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To ensure the reliability of oil-immersed power transformers in long-term operation, the influence of aging on various characteristics of their insulating elements must be clarified. The present paper reviewed the degradation status of insulating oil and paper of field-aged transformers, covering investigative results ranging from about 30 years ago to a relatively recent period. The field transformers treated were diverse in terms of their manufacturing year, manufacturer, structure, and voltage class. Despite the examination results of such wide-ranging transformers, there were similar changes in various characteristics due to the aging of insulating oil and paper. For example, as for the insulating oil, due to the aging for about 30 years, the characteristics of the total acid value and volume resistivity had degraded, whereas the breakdown voltage decreased only slightly. Regarding the insulating paper, mechanical characteristics such as the average polymerization degree (DP) were subject to age-related decline, whereas the breakdown voltage did not significantly decrease as with insulating oil. Therefore, based on use of about 30 years, since the life of a transformer is determined by factors such as the degradation of mechanical strength due to thermal stress, insulation degradation is considered less likely to pose a problem at an early stage. Even though it is difficult to directly measure the degree of degradation of insulating paper, this can be indirectly estimated by measuring the CO2 and CO content and furfural content in insulating oil. On the other hand, given the increasing number of transformers remaining in service over 30 years, which had been deemed the expected service life, consideration must be taken to aging degradation of the insulation performance. It emerged that, in order to identify the degree of degradation of these transformers, it was effective to manage the volume resistivity and dielectric loss tangent trends in electrical terms, the interfacial tension trend in physical terms and the total acid value trend in chemical terms. Analysis of the insulating oil components is also considered an effective means of evaluating aging degradation. [ABSTRACT FROM AUTHOR]

Dissolved Gas Analysis (DGA) is a well established method to monitor and predict the condition of devices with oil-cellulose insulation, especially power transformers. However, the effect of the migration of theses gases between the liquid and solid insulation is often ignored. The migration phenomenon is temperature dependent and, if ignored, can potentially lead to erroneous condition assessment by the DGA method. This paper addresses the dynamic nature of propagation of these gases in such systems based on temperature variations. Diffusion times, and therefore diffusivity of the gases, in oil-impregnated cellulose are calculated by identifying the diffusion process as a linear system. The diffusion time-constants, and steady-state condition at the working concentrations, are estimated based on the identified model. A sensitivity study is performed to show the dependency of the diffusion time-constants to the temperature and the oil-cellulose ratio in the system. The equilibrium curves are obtained in the case of carbon dioxide by using solubility information of this gas in the oil and paper pulp, similar to the case of moisture equilibrium. The results are compared with the experimental data. An example of the implication of the obtained data is shown. [ABSTRACT FROM AUTHOR]

Achieving the low-carbon transition of power systems requires the coordination of renewable energy generation and other emerging electricity technologies. Their technical indicators are changing rapidly since these technologies are in the initial stages of development. Determining the technical and policy targets for achieving the low-carbon transition is critical for regulators and power system planners. This paper defines this problem as a backcasting problem, whose concept is derived from environmental science research. We introduce it into the power system planning field and innovatively model it as a bi-level optimization problem. According to the characteristics of the backcasting problem, an improved barrier method is proposed to solve it efficiently. The effectiveness of the proposed model and algorithm are verified through case studies on a modified Garver’s 6-bus system and a realistic Northwest China power system, and they are compared with state-of-the-art solution techniques. The results of the backcasting problem provide a new perspective on the economic impacts of the low-carbon transition and are helpful in energy policy formulation for power systems. [ABSTRACT FROM AUTHOR]

