Positive Energy Districts (PEDs) aim to generate more energy than they consume by leveraging renewable energy sources (RES) and innovative energy systems. These districts represent a transformative urban development approach prioritizing sustainability, resilience, and carbon neutrality. District heating can be a key component in achieving PED objectives. However, existing district heating networks often rely on fossil fuels, thus not contributing to PED targets. The research aims to understand how cost-minimal investment portfolios in district heating supply change when considering PED constraints. The study addresses a main research objective: identifying the cost-optimal portfolios for decarbonized district heating generation in PEDs, considering locally available renewable energy and excess heat potential. The methodology involves modeling the district heating supply mix by optimizing supply investment and dispatch, integrating renewable energy sources and excess heat, and incorporating PED constraints into the optimization procedure. The model is designed to run on synthesized cases, which vary in terms of local energy resources. The Hotmaps district heating supply investment and dispatch models are expanded for this purpose, ensuring a net positive balance on an annual level while minimizing the total cost of the district heating supply. The expected results include the identification of a cost-minimal technology portfolio, such as using heat pumps and thermal storage, to minimize carbon emissions while meeting heating demands in PEDs. The study will provide insights into the technology shift when integrating constraints specific to PEDs into the district heating supply investment and dispatch model. In conclusion, the study is expected to offer important perspectives on the planning and enhancing district heating systems in Positive Energy Districts.