The Energy Internet is a proposed framework for maximising the efficient collection, distribution, and management of energy sources using networked computing and communication systems. Energy Internet,sponsored by Chinese Society for Electrical Engineering (CSEE), and published by China Electric Power Research Institute (CEPRI) in cooperation with the Institution of Engineering and Technology (IET), is a multidisciplinary gold open access journal covering power and energy, power. 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. Extensive electrification based on renewable energy sources is seen as one of the most potential growth options to tackle these issues in the medium to long term. In any case, this is real if and only if the power grid can handle increased use of renewable energy sources and distributed energy. However, at present, with the pressure of energy crisis and the development of novel energy conversion technologies, such as natural-gas unit, combined heat and power (CHP), the concept of energy internet (EI), which combine different types of energy carriers, such as electricity, natural gas, and. This chapter presents the development of the Energy Internet throughout the history as an evolutionary solution based on modern technological development and needs, with the respect of its architecture, key features, and key concepts, such as energy router, prosumer, and virtual power plant.