With the rapid development of aviation industry and its increasing impact on the global climate change,the contributions of carbon emissions frominternational flights are attracting more and more attention worldwide.T...With the rapid development of aviation industry and its increasing impact on the global climate change,the contributions of carbon emissions frominternational flights are attracting more and more attention worldwide.This study,taking Macao as the aviation hub,established the cross-border aviation carbon emission evaluation model to explore dynamic carbon emissions and net-zero path of international flights.The aviation hubmainly covers 58 routes and five types of civil aircraft from 12 countries or regions during 2000-2022.The results show that the aviation transportation in Macao emitted about 1.44 million tons CO_(2)eq in 2019,which is high 3.6 times that of 2000.The COVID-19 has led to a rapid decline in aviation carbon emissions in a short period of time,carbon emissions in 2020 decreased by 80%compared to 2019.In terms of cumulative carbon emissions from 2000 to 2019,the A321 and A320 Airbus contribute to 80%of carbon emissions.And the Chinese mainland(37%)and Taiwan(29%)are the main sources of emissions.In 2000-2019,the proportion of carbon emissions from China(including Taiwan and Hong Kong)decrease from 91%to 53%,while the contribution from Southeast Asia(from 5% to 26%),Japan and South Korea(from 2% to 19%)keep the growth trends.In the optimal scenario(B3C3),net zero emissions of cross-border aviation in Macao can be not achieved,and there is still only by removing 0.3 million tons CO_(2)eq.Emission reduction technology and new energy usage are priorities for the aviation emission reduction.展开更多
Net-zero energy buildings and communities, which are receiving increasing interest, and the role of energy storage in them, are described. A net-zero energy building or community is defined as one that, in an average ...Net-zero energy buildings and communities, which are receiving increasing interest, and the role of energy storage in them, are described. A net-zero energy building or community is defined as one that, in an average year, produces as much energy from renewable energy as it consumes. Net-zero energy buildings and communities and the manner in which energy sustainability is facilitated by them are described and examples are given. Also, energy storage is discussed and the role and importance of energy storage as part of net-zero buildings and communities are explained. The NSERC Smart Net-zero Energy Buildings Research Network, a major Canadian research effort in smart net-zero energy buildings and communities, is described.展开更多
Methane looping reforming to produce syngas is an alternative to partial methane oxidation because it allows for better control of the oxidation reaction and safely separates oxygen from syngas.However,most systems ar...Methane looping reforming to produce syngas is an alternative to partial methane oxidation because it allows for better control of the oxidation reaction and safely separates oxygen from syngas.However,most systems are monofunctional and lack the cascading utilization of energy flows,resulting in significant exergy loss.This study proposes a novel net-zero emission system that utilizes methane looping reforming for multi-generation of electricity,heating,cooling,and methanol.The reduction of high-valent manganese oxides by decoupling the partial oxidation reaction of methane into an Mn-based oxygen carrier redox cycle yielded products with H_(2)/CO ratios suitable for methanol synthesis,resulting in approximately 100%CH_(3)OH conversion rate.The oxidation of low-valent manganese oxides provides high-temperature heat for heat recovery,and the lithium bromide refrigeration section produces domestic hot and cold water as by-products.The proposed system reaches 77.1%and 65.7%energy and exergy efficiencies,which are 1.04-and 1.61-fold higher than those of traditional partial oxidation systems,respectively.Our research presents a new system integration concept that enables the efficient and controllable loop reforming of methane for methanol production.展开更多
