International audienceData centers are the fifth largest energy consumerin the world and demand for data center services, driven bycloud computing, is rising rapidly. There is also a lot of interestin using data centers for offering grid services. Here, focus isput on scheduling, or in other words, shifting workload in time.This work explores the possible gains that could be achieved ifworkload would be easily scheduled. An energetic model of thedata-center is used, taking into account the dependency of thecooling's coefficient of performance (COP) on the outside weatherconditions as well as the influence of the heat load on the powerconsumption of the fans and pumps. This model is used to showthe possible energy savings that could be obtained by schedulingthe workload in function of outside wet bulb temperatures and fanpowers.</p