能源与电网

Yang Zhao, Ziyue Jiang, Xinyu Chen, Peng Liu, Tianduo Peng, and Zhan Shu. 2023. “Toward environmental sustainability: data-driven analysis of energy use patterns and load profiles for urban electric vehicle fleets.” Energy, 285, 15 Dec 2023, Pp. 129465. Publisher's VersionAbstract
The scale-up of urban electric vehicle (EV) fleets, driven by environmental benefits, is resulting in surging aggregate energy demands that may reshape a city's power supply. This paper establishes an integrated data-driven assessment model for investigating the energy use (kWh) patterns and charging load (kW) profiles of urban-scale EV fleets. To this end, urban EV operating and operational datasets are linked with climate data and vehicle specifications. Four vehicle fleet types are distinguished: private, taxi, rental, and business fleets. Statistical models regarding distribution analysis, spectrum analysis, and identical distribution tests are employed to analyze the patterns of driving distances, energy consumption, and shares of active charging EVs. The minute-level changes in charging EV numbers and aggregate charging power are examined to reflect the grid load impact. The results show that private light-duty EVs in Beijing consume an average of 9.1 kWh/day, with more charging activities on Fridays. The primary load peaks of light-duty EVs in Beijing usually occur between 11 p.m. and 1 a.m., attributable chiefly to the private fleet's midnight peak load estimated at 28 % of the total daily charging private EV count multiplied by 5.5 kW/EV. Secondary peaks occur between 8 a.m. and 10 a.m. on weekdays for private fleets, and at 4 p.m. for public fleets. Our work can be extensively used for analyses on transport emissions, urban power supply, infrastructure build-ups, and policymaking.
Xi Yang, Chris P. Nielsen, Shaojie Song, and Michael B. McElroy. 2022. “Breaking the “hard-to-abate” bottleneck in China’s path to carbon neutrality with clean hydrogen.” Nature Energy. Publisher's VersionAbstract
Countries such as China are facing a bottleneck in their paths to carbon neutrality: abating emissions in heavy industries and heavy-duty transport. There are few in-depth studies of the prospective role for clean hydrogen in these ‘hard-to-abate’ (HTA) sectors. Here we carry out an integrated dynamic least-cost modelling analysis. Results show that, first, clean hydrogen can be both a major energy carrier and feedstock that can significantly reduce carbon emissions of heavy industry. It can also fuel up to 50% of China’s heavy-duty truck and bus fleets by 2060 and significant shares of shipping. Second, a realistic clean hydrogen scenario that reaches 65.7 Mt of production in 2060 could avoid US$1.72 trillion of new investment compared with a no-hydrogen scenario. This study provides evidence of the value of clean hydrogen in HTA sectors for China and countries facing similar challenges in reducing emissions to achieve net-zero goals.
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.

Shaojie Song, Haiyang Lin, Peter Sherman, Xi Yang, Chris P. Nielsen, Xinyu Chen, and Michael B. McElroy. 2021. “Production of hydrogen from offshore wind in China and cost-competitive supply to Japan.” Nature Communications, 12, 2021, Pp. 6953. Publisher's VersionAbstract
The Japanese government has announced a commitment to net-zero greenhouse gas emissions by 2050. It envisages an important role for hydrogen in the nation’s future energy economy. This paper explores the possibility that a significant source for this hydrogen could be produced by electrolysis fueled by power generated from offshore wind in China. Hydrogen could be delivered to Japan either as liquid, or bound to a chemical carrier such as toluene, or as a component of ammonia. The paper presents an analysis of factors determining the ultimate cost for this hydrogen, including expenses for production, storage, conversion, transport, and treatment at the destination. It concludes that the Chinese source could be delivered at a volume and cost consistent with Japan’s idealized future projections.
Combined solar power and storage as cost-competitive and grid-compatible supply for China’s future carbon-neutral electricity system
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.
Jianglong Li and Mun Sing Ho. 2024. “End-year China wind power installation rush reduces electric system reliability.” Energy Economics, 133, May 2024, Pp. 107507. Publisher's VersionAbstract
The urgent challenge posed by climate change has catalyzed global efforts to transition towards sustainable energy sources, with wind power emerging as a pivotal component. However, the rapid expansion of renewable energy sources has raised concerns about electric system reliability, given their intermittent and hard-to-forecast nature. China has provided incentives that promoted the rapid expansion of wind. However, the structure of some incentives led to the phenomenon of end-year rushes to install wind power before incentives expire. Leveraging panel data from China's provinces, we empirically estimate the impact of these installation rushes on electric reliability. We find significant adverse effects, with a one-standard-deviation increase in installation rush corresponding to a 0.767% decrease in the reliability rate and a 39.6-min increase in annual outage duration. Notably, urban areas and the northwestern grid are particularly vulnerable to the disruptions caused by year-end installation rushes. In the urban areas of the northwestern grid, we identify the potential for substantial improvements in the lower bound of the reliability rate, from 98.86% to 99.37%, or a reduction in outage duration from 11.65 h to 7.16 h. These findings show the importance of structuring incentives properly and the importance of improvements in grid infrastructure and management in the transition to a low-carbon world.
2024 Feb 01

Application Deadline for Visiting Researcher or Postdoctoral Fellow Positions

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Applications are now open to join us for academic year 2024-25. Visits will typically fall between August 2024 and August 2025, although visits that fall outside of the academic year would also be considered. Click here for more information on our Visiting Researcher program. 

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2024 Jan 31

Progress in China’s electricity market reform and assessing its impact on generation efficiency

3:00pm to 4:00pm

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Pierce Hall Room 100F, 29 Oxford Street, Cambridge

A Harvard-China Project Research Seminar with Feng Song, Associate Professor, Renmin University of China and Harvard-China Project Visiting Scholar

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Speaker Bio: Feng Song is an Associate Professor at Renmin University of China, where she works...

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