城市净零路径研究——以苏州吴中区为例（英）-IRENA.pdf

 SECTOR COUPLING IN FACILITATING INTEGRATION OF VARIABLE RENEWABLE ENERGY IN CITIES NET ZERO PATHWAYS FOR CITIES: THE CASE STUDY OF WUZHONG DISTRICT, SUZHOU, CHINA© IRENA 2022 Unless otherwise stated, material in this publication may be freely used, shared, copied, reproduced, printed and/or stored, provided that appropriate acknowledgement is given of IRENA as the source and copyright holder. Material in this publication that is attributed to third parties may be subject to separate terms of use and restrictions, and appropriate permissions from these third parties may need to be secured before any use of such material. ISBN: 978-92-9260-425-7 IRENA (2022), Net-Zero Pathways for Cities: The Case Study of Wuzhong District, Suzhou, China, International Renewable Energy Agency, Abu Dhabi. About IRENA The International Renewable Energy Agency (IRENA) serves as the principal platform for international co-operation, a centre of excellence, a repository of policy, technology, resource and financial knowledge, and a driver of action on the ground to advance the transformation of the global energy system. An intergovernmental organisation established in 2011, IRENA promotes the widespread adoption and sustainable use of all forms of renewable energy, including bioenergy, geothermal, hydropower, ocean, solar and wind energy, in the pursuit of sustainable development, energy access, energy security and low-carbon economic growth and prosperity. www.irena.org Acknowledgements IRENA would like to express sincere appreciation to Empa for its technical contribution to the modelling development and analyses. IRENA is also thankful to the experts who reviewed the report. Insightful comments and constructive suggestions were provided by Jiejun Chen, Qian Chen, Hangping Pan and Zhihuang Sun (State Grid Suzhou City and Energy Research Institute). Special thanks go to Paul Komor, who provided helpful feedback and advice. IRENA colleagues Prasoon Agarwal, Francisco Boshell, Imen Gherboudj, Jack Kiruja, Michael Renner, Elizabeth Press and Nicholas Wagner provided valuable review and input. IRENA is grateful for the support of Germany’s International Climate Initiative (IKI) project in producing this publication. IKI support This report forms part of the Energy Solutions for Cities of the Future project, which is supported by the International Climate Initiative (IKI). The German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) supports this initiative on the basis of a decision adopted by the German Bundestag. Contributing authors This report was prepared, under the guidance of Dolf Gielen, by the sustainable urban energy team at IRENA’s Innovation and Technology Centre. It was authored by Yong Chen (IRENA), Mashael Yazdanie, and Chenyu Zhou (Empa), Weiyang Li, Weimin Xi and Chanxia Zhu (SGCERI), with additional support from Julien Marquant and Fabia Miorelli (former IRENA colleagues). Disclaimer This publication and the material herein are provided “as is”. All reasonable precautions have been taken by IRENA to verify the reliability of the material in this publication. However, neither IRENA nor any of its officials, agents, data or other third-party content providers provides a warranty of any kind, either expressed or implied, and they accept no responsibility or liability for any consequence of use of the publication or material herein. The information contained herein does not necessarily represent the views of all Members of IRENA. The mention of specific companies or certain projects or products does not imply that they are endorsed or recommended by IRENA in preference to others of a similar nature that are not mentioned. The designations employed, and the presentation of material herein, do not imply the expression of any opinion on the part of IRENA concerning the legal status of any region, country, territory, city or area or of its authorities, or concerning the delimitation of frontiers or boundaries.NET ZERO PATHWAYS FOR CITIES: THE CASE STUDY OF WUZHONG DISTRICT, SUZHOU, CHINA 3 TABLE OF CONTENTS ABBREVIATIONS 5 EXECUTIVE SUMMARY 6 1. INTRODUCTION 9 1.1 China’s new carbon targets are guiding cities’ energy development 9 1.2 Wuzhong District: A pilot on the race to net-zero 11 1.3 Objectives of this report 13 2. METHODOLOGY 15 2.1 Model 15 2.2 Data constraints, estimation and assumptions 18 2.3 Limitations 33 3. MODELLING SCENARIOS AND RESULTS 35 3.1 Baseline case 35 3.2 Carbon policy 37 3.3 Sustainable development scenarios 39 3.4 Net-zero CO 2 scenario 42 3.5 Pareto efficiency 43 4. DISCUSSION 46 4.1 Integrated solar PV holds untapped potential for cities 46 4.2 Enhancing demand-side flexibility in support of grid integration of renewables 48 4.3 Role of green hydrogen 49 4.4 Importance of sustainable urban energy planning 50 5. CONCLUDING REMARKS 53 REFERENCES 554 Figures FIGURE 1: Location of Wuzhong District in Suzhou city 12 FIGURE 2: Model reference energy system