A device and a method for operating decentralized functional units in an industrial system include a) a higher-level control system which exchanges information with the decentralized functional units by data telegrams, b) a data transport network with network access points; c) communication units connected to a network access point and providing the decentralized functional units with access to the data transport network; d) an energy transport network to which the decentralized functional units are connected and which supplies electric energy to the decentralized functional units; e) intelligent energy storage devices connected to the energy transport network and consuming or outputting energy in accordance with the higher-level control system and/or with at least one of the remaining energy storage devices. The energy transport network has energy supply points distributed along a bus structure. Selectively one of at least two independent energy backbones can supply corresponding electric power to the supply points.