Regarding the continuing increase of anthropogenic carbon emissions in the power system with growing energy consumption, researchers have focused on managing the demand side to achieve low-carbon transition. However, such a low-carbon transition cannot be achieved effectively without the proper incentive scheme. Moreover, it is desired to improve the computation quality of carbon tracing tools and extend their applications by state-of-art techniques. To fulfil these existing research gaps, this paper proposes a low-carbon optimal scheduling model with demand response (DR) based carbon intensity control. It aims to reduce the dependence of customers on energy sources with high carbon intensities while decreasing reasonable energy consumption. Likewise, a data-driven approach conducted with the Bayesian interfere regression is proposed to carry out the carbon emission flow (CEF) model to cope with the drawbacks of the conventional emission calculation. Moreover, the storage emission and relevant dynamic impacts to the system are fully considered. The proposed data-driven approach is tested on a series of IEEE systems with different sizes, its high accuracy and efficiency are proved by the simulation results. Further, simulation results indicate that the proposed scheduling model can effectively achieve carbon emission mitigation. [ABSTRACT FROM AUTHOR]

The rapid development of power-to-gas (P2G) technology is promoting the integration of renewables and the interaction between multiple energy systems. In this paper, the concept of combined P2G and gas-fired power plant (GFPP) system is proposed as a potential solution for the globally recognized imperatives to reduce CO2 emission and utilize renewable energy. The proposed system is featured by the on-site conversion of CO2 back to the fuels of GFPP and thus recycles CO2 without long-distance transport. This paper further establishes the mathematical model of the proposed system. Detailed gas, electricity and heat flow inside the system are explained and the input/output relationship is derived as well. This paper also studies the operational range and optimal scheduling method of the proposed system to quantify its ability on the reduction of CO2 emission and utilization of renewables. According to the estimation, the GFPP-P2G system is able to utilize approximately 30% of the surplus renewables for electricity generation and 20% for heat generation. The combined GFPP-P2G system is also compared with the standalone GFPP through several cases. The numerical study shows great effect of the proposed system on the utilization of renewables and reduction of CO2 emission. [ABSTRACT FROM AUTHOR]

Globally, the efficiency of industrial motors is regulated through minimum energy performance standards (MEPS) to reduce energy consumption and CO2 emission. Induction motor, used as a representative industrial motor, has a limit to efficiency improvement as the result of the additional copper loss of the rotor. To replace the induction motor, design of synchronous reluctance motor (SynRM) and permanent magnet assisted synchronous reluctance motor (PMa-SynRM), and the application of a small amount of permanent magnet, is actively studied in the industry. However, it is necessary to develop an ultrapremium efficiency motor beyond the superpremium efficiency to fulfill MEPS, which will be strengthened in the future. Therefore, this paper presents the optimal design method of SynRM by using the finite element method and response surface method to achieve superpremium efficiency. Furthermore, the redefinition of the loading ratio with shape parameters, and the design method of PMa-SynRM, using the loading ratio, is proposed to meet the ultrapremium efficiency. It is an effective design method that can shorten the time and process when designing ultrapremium efficiency PMa-SynRM from the existing SynRM, which is already mass-produced. [ABSTRACT FROM AUTHOR]

To contribute to a smart grid, the unit commitment and dispatch (UCD) is a very important problem to be revisited in the future microgrid environment. This paper studies the UCD problem by taking account of both traditional thermal units and distributed generation units while considering demand response and carbon emissions trading. First, the UCD problem is reformulated as an optimal switching problem of a hybrid system. The reformulation allows for convenient handling of time-dependent start-up cost by dynamic programming. Then, we propose a closed-loop hierarchical operation (CLHO) algorithm, which produces the optimal schedule with a closed-loop feature. Theoretical analysis shows the equivalence of the reformulation and the effectiveness of the CLHO algorithm. Finally, the closed-loop feature and the effectiveness of the proposed algorithm are further verified by simulations. The simulations also show that low emission allowance and high emissions trading price can reduce the total carbon emissions. [ABSTRACT FROM AUTHOR]

