Your data is stored under a park. Its heat warms 6,000 homes.
PAFworks runs in D4, Infomaniak's data centre built in the basement of a residential neighbourhood in Geneva.
All the electricity used by the servers is recovered as heat and fed into the canton's district heating network.
A typical data centre dumps its heat outside. D4 gives it to the neighbourhood.
A data centre that doesn't cool. It heats.
D4 sits in Plan-les-Ouates, in the basement of the La Bistoquette cooperative, under a public park. Infomaniak designed it with the cooperative and Services Industriels de Genève (SIG). In service since 11 November 2024, it is ramping up gradually until 2028.
All the electricity used by servers, inverters and ventilation ends up as heat, at around 40 to 45 °C.
Air-to-water exchangers capture the heat, then heat pumps raise its temperature.
The heat goes into Geneva's district heating: heating and hot water for around 6,000 homes.
Water returns at around 28 °C and cools the servers. No air conditioning, no cooling tower, no water consumed.
What D4 changes, in figures.
of energy recovered
The electricity consumed is fed back in full as heat into the canton's network.
average PUE
For 1 kWh used by the servers, only 0.09 kWh for everything else. The European average is 1.6.
homes heated
At full capacity, 1.7 MW of heat, or 14.9 GWh a year, for at least 20 years.
CO₂eq avoided per year
The natural gas the network no longer needs to burn. Compared with pellets, it is 5,500 t.
of water for cooling
No air conditioning, no cooling tower. The electricity is 100% renewable, hydro and solar.
of extra land built on
1,800 m² underground beneath a park: no industrial building, no impact on the landscape.
A model published to be copied.
Infomaniak did not keep D4 to itself. The project was documented by EPFL, IMD and the University of Lausanne as part of the E4S programme, and published freely at d4project.org.
So another operator can replicate the same data centre model.
Energy performance is published continuously, not just announced.
To help raise construction standards for data centres.
Swiss Ethics Prize and the Canton of Geneva Sustainable Development Prize, in 2023.
What it means for your organisation.
Your files, email, calendars and video meetings run on infrastructure whose energy is used twice. A concrete point for your CSR report.
Hosted in Switzerland, by an independent Swiss operator, under a legal framework the European Commission recognises as adequate.
D4 is documented as open source. PAFworks is built on open standards (IMAP, CalDAV, CardDAV, WebDAV): you stay in control of your data.
Further reading.
- d4project.org · open-source documentation, technical guide and real-time data
- Infomaniak · D4 inauguration announcement
- Inside Infomaniak · video tour of D4 (French)
- Services Industriels de Genève · press release (PDF, French)
- Trane · the heat pumps and the CO₂ avoided
A complete workspace, hosted in a data centre that heats Geneva.
PAFworks is available by invitation. Tell us how your team works: we'll send you an invitation and a migration plan that fits.