Building a sustainable hub for Europe’s digital infrastructure

Green Rocks is on track to become one of Europe’s most advanced and sustainable data centre sites.

We’ve been appointed by Norwegian data centre company Green Mountain and German energy firm KMW, to manage the construction of Green Rocks, the first of three data centres being built in Mainz. Each data centre will provide an IT load of 18 MW.

When finished, the 25,000 square metre campus will be one of the most sustainable data centres in the world.

Built for Sustainability

Green Rocks will run fully on renewable energy supplied by KMW and use water from the Rhine river to stay cool. It is aiming for a Power Usage Effectiveness (PUE) below 1.3 industry average, meaning it will use energy very efficiently.

Instead of diesel generators, it will use a cleaner gas-powered backup system. This setup will lower its lifetime environmental impact.

Powering the Community

The data centre will also send up to 60 megawatts of waste heat into Mainz’s district heating system, helping to warm around 20,000 homes. Being close to the Frankfurt DE-CIX hub will make for a more responsive, resilient internet experience and make Mainz an important part of Europe’s data network.

Delivering Certainty in a Complex Environment

Building a five-storey data centre by the river in a busy urban area comes with challenges. There’s a risk of flooding, changing groundwater levels, limited space, and tough environmental rules.

We have tackled these with a smart, resilient design. The building is compact, waterproof, and fireproof, with strong environmental safeguards. Our experience in managing complex projects means we can keep everyone aligned, respond quickly, and stay on track.

Expertise Across Every Stage

We are leading every stage of this project with clear coordination and a focus on delivery.

• Project Management: We are managing the project using Germany’s AHO rules – a common framework. This is helping the team work better together, make faster decisions, and keep things moving. Our clear structure is cutting down delays and keeping the work aligned with the client’s goals.
• Programme Management: We have updated the project plan and brought all schedules into one timeline. Design, engineering, and construction teams are now fully in sync. This means issues are solved quickly, and the project stays on track, even in a complex setting like a riverside city site.
• Quality Control: We are focused on keeping the building safe and strong. Our team is checking all construction work to make sure it is waterproof and fireproof. We are using strong, approved materials to meet safety rules and reduce risks from flooding or fire.
• Cost Control: We are keeping a close watch on the budget. We are tracking every cost and suggesting ways to save money without lowering quality. This helps keep the project within budget and gives the client peace of mind.

Driving Progress, Anchored in Sustainability

With bold targets and careful planning, we are turning our client’s vision into reality. Green Rocks will show how digital infrastructure can grow without increasing carbon and strengthen Europe’s place in the global digital economy.