New framework of low-carbon city development of China: Underground space based integrated energy systems

Cities play a vital role in social development, which contribute to more than 70% of global carbon emission. Low-carbon city construction and decarbonization of the energy sector are the critical strategies to cope with the increasingly serious climate change problems, and low-carbon technologies have attracted extensive attention. However, the potential of such technologies to reduce carbon emissions is constrained by various factors, such as space, operational environment, and safety concerns. As an essential territorial natural resource, underground space can provide large-scale and stable space support for existing low-carbon technologies. Integrating underground space and low-carbon technologies could be a promising approach towards carbon neutrality, and hence, warrants further exploration. First, a comprehensive review of the existing low-carbon technologies including the technical bottlenecks is presented. Second, the features of underground space and its low carbon potential are summarized. Moreover, a framework for the underground space based integrated energy system is proposed, including system configuration, operational mechanisms, and the resulting benefits. Finally, the research prospect and key challenges required to be settled are highlighted.