This thesis provides a comprehensive analysis of the conversion of an existing electrical grid that caters to a harbour in southern Sweden. The conversion would be into a smart and decentralized grid in order to accommodate the demands of the energy transition in the region. The primary aim is to improve the existing infrastructure's ability to accommodate potential electrical loads in accordance with forthcoming energy requirements through retrofitting. A systematic methodology was implemented, starting with the creation of a digital twin model of the current grid infrastructure to enable accurate power flow analysis and simulation of expected future load conditions. Following the determination and examination of power flow parameters, the investigation's offer recommendations that aim to enhance the grid's capability to accommodate future load integration without requiring excessive reconstruction. This approach highlights the capacity of retrofitting to serve as a sustainable means of modernizing power grids, thereby contributing to the wider discussion on optimizing energy infrastructure in response to changing consumption patterns and technological progress.