The Port of Rotterdam, already a hive of hydrogen ambition, is about to host another experiment in the race to crack one of clean energy's stubborn puzzles: how to split water into hydrogen cheaply enough to matter.
Spiral Hydrogen, nearly a two-year-old startup straddling Estonia and the Netherlands, announced this week it has raised €2.7 million to build what it claims will be a fundamentally different kind of electrolyzer—one that sidesteps the bubble problem that has bedeviled the technology for decades. The April 30 funding round combined €2 million in equity, led by Copenhagen-based byFounders alongside Norrsken Evolve and Superangel, with €700,000 in grants the company had assembled earlier.
Now comes the hard part. Spiral aims to complete its first pilot unit at Rotterdam's industrial waterfront within two years, partnering with SwitcH2 Offshore, a developer of offshore ammonia systems in collaboration with shipping giant BW Offshore. The pilot will test whether the company's unconventional design—which routes gases through porous electrodes and uses rotation to pump and cool the system—can deliver on efficiency claims that remain, for now, unverified beyond the lab.
A Different Approach to an Old Problem
Traditional electrolyzers generate hydrogen by passing electricity through water, splitting H₂O into oxygen and hydrogen. Simple in concept, messier in execution. Bubbles form on the electrodes, clinging stubbornly and blocking the surface where reactions occur. The result: wasted energy and lower efficiency.
Spiral's founders say they've engineered around this. Their design employs hydrophobic—water-repelling—porous electrodes that funnel gases into dedicated channels before bubbles can form and interfere. Rotation handles both electrolyte circulation and cooling, eliminating the external pumps and cooling loops that add cost and complexity to conventional systems.
The company claims its electrolyzer operates at 95% efficiency on a higher heating value basis, consuming roughly 41.74 kilowatt-hours per kilogram of hydrogen produced. Job postings from the company reference "10x lower CAPEX" compared to existing systems—a bold assertion that will face scrutiny once the Rotterdam pilot generates real-world data.
For context, Australia's Hysata reported 98% cell efficiency in a 2022 Nature Communications paper using a different capillary-fed alkaline method, which typically translates to about 95% at the system level. Whether Spiral's rotating design can match or exceed that benchmark remains an open question.
Rotterdam: Proving Ground for Hydrogen's Future
The choice of Rotterdam is no accident. Europe's largest port has bet heavily on becoming a hydrogen hub, constructing a pipeline network—the HyNetwork—whose first section came online this year. The port wrapped up ammonia bunkering trials just last April, part of a broader push to position itself at the center of a low-carbon maritime economy.
Spiral will set up shop at the RDM Campus, a repurposed shipyard turned innovation district. According to an April job posting, the startup intends to build a 10-kilowatt pilot system in Rotterdam and Delft first, then scale to 100 kilowatts. It's an incremental approach, perhaps more cautious than the breathless promises that have characterized some corners of the hydrogen space.
SwitcH2 Offshore, Spiral's partner in the venture, brings experience in offshore energy systems—critical if hydrogen production eventually moves to sea, where abundant wind and space might make large-scale electrolysis more economical.
Grants, Accelerators, and the Long Road Ahead
Before this pre-seed round, Spiral had already scraped together about €230,000 in non-dilutive funding—the kind of grants that keep early-stage hardware startups alive while they build prototypes. The European Space Agency's business incubator in Estonia contributed €60,000 in June of last year; Estonia's Prototron program added €35,000 in May. Smaller grants from Estonian development agencies supported electrode development and digital modeling work.
The company, legally registered as Spiral Hydrogen OÜ in Tallinn, was co-founded by Juri Volodin and Fedor Stomakhin. Volodin, the CEO, holds master's degrees in wind energy and electrical power systems from TU Delft and the Norwegian University of Science and Technology—credentials that signal a deep grounding in the physics of renewable energy. Stomakhin, the COO, comes from data science and software, a combination that hints at the computational modeling underpinning the company's design.
Spiral has cycled through several accelerator programs: Creative Destruction Lab in Paris, H2UB SPRINT, and Hello Tomorrow's Deep Tech Pioneer cohort. These programs offer mentorship and connections, but the real test arrives when hardware meets the physical world.
The startup is hiring engineers now—positions based in Delft and Rotterdam—to support construction of the pilot and prepare for whatever comes next. Whether that's a triumphant scale-up or a humbling return to the drawing board will depend on what happens when Spiral's electrolyzer finally hums to life at the edge of the North Sea.
For now, the company joins a crowded field of startups convinced they've found a better way to make hydrogen. Some will succeed. Most won't. The Rotterdam pilot will offer the first real clue as to which category Spiral belongs in.