diagram 19 FIGURE 3: Hourly electricity demand profile – industrial sector 20 FIGURE 4: Hourly electricity demand profile – service sector 21 FIGURE 5: Hourly electricity demand profile – residential sector 21 FIGURE 6: Process heating demand profile – industrial sector 21 FIGURE 7: Space heating demand profile – service sector 22 FIGURE 8: Space heating demand profile – residential sector 22 FIGURE 9: Space cooling demand profile – service sector 23 FIGURE 10: Space cooling demand profile – residential sector 23 FIGURE 11: Hot water demand profile – service sector 24 FIGURE 12: Hot water demand profile – residential sector 24 FIGURE 13: GDP growth in Wuzhong District, 2013-2017 25 FIGURE 14: National Chinese population scenarios 25 FIGURE 15: Population growth for the Wuzhong District 26 FIGURE 16: Electricity demand projections across sectors 26 FIGURE 17: Process heat demand projection – industrial sector 27 FIGURE 18: Building area growth for Wuzhong District 27 FIGURE 19: Space heating demand projections – service and residential sectors 28 FIGURE 20: Space cooling demand projections – service and residential sectors 28 FIGURE 21: Hot water demand projections – service and residential sectors 29 FIGURE 22: Total demand for all energy services in the Wuzhong District 29 FIGURE 23: Normalised seasonal solar radiation profiles 30 FIGURE 24: Biomass waste potential projection 30 FIGURE 25: Relative efficiency improvements for electrical appliances across sectors 31 FIGURE 26: Carbon emission factor for grid electricity 32 FIGURE 27: Baseline scenario – electricity and heat production 36 FIGURE 28: CP scenario – electricity and heat production 38 FIGURE 29: SD-CO 2 Min – electricity and heat production 39 FIGURE 30: SD-CostMin – electricity and heat production 40 FIGURE 31: SD-CO 2 Mid – electricity and heat production 41 FIGURE 32: SD-CO 2 Min-LD – electricity and heat production 41 FIGURE 33: Net-zero CO 2 emissions scenario – electricity and heat production 42 FIGURE 34: Costs versus CO 2 emissions across scenarios and Pareto efficiency curve 43 Tables TABLE 1: Model structural scope 16 TABLE 2: Model energy conversion technology options and associated outputs or functions 17 TABLE 3: Parameters applied to calculate annual residential hot water demand 23NET ZERO PATHWAYS FOR CITIES: THE CASE STUDY OF WUZHONG DISTRICT, SUZHOU, CHINA 5 ABBREVIATIONS BC baseline case BIPV building-integrated photovoltaic CCP combined cycle power plant CCS carbon capture and storage CHP combined heat and power plant CO 2 carbon dioxide CP carbon policy GDP gross domestic product IGCC integrated gasification combined cycle NZC net-zero CO 2 emissions PV photovoltaic SD sustainable development SGCERI State Grid City and Energy Research Institute 6 EXECUTIVE SUMMARY In 2020, Chinese President Xi Jinping announced, at the 75th United Nations General Assembly, that China will aim to peak carbon dioxide (CO 2 ) emissions before 2030 and achieve carbon neutrality by 2060. At the national level, China has – over the past decade – made remarkable progress in renewable energy development, in particular in solar photovoltaics (PVs) and wind power. By the end of 2020, renewable electricity accounted for around 30% of total electricity output and 42% of national installed power generation capacity. In spite of this, fossil fuels remain dominant in Chinese energy use, including in the power sector and in end-use sectors such as transportation, buildings and industry. Cities, including their suburban areas, where the majority of these sectors’ activities take place, will therefore have an important role to play in achieving the goals announced by President Xi Jinping. In 2020, about 60% of Chinese people lived in cities. Cities already consume 85% of the total national energy supply in China and are responsible for around 70% of total national energy- related CO 2 emissions. Yet, over the next three decades, it has been projected that another 250 million people will become urban dwellers in China. How can local decision makers support the national energy transition and the achievement of the national climate objectives while sustaining local economic and social development? This study used the Wuzhong District of Suzhou city as a case study to explore pathways towards a net-zero emissions future, particularly for those cities where the potential for renewable energy production is less abundant. The study took a unique approach. The first question probed was what options Wuzhong would have if the district used conventional emission abatement technologies to reduce its carbon emissions from its current energy mix. Considerations taken into account in answering this question included (a) the constraints district governance might face in making a dramatic and systemic change and (b) the district’s limited renewable energy resources and its constraints on land use due to the ecological preservation zone it is located in. The modelling results