Elevated atmospheric carbon dioxide(CO_(2)) concentrations have caused global climate change such as global warming and more frequent climate extremes. Countries worldwide have proposed carbon neutrality strategies to...Elevated atmospheric carbon dioxide(CO_(2)) concentrations have caused global climate change such as global warming and more frequent climate extremes. Countries worldwide have proposed carbon neutrality strategies to curb the rising CO_(2) concentrations. To investigate the impact of China's carbon neutrality goal on atmospheric CO_(2) concentrations, we conducted a series of ideal simulations from 2015 to 2019 using a global 3D chemistry transport model, Goddard Earth Observing System Chemistry(GEOS-Chem). Compared with the column-averaged dry-air mole fraction of atmospheric CO_(2) (XCO_(2) ) from Orbiting Carbon Observatory-2(OCO-2) and surface CO_(2) measurements in Obs Pack, we find that GEOS-Chem effectively reproduces the spatiotemporal variability of CO_(2) . The model exhibits a root mean square error(RMSE) of 1.51 ppm(R^(2)=0.89) for OCO-2 XCO_(2) in China and 2.65 ppm(R^(2)=0.75) for surface CO_(2) concentrations at the WLG station. Further, compared to 2.83 ppm yr^(-1)in the control experiment, we suggest that net-zero CO_(2) emissions in China decelerate the increasing trends of XCO_(2) to 1.81 ppm yr^(-1),making a decrease of approximately 35.89%. Meanwhile, the seasonal cycle amplitude(SCA) of XCO_(2) is moderately reduced from 7.39±0.81 to 6.75±0.70 ppm, representing a relative reduction of 9.91%. Spatially, net-zero CO_(2) emissions induce a more significant decrease in XCO_(2) trends over northern and southern China, while their impact on SCA is more evident in northern and northeastern China. Moreover, ideal experiments demonstrate that zero fossil CO_(2) emissions lead to a greater attenuation of the linear trends of XCO_(2) by 40.81%, while the absence of terrestrial CO_(2) sinks largely diminishes the SCA by 16.61%. Additionally,trends and SCA in surface CO_(2) concentrations exhibit almost identical decreasing responses to net-zero CO_(2) emissions but display greater sensitivities compared to XCO_(2) . Overall, our study underscores the potential of China's carbon neutrality goal in mitigating global warming, underscoring the need for concerted and collaborative efforts from nations worldwide.展开更多
To provide guidance for photovoltaic(PV)system integration in net-zero distribution systems(DSs),this paper proposes an analytical method for delineating the feasible region for PV integration capacities(PVICs),where ...To provide guidance for photovoltaic(PV)system integration in net-zero distribution systems(DSs),this paper proposes an analytical method for delineating the feasible region for PV integration capacities(PVICs),where the impact of battery energy storage system(BESS)flexibility is considered.First,we introduce distributionally robust chance constraints on network security and energy/carbon net-zero requirements,which form the upper and lower bounds of the feasible region.Then,the formulation and solution of the feasible region is proposed.The resulting analytical expression is a set of linear inequalities,illustrating that the feasible region is a polyhedron in a high-dimensional space.A procedure is designed to verify and adjust the feasible region,ensuring that it satisfies network loss constraints under alternating current(AC)power flow.Case studies on the 4-bus system,the IEEE 33-bus system,and the IEEE 123-bus system verify the effectiveness of the proposed method.It is demonstrated that the proposed method fully captures the spatio-temporal coupling relationship among PVs,loads,and BESSs,while also quantifying the impact of this relationship on the boundaries of the feasible region.展开更多
As part of a broad strategy to reach net-zero greenhouse gas emissions and limit global warming,many countries are requiring all new buildings to have net-zero energy use.This requires that on-site energy use not exce...As part of a broad strategy to reach net-zero greenhouse gas emissions and limit global warming,many countries are requiring all new buildings to have net-zero energy use.This requires that on-site energy use not exceed on-site generation of renewable energy(taken here to be solar energy),or equivalently,that the building Energy Use Intensity(EUI,kWh/m^(2)a)not exceed the supply of on-site solar energy(electricity and heat)per m^(2)of floor area per year.On this basis,we find that achieving net-zero energy performance in an archetype 40-story square building in 16 different cities of North America requires EUI of 17–24 kWh/m^(2)a using PV panels,and 19–28 kWh/m^(2)a using PVT collectors.Changing building orientation to a non-square floor shape can improve maximum permitted EUI by up to 50%in PV and 60%in PVT case.Conversely,the best-performing residential and commercial buildings have EUIs of 50–75 kWh/m^(2)a.Only if building heights are limited to 5–10 floors does the available solar energy,and thus the permitted EUI,reach 50–75 kWh/m^(2)a.Therefore,we recommend that policymakers not require high-rise buildings to be net-zero energy,unless they are prepared to limit building heights to 5–10 floors.展开更多
