Tracing and Evaluating Life-Cycle Carbon Emissions of Urban Multi-Energy Systems.

With the acceleration of urbanization, urban multi-energy systems (UMESs) generate more and more carbon emissions, causing severe environmental issues. The carbon generated by UMESs includes not only emissions from the consumption of fossil fuels for electricity generation during operation phases, but also those from the transportation, extraction, and recycling of materials during construction phases. Meanwhile, as carbon emissions are delivered with the energy flow among devices in the UMES, they are distributed differently across devices. Under this background, analyzing the carbon emissions of UMESs considering different life-cycle phases (i.e., operation and construction) and carbon flow characteristics is essential for carbon reduction and environmental protection. Considering that, a novel framework for tracing and evaluating life-cycle carbon emissions of UMESs is proposed in this paper. Firstly, the carbon emission models of different devices in UMESs, including energy sources and energy hub (EH), are established considering both the construction and operation phases. On this basis, the carbon flow matrixes of EHs coupled with the energy flow model are formulated to trace the distribution of life-cycle carbon emissions in UMESs. Moreover, different evaluation indices including the device carbon distribution factor (DCDF) and consumer carbon distribution factor (CCDF) are proposed to quantify the carbon emissions of devices and consumers in UMESs. The case study results based on a typical test UMES are presented to verify the effectiveness of the proposed framework. The analysis results of the test system show that about 60% of carbon emissions are delivered to electricity loads and the construction-produced carbon emissions of energy sources and EH devices account for nearly 35% of total carbon emissions at some periods. [ABSTRACT FROM AUTHOR]