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The UN Sustainable Development Goals (SDGs) and the Paris Agreement have ushered in a new era of policymaking to deliver on the formulated goals. Energy policies are key to ensuring universal access to affordable, reliable, sustainable, and modern energy (SDG7). Yet they can also have considerable impact on other goals. To successfully achieve multiple goals concurrently, policies need to balance different objectives and manage their interactions. Refining previously contemplated design principles, we identify three key principles - complementary, transparency and adaptability - as highly pertinent for multiple-objective energy policies based on a synthesis of seventeen coordinated policy case studies. First, policies should entail complementary measures and design provisions that specifically target non-energy objectives (complementarity). Second, policy impacts should be tracked comprehensively in both energy and non-energy domains to uncover diminishing returns and facilitate policy learning (transparency). Third, policies should be capable of adapting to changing objectives over time (adaptability). These principles are rarely considered in current policies, implying the need to mainstream them into the next generation of policymaking by pointing to best practices and new tools.

Abstract Threats posed by global climate change have heightened the urgency for economies to transition to sustainability. However, quantitative metrics that measure sustainability status remain under development, hampered in part by the difficulty of identifying clear relationships between economic growth and sustainability. The Environmental Kuznets Curve hypothesis provides a framework for describing sustainability status relative to socioeconomic development. In this study, the Environmental Kuznets Curve hypothesis was adopted to investigate statistical relationships between the carbon intensity of human well-being (as an indicator of sustainability) and economic development in eight economic zones of China during 1997–2015. The results provide new evidence that seven of eight Chinese economic zones began advances to sustainability (defined here as downward turning points marked by inverted “N” shapes in the Environmental Kuznets Curve) between 2012 and 2015. The lone exception was the Northwestern economic zone, in which an approach to sustainability had not yet occurred by 2015. This study thus supports the contention that environmental policies and technologies have contributed to improving sustainability in terms of carbon intensity. The results suggest two strategic options for further increasing sustainability in China: 1) “first help the weakest”; and 2) “first help the latest to sustainability”.

AbstractThe demand‐side DC electricity‐using equipment and newly integrated renewables are driving the transformation of power distribution and utilization mode. The building system based on DC technology is emerging as a promising option. In the low‐voltage DC building distribution and utilization system (LVDCBDUS), global energy optimization management and operational control arrangement are key components. To obtain exemplary achievements of those, two different DC building energy management system (DC BEMS) integration schemes are investigated according to the respective features and application‐required functions of various system networking structures. Centralized and decentralized control strategies are presented and discussed for buildings with AC–DC transformation and newly built LVDCBDUSs. On this basis, the centralized DC BEMS and operational control strategy are applied to the first multi‐scenario low‐carbon city‐based future building project—Shenzhen IBR Future Complex. The operation data are recorded and analysed. Problems encountered during the implementation are summarized, and requirements of converter equipment, new technologies and marketization are further discussed to promote the high‐quality development of the LVDCBDUS.

A lean-premixed swirling combustor with synthesis gases is studied in non-reacting and reacting cases using large-eddy simulation. Code validation and grid dependence test are performed to validate the models and mesh resolution. With the introduction of unmixedness and correlation coefficients in the non-reacting cases, the influence of Reynolds number on recirculation, vorticity breakdown and mixing is studied. In reacting cases, instant and time-averaged scalar fields are examined to study the flame dynamics for a varied fuel composition and operating conditions. The results reveal the effects of hydrogen concentration, Reynolds number, equivalence ratio and pressure on the combustion processes. Conclusions for syngas combustion operation from this work are expected to provide useful information for gas turbine combustor design.