The morphology of urban areas plays a crucial role in determining solar potential,which directly affects photovoltaic capacity and the achievement of net-zero outcomes.This study focuses on the City of Melbourne to in...The morphology of urban areas plays a crucial role in determining solar potential,which directly affects photovoltaic capacity and the achievement of net-zero outcomes.This study focuses on the City of Melbourne to investigate the utilization of solar energy across different urban densities and proposes optimized morphologies.The analysis encompasses blocks with diverse population densities,examining medium and high-density areas.By utilizing a multi-objective genetic optimization approach,the urban morphology of these blocks is refined.The findings indicate that low-density blocks exhibit photovoltaic potential ranging from 1 to 6.6 times their total energy consumption.Medium and high-density blocks achieve photovoltaic potential levels approximately equivalent to 40%-85%of their overall energy consumption.Moreover,significant variations in photovoltaic potential are observed among different urban forms within medium and high-density blocks.An“elevated corners with central valley”prototype is proposed as an effective approach,enhancing the overall photovoltaic potential by approximately 14%.This study introduces novel analytical concepts,shedding light on the intricate relationship between urban morphologies and photovoltaic potential.展开更多
Battery energy storage systems(BESSs)serve a crucial role in balancing energy fluctuations and reducing carbon emissions in net-zero power systems.However,the efficiency and cost performance have remained significant ...Battery energy storage systems(BESSs)serve a crucial role in balancing energy fluctuations and reducing carbon emissions in net-zero power systems.However,the efficiency and cost performance have remained significant challenges,which hinders the widespread adoption and development of BESSs.To address these challenges,this paper proposes a real-time energy management scheme that considers the involvement of prosumers to support net-zero power systems.The scheme is based on two shared energy storage models,referred to as energy storage sale model and power line lease model.The energy storage sale model balances real-time power deviations by energy interaction with the goal of minimizing system costs while generating revenue for shared energy storage providers(ESPs).Additionally,power line lease model supports peer-to-peer(P2P)power trading among prosumers through the power lines laid by ESPs to connect each prosumer.This model allows ESP to earn profits from the use of power lines while balancing power deviations and better consuming renewable energy.Experimental results validate the effectiveness of the proposed scheme,ensuring stable power supply for net-zero power systems and providing benefits for both the ESP and prosumers.展开更多
Carbon Capture,Utilization,and Storage(CCUS)is a crucial technology for achieving carbon neutrality,but it faces significant challenges.Despite substantial investments and policy support,CCUS projects have underperfor...Carbon Capture,Utilization,and Storage(CCUS)is a crucial technology for achieving carbon neutrality,but it faces significant challenges.Despite substantial investments and policy support,CCUS projects have underperformed due to technical difficulties,high costs,and controversies surrounding the fossil fuel industry's involvement.The effectiveness and feasibility of CCUS in reducing carbon emissions remain uncertain.This viewpoint provides a comprehensive analysis of the current state of CCUS technology,examining its potential to reduce carbon emissions,the challenges hindering its deployment,and the strategies needed to overcome these barriers.We discuss the need for a combinatorial approach to unlock CCUS's full potential,and also emphasize the importance of selecting optimal CO_(2)utilization pathways to maximize economic benefits and CO_(2)absorption.Although CCUS faces technical,economic,and social barriers,it can still play a valuable role in mitigating emissions from hard-to-abate sectors when supported by comprehensive strategies and collaborative efforts among governments,industries,and research institutions.By addressing these challenges and investing in innovation,CCUS can contribute to achieving carbon neutrality and building a sustainable,low-carbon future.展开更多
基金supported by the Science and Technology Development Fund,Macao SAR,China(Nos.0033/2022/AFJ and 0011/2023/AMJ)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515012017).