The Vostok ice core provides measurements of the CO2 concentration during the last 414 x 10³ years (yr). Estimations of power spectra show peaks, with the strongest one corresponding to a time period of around 100 x 10³ yr. In this paper, a new reconstruction method from irregular sampling is used, allowing more accurate estimation of spectral peaks. This method intrinsically decomposes the analyzed signal as a sum of sines, providing amplitudes but also phase measurements of periodic tendencies (due to the nature of the studied phenomena). This decomposition can be conducted with noisy and inaccurate measurements of the sampling instants and the concentrations. The widely used Vostok data were chosen as an example, but the method could also be applied to data from other places (e.g., dome C, Antarctica) or to study other phenomena as nitrogen dioxide NO2, methane CH4, oxygen isotope 18O (closely linked to temperature), deuterium ²H, or dust concentrations. [ABSTRACT FROM AUTHOR]

Among gas sensors, the ones measuring carbon dioxide and oxygen are crucial for many application fields: the monitoring of air quality, the control of food packaging processes, the study of biochemical mechanisms, and specific reactions related to many different studies in the biomedical context. Many of the sensors used for the measure of carbon dioxide (CO2) and oxygen (O2) are based on electrochemical, optical, and conductometric working principles, which allow to cover the very different ranges of concentration which represent the target of each different field or specific application with good reproducibility and sensitivity. This paper presents a voltammetric sensor showing an innovative approach for the measure of gas and vapors by the interaction of a screen-printed electrode system with the liquid solution, where the gases are conveyed. The design and realization of this sensor system are reported. Calibration tests with CO2 and O2 have given acceptable reproducibility and sensitivity. Besides, this paper shows that new results have been obtained by analyzing exhaled breath collected by control individuals. [ABSTRACT FROM PUBLISHER]

This paper investigates the dynamic dielectric recovery synergy (DDRS) of hybrid circuit breakers (HCBs) with CO2 gas and vacuum gaps in series. The interaction between the vacuum arc and CO2 gas arc is simulated by the continuous transient arc model and Mayr arc model. The simulation results indicate that the extra methods, for example, dividing capacitors, are needed to obtain optimal DDRS of HCB. The prototype of HCB and the test circuit are established. The influence of the coordination of arcing time, dividing capacitors, and the CO2 gas pressures on the transient recovery voltage (TRV) distribution and the breaking capacity is investigated. The differences of HCBs with SF6 gas and CO2 gas are also compared. According to the results, favorable DDRS in HCB can be obtained in the condition that the vacuum gap endures the initial TRV while the following major TRV distribution is mainly depended on the dynamic dielectric in CO2 gas gap. However, the dynamic dielectric recovery of CO2 gas gap is limited by the structure of rotating arc CO2 gas interrupter in this paper. In the future, the interruption capacity of HCB based on CO2 gas can be improved by synergy control, as the development of CO2 gas circuit breakers. [ABSTRACT FROM PUBLISHER]

This paper investigates the AC insulation properties and explores the influence of electric field inhomogeneity on the breakdown voltage of HFO-1336mzz(E)/CO 2 gas mixture. The electrical field sensitivity of HFO-1336mzz(E)/CO 2 and SF 6 is further compared. It is found that the insulation performance of HFO-1336mzz(E)/CO 2 mixture with 25–30% HFO-1336mzz(E) can reach up to 75-85% of SF 6 under the quasi-uniform electric field and there is a favorable positive synergistic effect between HFO-1336mzz(E) and CO 2. The breakdown voltage of HFO-1336mzz(E)/CO 2 gas mixture demonstrates a “hump” effect with gas pressure under the highly non-uniform electric field and its sensitivity to the electric field inhomogeneity is significantly lower than that of SF 6. The insulation performance of HFO-1336mzz(E)/CO 2 with HFO-1336mzz(E) content higher than 20% reaches 0.99–1.05 times that of SF 6 under highly non-uniform electric field. The AC breakdown voltage of HFO-1336mzz(E)/CO 2 gas mixture and SF 6 decreases first and then increases with the electric field inhomogeneity (f), demonstrating a “U-shaped” like curve and finally tends to be stable. The related results of this paper systematically reveal the AC insulation properties of HFO-1336mzz(E)/CO 2 gas mixture and provide an important reference for its engineering application. [ABSTRACT FROM AUTHOR]

