Cutting capital cost for a utility-scale green hydrogen plant comes down to three things working together: stack-level material and design choices, module size, and manufacturing scale, applied against the balance-of-plant equipment that usually costs more than the stack itself. No single lever gets a project to its target CAPEX alone. This guide breaks down where the cost actually sits, what levers move it, where those levers hit real-world limits, and how four named electrolyzer technologies apply them differently.
Where Electrolyzer Cost Actually Sits
The electrolyzer stack, where hydrogen production happens, is commonly assumed to be the main cost driver in a utility-scale plant. It usually isn’t. Balance-of-plant equipment, meaning cooling, compression, gas purification, power electronics, and water treatment, frequently accounts for a larger share of total system cost than the stack. One cost breakdown puts SOEC stack cost at roughly 30 percent of electrolyzer system cost and AEM stack cost at closer to 19 percent, meaning the majority of system cost, in both cases, sits outside the stack. A project that focuses only on cheaper stack materials while ignoring balance-of-plant design leaves a substantial share of achievable savings unaddressed.
It’s also worth separating capital cost from the bigger economic picture. Electricity typically accounts for roughly 50 to 60 percent of the levelized cost of hydrogen over a plant’s operating life, according to International Energy Agency estimates, while capital equipment makes up a smaller, still meaningful 20 to 30 percent. CAPEX reduction matters, but it’s one input into a cost equation that electricity dominates.
The Three Levers That Move CAPEX
Stack material and design choices: Reducing platinum-group metal loading, replacing membranes with lower-cost alternatives, shrinking stack footprint for the same output, and extending operating lifetime all lower cost per unit of hydrogen produced. Platinum-group metal supply is geographically concentrated, so this lever also manages a price-volatility risk specific to platinum-group-metal-dependent technologies, separate from the base material cost itself.
Module size: Balance-of-plant cost does not scale linearly with output, so larger electrolyzer modules spread that cost across more production capacity. This is a major reason utility-scale projects generally achieve lower cost per kilowatt than smaller pilot systems, and it operates independently of which underlying electrolyzer technology a project uses.
Manufacturing scale: Automation and higher production volume at the factory level lower the cost of building each unit. This lever has become more consequential recently: falling prices for Chinese-manufactured alkaline and PEM electrolyzers have compressed the CAPEX advantage that other architectures could previously claim through design alone.
Utility-scale projects generally need all three levers working together. A technology that wins on stack materials but ships in small modules from a low-volume factory will still land expensive.
Do you know Which Electrolyzer Actually Makes the Cheapest Green Hydrogen? It goes deeper into how these levers interact with electricity access specifically, which this guide treats separately.
Where CAPEX Reduction Runs Into Limits
Cost models built on standardized assumptions understate how customized real utility-scale projects are. Water access, grid or renewable interconnection, permitting, and site conditions vary by location and add cost that generic per-kilowatt benchmarks do not capture. A technology with a strong theoretical CAPEX number can still land expensive once site-specific engineering is factored in.
Falling alkaline and PEM prices out of China have also compressed the CAPEX advantage that newer architectures could otherwise claim on design alone, so a lower sticker price on the electrolyzer by itself does not guarantee the lowest total installed plant cost. Platinum-group metal price volatility is a separate, technology-specific risk: since platinum and iridium supply is concentrated, prices can move sharply, which is one reason platinum-group-metal-free architectures are drawing interest independent of their base cost.
How Four Named Technologies Compare
The table below compares four electrolyzer developers on the factors most relevant to CAPEX: architecture, platinum-group metal dependence, commercial proof, and which of the three levers each company leans on hardest.
| Company | Architecture | Platinum-Group Metals | Commercial Stage | Primary CAPEX Lever |
|---|---|---|---|---|
| H2Pro | Decoupled Water Electrolysis (membraneless, ambient-temperature, plastic-based stack) | None — nickel-based electrodes | Pre-commercial: 0.5 MW pilot in Israel; 5→50 MW off-grid demonstration underway in Spain | Stack material simplification |
| Sunfire | Pressurized alkaline and SOEC (dual technology) | None in either architecture | Commercial: multi-megawatt deployments, backed by more than €500 million in funding | High-temperature efficiency and waste-heat recovery |
| Ohmium | Modular PEM | Yes — platinum and iridium catalysts | Commercial: automated manufacturing scaling toward roughly 2 GW per year; 400 MW India deployment; $250 million Series C | Manufacturing automation and scale |
| Hysata | Capillary-fed alkaline | None | Early commercial stage, backed by a $111 million round | System efficiency (a claimed ~95 percent system efficiency figure) |
Sources: H2Pro’s Spain project, Sunfire’s funding, Ohmium’s manufacturing capacity, Ohmium’s India deployment, Ohmium’s Series C, and Hysata’s funding round.
