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Renewable and Low-Carbon Electric Power and Grid Integration

Xi Lu, Liang Cao, Haikun Wang, Wei Peng, Jia Xing, Shuxiao Wang, Siyi Cai, Bo Shen, Qing Yang, Chris P. Nielsen, and Michael B. McElroy. 2019. “Gasification of coal and biomass as a net carbon-negative power source for environment-friendly electricity generation in China.” Proceedings of the National Academy of Sciences, 116, 17, Pp. 8206-8213. Publisher's VersionAbstract
PNAS paper.pdf
Realizing the goal of the Paris Agreement to limit global warming to 2 °C by the end of this century will most likely require deployment of carbon-negative technologies. It is particularly important that China, as the world’s top carbon emitter, avoids being locked into carbon-intensive, coal-fired power-generation technologies and undertakes a smooth transition from high- to negative-carbon electricity production. We focus here on deploying a combination of coal and biomass energy to produce electricity in China using an integrated gasification cycle system combined with carbon capture and storage (CBECCS). Such a system will also reduce air pollutant emissions, thus contributing to China’s near-term goal of improving air quality. We evaluate the bus-bar electricity-generation prices for CBECCS with mixing ratios of crop residues varying from 0 to 100%, as well as associated costs for carbon mitigation and cobenefits for air quality. We find that CBECCS systems employing a crop residue ratio of 35% could produce electricity with net-zero life-cycle emissions of greenhouse gases, with a levelized cost of electricity of no more than 9.2 US cents per kilowatt hour. A carbon price of approximately $52.0 per ton would make CBECCS cost-competitive with pulverized coal power plants. Therefore, our results provide critical insights for designing a CBECCS strategy in China to harness near-term air-quality cobenefits while laying the foundation for achieving negative carbon emissions in the long run.
2019 Mar 07

China and Asia in a Changing Climate: Natural Science for the Non-Scientist

12:15pm to 1:45pm

Location: 

CGIS South S020, Belfer Case Study Room, 1730 Cambridge St., Cambridge, MA

 

 

Panelists:

  • Professor John Holdren, Teresa and John Heinz Professor of Environmental Policy, Harvard Kennedy School (HKS) and Department of Earth and Planetary Sciences, Harvard University; Co-Director of Science, Technology, and Public Policy Program, HKS; former Science Advisor to President Barack Obama and former Director of the White House Office of Science and Technology Policy
  • Professor Peter Huybers, Department of Earth and Planetary Sciences, Harvard University, and Harvard John A. Paulson School of Engineering and Applied Sciences
  • Professor Elsie Sunderland, Gordon McKay Professor of Environmental Chemistry, Harvard John A. Paulson School of Engineering and Applied Sciences and Harvard T.H. Chan School of Public Health
  • Professor Steve Wofsy, Abbott Lawrence Rotch Professor of Atmospheric and Environmental Science, Department of Earth and Planetary Sciences, Harvard University, and Harvard John A. Paulson School of Engineering and Applied Sciences

Chair: Professor Mike McElroy, Gilbert Butler Professor of Environmental Studies, Department of Earth and Planetary Sciences, Harvard University, and Harvard John A. Paulson School of Engineering and Applied Sciences; Chair, Harvard-China Project on Energy, Economy and Environment... Read more about China and Asia in a Changing Climate: Natural Science for the Non-Scientist

Qing Yang, Hewen Zhou, Xiaoyan Zhang, Chris P. Nielsen, Jiashuo Li, Xi Lu, Haiping Yang, and Hanping Chen. 2018. “Hybrid life-cycle assessment for energy consumption and greenhouse gas emissions of a typical biomass gasification power plant in China.” Journal of Cleaner Production, 205, Pp. 661-671. Publisher's VersionAbstract

Among biomass energy technologies which are treated as the promising way to mitigate critical energy crisis and global climate change, biomass gasification plays a key role given to its gaseous fuels especially syngas for distributed power plant. However, a system analysis for the energy saving and greenhouse gas emissions abatement potentials of gasification system has been directed few attentions. This study presents a system analysis that combines process and input-output analyses of GHG emissions and energy costs throughout the full chain of activities associated with biomass gasification. Incorporating agricultural production, industrial process and wastewater treatment which is always ignored, the energy inputs in life cycle are accounted for the first commercial biomass gasification power plant in China. Results show that the non-renewable energy cost and GHG emission intensity of the biomass gasification system are 0.163 MJ/MJ and 0.137 kg CO2-eq/MJ respectively, which reaffirm its advantages over coal-fired power plants in clean energy and environmental terms. Compared with other biomass energy processes, gasification performs well as its non-renewable energy cost and CO2 intensity are in the central ranges of those for all of these technologies. Construction of the plant is an important factor in the process’s non-renewable energy consumption, contributing about 44.48% of total energy use. Wastewater treatment is the main contributor to GHG emissions. The biomass gasification and associated wastewater treatment technologies have critical influence on the sustainability and renewability of biomass gasification. The results provide comprehensive analysis for biomass gasification performance and technology improvement potential in regulating biomass development policies for aiming to achieve sustainability globally.

