The last few years have seen a growing interest in reducing the energy consumption of production systems since they are responsible for more than 50% of the global delivered energy worldwide (U.S. Energy Information Administration 2016). Besides technological advances, the consideration of energy consumption during operations management is an efficient approach to reduce energy wastes. Three main energy efficiency measures exist in scheduling : (1) total energy consumption; (2) time-of-use pricing; (3) peak power limit. This work focuses on power peak constraint, which prevents to exceed the power threshold contracted between the factory and its energy supplier. In other words, this constraint prevents the simultaneous processing of multiple operations with high energy consumption. Most of the literature on scheduling with energy constraints concerns the total energy consumption and time-of-use pricing, and very few works consider peak power limitations (Giret et. al. (2015)). Recently, Kemmoe et. al. (2017) proposed a method for the job shop scheduling problem with power thresholds. In the present work, we investigate the extent to which a more flexible shop-floor organization (namely, the group shop) improves the productivity under power limitations.