Abstract Biomass energy is an emerging alternative energy source with an attractive carbon balance in its life cycle. Recently, a biomass fast pyrolysis fuel was produced from rice husk, and it was further upgraded using supercritical ethanol with a 5%Pt/SO 4 2− /ZrO 2 /SBA-15 catalyst in a hydrogen atmosphere. This upgraded biomass pyrolysis fuel is mainly composed of ethers, esters, alcohols and ketones. After analysing the composition of this upgraded biomass pyrolysis fuel, the authors reproduced a mixed fuel to mimic the upgraded biomass pyrolysis fuel. This mixed fuel contained ethanol, ethyl acetate, diethyl ether, acetone, and 2-butanone, with mass ratios of 9:6:2:1:1. This fuel has been used in a gasoline engine with some minor modifications; however, there is no data available for its laminar burning characteristics. In this study, the laminar burning characteristics of this mixed fuel were investigated in a constant volume combustion chamber (CVCC) at an initial pressure of 0.1 MPa and initial temperatures of 358, 388 and 418 K), and at an initial temperature of 358 K and initial pressures of 0.1, 0.2 and 0.4 MPa. By using a Schlieren high-speed imaging technique and a linear extrapolation method, laminar burning characteristics including the unstretched flame propagation speed, laminar burning velocity and other key parameters were calculated and discussed. Experiments were also conducted for two main components, ethanol and ethyl acetate, and results were used as benchmarks. The results indicated that the peak laminar burning velocity of the mixed fuel can be observed near the equivalence ratio of 1.1 under the tested conditions. At the same equivalence ratio, the laminar burning velocity was increased as initial temperature was increased, and it was decreased as initial pressure was increased. Markstein length decreased as equivalence ratio was increased, and it dropped below zero when the equivalence ratio was 1.4, indicating increased flame instability with equivalence ratio increased. Among the three examined fuels, the laminar burning velocity ranking was: ethanol > mixed fuel > ethyl acetate.

Organo-lead-halide perovskite based solar cells have achieved remarkable advancements in power conversion efficiencies (PCEs) in recent years. Given their attractive properties, possible applications for perovskites are wide ranging and among others, particularly appealing for building integrated photovoltaics (BIPVs). In this study, patterned perovskite films were successfully fabricated based on a microsphere lithography SiO2 honeycomb scaffold template, which was derived by a combination of air-water interface self-assembly and O2 plasma etching. These patterned perovskite films exhibited near-neutral-color and tunable semitransparency, which meet the requisites of semitransparent solar cells for BIPVs application. O2 plasma etching of the microsphere template could effectively improve the active layer average visible transmission (AVT), and the existence of the SiO2 nanoscaffold effectively smoothed the internal trade-off of active layer AVT and device PCE. Solar cell devices fabricated with these optimized patterened perovskite films yielded a maximum PCE of 10.3% with relatively high active layer AVT of 38%. This nanoscaffold patterned perovskite opens up a new strategy for design and fabrication of functional photoelectric device based on organo-lead-halide perovskite.

The authors are grateful for the support provided by the National Key Technology R&D Program from Ministry of Science and Technology of Grant NO. 2012BAC20B07. We acknowledge the support of the National Key Technology R&D Program and the Institute for Energy, Environment, and Economy at Tsinghua University, which is supporting Tianyu Qi’s doctoral research as a visiting scholar at the Massachusetts Institute of Technology. We acknowledge the support of ENI, ICF and Shell, initial Founding sponsors of the China Energy and Climate Project. This consortium of sponsors has provided support for researchers in the MIT Joint Program to engage in a five-year program of research focused on China. None of the sponsoring organizations played a role in the study design, collection, analysis, or interpretation of the data used for this study, nor did they influence our decisions to submit the article for publication, and all errors are our own.

The rapid and extensive changes in household consumption patterns during the coronavirus disease 2019 (COVID-19) pandemic can serve as a natural experiment for exploring the environmental outcomes of changing human behavior. Here, we assess the carbon footprint of household consumption in Japan during the early stages of the COVID-19 pandemic (January-May 2020), which were characterized by moderate confinement measures. The associated lifestyle changes did not have a significant effect on the overall household carbon footprint compared with 2015-2019 levels. However, there were significant trade-offs between individual consumption categories such that the carbon footprint increased for some categories (e.g., eating at home) or declined (e.g., eating out, transportation, clothing, and entertainment) or remained relatively unchanged (e.g., housing) for others. Furthermore, carbon footprint patterns between age groups were largely consistent with 2015-2019 levels. However, changes in food-related carbon footprints were visible for all age groups since March and, in some cases, since February.