Assessment of energy systems configurations in mixed-use Positive Energy Districts through novel indicators for energy and environmental analysis

Positive Energy Districts may support the energy transition of urban city centres as well as the decarbonization of other sectors in addition to buildings, such as industry. In this framework, this work aims at identifying the optimal configuration of energy systems serving a mixed-use district located in the industrial area of a city in the South of Italy. Evacuated tube collectors are installed along with renewable-based plants for electricity supply (that is, photovoltaic panels and wind turbines). Moreover, the district is equipped with an electrolyser for green hydrogen production. Two novel indicators have been introduced for performing the energy and environmental assessment: the Positive Balance Check and the Carbon Neutrality Check. These indexes are useful to verify the accomplishment of the targets of Positive Energy Districts. Therefore, they may serve to guide the design of novel district-based energy systems as well as the renovation of existing ones, as with the case study investigated in this work. Indeed, the district under analysis is provided with surplus renewable thermal and electric energy and achieves carbon neutrality in the optimal configuration chosen. The results obtained highlight the relevance of designing multi-vector energy systems, aiming to decarbonize both electric and heating energy requests.