With energy shortages anticipated this coming winter in Europe, CERN is implementing measures to contribute to the collective effort and minimise disruption.

In order to play its part, CERN has advanced the start of the year-end technical stop (YETS) of the accelerator complex by two weeks, to 28 November, and reduced the running period of the accelerators by 20% in 2023. In addition, on 2 November, CERN signed an agreement with electricity supplier EDF to manage further energy reductions, if needed, before the start of the YETS. The agreement stipulates that EDF may ask CERN to reduce its electricity consumption for periods of 3–6 hours, once per day, subject to two days’ notice. CERN will endeavour to accept such requests up to three times per week. These reductions will be entirely managed from the CERN Control Centre and will have no impact beyond the accelerator complex. No action is required on the part of CERN personnel in this context.

If circumstances in France so require, CERN’s EDF electricity supply could be cut off at short notice. This is not unprecedented and, under normal circumstances, the site network automatically switches – possibly with a short interruption – to a Swiss supply, which has limited capacity. Were this to happen, accelerator operation would be interrupted until the EDF supply was re-established.

Given the unusual energy situation this winter, CERN is preparing for the unlikely eventuality that both French and Swiss electricity supplies might be lost at the same time. If this happens, essential services, including safety systems, the CERN Control Centre and one area of the Data Centre, will receive emergency power from CERN’s diesel generators, which can maintain a supply for up to two days with on-site diesel stocks, and possibly longer, subject to diesel deliveries.

In the event of a blackout, members of the personnel will receive instructions via email and SMS.

The Data Centre status will be regularly updated on the IT status board.

Efforts have also been made to reduce CERN’s consumption of gas, which is used to heat the Meyrin and Prévessin sites. The start of heating was postponed by one month this year, and a slight reduction in temperature is being implemented. Further reductions, or gas supply interruption, should the Host States so require, would have an impact on operations. Mitigation measures are being prepared.

Energy savings are the day-to-day responsibility of all of us and we can all contribute to the collective effort. If you live in France, you can keep up to date with the current status of supply, along with measures you can take, on the website https://www.monecowatt.fr. At work, look out for messages on home.cern and on the information screens around the Laboratory, informing you of measures taken by CERN and what you can do to play your part.