Energy generation and management are relevant for both utilities and electricity users, and they can be improved by incorporating sophisticated technology on smart grid. This opens up the possibility of transforming existing industries into a new era of enhanced networks that will give an intelligent, responsive, and bi-directional automatic management system for power generation, transmission, and distribution. The traditional grid is transitioning from a centralized generation structure to a more dispersed smart grid structure. In order to build this new decentralized structure, loads must be fully integrated into the grid and adequately separated from the main grid. The smart grid allows for the integration of loads that are clean, cost-effective, and efficient. The growing level of distributed generation (DG) integration puts the grid under strain, resulting in perturbations with dynamic responses. This paper discussed a detailed review of current developments in smart grid through the integration of renewable energy resources (RERs) into the grid. The purpose of this study is to present a comprehensive, up-to-date review of RERs integration on grid to evaluate research directions, progress, challenges, and potential solutions. It focuses on the concepts and structure of smart grids, followed by an in-depth examination of smart grid overview, energy sources, inertia issues, and applications. This evaluation will assist other researchers investigating smart grid energy resources in identifying research problems and gaps.