The research on characteristics of C 4 F 7 N and epoxy resin insulation system affected by long-term electro-thermal accelerated aging can provide the reference for the application of C 4 F 7 N/CO 2 gas mixtures. In this paper, a long-term electro-thermal accelerated aging experimental platform of gas-solid insulation system is established, and more than 3000 hours of experiments are carried out. The results show that there is not a significant change in leakage current in the system, at the same time, none of the gas decomposition products are detected in the C 4 F 7 N/CO 2 gas mixtures during the aging experiment. With the increase of aging experiment time, the number of tiny holes on the epoxy resin surface increases significantly. The surface of the epoxy resin sample near the high voltage electrode is most obviously damaged. The surface of epoxy resin shows slightly fluorinated, and the color of it has changed from white to yellow on account of the adsorption of C 4 F 7 N gas by the holes on the sample surface. Flashover voltage of epoxy resin is basically consistent before and after aging by the power frequency or negative lightning impulse applied. It proves that the gas-solid insulation system of C 4 F 7 N and epoxy resin can keep the insulation performance basically consistent, affected by longterm electro-thermal accelerated aging. [ABSTRACT FROM AUTHOR]

The emergence of microsources holds promise to reduce the carbon emissions and exploit more renewables in order to meet the worldwide growing electrical energy demands. However, there exist several challenges, such as optimizing the tradeoff between the use of renewable and nonrenewable energy sources, to leverage affordable electric power while minimizing carbon emissions. Game theoretic approaches have been widely used in various scientific domains and have recently also increasingly been used in smart grids, whereby evolutionary paradigms have been widely deployed as a popular heuristic search method to solve and optimize complex real-life scientific problems. A promising approach is the development of such evolutionary algorithms and game theoretic approaches in the context of open energy markets. In this paper, we develop an analytic model of a multileader and multifollower Stackelberg game approach and propose a bi-level hybrid multiobjective evolutionary algorithm to find optimal strategies that maximize the profit of utilities, and minimize carbon emissions in an open energy market among interconnected microsources. [ABSTRACT FROM PUBLISHER]

In this paper, we report the vertical profiles of CO2 and CH4 measured with a cavity ring-down spectrometer (CRDS) on a research aircraft from near-ground level to 8 km above mean sea level. The airborne platform employed in this paper is an Alpha Jet aircraft operated from NASA's Ames Research Center. Flights were undertaken to Railroad Valley, NV, USA, to coincide with overpasses of the Greenhouse Gases Observing Satellite (GOSAT). Ground-based CO2 and CH4 were simultaneously measured using CRDS, at the time and location of the airborne and satellite measurements. Results of three GOSAT coordinated aircraft profiles and ground-based measurements in June 2011 are presented and discussed in this paper. The accuracy of the CO2 and CH4 measurements has been determined based upon laboratory calibrations (World Meteorological Organisation traceable standard) and pressure/temperature flight simulations in a test chamber. The overall uncertainty for the airborne measurements ranged from 0.31 to 0.39 ppm for CO2 and from 3.5 to 5.6 ppb for CH4. Our column-averaged CO2 and CH4 measurements, which include about 61% of the total atmospheric mass, are extrapolated, using different techniques, to include the remainder of the tropospheric and stratospheric CO2 and CH4. The CO2 data are then analyzed using the Atmospheric CO2 Observations from Space 2.9 and 3.3 algorithms. For methane data, the RemoTeC v2.1 algorithm was used in its full physics setup. Column-averaged CO2 and XCO2, measured by GOSAT and analyzed from our data, ranged from 388.1 to 396.4 ppm, and XCH4 ranged from 1.743 to 1.822 ppm. The agreement of the satellite and aircraft CO2 mixing ratios, as well as ground measurements, falls within the uncertainties of the methods employed to acquire these numbers. [ABSTRACT FROM PUBLISHER]

