The rapid development of the Internet of Things (IoT) is pouring the development of the energy sector through successful efficiency, cost reduction and enabling sustainable energy regulation. IoT-based solutions transform conventional energy systems into smart grids, improve renewable energy integration, control energy consumption and facilitate predictive maintenance. This paper illustrates the role of IoT in sustainable energy systems by focusing on sustainable energy resources and important technologies used in sustainable energy as well as the important benefits and technical challenges of IoT in sustainable energy.