How CERN is encouraged to not do atom or quark smashing, during periods of high demand and low power station availablity, by means of the EJP tarrif


This page is extracted from the official CERN newsletters, shows that even CERN obeys the economic imperatives of the French EJP tariff, designed to force customers to use less power during high demand periods / unavailability of nuclear reactors – lin other words they turn the giant quark smasher off during the unavailablity of nuclear ower. (Link is now inoperative however)
In previous years CERN was able to limit its electricity consumption during the winter months sufficiently to be supplied from the Swiss grid. In order to make enough power available for the LHC machine and experiments at the lowest possible cost during the coming winter 2005 / 2006 CERN is supplied from the French grid by EDF (Electricité de France). As a consequence, when the grids are at peak demand during the tariff period ‘Effacement Jour de Pointe’ (EJP) in France, the energy price is at least four times as high as for the usual winter period.

From 1st November until 31st March these increased prices are applicable during twenty-two 18-hour periods, each beginning at 7 a.m. and ending at 1 a.m. the following day. Notice will be given by EDF to the Technical Infrastructure Control Room (TI) at 5 p.m. the previous day. The notice period may be reduced to two hours for days following weekends and public holidays, or omitted entirely for technical reasons.

During these days of EJP CERN has a strong financial interest to reduce its power consumption as much as possible whilst minimizing disruptions for LHC machine and experiment commissioning, accelerator and experiment tests and start-up.

In order to inform staff and users EJP days will be announced via the NICE Alerter and also on the luminous panels at the entrances of the Meyrin and Prévessin sites.

Reduce Consumption

Information will also be placed on the public PS, SPS and TI video pages, as well as in several CERN NEWS groups.

In the interests of all, staff should refrain from carrying out tests or work requiring additional power during these periods.

For more details please contact:

TI 72201 or

Mario Batz TS/CV – Energy Management Panel

Extracted from:


See also The French EJP Tarrif  and How diesels are used in France and UK to cope with intermittency of large power stations