(Video in French only)
In 1978, we made a visionary decision to install a plant on our Lausanne campus that draws thermal energy from Lake Geneva. This energy was initially used for the cooling system on our main campus in Lausanne, and then, following the addition of heat pumps in 1986, for the campus’ heating system. The plant was subsequently renovated so that, by 2022, the campus was entirely oil-free and we had reduced our carbon emissions by 1,400 tons CO2-eq per year.
In 2022, more than 85% of the energy used for heating and cooling on our Lausanne campus came from renewable sources. The remaining 15% related to power for running our heat pumps, which is not entirely renewable.
As part of the renovation work, the thermal power plant was connected to a 2-MW data center, so that the center’s servers are cooled with lake water and the heat they generate is recovered.
The main source of cooling for our Lausanne campus since 1978 has been water drawn from Lake Geneva. This cooling water is pumped and distributed throughout the campus.
Since the installation of the two heat pumps in 1986, the energy drawn from Lake Geneva has been the main source of energy for heating the buildings on our Lausanne campus. These pumps extract energy from the water and convert it – through a thermodynamic process that requires electrical power – into heat that’s used to warm our buildings.
However, until 2018, two oil-fired turbines were employed in addition to the heat pumps during particularly cold periods. We therefore installed two more heat pumps, meaning the plant is now powered by four heat pumps, each with a thermal capacity of 6 MW, for a total of 24 MW. We also installed a second pipe to draw water from Lake Geneva, next to the existing pipe.
The water used to cool buildings on our Lausanne campus is also used to heat the SwissTech Convention Center, thanks to a heat pump installed in 2015. This enables us to generate heat in winter and cooling water in summer. At the end of this cycle, the water is returned to Lake Geneva via the nearby Sorge river, without causing any harm to the environment.
The 2-MW data center on our Lausanne campus is cooled by discharge water from the power plant. This cooling water in turn recovers the heat generated by the servers.