Nabiax has begun construction of Alcalá Data Center 3 (ADC3) in Alcalá de Henares, marking the next major expansion of its Madrid infrastructure footprint. The Spanish operator held a cornerstone ceremony last week for the facility, which will complete its existing Alcalá campus and require an investment of nearly €800 million ($918 million). ADC3 will progressively deliver as much as 100MW of IT capacity by 2029, targeting hyperscale customers, cloud platforms and increasingly demanding artificial intelligence workloads. The expansion will lift Nabiax’s installed IT capacity in Spain to 135MW across its Madrid and Catalonia operations.
Nabiax Expands Madrid’s AI Infrastructure Pipeline
The scale of ADC3 reflects how Madrid’s data center market is shifting from conventional capacity expansion toward infrastructure capable of supporting higher-density computing. Nabiax is positioning the project around three overlapping demand pools: hyperscale deployments, cloud services and AI workloads that require substantially more computing capacity. The company’s existing Alcalá campus already serves hyperscale customers, with its first two phases providing more than 22MW of current IT power and infrastructure designed for further expansion. Nabiax’s own campus information identifies the site as a carrier-neutral environment and places its medium-term potential at 100MW.
For Nabiax CEO Pablo Ruiz-Escribano, that shift makes the physical data center increasingly central to the digital economy rather than simply a facility supporting it. “Today, they are also the home of artificial intelligence,” he said, highlighting its role in applications ranging from medical research to public services,” he said. His comments place ADC3 within Spain’s wider effort to strengthen its position as a European digital hub, with energy availability, connectivity, skilled talent and geographic location forming part of the infrastructure proposition. The project therefore represents both additional data center capacity and a bet on Madrid’s ability to absorb the next phase of AI-driven digital demand.
Nabiax Calls for Investment Certainty
The ADC3 groundbreaking also comes as Spain debates how its data center sector should develop under a changing regulatory environment. Ruiz-Escribano argued that sustainability objectives and investment certainty need to advance together, particularly for projects that have already moved through financing, licensing or construction milestones. “The challenge is not choosing between sustainability and growth; the challenge is ensuring they go hand in hand,” stated the CEO of Nabiax, who called for distinguishing between mature projects – with approved financing, obtained licenses, or construction already underway – and new developments.
That distinction matters because large data center projects operate on long investment cycles and require major commitments before facilities begin generating revenue. For an operator investing close to €800 million in one campus expansion, changes to the regulatory environment can affect decisions that span years rather than quarters. Nabiax is consequently framing ADC3 as part of an existing development pipeline rather than a standalone response to the latest AI demand surge. The company’s earlier expansion plans already identified the Alcalá campus as a route toward substantially higher capacity.
Madrid’s Data Center Pipeline Continues to Grow
Madrid’s regional government also highlighted the scale of the market during the event. Isabel Díaz Ayuso said Madrid currently has 58 data center projects, with 41 operational and 15 under construction, while another 40 projects form part of a pipeline representing approximately €15 billion ($17.1 billion) in investment, according to figures presented at the ceremony. “Data centers are not a problem, but rather part of the solution and an opportunity that we certainly intend to take advantage of,” she stated. Those figures illustrate the size of the development pipeline surrounding Madrid as operators pursue capacity for cloud, digital services and AI.
ADC3 will join an Alcalá campus that has developed in stages rather than appearing as a single large-scale deployment. ADC1 began operations in 2013 with 4,800 square meters of space, while ADC2 followed in 2022 with 6,000 square meters. The two facilities together account for about 22MW of IT capacity, according to information provided for the project, creating the foundation for ADC3’s much larger expansion.
Nabiax Builds From a Larger Spanish Footprint
The new project also changes the balance of Nabiax’s Spanish portfolio. Once ADC3 reaches its planned capacity, the company expects its installed IT power in Spain to reach 135MW, combining its Madrid campuses with facilities in Catalonia. Beyond Alcalá, Nabiax operates the 10MW Julián Camarillo Data Center near Madrid and a 1.3MW facility in Terrassa outside Barcelona. The company’s campus portfolio gives it exposure to both large-scale capacity and more urban data center deployments.
Nabiax itself emerged from Telefónica’s data center assets, with Asterion Industrial Partners establishing the company in 2019 through the acquisition of 11 facilities across Spain and Latin America. Telefónica later contributed three additional assets in exchange for a 20 percent stake in Nabiax in 2021, before Nabiax sold its Latin American portfolio to Actis in 2023. Aermont, the European asset management company linked to Keppel, acquired Nabiax in 2024.
ADC3 now represents the next stage of that transformation, with the Alcalá campus becoming the central vehicle for Nabiax’s Spanish capacity expansion. The project combines a large power commitment with infrastructure aimed at AI and cloud customers, while its cooling design and university partnership address two constraints that sit outside the headline megawatt figure. As construction progresses toward 2029, the critical question will be how quickly that capacity can translate into deployed compute for customers. For Madrid, ADC3 adds another major block of capacity to a market increasingly defined by the race to secure power, cooling and infrastructure capable of carrying Europe’s next generation of AI workloads.
