Abstract
This study presents a replicable methodological framework for supporting the decarbonization of district heating (DH) systems, addressing both technical and economic aspects. The approach integrates spatial mapping of renewable energy sources (RES) and waste heat (WH), pre-screening of individual technologies through parametric analyses, and hourly aggregated simulation of decarbonization scenarios. The pre-screening step helps identify promising technologies early on and reduces the number of scenario simulations needed. The aggregated model accounts for temperature-dependent heat losses and dispatch priorities, and is calibrated using real operational data to ensure accurate performance representation. The methodology combines source mapping, technology economic evaluation, and scenario simulation in a structured workflow designed to support early-stage planning and local decision-making in line with the desired decarbonization targets. The methodology is applied to the DH network of Vukovar in Croatia, which is currently reliant on natural gas and features a 3% solar thermal contribution. In 2023, the total heat production of the network amounted to 12.7 GWh. RES and WH options—such as river water, air-source and shallow geothermal heat pumps, supermarket waste heat, and solar thermal—are assessed based on local availability and expected performance. Among the scenarios investigated, the one combining an extension of the solar field size up to 3000 m2, a 1.25 MW river-source heat pump, and a 5 MWh thermal storage unit emerged as the most cost-effective solution capable of achieving the target of a 50% RES + WH share—aligned with the 2035 European definition of Efficient District Heating and Cooling. This scenario also proves to be economically competitive, with a Levelized Cost of Heat (LCOH) below the current district heating tariff.