空气污染、温室气体与气候

Peter Sherman, Haiyang Lin, and Michael B. McElroy. 2022. “Projected global demand for air conditioning associated with extreme heat and implications for electricity grids in poorer countries.” Energy and Buildings. Publisher's VersionAbstract

Human-induced climate change will increase surface temperatures globally over the next several decades. Climate models project that global mean surface temperature could increase by over 2˚C by 2050 relative to the preindustrial period, with even greater changes at the regional level. These temperature changes have clear and pertinent implications for extremes, and consequentially, heat-induced health issues for people living in particularly hot climates. Here, we study future projections in the demand for AC globally in the 2050s associated with extreme heat events. To do this, we employ an ensemble of CMIP6 models under high and low emissions scenarios. We find that the increasing frequency of extreme temperatures will cause a significant portion of the global population to be exposed to conditions that require cooling. This issue will be especially pervasive in poor countries such as India and Indonesia, which at present lack the AC units required to handle rapidly growing populations and increased frequencies of extreme temperatures. The electricity needed for cooling in these countries could reach as high as 75% of the current total annual electricity demand, which could place serious strain on the electricity grid infrastructure during peak cooling hours. We conclude that demand for cooling in the future will pose a significant challenge for poorer countries whose people will require AC units to handle extreme temperatures. In some countries, the grid infrastructure is insufficient at present to meet projected AC demands, and this need must be considered in future power systems planning.

Rong Tang, Jing Zhao, Yifan Liu, Xin Huang, Yanxu Zhang, Derong Zhou, Aijun Ding, Chris Nielsen, and Haikun Wang. 2022. “Air quality and health co-benefits of China's carbon dioxide emissions peaking before 2030.” Nature Communications, 13, 1008. Publisher's VersionAbstract

Recent evidence shows that carbon emissions in China are likely to peak ahead of 2030. However, the social and economic impacts of such an early carbon peak have rarely been assessed. Here we focus on the economic costs and health benefits of different carbon mitigation pathways, considering both possible socio-economic futures and varying ambitions of climate policies. We find that an early peak before 2030 in line with the 1.5  C target could avoid ~118,000 and ~614,000 PM2.5 attributable deaths under the Shared Socioeconomic Pathway 1, in 2030 and 2050, respectively. Under the 2  C target, carbon mitigation costs could be more than offset by health co-benefits in 2050, bringing a net benefit of $393–$3,017 billion (in 2017 USD value). This study not only provides insight into potential health benefits of an early peak in China, but also suggests that similar benefits may result from more ambitious climate targets in other countries.