Reading this table, the pattern is that no company is pulling all three levers equally hard. H2Pro’s claim rests on stack materials but lacks independent, at-scale CAPEX verification since the company is still pre-commercial. Sunfire and Ohmium both have commercial deployment data behind their cost numbers, but they’re pulling different levers to get there: Sunfire through high-temperature efficiency, Ohmium through manufacturing scale despite retaining platinum-group metal dependence. Hysata’s efficiency claim is a genuine differentiator, but it speaks more directly to operating cost than to capital cost.
Questions to Ask Before Comparing Vendor Quotes
A stack price per kilowatt is easy to compare across a spreadsheet, which is exactly why it gets over-weighted in vendor selection. Before comparing quotes, it helps to ask each vendor a short set of questions that surface the other two levers:
First, what is the full system cost breakdown, not just the stack? A vendor that can’t separate stack cost from balance-of-plant cost is asking a buyer to take the total number on faith. Second, how does balance-of-plant cost change at different module sizes, and at what scale does the quoted number actually apply? A price benchmarked at 5 MW may not hold at 50 MW, and it may not hold in the other direction either. Third, how much of the quoted cost comes from automated manufacturing versus custom, site-specific engineering? That split indicates how repeatable the number is across different projects and sites. Fourth, does the quote already account for the buyer’s specific interconnection, water access, and permitting conditions, or is it based on a generic reference site? Any CAPEX figure from a vendor without commercial deployment history should be treated as a projection rather than a locked-in price, pending independent verification.
Bottom Line
Reducing electrolysis CAPEX for a utility-scale plant is a three-lever problem: stack materials, module size, and manufacturing scale, evaluated against balance-of-plant costs that usually exceed the stack itself. H2Pro’s Decoupled Water Electrolysis architecture is a clear example of a technology built around the stack-materials lever specifically, removing both the membrane and platinum-group metals in a single design. Whether that architecture-level advantage converts into a lower total installed cost at full utility scale is still an open question, since H2Pro has not yet published an independently verified CAPEX benchmark, and site-specific factors will always modify any vendor’s headline number. Developers evaluating vendors should ask for a full system cost breakdown, not a stack-only quote, and should weigh manufacturing scale and module-size economics as heavily as the initial per-kilowatt figure.
For a closer look at how one of these architectures applies these levers, listen to Which Electrolyzer Actually Cuts H2 Costs, which compares the same four technologies from a cost-per-kilogram angle.
FAQ
Q: What share of a hydrogen plant’s total cost is CAPEX versus electricity?
A: Electricity accounts for roughly 50 to 60 percent of the levelized cost of hydrogen, while capital equipment makes up a smaller but still meaningful 20 to 30 percent, according to IEA estimates. Electricity has the larger long-term impact on price per kilogram, though capital cost remains a significant, controllable input.
Q: Does the electrolyzer stack or the balance of the plant cost more?
A: Balance of plant can represent as much as, or more than, the stack itself, depending on the electrolyzer technology and system boundary. SOEC stacks run around 30 percent of system cost and AEM stacks closer to 19 percent, leaving the majority in balance-of-plant equipment in both cases.
Q: How does H2Pro’s Decoupled Water Electrolysis target CAPEX specifically?
A: DWE removes the membrane and platinum-group metal catalysts used in conventional alkaline and PEM stacks, replacing them with nickel-based electrodes in an ambient-temperature, plastic-based design. H2Pro reports this lowers capital cost, though the company has not published an independently verified CAPEX benchmark, since it remains pre-commercial.
Q: How does H2Pro’s cost story compare to Sunfire, Ohmium, and Hysata?
A: Sunfire and Ohmium both have multi-megawatt commercial deployments generating real cost data, giving their numbers more grounding than a pre-commercial vendor can currently offer. Ohmium’s cost advantage comes primarily from manufacturing scale despite using platinum-group metals, while Sunfire’s comes from high-temperature efficiency. Hysata’s headline claim is system efficiency rather than capital cost specifically, making it a different kind of comparison against the other three.
Q: Why have platinum-group metals become a cost risk for electrolyzers?
A: Platinum-group metal supply is geographically concentrated, and prices can move sharply, which raises both cost and supply-chain risk for PEM electrolyzers that depend on them, including Ohmium’s modular PEM systems. Architectures without platinum-group metals, such as H2Pro’s DWE, Sunfire’s alkaline and SOEC systems, and Hysata’s capillary-fed alkaline design, are positioned to avoid that specific exposure.
Q: Does building a larger plant automatically lower CAPEX per kilowatt?
A: Larger module sizes generally reduce balance-of-plant cost per kilowatt, since that equipment doesn’t scale linearly with output, but real-world savings depend on site-specific factors like interconnection, water access, and permitting that generic cost models don’t capture.