Energy Internet, a futuristic evolution of electricity system, is conceptualized as an energy sharing network. Its features, such as plug-and-play mechanism, real-time bidirectional flow of energy, information, and money can lead to significant benefits and innovation in electricity production and utilization. Energy Internet integrates small-scale renewable energy systems, electric loads, storage devices, and electric vehicles for effective transaction of power backed by emerging technologies such as Internet of Things, vehicle-to-grid, and blockchain. At present, there is no scaled-up working model of Energy Internet, and literature is scarce, which makes the research in this domain significant, novel, and timely. Given this, an attempt is made to develop the conceptual model of an Energy Internet, elaborate its structure and components, and discuss its operational principles. First, a comprehensive overview of Energy Internet is presented along with its aptness as a future evolution of electricity system. Second, concepts, architectures, and features that underpin Energy Internet are outlined. Third, concept of ‘Energy Intranet’ is introduced to denote the scaled-down version of Energy Internet, which embodies energy prosumers and local energy markets to form a local energy cluster. Finally, discussion is presented on the network structure of Energy Internet, relevance of emerging technologies and innovative operational mechanisms.