With the growing awareness of global warming, many companies worldwide are improving their supply chain sustainability, under pressure from the government or their own shareholders. However, not all countries around the world equally emphasize the threat. For example, some countries still have not implemented any carbon dioxide emission regulations to address this problem. Carbon regulations in only subglobal areas may result in even higher global emissions because of carbon leakage. One possible approach to cope with the carbon leakage problem is to impose carbon tariffs on the goods from unregulated countries. In this paper, a mathematical model is built to explore the impacts of carbon tariff imposition on the supply chain network design, where the carbon tariff is imposed when the goods flow from unregulated countries to regulated countries. Moreover, our paper provides a complete experimental study by applying this model in a real case study, Company G, a major Taiwan-based multinational company in the electronic products industry. The outcomes demonstrate the conditions where the introduction of carbon tariffs forces firms from unregulated countries to take actions to reduce carbon emissions. [ABSTRACT FROM PUBLISHER]

Coordinating multiple energy systems (MES) enables the synergies of different energy sectors to be exploited. The concept of low-carbon development changes planning approaches for both the district level and the multi-regional level of MES. This paper proposes a bi-level expansion planning model of MES that considers the emission constraints under a decentralized approach. The upper-level model investigates the optimal planning scheme for integrated power and natural gas networks in the multi-regional MES. The lower-level model examines the optimal energy supply configuration of multiple energy carriers in the district MES based on the energy hub modeling approach. The carbon emission flow model is used to allocate the overall carbon emission cap among district MES from the consumption-based perspective and to coordinate the planning of the district level and the multi-regional level. An illustrative example based on a 6-node MES verifies the effectiveness of the proposed model. Finally, a realistic case study based on an MES in northern China is implemented to show the effects of carbon emission constraints on the planning of real-world energy systems. [ABSTRACT FROM AUTHOR]

Multiple energy systems (MESs) bring different types of energy together and are able to improve energy utilization efficiency and promote the integration of renewable energy. The embedded carbon emission in MES is coupled among the energy flow across different energy systems. The understanding of how the embedded carbon emission should be allocated along with the energy delivery and conversion is significant in the policy making and market design to facilitate carbon emission reduction. A novel analytical model for carbon emission flow (CEF) in MES is proposed in this paper to quantify the carbon emission associated with the energy delivery and conversion process. First, key indicators and basic principles of CEF are defined. Then, the explicit CEF models for different energy networks, including the power network, gas network and heating network, are established. On the basis of the CEF models of energy converters, the CEF model for an energy hub is further formulated to analyze the flow of carbon emission across different energy systems during the conversion process. Finally, the procedure of CEF calculation in MES is provided. The case study results based on two systems are presented to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Regarding carbon emission as a principal cause of global warming, governments begin to take note of the urgency of emission reduction and propose feasible carbon regulations. Consumers also become more caring about the carbon emission factor when purchasing product. In response, the firms have exerted considerable efforts to reduce their emissions. In this paper, we investigate a supply chain facing carbon-sensitive demand market. Two major carbon regulations, absolute-cap (AC) and intensity-cap (IC), are considered. We explore the optimization problems for the centralized and decentralized models, and derive the optimal solutions for the production quantity as well as the emission reduction effort. We find that under regulation IC, a higher emission cap will lower the carbon emission of unit product but raise the total production quantity, while the emission cap is irrelevant to these operational decisions under regulation AC. In addition, the production quantity and the emission reduction effort under regulation AC are lower than those under regulation IC. We further show double marginalization within this supply chain manifests as not only a lower production quantity but also a higher unit carbon emission. Finally, numerical experiments are conducted to obtain more insights. [ABSTRACT FROM AUTHOR]

