A micro-grid is a small scale power supply network that is designed to provide electricity to a small community with its own renewable energy sources. Due to distributed generation variability, security and load sharing issues, an efficient communication infrastructure is necessary between its agents (load, generation and storage units). Numerous research efforts are being developed to come up with such communication techniques that can overcome the barriers to implement the concept of micro-grids. This paper covers the features, characteristics and challenges of micro-grids and their associated communication techniques.