 The integration of renewable energy sources and optimization of energy use are essential components of any sustainable energy transition. The Internet of Things, IoT, offers a variety of applications in the energy sector from improving energy efficiency to increasing the share of renewable energy sources and reducing environmental impacts of energy use. This paper surveys the existing literature on the application of IoT in energy systems, focusing specifically on its potential in smart grid networks. It also examines the challenges associated with deploying IoT in the energy sector, such as privacy and security concerns, and suggests possible solutions, such as blockchain technology. Overall, this survey provides energy policy makers, energy economists, and managers with an overview of the role of IoT in optimizing energy systems. This article was authored by Nasir Hossein Motlak, Massa Mohameder Zi, Julian Hunt, and others.