 

Xinyu Chen, Jiajun Lv, Michael B. McElroy, Xingning Han, Chris Nielsen, and Jinyu Wen. 2018. “Power system capacity expansion under higher penetration of renewables considering flexibility constraints and low carbon policies.” IEEE Transactions on Power Systems, 33, 6, Pp. 6240-6253. Publisher's VersionAbstract
Deploying high penetration of variable renewables represents a critical pathway for deep decarbonizing the power sector. The conflict between their temporal variability and limited system flexibility has been largely ignored currently at planning stage. Here we present a novel capacity expansion model optimizing investment decisions and full-year, hourly power balances simultaneously, with considerations of storage technologies and policy constraints, such as carbon tax and renewable portfolio standards (RPS). Based on a computational efficient modeling formulation, all flexibility constrains (ramping, reserve, minimum output, minimal online/offline time) for the 8760-hour duration are incorporated. The proposed model is applied to the northwestern grid of China to examine the optimal composition and distribution of power investments with a wide range of renewable targets. Results indicate that the cost can increase moderately towards 45% of RPS, when properly designing the generation portfolio: prioritizing wind investments, distributing renewable investments more evenly and deploying more flexible mid-size coal and gas units. Reaching higher penetrations of renewables is expensive and the reductions of storage costs are critically important for an affordable low-carbon future. RPS or carbon taxes to reach a same target of emission reduction in China will result in similar overall costs but different generation mixes.
China ev

《金融时报》报道中国项目关于电动汽车充电方式对中国环境影响的最新研究

May 23, 2018

《金融时报》一篇文章详细探讨了电动汽车是否对中国环境有积极影响。文章认为，中国的能源市场目前依然由矿物燃料主导，尚未完成转型，电动汽车对环境会有哪些影响尚未有定论。文章引述了多篇相关领域的研究论文，包括中国项目最近发表于《自然·能源》期刊的一篇研究。这项研究由来自哈佛大学和清华大学的团队共同合作完成，成员包括哈佛大学中国项目主席Michael B. MCELROY教授、项目执行总监Chris P. NIELSEN先生、博士后研究员陈新宇，以及访问博士生吕家君。此外，哈佛大学Paulson工程与应用科学学院也就该项研究发布了...

Read more about 《金融时报》报道中国项目关于电动汽车充电方式对中国环境影响的最新研究
Xinyu Chen, Junling Huang, Qing Yang, Chris P. Nielsen, Dongbo Shi, and Michael B. McElroy. 2018. “Changing carbon content of Chinese coal and implications for emissions of CO2.” Journal of Cleaner Production, 194, Pp. 150-157. Publisher's VersionAbstract
The changing carbon content of coal consumed in China between 2002 and 2012 is quantified using information from the power sector. The carbon content decreased by 7.7% over this interval, the decrease particularly pronounced between 2007 and 2009. Inferences with respect to the changing carbon content of coal and the oxidation rate for its consumption, combined with the recent information on coal use in China, are employed to evaluate the trend in emissions of CO2. Emissions are estimated to have increased by 158% between 2002 and 2012, from 3.9 Gt y-1 to 9.2 Gt y-1. Our estimated emissions for 2005 are notably consistent with data reported by China in its “Second National Communication” to the UN (NDRC, 2012) and significantly higher than the estimation published recently in Nature. The difference is attributed, among other factors, to the assumption of a constant carbon content of coal in the latter study. The results indicate that CO2 emissions of China in 2005 reported by Second National Communication are more reliable to serve as the baseline for China's future carbon commitments (e.g. those in Paris Agreement of the UNFCCC). Discrepancies between national and provincial statistics on coal production and consumption are investigated and attributed primarily to anomalous reporting on interprovincial trade in four heavily industrialized provinces.
wind turbines pic

哈佛大学中国项目论文位列《自然科学报告》2017年阅读次数最多的100篇论文之一

April 25, 2018

论文 “Wind-generated Electricity in China: Decreasing Potential, Inter-annual Variability and Association with Changing Climate” 探究了地表温度上升对风速的影响。该文由研究生Peter Sherman、博士后研究员陈新宇和Michael B. McElroy教授合著，并位列《自然科学报告》2017年阅读次数最多的前100篇地球科学论文。

我们就该论文采访了作者之一Peter Sherman，...

Read more about 哈佛大学中国项目论文位列《自然科学报告》2017年阅读次数最多的100篇论文之一
liu zhenya headshot

中国国家电网公司前董事长刘振亚就全球能源互联网在哈佛大学发表公开演讲

April 17, 2018

2018年4月17日，中国国家电网公司(SGCC)前董事长、现全球能源互联网发展合作组织(GEIDCO)主席刘振亚先生在哈佛大学法学院发表题为“能源创新之道：从特高压电网到全球能源互联网”的公开演讲。演讲探讨了建立全球智能电网的需求与潜力，通过全球能源互联网，用可再生资源生产的能源能够以更低的成本进入千家万户。本次活动由哈佛大学中国能源、经济与环境项目，哈佛法学院东亚法律研究项目，哈佛John A. Paulson工程与应用科学学院，以及哈佛环球学院联合举办。点击此处阅读有关报道。

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Read more about 中国国家电网公司前董事长刘振亚就全球能源互联网在哈佛大学发表公开演讲
Xinyu Chen, Zhiwei Xu, Chris P Nielsen, and Michael B. McElroy. 2018. “Impacts of fleet types and charging modes for electric vehicles on emissions under different penetrations of wind power.” Nature Energy, 3, Pp. 413-421. Publisher's VersionAbstract
Current Chinese policy promotes the development of both electricity-propelled vehicles and carbon-free sources of power. Concern has been expressed that electric vehicles on average may emit more CO2 and conventional pollutants in China. Here, we explore the environmental implications of investments in different types of electric vehicle (public buses, taxis and private light-duty vehicles) and different modes (fast or slow) for charging under a range of different wind penetration levels. To do this, we take Beijing in 2020 as a case study and employ hourly simulation of vehicle charging behaviour and power system operation. Assuming the slow-charging option, we find that investments in electric private light-duty vehicles can result in an effective reduction in the emission of CO2 at several levels of wind penetration. The fast-charging option, however, is counter-productive. Electrifying buses and taxis offers the most effective option to reduce emissions of NO x , a major precursor for air pollution.

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