering Support for Accelerating Hydrogen Projects, Manufacturing, Electricity Generation Solutions
Employees
51-100
Locations
3
Revenueg model
$5M-$10M
/Business pillars
Cost-Effective Electrolyser Stack Designs, Alkaline Electrolysis Technology, Scalable Electrolyser Systems, Novel Ceramic Catalyst Materials for Electrolysis, Modular Electrolyser Systems
/Core offerings
Alkaline Electrolyser Stack Manufacturing, Containerised Turn-key Hydrogen Production Systems, Industrial Decarbonization Solutions, Hydrogen System Engineering Support, Green Hydrogen Solutions for Steel, Chemicals and Transport
/Core technologies
Ceramic-Based Catalyst for Alkaline Electrolysis, Proprietary Stack Design, Modular Containerised Electrolyser Systems, Exsolution Materials Research (EXSOTHyC), Control Systems for Electrolyser Plants
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The score
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GROWTH READINESS
85
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COMMERCIAL MATURITY
75
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TECH DEPTH
95
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BUSINESS MODEL
75
Score rationale
This is how we approached it and reached the numbers
Growth readiness
Factory deliveries active across Europe, Turkey, India, and the Middle East. MoU with Saudi Arabia's RDI to explore regional headquarters in Riyadh. Partnerships with Fortum (Finland), OX2 (Nordic), and BASF (Germany). Production fully booked through 2025. Not higher because actual commercial revenue is still early-stage and the international footprint is primarily through partnerships and signed agreements rather than established local operations.
Commercial maturity
First hydrogen produced at Fortum's Kalla Test Centre (December 2025). Multiple paying customers across geographies. Factory at full 2025 capacity. However, revenue remains modest relative to €63.7M raised, EV/Revenue ratio on Dealroom implies very early revenue base. The commercial engine is proving itself but has not yet reached meaningful scale.
Tech depth
Patented ceramic-based catalyst eliminating precious metals from alkaline electrolysis. Proprietary stack design informed by lithium-ion battery development methodology. Performance independently validated by ZSW Stuttgart. IPCEI designation. CTO Dr. Küngas holds a Fulbright Science & Technology Award and Electrochemical Society Award. Coordinating the EU-funded EXSOTHyC research project with University of St Andrews, Agfa-Gevaert, Eindhoven University, and Fraunhofer IFAM. One registered patent in electrolytic processes. IP portfolio covers materials, electrodes, stack, and control systems.
Business model
B2B hardware manufacturer with two product lines targeting different buyer profiles (integrators and project developers). Strategic customers investing in the company (GIGA, UG Investments) validates the demand signal. Modular factory scaling strategy avoids the gigafactory trap. Capital-intensive manufacturing but unit economics improve as factory utilization rises and stack size scales from 0.5 MW to planned 5 MW units.
Why they made the list?
Stargate Hydrogen is doing something most of the hydrogen industry has not managed: building and selling actual electrolysers, from a factory in Estonia, with a full 2025 order book. Founded in Tallinn in 2021 by Marko Virkebau and Dr. Rainer Küngas, the company has raised €63.7M including a €42M seed round from UG Investments and IPCEI, a €11M Series A at a €210M valuation, and a strategic investment from Repsol, Spain's largest hydrogen producer and consumer. In June 2025, the Prime Minister of Estonia opened Stargate's new factory, which can deliver 140 MW of electrolysers annually and scale to 1 GW+ with modest additional investment. In December 2025, first hydrogen was produced at Fortum's Kalla Test Centre in Finland using Stargate's 1 MW system. The company's CTO invented a ceramic-based catalyst that eliminates the need for precious metals in alkaline electrolysis, a materials-science breakthrough that allows Stargate to target a levelised cost of €1 per kilogram of green hydrogen. The technology has been validated by ZSW Stuttgart, the leading European test centre, and the company holds IPCEI status alongside peers including Enel Green Power, De Nora, and Sunfire. The broader green hydrogen market is struggling while Stargate is shipping. That contrast, from a Baltic deep-tech company founded four years ago, is the reason it is on this list.
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Funding
Funding stage
Series A
Last funding year
2025
Funding
$68,500,000
/Key investors
UG Investments, SmartCap, GIGA Venture, Repsol Energy Ventures, European Commission, Important Projects of Common European Interest (IPCEI)
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