Coordinated restoration optimization of power-gas integrated energy system with mobile emergency sources

In an integrated energy system(IES) composed of multiple subsystems, energy coupling causes an energy supply blockage or shutdown in one subsystem, thereby affecting the energy flow distribution optimization of other subsystems.The energy supply should be globally optimized during the IES energy supply restoration process to produce the highest restoration net income. Mobile emergency sources can be quickly and flexibly connected to supply energy after an energy outage to ensure a reliable supply to the system, which adds complexity to the decision. This study focuses on a powergas IES with mobile emergency sources and analyzes the coupling relationship between the gas distribution system and the power distribution system in terms of sources, networks, and loads, and the influence of mobile emergency source transportation. The influence of the transient process caused by the restoration operation of the gas distribution system on the power distribution system is also discussed. An optimization model for power-gas IES restoration was established with the objective of maximizing the net income. The coordinated restoration optimization decision-making process was also built to realize the decoupling iteration of the power-gas IES, including system status recognition, mobile emergency source dispatching optimization, gas-to-power gas flow optimization, and parallel intra-partition restoration scheme optimization for both the power and gas distribution systems. A simulation test power-gas IES consisting of an 81-node medium-voltage power distribution network, an 89-node medium-pressure gas distribution network, and four mobile emergency sources was constructed. The simulation analysis verified the efficiency of the proposed coordinated restoration optimization method.

Review on recent progress in on-line monitoring technology for atmospheric pollution source emissions in China

Emissions from mobile sources and stationary sources contribute to atmospheric pollution in China,and its components,which include ultrafine particles(UFPs),volatile organic compounds(VOCs),and other reactive gases,such as NH3and NOx,are the most harmful to human health.China has released various regulations and standards to address pollution from mobile and stationary sources.Thus,it is urgent to develop online monitoring technology for atmospheric pollution source emissions.This study provides an overview of the main progress in mobile and stationary source monitoring technology in China and describes the comprehensive application of some typical instruments in vital areas in recent years.These instruments have been applied to monitor emissions from motor vehicles,ships,airports,the chemical industry,and electric power generation.Not only has the level of atmospheric environment monitoring technology and equipment been improving,but relevant regulations and standards have also been constantly updated.Meanwhile,the developed instruments can provide scientific assistance for the successful implementation of regulations.According to the potential problem areas in atmospheric pollution in China,some research hotspots and future trends of atmospheric online monitoring technology are summarized.Furthermore,more advanced atmospheric online monitoring technology will contribute to a comprehensive understanding of atmospheric pollution and improve environmental monitoring capacity.

Recent advances and perspectives towards emission inventories of mobile sources:Compilation approaches,data acquisition methods,and case studies

In recent years,great efforts have been devoted to reducing emissions from mobile sources with the dramatic growth of motor vehicle and nonroad mobile source populations.Compilation of a mobile source emission inventory is conducive to the analysis of pollution emission characteristics and the formulation of emission reduction policies.This study summarizes the latest compilation approaches and data acquisition methods for mobile source emission inventories.For motor vehicles,a high-resolution emission inventory can be developed based on a bottom-up approach with a refined traffic flow model and real-world speed-coupled emission factors.The top-down approach has advantages when dealing with macroscale vehicle emission estimation without substantial traffic flow infrastructure.For nonroad mobile sources,nonroad machinery,inland river ships,locomotives,and civil aviation aircraft,a top-down approach based on fuel consumption or power is adopted.For ocean-going ships,a bottom-up approach based on automatic identification system(AIS)data is adopted.Three typical cases are studied,including emission reduction potential,a cost-benefit model,and marine shipping emission control.Outlooks and suggestions are given on future research directions for emission inventories for mobile sources:building localized emission models and factor databases,improving the dynamic updating capability of emission inventories,establishing a database of emission factors of unconventional pollutants and greenhouse gas from mobile sources,and establishing an urban high temporalspatial resolution volatile organic compound(VOC)evaporation emission inventory.