Xi Lu, Chris P. Nielsen, Chongyu Zhang, Jiacong Li, Xu He, Ye Wu, Shuxiao Wang, Feng Song, Chu Wei, Kebin He, Michael P. McElroy, and Jiming Hao. 2021. “Combined solar power and storage as cost-competitive and grid-compatible supply for China’s future carbon-neutral electricity system.” Proceedings of the National Academy of Sciences, 118, October, Pp. 42. Publisher's VersionAbstract
As the world’s largest CO2 emitter, China’s ability to decarbonize its energy system strongly affects the prospect of achieving the 1.5 °C limit in global, average surface-temperature rise. Understanding technically feasible, cost-competitive, and grid-compatible solar photovoltaic (PV) power potentials spatiotemporally is critical for China’s future energy pathway. This study develops an integrated model to evaluate the spatiotemporal evolution of the technology-economic-grid PV potentials in China during 2020 to 2060 under the assumption of continued cost degression in line with the trends of the past decade. The model considers the spatialized technical constraints, up-to-date economic parameters, and dynamic hourly interactions with the power grid. In contrast to the PV production of 0.26 PWh in 2020, results suggest that China’s technical potential will increase from 99.2 PWh in 2020 to 146.1 PWh in 2060 along with technical advances, and the national average power price could decrease from 4.9 to 0.4 US cents/kWh during the same period. About 78.6% (79.7 PWh) of China’s technical potential will realize price parity to coal-fired power in 2021, with price parity achieved nationwide by 2023. The cost advantage of solar PV allows for coupling with storage to generate cost-competitive and grid-compatible electricity. The combined systems potentially could supply 7.2 PWh of grid-compatible electricity in 2060 to meet 43.2% of the country’s electricity demand at a price below 2.5 US cents/kWh. The findings highlight a crucial energy transition point, not only for China but for other countries, at which combined solar power and storage systems become a cheaper alternative to coal-fired electricity and a more grid-compatible option.
Lu et al. is the cover article of this October issue of PNAS. Read the Research Brief.
Shaojie Song, Haiyang Lin, Peter Sherman, Xi Yang, Shi Chen, Xi Lu, Tianguang Lu, Xinyu Chen, and Michael B. McElroy. 2022. “Decarbonization of the Indian economy: 2050 prospects for wind, solar, and green hydrogen.” iScience, 25, 6, Pp. 104399. Publisher's VersionAbstract
The paper explores options for a 2050 carbon free energy future for India. Onshore wind and solar sources are projected as the dominant primary contributions to this objective. The analysis envisages an important role for so-called green hydrogen produced by electrolysis fueled by these carbon free energy sources. This hydrogen source can be used to accommodate for the intrinsic variability of wind and solar complementing opportunities for storage of power by batteries and pumped hydro. The green source of hydrogen can be used also to supplant current industrial uses of gray hydrogen produced in the Indian context largely from natural gas with important related emissions of CO2. The paper explores further options for use of green hydrogen to lower emissions from otherwise difficult to abate sectors of both industry and transport. The analysis is applied to identify the least cost options to meet India’s zero carbon future.
Ziwen Ruan, Xi Lu, Shuxiao Wang, Jia Xing, Wei Wang, Dan Chen, Chris P. Nielsen, Yong Luo, Kebin He, and Jiming Hao. 2022. “Impacts of large-scale deployment of mountainous wind farms on wintertime regional air quality in the Beijing-Tian-Hebei area.” Atmospheric Environment, 278, June, Pp. 119074. Publisher's VersionAbstract
The development of wind power plays an essential role in achieving China's carbon neutrality goals and air quality standards. A large number of studies have addressed the benefits of substituting fossil fuels with wind power on climate and air quality (defined as indirect impact) by macro-scale methodology. In recent years, more and more researchers have discussed its impacts on the general atmospheric circulation and air pollution dispersion (defined as direct impact) by parameterizing wind energy extraction in meso-micro scale models. However, the comprehensive investigation (considering both direct and indirect impacts) of the utilization of wind power on atmosphere environmental impacts remains vacant. Our study first evaluated both the direct and indirect impacts of wind power on air quality through an integrated methodological framework by using WRF-CMAQ system. The present analysis took wind farms located in Zhangjiakou to explore their impacts on air quality in winter, particularly over the downwind Beijing municipal area in the North China Plain. Results indicated that the deployment of wind power leads to spatially mixed direct impacts on PM2.5 concentrations in Beijing with a monthly net increase of 0.067 μg/m3 (0.08%) relative to the regional average. Contrarily, the substitution of coal-burning with wind power in rural household heating would result in notable indirect benefits to monthly PM2.5 concentrations in Beijing, specifically, reducing emissions of CO2 and conventional air pollutants by 64% in rural heating sector. The combined impacts of wind power displayed regional differences: in the wintertime (January), Zhangjiakou PM2.5 concentrations increased (+0.147 μg/m3) whereas, decreases are achieved (−5.642 μg/m3) in Beijing. Therefore, to support the large-scale deployment of wind power, future energy policies should take comprehensive account of the diverse environmental impacts, including both the indirect benefits of fossil energy substitution and the potential direct atmospheric effects on regional air quality.
Jack Walker

认识 哈佛中国项目本科生研究员: Jack Walker '24

March 21, 2022

一个八年级的科学研究项目激发了 Jack Walker ‘24 致力于研究清洁能源的承诺。研究任务是展示一种特定的替代能源,Jack创造性地模仿了说唱歌手德雷克的“六人组的观点”专辑,杰克将这张专辑改名为“六人组的燃料”。该项目的杰克说:“模仿这些歌曲实际上帮助我对核裂变的理解程度更高;我发现了关于核能的新事实和新观点。” 杰克在整个高中期间一直关注替代能源,最终在弗雷德里克国家实验室研究了用于生产氢燃料的微生物电解电池。现在,作为一名化学和环境科学与公共政策双专业人士,Jack 正在担任 哈佛中国项目研究助理,负责全球航运业的脱碳,该项目建立在他的哈佛中国项目夏季研究之上。杰克的夏季研究分析了现代航行、绿色氢、绿色氨和电池推进的潜力。他所在的团队发现,混合动力推进机制可能是大多数海事部门的最佳选择——使用电池进行港口机动,使用绿色氨/氢燃烧进行公海旅行。 毕业后,杰克将在美国空军担任第二中尉。