文摘With the rapid development of aviation industry and its increasing impact on the global climate change,the contributions of carbon emissions frominternational flights are attracting more and more attention worldwide.This study,taking Macao as the aviation hub,established the cross-border aviation carbon emission evaluation model to explore dynamic carbon emissions and net-zero path of international flights.The aviation hubmainly covers 58 routes and five types of civil aircraft from 12 countries or regions during 2000-2022.The results show that the aviation transportation in Macao emitted about 1.44 million tons CO_(2)eq in 2019,which is high 3.6 times that of 2000.The COVID-19 has led to a rapid decline in aviation carbon emissions in a short period of time,carbon emissions in 2020 decreased by 80%compared to 2019.In terms of cumulative carbon emissions from 2000 to 2019,the A321 and A320 Airbus contribute to 80%of carbon emissions.And the Chinese mainland(37%)and Taiwan(29%)are the main sources of emissions.In 2000-2019,the proportion of carbon emissions from China(including Taiwan and Hong Kong)decrease from 91%to 53%,while the contribution from Southeast Asia(from 5% to 26%),Japan and South Korea(from 2% to 19%)keep the growth trends.In the optimal scenario(B3C3),net zero emissions of cross-border aviation in Macao can be not achieved,and there is still only by removing 0.3 million tons CO_(2)eq.Emission reduction technology and new energy usage are priorities for the aviation emission reduction.
文摘Net-zero energy buildings and communities, which are receiving increasing interest, and the role of energy storage in them, are described. A net-zero energy building or community is defined as one that, in an average year, produces as much energy from renewable energy as it consumes. Net-zero energy buildings and communities and the manner in which energy sustainability is facilitated by them are described and examples are given. Also, energy storage is discussed and the role and importance of energy storage as part of net-zero buildings and communities are explained. The NSERC Smart Net-zero Energy Buildings Research Network, a major Canadian research effort in smart net-zero energy buildings and communities, is described.
基金supported by the Distinguish Young Scholars of the National Natural Science Foundation of China(Grant No.52225601)the Major Program of the National Natural Science Foundation of China(Grant No.52090061).
文摘Methane looping reforming to produce syngas is an alternative to partial methane oxidation because it allows for better control of the oxidation reaction and safely separates oxygen from syngas.However,most systems are monofunctional and lack the cascading utilization of energy flows,resulting in significant exergy loss.This study proposes a novel net-zero emission system that utilizes methane looping reforming for multi-generation of electricity,heating,cooling,and methanol.The reduction of high-valent manganese oxides by decoupling the partial oxidation reaction of methane into an Mn-based oxygen carrier redox cycle yielded products with H_(2)/CO ratios suitable for methanol synthesis,resulting in approximately 100%CH_(3)OH conversion rate.The oxidation of low-valent manganese oxides provides high-temperature heat for heat recovery,and the lithium bromide refrigeration section produces domestic hot and cold water as by-products.The proposed system reaches 77.1%and 65.7%energy and exergy efficiencies,which are 1.04-and 1.61-fold higher than those of traditional partial oxidation systems,respectively.Our research presents a new system integration concept that enables the efficient and controllable loop reforming of methane for methanol production.