Food-delivery behavior under crowd sourcing mobility services

The rapid development of the online food-delivery industry,has led to not only increases in the number of the crowd-sourced shared food-delivery service drivers on our roads,but also growing urban traffic safety management concerns.This study investigates the decision-making behaviors that exist between delivery drivers,their food-delivery platform and their potential impact on traffic safety.Using the evolutionary game theory,stakeholder decision-making behaviors involving traffic safety within the food-delivery industry were analyzed.From our analysis,several behavioral influencers were identified,including penalties for traffic violations,the opportunity cost of delivery drivers complying with traffic rules,the costs associated with risk and strict management approaches,reputation incentives,costs related to the delivery platform being punished,the probability of compliance with traffic rules,and the probability of adopting a strict management approach by the delivery platform.Our study demonstrates that stabilization strategies used by the food service industry differ when the types of government control measures also differ.When the government takes a more aggressive approach to regulation and control,compliance with the traffic rules and the adoption of strict enforcement measures by management are the only evolutionary stability strategies available to food-delivery platforms.As part of a strict management strategy,appropriate compensation or incentive measures should be provided by the distribution platform.Furthermore,the fines given for traffic violations should be increased to create a safer road environment that has fewer traffic accidents involving food-delivery drivers.

Source apportionment of atmospheric particulate carbon in Las Vegas,Nevada,USA

A study was conducted to quantify wintertime contributions of source types to carbonaceous PM2.5 at four urban sites in the Las Vegas Valley, one of the most rapidly growing urban areas in the southwestern United States. Twenty-four hour average ambient samples were collected for mass, ions, elements, organic carbon （OC）, elemental carbon （EC）, and trace organic markers analysis. Additional measurements were made to determine diurnal patterns in light-absorbing black carbon （BC） as a marker for combustion sources. Carbonaceous PM sources of on-road gasoline vehicles, on-road diesel vehicles, and off-road diesel engines were characterized with their chemical profiles, as well as fuel-based emission factors, using an In-Plume Sampling System. The Effective Variance Chemical Mass Balance （EV-CMB） source apportionment model was applied to the ambient samples collected, using source profiles developed in this study as well as profiles from other relevant studies. Four main sources contributed to PM2.5 carbon within the Las Vegas Valley： （1） paved road dust, （2） on-road gasoline vehicles, （3） residential wood combustion, and （4） on-road diesel vehicles. CMB estimated that on-road mixed fleet gasoline vehicles are the largest source for OC and EC at all the sites. The contribution of paved road dust to both OC and EC was 5-10% at the four sites. On-road diesel vehicles contribute 22% of the OC and 34% of the EC at a site near the city center, which is located immediately downwind of a major freeway. Residential wood combustion is a more important source than on-road diesel vehicles for two residential neighborhood sites, These results are consistent with our conceptual model, and the research methodology may be applied to studying other urban areas.

Resilient outage recovery of a distribution system: co-optimizing mobile power sources with network structure

Outage recovery is important for reducing the economic cost and improving the reliability of a distribution system(DS)in extreme weather and with equipment faults.Previous studies have separately considered network reconfigu-ration(NR)and dispatching mobile power sources(MPS)to restore the outage load.However,NR cannot deal with the scenario of an electrical island,while dispatching MPS results in a long power outage.In this paper,a resilient outage recovery method based on co-optimizing MPS and NR is proposed,where the DS and traffic network(TN)are considered simultaneously.In the DS,the switch action cost and power losses are minimized,and the access points of MPSs are changed by carrying out the NR process.In the TN,an MPS dispatching model with the objective of mini-mizing power outage time,routing and power generation cost is developed to optimize the MPSs’schedule.A solu-tion algorithm based on iteration and relaxation methods is proposed to simplify the solving process and obtain the optimal recovery strategy.Finally,numerical case studies on the IEEE 33 and 119-bus systems validate the proposed resilient outage recovery method.It is shown that the access point of MPS can be changed by NR to decrease the power outage time and dispatching cost of MPS.The results also show that the system operation cost can be reduced by considering power losses in the objective function.

Origin of high particle number concentrations reaching the St. Louis, Midwest Supersite

Ultrafine particles are associated with adverse health effects. Total Particle Number Concentration（TNC） of fine particles were measured during 2002 at the St. Louis — Midwest supersite. The time series showed overall low level with frequent large peaks. The time series was analyzed alongside criteria pollutant measurements and meteorological observations. Multiple regression analysis was used to identify further contributing factors and to determine the association of different pollutants with TNC levels. This showed the strong contribution of sulfur dioxide（SO2） and nitrogen oxides（NO x） to high TNC levels. The analysis also suggested that increased dispersion resulting from faster winds and higher mixing heights led to higher TNC levels. Overall, the results show that there were intense particle nucleation events in a SO2 rich plume reaching the site which contributed around 29% of TNC. A further 40% was associated with primary emissions from mobile sources. By separating the remaining TNC by time of day and clear sky conditions,we suggest that most likely 8% of TNC are due to regional nucleation events and 23% are associated with the general urban background.