 

Candice Chen

认识 哈佛中国项目本科生研究员: Candice Chen '22

March 21, 2022

在智利圣地亚哥度过了她的大一暑假,Candice Chen '22 研究了烟雾对呼吸系统健康的影响。 这促使 Candice 报名参加大气化学课程,最终报名参加了环境科学与工程和地球与行星科学双学位课程。 “我发现自己对气候和环境科学的热爱是因为我喜欢探索人为气候变化下地球可居住性和人类福祉的基本问题,” Candice说。 现在,作为 哈佛中国项目研究助理,Candice 正在研究北京地区从煤炭向天然气的转变。 “这项工作将为 甲烷泄漏的估计提供信息,为煤制气转化和缓解策略的成本效益分析提供信息,”Candice 解释说。

 

欢迎哈佛中国项目的访问学生

欢迎哈佛中国项目的访问学生

March 8, 2022

王铮

王峥,博士。 来自北京大学,对能源的兴趣是他童年的一部分。 他成长于中国陕西延安,东汉时期(公元32年左右)有“水能烧(油)”的记载,中国第一口油井于1905年在郑氏国小修筑。 “在成长过程中,我与燃料和能源有着密切的接触,这让我对能源在工业发展和社会经济进步中的作用,以及能源作为当地政府主要收入来源之一的作用有了一定的认识, ”铮解释道。 “这让我对能源在社会经济中的真正作用感到好奇。” 随着家乡向风能和太阳能等可再生能源转型,铮亲眼目睹了能源在社会中的角色转变。 他计划在哈佛继续他的可再生能源研究。 他首先计划计算中国陆上和海上风电在不同时间(2030年、2060年)不同场景(如并网、多样化储能)下的容量潜力。 他将利用这些数据探索不同海拔高度风电的效率和经济成本,并比较中国风电和光伏的成本。 铮还计划将气候变化模型和陆面模型模拟结合起来,考虑计算不同地区风-光-储系统长期储能的容量需求。

 

向晨

对于香港大学博士研究生向晨来说,她有过一次前往危地马拉安提瓜的环境志愿服务之旅,在那里她从事水过滤工作,从而开启了她在环境治理方面的职业生涯。 “...

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Peter Sherman

介绍哈佛中国项目的新进博士后: Peter Sherman

February 28, 2022

Peter Sherman

Peter Sherman, 哈佛中国项目博士后,他最近获得了博士学位。他毕业于哈佛大学地球与行星科学系。他说,回顾他在哈佛的研究生时光,他感恩对本科生和当地高中生的指导。“让年轻人有机会了解(偶尔会遇到困难!)研究帮助我以我开始指导时没有想到的方式完善了我的教学和科学观点,”彼得解释道。 “从这些经验中,我学会了如何更好地综合和呈现研究,从而更容易‘坚持’人们学习气候变化科学。” 彼得对能源和气候变化研究的热情转化为他作为哈佛中国项目博士后研究员的新角色,他正在努力帮助了解气候危机的范围并提供可以实施以缓解这些问题的解决方案。 彼得的重点是区域气候变化如何影响人们,以及我们如何通过使我们的能源系统脱碳来减少一些主要后果——其中大部分是建立在他的博士学位基础上的研究。“我们特别关注电力部门以及一些难以减排的部门的脱碳方法,并考虑了一些项目,旨在跟进我们过去对印度电力部门和绿色能源所做的研究,”彼得说。“我还对关注气候和能源交叉的项目感兴趣,目前正在开展一个较小的项目,研究气候变化对未来空调需求的影响(以及由此对电网造成的影响)。 ” 彼得期待继续与哈佛中国项目的同事合作,并指出“整个团队非常棒,因为有来自各个领域的专家,从气候到大气化学再到能源系统规划。...

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