# Internet of Things Applications as Energy Internet in Smart Grids and Smart Environments
## 1 Introduction  
The most recent data [1; 2; 3] show that fossil-based resources are going to fade away in the near future. Therefore, it has led to a variety of concerns in both academia and industry to discover efficient ways of ensuring sustainable energy in the future. These concerns are generally originated from greenhouse gas emission [4], energy cost [5], and security of distributed generation (DG) systems [6; 7; 8]. A new concept called \"Energy Internet\" has been recently introduced to deal with these challenges. Energy Internet (EI) vision tends to overcome some important challenges, such as improving sustainable and eco-friendly energy sources, new models for hybrid energy sources, more secure and effective energy management, and control systems [9]. The EI that is also considered as the smart grid evolution purposes a sustainable computing platform by combining different energy types in an extremely flexible grid structure. The idea behind EI is similar to the internet concept and is inspired by the essential principles of internet development for the energy field. Even though EI was first introduced more than a decade ago, a wide consensus has not been achieved about the concept [10]. The EI is considered an energy management system (EMS), covering conventional power grids and DG sources in [11]. The E-energy concept combines information and communication technologies (ICT) with energy systems to create the EI, according to the studypresented in [12]. As a general definition, an EI system is composed of the combination of three important components that are energy systems, network systems, and ICT systems. In addition, these subsystems are connected to each other over energy routers, which comprise the main section of EI infrastructure. The energy routers are able to manage data and energy flow between these systems. The energy router idea is firstly proposed in [13], where they have two significant targets. While one of these targets is to perform dynamic scheduling of energy flows, the other is to enable communication with power devices. Different proposals related to system designs are reported in [14; 15; 16; 17]. The use of communication technologies in EI is quite crucial to accomplish the goals of this vision. Therefore, ICTs are intensely adapted for enabling monitoring, controlling, and management processes in the EI concept. The wired and wireless communication technologies, such as ZigBee, WiMAX, cognitive radio, cellular communications, and the software-defined network (SDN), which are managed via the network system, are applied in the EI system to carry out monitoring, controlling, and management transactions in real-time [10]. One of the most recent communication technologies is the Internet of Things (IoT) [18; 19] that has provided the development of numerous different communication protocols. The IoT can be exploited to ensure communication between devices employing dissimilar data types. Moreover, in order to present a communication platform in both machine-to-machine (M2M) and human-to-machine (H2M) environments, IoT technologies utilize several communication mediums, protocols, and layer architectures. A number of studies researching EI are available in the literature, which is only focused on the architecture of energy routers, techniques for system integration, SDNs, and big data analysis in the EI. To the best of our knowledge, any study surveying IoT applications in smart grids and smart environments has not been presented so far. We intend to present a comprehensive analysis of IoT applications in smart grids, smart cities, smart homes, smart metering, and EMSs to provide a further understanding of the EI concept. It is expected that these application areas will be promising key areas of the EI since IoT will be one of the most important driving factors of the EI. In light of this vision, our primary aim is to analyze IoT applications in the smart grids and smart environments and examine their potential contributions for the EI.