The concept of Positive Energy Districts (PEDs) i.e. urban units that produce surplus energy, has been recognized as a possible enabler of energy change. In literature, PEDs are defined in three main ways: virtual, dynamic, and autonomous, each offering different system boundaries for energy production. This paper examines these definitions while varying the inclusion of energy sectors (industry, transportation, buildings), enabling an assessment of PEDs as a tool to quantify the impact of district size and sectoral coverage. The general methodology presented in the study has been applied to district of Aalborg East in Denmark, to demonstrate its practical utility. Results indicate that system complexity significantly affects PED feasibility, influenced by local conditions such as weather and land availability. The choice of PED definition determines which energy sectors can be feasibly included. In this case, when energy-intensive sectors like industry and transportation are considered, the most feasible PED is achieved through the virtual approach. Compared to PEDs in which energy is strictly produced within the system boundaries, the annual costs of the PED virtual are 6 % lower than those of the PED dynamic model. Furthermore, even when the PED includes only households, the amount of energy produced but not utilized within the PED in the virtual model is 77 % lower compared to the autonomous model, and 20 % lower compared to the dynamic model. Finally, the study highlights the importance of tailoring PED strategies to local contexts and integrating them into broader urban energy networks. This ensures electricity exchange between districts, supports national decarbonization goals, and promotes social inclusion and climate neutrality.</p
