The European Data4 has laid the first stone of its new mega data center campus on the grounds of the former military base in Großauheim, in Hanau, just 25 kilometers from Frankfurt. The ceremony was attended by Hesse’s Minister for Digital Affairs, Prof. Dr. Kristina Sinemus, Hanau’s mayor Claus Kaminsky, France’s Consul General in Frankfurt, Nicolas Bergeret, and Data4’s President and CEO, Olivier Micheli, along with business and political representatives. Beyond the official photo, the project makes impressive headway with figures: 25 hectares of land, 180 MW of planned capacity, and a doubling of investment compared to the initial plan, increasing from 1 billion to over 2 billion euros.
The site aims to become one of the most significant AI and cloud platforms in Europe and a new strategic digital traffic node within the Rhine-Main area. For the local government, it also represents a socioeconomic boost: as a reference, Data4’s Marcoussis campus (France) hosts up to 1,000 people daily, and the company anticipates the creation of several hundred direct and indirect jobs in Hanau.
A campus for Europe’s “digital sovereignty”
In his speech, Kristina Sinemus emphasized that the project is a “pillar for the digital transformation of the region and of Germany”. Her argument is compelling: AI and critical applications can only grow at the pace that the infrastructure allows. Without high-performance data centers, there is no model training, low-latency inference, or digitized public services. And if this data resides and is processed within European soil, she added, it enhances digital sovereignty and data protection under frameworks like the GDPR.
This commitment aligns with Data4’s strategy: wherever they deploy, they bet on large-scale campuses with substantial land and energy reserves. The new German site adds to a network of 10 campuses across 6 countries (France, Italy, Spain, Poland, Greece, and now Germany), and raises the group’s investment bar in one of Europe’s most demanding markets.
Hanau, an additional gateway to the Rhine-Main ecosystem
For Claus Kaminsky, Hanau’s mayor, the announcement supports the region as a location for critical digital infrastructure. Its proximity to Frankfurt, one of Europe’s most powerful interconnection hubs, offers latency, connectivity, and redundancy advantages for cloud providers, hyperscalers, AI platforms, and local businesses. The company sums it up in network terms: the future campus will be a “strategic data traffic hub in the Rhine-Main area”.
It is no coincidence that Data4 acquired the former military site of 25 hectares eighteen months ago. The contiguous land and the urban-industrial environment facilitate the design of modular blocks (buildings, substations, internal networks) that can grow in phases based on demand, avoiding chaos of disjointed small parcels.
180 MW for AI: power with a sustainable profile
The 180 MW figure places the campus among the most powerful in Europe. But the company emphasizes that the electric capacity will come with an energy plan based on two principles: decarbonization and resource reuse.
- 100% decarbonized energy. Data4 plans to power the complex with renewable sources, supporting the construction of a combined heat and power plant (cogeneration) and a dedicated substation to ensure stable supply and power quality demanded by AI compute clusters.
- Residual heat reuse. The heat emitted by servers won’t be wasted: the plan includes injecting it into the urban district heating network (district heating) to serve the residents of Hanau. This approach echoes group initiatives like the biomass project launched in Marcoussis alongside Université Paris-Saclay, and responds to clear social demand: datar centers returning useful energy to their environment.
- Circular economy in construction. In remediating the old military base, Data4 plans to reuse demolition materials such as recycled aggregates, reducing transportation footprint and raw material consumption.
Minister Sinemus summarized this in terms of compatibility: digitalization and environmental protection can go hand in hand if they incorporate energy efficiency, renewables, and heat reuse in design.
AI, cloud, and data under European jurisdiction
Olivier Micheli’s corporate message was direct: Germany is strategic, and Hanau will be one of the most powerful, sustainable, and innovative sites in its network. Technologically, the campus is ready for AI workloads (training and inference), hybrid cloud, and low-latency services. On the regulatory front, Data4 emphasizes that clients’ data and applications — operated within European borders — are subject to the highest standards of protection and security.
This jurisdictional anchor is significant for banks, public sector, healthcare, and critical industries, for whom data location is not a trivial matter but a requirement (whether due to sectoral regulations, NIS2, or internal risk policies). The campus thus positions itself as a key component of Europe’s strategic digital autonomy.
Jobs, supply chain, and ripple effects
The experience of the Marcoussis campus (hosting up to 1,000 people daily including staff, suppliers, and clients) provides concrete insights. In Hanau, Data4 anticipates several hundred direct and indirect jobs in operations, maintenance, security, facility management, engineering, and related services. On a regional scale, multiplier effects include:
- Specialized construction (civil work, networks, high-capacity electrical installations).
- TIC ecosystem (system integrators, cybersecurity, monitoring, smart metering).
- Local services (logistics, catering, transportation).
This ongoing economic spillover — recognizing that a campus is not a one-time project but a living infrastructure for decades — helps diversify the local economic fabric and retain technical talent.
Why Hanau and why now?
Several trends converge to explain this decision:
- Explosive growth in AI demand. Training foundational models and deploying them increases power, cooling, and connectivity needs across Europe.
