The smart grid has been conceived as an evolution of elec- tric power systems due to the increasing diffusion of distributed generation by renewable sources, but with the additional aim to enhance efficiency, reliability, and safety of the existing power grid. To this end, remote and timely information gathering about equipment failures, capacity limitations, and natural accidents is extremely critical for ensuring proactive and real-time and reli- able diagnosis of possible failures in the smart grid. This makes cost-effective remote sensing technologies vital for safe, seam- less, and efficient power delivery in the smart grid. In this paper, communications technologies and requirements for smart grids have been discussed. The QoS mechanism is in- troduced and standards are presented. Clearly, there are many important open research issues for the realization of smart grid communications and applications. Future work includes dis- cussion of grid characteristics, architectures, key players, pilot projects, applications, and research challenges on ICT issues, in order to give a complete overview on the subject.