The concept of smart cities, which was first proposed as conceptual models, is now becoming a reality. Flexible, reliable and efficient energy and load distribution systems are key elements to power smart services such as hospitals, buildings, factories and smart transportation. These services should operate without interruption using smart electricity networks. Smart energy networks play a vital role in managing and optimizing energy distribution. They must automatically respond to changes in demand and generation, especially of renewable sources such as solar and wind. Technologies such as the Internet of Things (IoT) and cloud computing serve as key tools for the coordination of municipal services and the integration of renewable energy sources. This article deals with the role of IoT in connecting renewable energy sources to the power grid. IoT improves the efficiency and stability of networks by analyzing big data and cloud computing. With the help of these technologies, smart grids can optimize and distribute energy while ensuring service stability. In the end, the article examines the challenges and opportunities of IoT integration in smart energy networks and solutions for better use of these technologies in the realization of smart cities.