<p>A smart grid refers to the rejuvenation of a power system network in conjunction with different technologies such as communication systems, dispersed generation, storage elements, and dispatchable loads that operate in islanded and grid-integrated modes. Power generation system in smart grids mainly depends on fossil fuels that are declining at a rapid pace and will become overpriced soon. Moreover, power generation from fossil fuels causes high carbon emissions, resulting in significant and long-term damage to the environment. Economic load dispatch provides optimal fuel cost, and economic emission dispatch provides optimal emission of power generating units. Another important phenomenon is optimal power flow (OPF), which looks for the optimisation of a given cost and reliability objective without violating the constraints of networked power flow. The metaheuristic approach has been depicted to work fruitfully for economic dispatch (ED) and OPF problems. In this proposed work, a vivid comprehensive review of the utilisation of metaheuristic search for ED and OPF through a unique way is performed while bearing in mind that such issues share many usual challenges and objectives. To derive quantitative conclusions, a tabular compilation of collective outcomes has been presented on a unified platform. The study concludes by highlighting promising future research directions, focusing on metaheuristic approaches, and emerging solution strategies to address the existing challenges of smart grids and guide their future optimisation.</p>