广域网视角下的城市能量系统及其规划

Urban energy system planning from wide area network perspective

城市是国家能源网络中的重要节点,其内部又包含多个层次的能源生产-转换-输配-存储-消费子系统.在多能互补集成优化理念引领下,将特定范围内多类供用能子系统统筹规划,构建综合能源系统的理论和方法引起了广泛关注.对于庞大而又复杂的城市供用能网络,探明其内部的层次结构及其与非能源系统间的交互关系,并将其分解为多个适于分析的子系统,是对其进行规划优化的前提.为此,本文从能源链条的终端用户出发追溯至能源资源获取,结合我国城乡规划建设模式和空间层次,梳理了整个能源供需链条和能流网络的自身结构.借用一次和二次能源市场的概念阐述供应侧与需求侧能源规划的区别与联系,基于规划对象和内涵的差异,提出了双层四阶段的城市能源规划体系.结合各类能源梯级转化和能量转移规律,剖析了城区各能源局域网间的相互关系,根据个体-部分-整体生成关系,提出了支撑城市供用能系统规划的基础信息系统框架.结合城市能流网络自身特性和既有研究进展,给出了城市能源系统深度集成优化面临的体制和技术障碍.

The urban energy system, consisting of multiple subsystems ranging from energy production, transformation, transmis- sion, storage, to consumption, plays a critical role in the national and regional energy network. Due to its complexity, to optimize the urban energy system from multiple aspects and scales are necessary. Currently, a large number of urban energy planning studies have focused on optimization methods and theories targeting integrated energy systems at com- munity scale. Several energy system optimization models have also been developed based on different technical ideas. However, from a wide area perspective, the integrated community energy system represents a small local network in the overall urban energy system network. Neglecting the mutual interaction between the local network and wide area network can result in a severe segmentation issue and low energy efficiency. But it is impractical to take into account each end-user individually during the optimization of the urban energy system, since the construction activities involved in the energy demand-supply planning cover a wide range of aspects and a long period. Therefore, the coordination be- tween the local and overall energy networks requires in-depth exploration of the incidence relation among them. In this study, the formation of the urban energy demand and supply chains and the structure of urban energy flow network being described by tracking the energy flow from the end-users to the energy source extraction. Based on the concepts of ＂primary energy market＂ and ＂secondary energy market＂ in urban regions and local areas, respectively, the differences and connections between energy flow networks from the supply and demand sides have been discussed. Sub- sequently, a two-layer four-stage urban energy planning system was proposed based on the planning objects and contents. Furthermore, the typical nested and parallel relations between different local networks were proposed based on energy transformations and dissipation flows. From the structure investigation of urban energy network, such conclusions are listed as flows： （1） The overall energy flow network can be divided into two independent layers. The first network is responsible for the optimization of energy extraction from sources and the trade of energy between difference cities. The formation and evolution of the first net- work is dominated by the price mechanism of primary energy. The second network is focused on the local distribution of different energy resources （e.g., electricity, gas） based on the demand, and its formation and evolution are governed by the urban municipal plan （local regulations or policies）. These two energy markets are independent systems intercon- nected by the energy price and the demand-supply information. （2） The topology of the primary energy market is flat, which indicated that there is no apparent monopoly of information or controlling center in the market. Therefore, the trading flow of energy resources forms naturally under the influence of price mechanisms. The secondary energy market is, however, controlled by an information center where the centralized processing of the scattered end-user information leads to a highly controlled limited energy market. （3） In order to integrate the different urban energy sources into an overall energy planning scheme, the current energy distribution situation with fixed beneficiaries should be changed drastically. However, there is a lack of leadership and motivation to drive such change. （4） The cost of electricity and gas used for cooling and heating in urban areas has a high impact on the secondary energy planning. An improper choice of energy price system will adversely affect the process of reducing energy consumption. （5） Establishing a smart energy supply system in urban areas requires a synergetic integration of information systems for both energy and social-economic systems. However, currently there is no study on the mutual interaction between energy systems and social-economic systems.