基金supported by the National Key Research and Development Program of China (Grant No. 2022YFB3904801)the National Natural Science Foundation of China (Grant No. 42475129)+2 种基金the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20221449)the Xizang Science and Technology Innovation Base Construction Project (Grant No. XZ202401YD0008)the National Key Scientific and Technological Infrastructure project “Earth System Numerical Simulation Facility” (Grant No. 2023-EL-ZD-00022)。
文摘Elevated atmospheric carbon dioxide(CO_(2)) concentrations have caused global climate change such as global warming and more frequent climate extremes. Countries worldwide have proposed carbon neutrality strategies to curb the rising CO_(2) concentrations. To investigate the impact of China's carbon neutrality goal on atmospheric CO_(2) concentrations, we conducted a series of ideal simulations from 2015 to 2019 using a global 3D chemistry transport model, Goddard Earth Observing System Chemistry(GEOS-Chem). Compared with the column-averaged dry-air mole fraction of atmospheric CO_(2) (XCO_(2) ) from Orbiting Carbon Observatory-2(OCO-2) and surface CO_(2) measurements in Obs Pack, we find that GEOS-Chem effectively reproduces the spatiotemporal variability of CO_(2) . The model exhibits a root mean square error(RMSE) of 1.51 ppm(R^(2)=0.89) for OCO-2 XCO_(2) in China and 2.65 ppm(R^(2)=0.75) for surface CO_(2) concentrations at the WLG station. Further, compared to 2.83 ppm yr^(-1)in the control experiment, we suggest that net-zero CO_(2) emissions in China decelerate the increasing trends of XCO_(2) to 1.81 ppm yr^(-1),making a decrease of approximately 35.89%. Meanwhile, the seasonal cycle amplitude(SCA) of XCO_(2) is moderately reduced from 7.39±0.81 to 6.75±0.70 ppm, representing a relative reduction of 9.91%. Spatially, net-zero CO_(2) emissions induce a more significant decrease in XCO_(2) trends over northern and southern China, while their impact on SCA is more evident in northern and northeastern China. Moreover, ideal experiments demonstrate that zero fossil CO_(2) emissions lead to a greater attenuation of the linear trends of XCO_(2) by 40.81%, while the absence of terrestrial CO_(2) sinks largely diminishes the SCA by 16.61%. Additionally,trends and SCA in surface CO_(2) concentrations exhibit almost identical decreasing responses to net-zero CO_(2) emissions but display greater sensitivities compared to XCO_(2) . Overall, our study underscores the potential of China's carbon neutrality goal in mitigating global warming, underscoring the need for concerted and collaborative efforts from nations worldwide.
基金supported by the Natural Science Foundation of Tianjin(No.22JCZDJC00820)。
文摘To provide guidance for photovoltaic(PV)system integration in net-zero distribution systems(DSs),this paper proposes an analytical method for delineating the feasible region for PV integration capacities(PVICs),where the impact of battery energy storage system(BESS)flexibility is considered.First,we introduce distributionally robust chance constraints on network security and energy/carbon net-zero requirements,which form the upper and lower bounds of the feasible region.Then,the formulation and solution of the feasible region is proposed.The resulting analytical expression is a set of linear inequalities,illustrating that the feasible region is a polyhedron in a high-dimensional space.A procedure is designed to verify and adjust the feasible region,ensuring that it satisfies network loss constraints under alternating current(AC)power flow.Case studies on the 4-bus system,the IEEE 33-bus system,and the IEEE 123-bus system verify the effectiveness of the proposed method.It is demonstrated that the proposed method fully captures the spatio-temporal coupling relationship among PVs,loads,and BESSs,while also quantifying the impact of this relationship on the boundaries of the feasible region.
文摘As part of a broad strategy to reach net-zero greenhouse gas emissions and limit global warming,many countries are requiring all new buildings to have net-zero energy use.This requires that on-site energy use not exceed on-site generation of renewable energy(taken here to be solar energy),or equivalently,that the building Energy Use Intensity(EUI,kWh/m^(2)a)not exceed the supply of on-site solar energy(electricity and heat)per m^(2)of floor area per year.On this basis,we find that achieving net-zero energy performance in an archetype 40-story square building in 16 different cities of North America requires EUI of 17–24 kWh/m^(2)a using PV panels,and 19–28 kWh/m^(2)a using PVT collectors.Changing building orientation to a non-square floor shape can improve maximum permitted EUI by up to 50%in PV and 60%in PVT case.Conversely,the best-performing residential and commercial buildings have EUIs of 50–75 kWh/m^(2)a.Only if building heights are limited to 5–10 floors does the available solar energy,and thus the permitted EUI,reach 50–75 kWh/m^(2)a.Therefore,we recommend that policymakers not require high-rise buildings to be net-zero energy,unless they are prepared to limit building heights to 5–10 floors.
