能源系统低碳转型既是应对气候变化的紧迫要求，也是实现可持续发展的必然趋势。投资规模大、服役时间长的能源基础设施是低碳转型的关键，能源基础设施的合理规划能够减少转型成本。中国已宣布2060年实现碳中和的目标，但紧迫的碳减排任务，持续增长的能源需求，庞大而复杂的能源系统，巨大的时空差异，服役年限普遍尚短的大规模化石能源基础设施，均是中国能源供应系统低碳转型面临的巨大挑战。因此，建立具有时空区分度且考虑能源基础设施的中国能源系统低碳转型研究方法，并提出在保障能源安全的前提下以较低成本实现转型目标的具体规划方案具有重要意义。本文对10个国际机构发布的17个能源展望情景进行对比梳理，为本文构建中国低碳转型路径的相关情景提供参考。本文通过文献综述指出已有模型工具并未刻画能源系统中的基础设施，并未提出基础设施规划方案，也未能提供区域性、季节性能源供需矛盾的解决方案。因此，本文首先提出了基于经济增速、能源强度和转型政策展望下的分地区、分行业、逐月的能源需求展望方法。其次，本文提出了超结构建模框架下刻画基础设施的能源系统最优化方法，并应用于煤炭、石油、天然气、电力和氢能供应系统。最后，本文提出了各能源品种供应系统相互关联的刻画方法，从而开发了中国多区域能源供应系统优化模型（CRESOM）。该模型区分了30个地区和8个用能行业，能刻画逐省逐月的能源供需平衡，并通过最优化计算得到长期总成本最小的能源供应系统规划方案。本文应用CRESOM开展了以下研究。首先，本文研究了既定减排目标下减排任务在能源供应侧和需求侧的分配方案对能源供应系统转型方案和成本的影响，揭示了既定目标下减排任务分配方案对系统规划和转型成本的影响规律。其次，本文研究了中国分别实现既定政策目标、2℃目标、1.5℃目标对应的能源供应系统规划方案，以及制氢技术路径选择对能源供应系统规划方案的影响，揭示了转型目标对系统规划和转型成本的影响规律。第三，本文提出了中国能源供应系统到2060年实现碳中和的转型路径，描绘了碳中和下“电网+氢网”主导的能源供应系统格局，跨区域、跨季节能源调配方案，以及实现碳中和所需的新增投资规模和化石能源资产退役损失。最后，本文对两个区域性、季节性能源供需矛盾典型案例进行研究并提出了解决方案，分别是西南地区丰水期弃水现象和冬季天然气供应紧张现象，为解决未来大规模风、光并网带来的季节性供需矛盾提供借鉴。
The low-carbon transition of the energy system is not only an urgent requirement to address climate change, but also an inevitable trend to achieve sustainable development. Energy infrastructure is pivotal in the transition due to massive investment and long life-span, and proper planning of the energy supply system could reduce transition costs. China has announced the target to achieve carbon neutrality by 2060 but with huge challenges of urgent carbon reduction tasks, growing energy demand, complex energy supply systems, regional disparity, and large-scale fossil energy infrastructure with short operating time. Therefore, developing infrastructure-based energy system planning methods with sufficient temporal-spatial resolution, and proposing the specific planning of energy supply systems in China with lower costs as well as ensuring energy security to achieve the transition target would benefit the low-carbon transition. This paper compares 17 energy outlook scenarios published by 10 international institutions so as to provide reference for scenario setting in low-carbon transition pathway analysis. This paper reviews existing studies and points out that energy infrastructure has not been described in existing models for low-carbon transition research, and specific infrastructure planning has not been proposed, and solutions for regional and seasonal energy supply and demand contradiction has not been provided. Therefore, firstly, this paper proposes a regional, sectoral, monthly energy demand forecast method based on economic growth rate, energy intensity and transition policy outlook. Secondly, this paper presents an optimization method of energy systems for characterizing infrastructure under the framework of superstructure modeling, and applies it to coal, oil, natural gas, power and hydrogen energy supply systems. Finally, this paper proposes a method to describe the interrelationship of energy supply systems, and develops China Regional Energy Supply System Optimization Model (CRESOM). This model distinguishes 30 regions and 8 energy-use sectors, and describes the monthly energy supply and demand balance of each province, and gets the energy supply system planning scheme with the minimum long-term total costs by optimization.In this paper, CRESOM is applied to carry out the following researches. Firstly, the impact of the allocation of emission reduction tasks in different sectors given the fixed transition target on the transition planning and costs of energy supply systems is analyzed, and the influence of emission reduction task allocation scheme on system planning and transition costs given the fixed transition target is pointed out. Secondly, the impact of achieving the stated policy target, 2-degree target and 1.5-degree target on energy system planning and corresponding costs is studied, and the impact of the choice on hydrogen production technology is also analyzed, so that the relationship amongst transition targets, system planning and transition costs is pointed out. Thirdly, this paper proposes the transition pathway of energy supply systems in China towards carbon neutrality by 2060, describing the layout of carbon-neutral energy supply systems dominated by hydrogen and power systems, energy flows amongst regions, infrastructure investment demand and stranded investment on fossil infrastructure to achieve carbon neutrality. Finally, two case studies describing regional and monthly contradiction between supply and demand are provided and solved, which are hydropower curtailment in Southwest regions in summer and supply shortage of natural gas in winter. It could be referenced to solve monthly fluctuation issues in future power systems with large-scale wind and solar capacity.
