In an emerging development of various sectors towards smart cities, Internet of things plays a major role. It is meant to provide reliable, smart and efficient power supply for perfect functioning of smart cities. The objective of this paper is to illustrate the role of IoT to monitor and meet the power quality and demand in renewable energy systems. The IoT makes use of several sensors for various purposes like generation, transmission, and distribution for effective monitoring and control. It also contributes for real time control from remote places. This in turn reduces operational expenses and requirement of fossil fuels. The application of renewable energy is predominant than conventional energy and helps to implement clean and green energy. There are several major benefits are offered by IoT in renewable energy systems such as cost efficiency, distributed system, automation, grid management and residential solutions. In an IoT, excellent tools are available for monitoring and controlling the power thereby achieves optimum power consumption. It mainly supports utility and suppliers to have good degree of control over their resources and also helps for best grid management system. In distributed system, IoT enables placing of sensors at substations and distribution lines for facilitating and monitoring the real time power consumption.