文摘The morphology of urban areas plays a crucial role in determining solar potential,which directly affects photovoltaic capacity and the achievement of net-zero outcomes.This study focuses on the City of Melbourne to investigate the utilization of solar energy across different urban densities and proposes optimized morphologies.The analysis encompasses blocks with diverse population densities,examining medium and high-density areas.By utilizing a multi-objective genetic optimization approach,the urban morphology of these blocks is refined.The findings indicate that low-density blocks exhibit photovoltaic potential ranging from 1 to 6.6 times their total energy consumption.Medium and high-density blocks achieve photovoltaic potential levels approximately equivalent to 40%-85%of their overall energy consumption.Moreover,significant variations in photovoltaic potential are observed among different urban forms within medium and high-density blocks.An“elevated corners with central valley”prototype is proposed as an effective approach,enhancing the overall photovoltaic potential by approximately 14%.This study introduces novel analytical concepts,shedding light on the intricate relationship between urban morphologies and photovoltaic potential.
基金supported in part by the National Key Research and Development Program of China(No.2018YFA0702200)the National Natural Science Foundation of China(No.52377079)the Liaoning Revitalization Talents Program(No.XLYC2007181)。
文摘Battery energy storage systems(BESSs)serve a crucial role in balancing energy fluctuations and reducing carbon emissions in net-zero power systems.However,the efficiency and cost performance have remained significant challenges,which hinders the widespread adoption and development of BESSs.To address these challenges,this paper proposes a real-time energy management scheme that considers the involvement of prosumers to support net-zero power systems.The scheme is based on two shared energy storage models,referred to as energy storage sale model and power line lease model.The energy storage sale model balances real-time power deviations by energy interaction with the goal of minimizing system costs while generating revenue for shared energy storage providers(ESPs).Additionally,power line lease model supports peer-to-peer(P2P)power trading among prosumers through the power lines laid by ESPs to connect each prosumer.This model allows ESP to earn profits from the use of power lines while balancing power deviations and better consuming renewable energy.Experimental results validate the effectiveness of the proposed scheme,ensuring stable power supply for net-zero power systems and providing benefits for both the ESP and prosumers.
基金funding from the National Natural Science Foundation of China(62074123)Key Research and Development Plan of Shaanxi Province(No.2024GXZDCYL-01-06)China National Petroleum Corporation(CNPC)Basic Research and Strategic Reserve Technology Research Fund Project(No.2023DQ03-26).
文摘Carbon Capture,Utilization,and Storage(CCUS)is a crucial technology for achieving carbon neutrality,but it faces significant challenges.Despite substantial investments and policy support,CCUS projects have underperformed due to technical difficulties,high costs,and controversies surrounding the fossil fuel industry's involvement.The effectiveness and feasibility of CCUS in reducing carbon emissions remain uncertain.This viewpoint provides a comprehensive analysis of the current state of CCUS technology,examining its potential to reduce carbon emissions,the challenges hindering its deployment,and the strategies needed to overcome these barriers.We discuss the need for a combinatorial approach to unlock CCUS's full potential,and also emphasize the importance of selecting optimal CO_(2)utilization pathways to maximize economic benefits and CO_(2)absorption.Although CCUS faces technical,economic,and social barriers,it can still play a valuable role in mitigating emissions from hard-to-abate sectors when supported by comprehensive strategies and collaborative efforts among governments,industries,and research institutions.By addressing these challenges and investing in innovation,CCUS can contribute to achieving carbon neutrality and building a sustainable,low-carbon future.