- Nearshoring data. Multinational companies repatriate or bring closer loads for compliance, low latency, or cost reasons in public clouds.
- Availability of plannable land and energy. Converting a 25-hectare military base into a campus with integrated substation and cogeneration reduces uncertainties compared to saturated sites.
- Regulatory window. Climate objectives and scrutiny over water, noise, or heat require sustainable designs from the start; the project incorporates these from inception as part of its proposal.
Future challenges: grid, water, and social license
No mega campus is without challenges. Some of the most common in Europe — and foreseen in Hanau — include:
- Grid capacity and resilience. Integrating 180 MW without stressing the grid demands detailed planning with the system operator, phased scaling, and flexibility (energy storage, demand response, high-efficiency UPS).
- Water management. Cooling technologies are evolving toward low water consumption solutions (closed circuits, free cooling, optimized adiabatic systems). Communicating metrics and seasonal scenarios will be key to avoiding friction.
- Community transparency. Explaining benefits (job creation, urban heat, taxes) and mitigated externalities (noise, traffic, lighting) helps to build trust and long-term social license.
Data4 appears to position itself proactively with decarbonized energy, heat recovery, and materials recycling, but execution will be the key to success.
Growing in Germany and beyond
“This is just the beginning,” Micheli announced, revealing plans to open more locations within the country and aim for European leadership in the sector. Germany offers market depth, digital industry, and investment capacity; Data4 provides a campus model, balance, and a ‘Data4 Good’ agenda built on four pillars (environment, people, community, governance).
If Hanau sets an example, the European cloud and AI map will gain a new entry point with a German seal and transboundary vocation.
Protagonists’ remarks
- Kristina Sinemus (Hesse): “AI offers enormous opportunities to strengthen German and European competitiveness. But it will only be possible if we have sufficient and sustainable infrastructure. This 180 MW campus is a clear step in that direction.”
- Olivier Micheli (Data4): “We want to develop Hanau as one of Europe’s most powerful, sustainable, and innovative campuses. Germany is a priority in our expansion: we have increased the planned investment to over 2 billion euros, and this is just the beginning.”
- Claus Kaminsky (Hanau): the project positions the city on the European data center map and accelerates its long-term economic and technological development.
Quick project facts
- Location: Former military site in Großauheim (Hanau, Hesse)
- Site area: 25 hectares
- Planned capacity: 180 MW
- Investment: > 2 billion euros (doubling initial plan of 1 billion)
- Energy: 100% decarbonized, with cogeneration and own substation
- Sustainability: Heat reuse for district heating; demolition material recycling
- Jobs: Several hundred expected (operations and supply chain); reference: up to 1,000 people/day at Marcoussis
- Network role: Data hub for Rhine-Main, focusing on AI and cloud
- Operator: Data4 Group, with 10 campuses across 6 European countries
Summary: Infrastructure to compete in the AI era
Data4’s mega campus in Hanau is not just another data center: it symbolizes powerful electric and computational capacity with a sustainable profile, data under European jurisdiction, and hub ambitions. In a time when AI drastically increases the demands for energy, cooling, and connectivity, the project anchors Germany—and by extension, Europe—in the global race for cloud and artificial intelligence.
The upcoming milestones—power connections, construction phases, procurement, residual heat agreements—will determine whether this promise translates into real benefits for the local economy, urban decarbonization, and the competitiveness of companies and institutions. For now, the first stone is in place.
Frequently Asked Questions
What capacity and size will the Data4 campus in Hanau have?
The plan features 180 MW over 25 hectares. With these figures, it will rank among the most powerful data center campuses in Europe, with phased growth based on demand.
Why is “digital sovereignty” mentioned in this project?
Because clients’ data and AI workloads hosted at the campus will reside within the EU, under European protection and security standards (e.g., GDPR). This reduces legal risks and clarifies responsibilities compared to outside frameworks.
How will it be powered, and what about residual heat?
Data4 has announced 100% decarbonized energy, with cogeneration and an own substation for supply stability. The residual heat will be reused in urban district heating networks, making heat cheaper and greener for residents.
What is the expected local economic impact?
Running such a campus creates hundreds of jobs and sustains a continuous value chain (specialized construction, energy, maintenance, TIC). Referencing Marcoussis, which reaches 1,000 people daily including staff, customers, and suppliers.
Why Hanau and why now?
The area combines available land, connectivity to the Rhine-Main hub, and energy viability at a moment of AI demand explosion and nearshoring trend. Converting a military base eases planning for substations, cogeneration, and modular expansion.
What investment has Data4 committed to, and what’s the schedule?
The company has doubled its plan, from 1 billion to over 2 billion euros. Construction has started with the first stone; deployment will proceed in phases (no specific public dates announced).
What makes Data4 different from other operators?
Its ultra-connected campus model, with reserved land and energy, focus on sustainability (“Data4 Good”), and European jurisdiction. It hosts hyperscalers, cloud operators, and multinational companies across France, Italy, Spain, Poland, Greece, and now Germany.