Planning for Low-Carbon Cities in China: the role of the underground space into a comprehensive Advanced Local Energy Plan

In large and congested metropolitan areas - where several millions of people live and work - as well as in medium size cities the need of offering to their inhabitants better life standards is a very urgent topic. In such a contest, suitable underground spaces, infrastructures and device networks - like district heating and cooling - can play a significant role for achieving reliable, efficient and high quality results for “smart” urban development. The solution of “going underground” can be usefully adopted for improving the mobility and reducing the traffic pollution through metro lines, road tunnels, parking devices and pedestrian connections. Furthermore, it permits to build and manage a series of public services for water, gas and other commodities, mainly if inserted into rational Multi-Utility Tunnel networks and to offer safe, reliable and low-energy spaces for several activities - commerce, services, and for leisure. In China, the current trends for more Sustainable Low-Carbon Cities aim to achieve relevant carbon emission reductions and local sustainable development. The interrelationships among the main factors that characterize the above mentioned objectives are complex and concern the urban form, the spatial development, the improvement of energy efficiency in industry and buildings, the use of low-carbon vehicles and public oriented transport systems, low-carbon waste and other services management. To achieve low-carbon outcomes, city leaders must develop a comprehensive set of actions requiring the use of a suitable set of tools, resulting in a so-called Advanced Local Energy Plan (ALEP) and involving, as much as possible, the two side of the urban land, over- and under-ground. This paper describes the local energy planning tool (LEP-CN) developed by the Energy Analysis and Model Laboratory of the Politecnico di Torino that can be applied to both existing and planned settlements and analyse over- and under-ground solutions for some significant energy infrastructures. The tool integrates a Bottom-up Simulation Model of the energy flows through all the main processes belonging to the urban sectors (residential, transportation, industry, commerce and services), a large Data Base with the characteristics (existing and foreseen) of these processes (including infrastructures) and a Geographical Information System which relates to the urban over- and under-ground space the above mentioned processes, the input data, the “smart” indicators and the effects of policies and actions adopted/suggested by the Modelling procedure (simulation, optimization or multi-criteria). A Beijing district has been used as reference exercise for the procedure explanations.