and scenario analyses show how Wuzhong’s energy system might evolve if the technological options and decarbonisation strategies are, to a large extent, confined to conventional technological pathways. Cost-optimal scenarios demonstrate significantly lower local installed capacities, as they rely heavily on grid imports. Carbon-optimal scenarios demonstrate significantly higher investments in gas, carbon capture and storage (CCS), ground- NET ZERO PATHWAYS FOR CITIES: THE CASE STUDY OF WUZHONG DISTRICT, SUZHOU, CHINA 7 or water-source heat pumps, and solar conversion technologies, making these scenarios more costly. The modelling exercise aimed to help local decision makers understand the limitations of the business-as-usual approach and why transformative measures might be needed. In addition, the modelling-derived results indicate that Wuzhong would have to rely on CCS for decarbonising natural gas and coal if it focused on decarbonisation of its own generation capacity to achieve net-zero. In less ambitious scenarios, natural gas is given an important role to play. These modelling results might not be aligned with the Chinese overall policy direction and multiple constraints that may exist in China, including limited potential of natural gas resources, lack of clarity on carbon storage capacity in the region, and the technology risks of CCS. Hence, the overall outlook for the supply of natural gas would need to be further discussed, as the demand for natural gas nationwide is expected to grow dramatically following the phasing down of coal consumption. Also, a detailed feasibility analysis of CCS technologies in the Suzhou area needs to be conducted. Given the above, the extent to which Wuzhong can adopt advanced renewable energy technologies – such as building-integrated photovoltaic (PV), city-integrated applications of solar PV, and innovative solutions such as extracting cold energy from water supply facilities – is crucial to increasing the uptake of renewables. Although waste energy resources (mainly biomass and municipal solid wastes) are fully utilised in every year of every modelled scenario, some advanced technologies might enable biodegradable feedstock to be used in a more efficient way, which might also expand the local resource spectrum; this option could be used in addition to importing underutilised wastes from neighbouring districts. The local geothermal potential and the applicability of advanced technologies for direct use of geothermal resources are also worth investigating. In all scenarios with the conventional emission abatement approach, natural gas is given an important role to play, under the assumption that the carbon emission factors of the electricity imported from the grid to Wuzhong District are higher than those associated with local natural gas-based electricity generation. However, the grid electricity could be decarbonised faster, with greater shares of solar PV and wind power being integrated into the grid, if cities could support grid operation with more demand-side flexibility. This will, in return, affect how cities respond to the paradigm change in the Chinese power sector and will consequentially affect the carbon emission factors of national and regional grid electricity to Wuzhong. The second step of the study looked at strategic areas enabling expansion of the decarbonisation options presented in the modelling results: building-integrated PV , demand-side flexibility, green hydrogen and urban energy planning. These areas are applicable not only for Wuzhong but in general for many districts and cities like Wuzhong with moderate local renewable energy resources and relatively high energy demand. Certainly, these strategic areas do not constitute an exhaustive list, but they do highlight the most relevant aspects that such cities or districts should look into and adjust to suit the characteristics of their localities. Overall, the Chinese leadership has boosted its ambition and stepped up its efforts to address the climate challenges. Cities will take this as guidance and make corresponding strategies and actions plans to contribute as much as they can to achieving the national carbon peak by 2030 and carbon neutrality by 2060. However, the actions they take and the decisions they make should be based on their resources. Those without abundant local renewable energy resources could explore other options with the aim of achieving net-zero for Chinese cities in a collective and collaborative fashion.8 © Daniel Hanscom/Getty Images 1NET ZERO PATHWAYS FOR CITIES: THE CASE STUDY OF WUZHONG DISTRICT, SUZHOU, CHINA 9 INTRODUCTION With the near-universal adoption in 2015 of the Paris Agreement – an international treaty on climate change – reaching net-zero emission of anthropogenic carbon dioxide (CO 2 ) around 2050 has become the key driver for the global energy transition (IPCC, 2018; UNFCCC, n.d.). Cities will play a critical role in reducing emissions as they are resp