Jump to main content


New sustainable data center under construction near Frankfurt

Powered by renewables, cooled by the river, supplying district heat and in the immediate vicinity of Germany’s most important internet hub.

54 MW

Power Capacity

18000 m2

IT Space available

30 km

Distance to Frankfurt

3 Buildings

Campus Size

Green Mountain and German Power Company KMW have teamed up in a joint venture to build a new 54 MW data center site in Mainz, just 30 km outside Frankfurt. The three planned data center buildings will be built in an established industrial area adjacent to KMW’s existing power plants. The site can support both multi-tenant customers as well as provide dedicated buildings for larger client installations. Located in the Rhine/Main area, the site benefits from its proximity to one of the world's largest internet hubs in Frankfurt.

Sustainability is at the core of this project – The site will be powered by 100% renewable energy from KMW’s wind and solar power portfolio, with gas turbine generators providing the backup power. The site will be efficiently and sustainably cooled by the river Rhine. Finally, the waste heat produced will be fed directly into the existing district heating network via heat pump to supply the city of Mainz. All of these plans will result in minimum CO2 emissions.


  • Ready for service: Q1 2025 Start of construction: Q3 2023 Number of buildings: 3 Site space: 25.000 m2 Available IT space: 18.000 m2 Designed to TierIII specifications
  • Power Capacity: 54 MW (80 MW in 2026) 100% renewable energy from KMW's portfolio of wind and solar power Cooling system implementing water from the Rhine river Emergency Power supplied by gas turbines instead of diesel generators Waste heat fed to the adjacent district heating plant Redundant 110 kV grid supplies
  • 24/7 onsite security personnel Biometric access systems & man traps Intelligent video surveillance Exceptional flood prevention measures constructed above the 1000-year high water mark (HQextreme) Nitrogen gas fire suppression system
  • Close proximity to one of the world's largest internet hubs Five independent fiber providers available Two fully redundant meet-me-rooms Office space for clients Smart Hands Services

Innovative River Cooling

The FRA-Mainz data center site by the river Rhine.

The Rhine River flows directly adjacent to the FRA-Mainz site and provides the perfect alternative source of cooling for the data center. With a combination of cold water from the Rhine and supply of heat to the adjacent district heating facility, the data center will be highly energy efficient.

Waste heat for district heating

KMW District Heating Plant

While in operation, providing cooling to client infrastructure, a data center produces large quantities of heat – traditionally dispersed directly to the air. In other words, this valuable source of energy is wasted. How can we avoid this environmentally unfriendly practice? The answer to this challenge is heat reuse and at the FRA-Mainz site we have the perfect solution.

The KMW power plant is already connected to the local district heating supplier, Mainzer Fernwärme GmbH – an associated company of KMW. The company supplies large parts of the Rhineland-Palatinate state capital with clean district heating via its 100-kilometre-long network – and has been doing so since 1960.

When the data center goes into operation, up to 60 MW of waste heat will be fed into the Mainz district heating system, ensuring that the energy resources serve the local community. This district heating grid supplies up to 1000 public and private sector properties in the local area.

No need for diesel generators

FRA-Mainz data center outside Frankfurt.

A data center requires a reliable emergency power supply to ensure continuous operation in case of power outages. Typically, this is achieved using environmentally burdening diesel-powered backup generators.
Green Mountain will use the adjacent KMW gas power plants currently in operation, as a reliable source of emergency power instead of diesel generators, enabling us to further reduce our CO2 emissions.