In January 2025, Infomaniak inaugurated a new kind of data center in Geneva: the DC4. What makes it special? It reuses 100% of the electricity consumed to heat residential buildings. A world first that demonstrates digital technology can be beneficial for the environment.
A Video Tour of DC4
Julien Larzillière, from our partner company Apresta, had the opportunity to visit DC4 alongside Boris Siegenthaler, founder and strategic director of Infomaniak. A fascinating tour that explains in detail how this revolutionary infrastructure works:
A Data Center That Wastes Nothing
Since 2013, Infomaniak has been cooling its data centers with filtered outside air, without relying on air conditioning. Regularly recognized for their exemplary energy efficiency, Infomaniak\'s other data centers boast some of the best PUE ratings in the industry.
But with DC4, Infomaniak goes even further:
- 100% of electricity reused – All energy consumed is converted into heat for the district heating network
- No air conditioning – No water or traditional cooling systems
- Underground construction – Located in a residential area with no landscape impact
- Full soundproofing – Sound-barrier walls protect the apartments above
PUE, ERE, ERF: Understanding the Metrics
- PUE (Power Usage Effectiveness) – Compares total energy consumed to the energy actually used by servers
- ERE (Energy Reuse Effectiveness) – Measures efficiency by accounting for thermal energy reuse
- ERF (Energy Reuse Factor) – Measures the proportion of energy reused outside the data center
6,000 Homes Heated and 3,600 tCO₂eq Avoided Every Year
Since November 11, 2024, all the electricity consumed by DC4 has been fed back as heat into the canton of Geneva\'s district heating network, operated by SIG (Services Industriels de Genève).
The numbers are impressive:
- 6,000 homes heated thanks to recovered energy
- 3,600 tonnes of CO₂ equivalent avoided per year (natural gas)
- 5,500 tonnes of CO₂ equivalent avoided per year (pellet equivalent)
- 211 trucks of 13 tonnes of pellets saved each year
Currently operating at 25% capacity, the data center will gradually ramp up to reach full power by 2028.
How Does It Work?
Unlike other projects that recover only a fraction of their heat, Infomaniak reuses 100% of the energy consumed. Here\'s the process:
Conversion to Heat
All electricity used (servers, UPS units, fans, etc.) is converted to heat at 40-45°C.
Air/Water Heat Exchanger
This heat is transferred to an air/water exchanger to heat a hot water circuit.
Heat Pumps
Heat pumps raise the water temperature to transfer the waste heat to the district heating network.
Natural Cooling
As it expands, the gas in the pumps drops the water temperature from 45°C to 28°C. This cooled water regulates the server temperature, eliminating the need for air conditioning.
European Technological Sovereignty
DC4 also strengthens Europe\'s technological sovereignty. Infomaniak relies exclusively on equipment manufactured in Europe, creating value for numerous local businesses.
This approach ensures:
- Independence from non-European suppliers
- Support for the local and European economy
- Full traceability of components
- Complete compliance with European regulations
An Open Source Model for Global Impact
Infomaniak isn\'t keeping this innovation to itself. The data center has been documented by UNIL, IMD, and EPFL as part of the e4s.center program to showcase its energy efficiency in real time and facilitate its replication.
Documentation Available
The D4 project is fully documented at d4project.org with:
- Real-time performance tracking to prove the system\'s efficiency
- A technical guide to help other organizations replicate this approach
- A brief for policymakers to adapt industry standards
Why Choose Infomaniak?
By hosting your services with Infomaniak, you benefit from infrastructure that is:
- 100% eco-friendly – Renewable energy and reused heat
- 100% Swiss – Data protected by Swiss law
- 100% independent – Family-owned company with no external investors
- 100% GDPR compliant – Full respect for privacy
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