The demand for increased power delivery, the extensive incorporation of distributed generators, such as the ones utilizing renewable energy sources, and the adoption of modern electronic devices with processing and communication capabilities, are transforming the power grid into a smart grid. In this work, we provide a brief review of smart grids and, particularly, an integral subsystem, the so-called smart micro-grid, as well as the associated communication technologies, operations and challenges. Furthermore, we outline a very useful connection between techniques that are able to extract information about the consumption signals of domestic appliances by utilizing the theory of sparse coding and the compression of this information when its transmission is required to a remote site. This connection can lead to compression methods that are suitable for transmitting device consumption signals, which constitute one of the most frequent type of smart-grid traffic.