Technology
A fuel cell converts fuel to electricity electrochemically rather than by burning it. That costs more per unit of energy and it produces almost nothing at the point of use that an air permit is written about — which, at constrained sites, is the argument that decides the technology.
In one sentence
A fuel cell converts fuel — at this scale usually natural gas, reformed on site — directly into electricity through an electrochemical reaction, with no combustion and correspondingly low local emissions.
Several chemistries exist and only one is deployed at data-centre scale in volume. Solid-oxide cells run hot enough to reform natural gas internally, which removes a separate reformer and lifts efficiency; molten carbonate systems occupy a similar niche. Low-temperature membrane cells run on pure hydrogen and are used in vehicles and materials handling rather than in campus power, because the hydrogen to feed them is not available at these sites.
The systems ship as repeating modules of a few hundred kilowatts, so a site is sized by how many are installed rather than by selecting a machine. That gives a short installation programme and a predictable footprint, and it is why fuel cells appear disproportionately at urban and permit-constrained sites where a combustion source would not be approved at all.
Electrochemical conversion produces negligible nitrogen oxides and particulates locally, which is exactly what a large-source air permit regulates. Where a site sits in an area already close to its limits, that difference is the difference between a project and no project — and it is why operators pay a premium per unit of energy that a purely economic comparison would not justify.
Cell stacks degrade with operating hours and are replaced on a schedule measured in years, so a fuel cell installation carries a recurring capital cost that a turbine does not. Service agreements usually bundle that replacement, which makes the contracted price per unit of energy the number to compare rather than the installed cost.
Almost every unit installed at a data centre today runs on natural gas. Systems are marketed as able to run on hydrogen, and the chemistry allows it, but there is no hydrogen delivery to these sites and no near-term prospect of one at the volumes involved. The carbon argument therefore rests on efficiency and on what the gas displaces, not on the fuel changing.
1 of these is marked as a chokepoint: a handful of qualified suppliers, a multi-year lead time, or a single geography.
A reforming fuel cell needs the same contracted gas connection as a combustion source, and that connection has its own queue.
Cells produce direct current, so every installation carries conversion and medium-voltage equipment drawn from the same constrained supply as the rest of the electrical chain.
TransformersThe inverter that turns stack output into usable alternating current is built on the same switching devices as every other high-power converter on the site.
Compound semiconductorsStack manufacturing depends on specialised ceramics and catalyst loadings whose production is small relative to the deployment being discussed.
The technology exists on these sites because of how permits treat non-combustion sources; a change in that treatment changes the case entirely.
Other pages in this map that name Fuel cells as something they cannot do without.
What each company supplies at this step, and — where a public figure exists — its share of this specific market — with what that share measures, the period it covers and who published it. Some rows also show the company’s own reported revenue for the segment covering this step, which is a different thing: it says how much this business matters to that company, not how much of the market it holds. Not a ranking and not a recommendation.
Supplies the solid-oxide systems behind most installed data-centre fuel-cell capacity.
Supplies molten carbonate and solid-oxide plant as an alternative non-combustion source.
Supplies stationary fuel-cell plant at utility and campus scale, principally in Korea.
Develops solid-oxide systems alongside the turbine business, aimed at the same on-site generation market.
Supplies membrane fuel-cell systems and the hydrogen supply chain they depend on.
Supplies membrane fuel-cell stacks, mainly for mobility rather than stationary power.
Manufactures stationary fuel-cell units and the stack technology behind them.
Whether installed fuel-cell capacity at data centres grows beyond the sites where permitting forces it.
Whether stack life and replacement cost improve enough to change the contracted price per unit of energy.
Whether any site is supplied with hydrogen rather than natural gas at meaningful scale.
Each page explains one technology in plain language, states what it depends on, and names companies by what they supply at that step. Company roles are described qualitatively and deliberately carry no market shares, revenue figures or rankings — those change faster than an explainer can, and a stale number is worse than none. Ticker links point at company pages on this site and are provided for reference only.
Nothing here is investment advice, a recommendation, or a forecast. A company named on a page about a technology is not thereby a good investment, and the chokepoints described are structural facts about supply chains rather than predictions about prices. Technology moves; where a page describes something as unresolved or in development, that was true when it was written.