TL;DR · 30-second read
The Short Version
A Barcelona company best known for keeping computers cool is spending about €1 billion to build and run its own huge computer warehouse for artificial intelligence.
Submer plans to put it on the grounds of an old chemical factory in the Spanish town of Flix, which stopped operating in 2023. Catalonia’s regional president turned out for the announcement.
What makes it interesting: a company that used to sell equipment to building owners now wants to be the owner. It has not yet said how big the site will be, when it opens, or who will use it.
Submer, the Barcelona-based company that built its name in immersion cooling, plans a €1 billion ($1.14 billion) AI data center on the site of the former Ercros chemical plant in Flix, Catalonia, Data Center Dynamics reported. The facility will be built in two phases and operated by Rubix Data Centers, the AI data center division Submer launched in June, which aims to lease it to a single tenant running AI workloads.
The project was unveiled on Saturday, July 11, at an event attended by Salvador Illa, president of the government of Catalonia, and Miquel Sàmper, the regional minister of business and labor. Submer has not disclosed the facility’s planned capacity or construction timeline; renders appear to show four data halls arranged around a central building.
Executive Summary
The headline number is €1 billion, but the more consequential fact is who is spending it. Submer’s business has been supplying cooling systems to other people’s data centers. With Flix, it becomes a developer and operator in its own right, following last year’s launch of the InferX AI cloud platform and June’s launch of Rubix Data Centers.
Submer CEO Patrick Smets framed the move as a deliberate climb up the value chain: “we will expand across the full stack, from land and power to cloud and Edge.” Rubix, led by former Stack executive John Eland, leads its pitch not with cooling technology but with a claim of 8GW of power available across vacant sites in the Americas, EMEA and APAC. That ordering signals where the company believes durable value in AI infrastructure now sits.
What the announcement does not yet establish is the project’s scale, power supply, financing or customer. Until those are disclosed, Flix is best read as a statement of strategy and site selection rather than a funded, contracted build.
From Selling Cooling to Owning the Building
Submer’s trajectory over roughly a year tells the story: an immersion cooling specialist (immersion cooling submerges servers in a non-conductive liquid to carry heat away more efficiently than air) launched an AI cloud platform, InferX, then a data center division, Rubix, and now a €1 billion campus. Each step moves the company closer to the end customer and further from being a component supplier.
The economic logic is straightforward. An equipment vendor is typically paid once per deployment, and its fortunes depend on how many facilities its customers build. An operator that leases a facility earns recurring rent for the life of the lease and controls the asset that everything else depends on: the site, the building and its power supply. Smets’ own phrasing, “from land and power to cloud and Edge,” puts land and power first. Eland made the same point from the operator’s side: “We intend to operate the facility we are building here, so we are not simply passing through Flix.”
That is the substance behind reading Flix as a bet on land and power rather than on cooling hardware. The company has not said whether Submer’s own immersion systems will be deployed at Flix, which underlines the point: the announcement is about owning capacity, not showcasing a product.
Why Power Is the Asset Rubix Leads With
For AI data centers, the scarce input is increasingly not buildings or servers but a site with a large, deliverable grid connection. That is why Rubix’s headline claim is 8GW of available power across vacant sites, a figure measured in gigawatts, or thousands of megawatts. Framing a data center business around power first reflects how the market now prices development opportunities.
Former heavy-industrial sites such as the Ercros plant are attractive candidates in principle, because industrial users often required substantial electrical infrastructure and the land is already zoned for industrial use. Ercros also operates a solar farm on the site today. But Submer has not said what grid capacity is available at Flix, whether it is already connected, or how the solar installation fits into the project’s power plans. Those details will determine how quickly and how large Flix can realistically become.
The 8GW figure deserves the same even-handed reading. It is a claim about power available across vacant sites, and Rubix has not broken it down by location, by grid status or by how much of it is contractually secured versus identified. As a signal of ambition it is clear; as a measure of deliverable capacity it is not yet substantiated.
The Single-Tenant Model Cuts Both Ways
Rubix aims to lease Flix to a single tenant for AI workloads. This build-to-suit approach is common for large AI campuses: one creditworthy customer on a long lease can anchor the financing for a very large build, and two-phase construction lets capital be deployed in step with demand.
The flip side is concentration. Until a tenant signs, the €1 billion figure describes an intended investment rather than a committed one, and the facility’s design, timing and financing will likely hinge on that single counterparty. Without a disclosed capacity, it is also impossible to judge whether €1 billion is a large or modest sum per megawatt relative to comparable AI builds.
A Supplier Becoming a Peer, With Political Backing
Moving into operations can create tension with existing customers: data center operators that buy Submer cooling may now find the same company bidding for AI tenants. How Submer manages that overlap between its cooling business and Rubix will be worth watching.
On the other side of the ledger, the project arrives with visible public support. The presence of Catalonia’s president and its business minister at the launch, and Submer’s framing of the project as part of the “reindustrialization of Flix,” suggest the regional government sees AI infrastructure as a use for idled industrial land. That backing can matter for permitting and grid access, though no specific commitments from the administration were announced.
Background
Submer, based in Barcelona, established itself as a specialist in immersion cooling, a technique that submerges servers in a non-conductive fluid to remove heat more efficiently than traditional air cooling, an approach that has gained attention as AI chips grow denser and hotter. Over the past year the company has expanded beyond cooling, launching the InferX AI cloud platform and, in June 2026, Rubix Data Centers, a division that develops and operates AI data centers and is headed by John Eland, formerly of data center operator Stack.
The Flix site was home to a chemical plant run by Ercros until industrial operations ceased in January 2023. Ercros now operates a solar farm on the site. Redeveloping former industrial land for data centers has become a recurring theme as developers look for sites with industrial zoning and access to power. Source: Submer plans €1bn data center at former chemical plant in Catalonia (Data Center Dynamics) — Submer’s Rubix division will build and operate a two-phase AI data center on the former Ercros site in Flix.Sources