This paper is focused on carbon coating of anatase type TiO2 by underwater discharge with a capillary in water carbon electrode. The discharge electrode consists of a graphite electrode covered by an alumina tube for insulation and a ground electrode. The aqueous solution used for discharging is tap water with an electric conductivity of about $120~\mu \text{S}$ /cm. The applied power for TiO2 carbon coating is about 500 W. As a result of TEM and energy dispersive spectrum measurements, a carbon layer with thickness of several nanometers was measured on the surface of TiO2. Raman analysis also confirmed that the layer is either graphite or glassy carbon. [ABSTRACT FROM AUTHOR]

This paper presents a density functional theory-based first principle study to investigate the atomic-scale interactions of formaldehyde (H2CO) molecules with different oxygen containing functional groups of graphene oxide to identify which particular functional group possesses better adsorption capability toward H2CO molecule. The detailed study on formaldehyde adsorption has been conducted in terms of changes in structural, energetic, electronic, and transport properties of graphene oxides modeled with sp3 hybridized hydroxyl (-OH) and epoxy (C-O-C) groups on the carbon basal plane. Our computational results suggest that the graphene oxidized with only -OH group shows the highest affinity toward formaldehyde as compared with epoxy oxidized graphene and graphene oxide containing both the functional groups. The influence of vacancy defect on improving the sensing response of graphene oxide has also been studied. The results of current–voltage (${I}$ – ${V}$) characteristics reveal that graphene oxidized with only hydroxyl group can achieve an improvement in sensitivity by almost two times and five times as compared with graphene oxide containing both the functional groups and the pristine graphene sheet, respectively. Moreover, the selectivity test for some common indoor air pollutants was also carried out and the test results suggest that H2CO molecule is highly selective toward the -OH group of graphene oxide as compared with the epoxy group. [ABSTRACT FROM AUTHOR]

The acceleration of distributed energy resources and carbon pricing policies have compelled utilities to act and to prioritize carbon-constrained infrastructure augmentation in their capital programs. To implement various carbon emission reduction policies, power system transmission planning has become more challenging. The existing energy system will face massive retirement of coal-fired power plants (CFPPs), large scale integration of renewable energy and network expansion. In this paper, an electricity network planning and transformation roadmap, which has two milestones, is put forward. In the first stage, a mathematical model is proposed based on the average cost of carbon emission reduction to realize the cooperation of CFPPs retirement and renewable energy investment. It can help the network carry out the transition from a fossil-fuel dominated system to a low-carbon oriented system. Because of the promising prospect of power-to-gas (P2G) technology, in the second milestone, a method based on carbon emission flow (CEF) is employed to help the power-to-gas stations (P2GSes) to select the construction site and capacity. The gas network constraints are modeled to guarantee that P2GSes can work smoothly without energy flow congestion in both electricity and gas networks. According to the simulation results in case studies, our method can reach the emission reduction target more economically and effectively, and the P2GSes can produce and absorb clean energy. [ABSTRACT FROM AUTHOR]

This paper presents a new method for quantifying the carbon storage in urban trees using multispectral airborne laser scanning (ALS) data. This method takes the full advantage of multispectral ALS range and intensity data and shows the feasibility of quantifies the carbon storage in urban trees. Our method consists of four steps: multispectral ALS data processing, vegetation isolation, dendrometric parameters estimation, and carbon storage modeling. Our results suggest that ALS-based dendrometric parameter estimation and allometric models can yield consistent performance and accurate estimation. Citywide carbon storage estimation is derived in this paper for the Town of Whitchurch–Stouffville, Ontario, Canada, by extrapolating the values within the study area to the entire city based on the specific proportion of each land cover type. The proposed method reveals the potential of multispectral ALS data in land cover mapping and carbon storage estimation at individual-tree level. [ABSTRACT FROM AUTHOR]

Due to the development of the green economy, green manufacturing has been a hot topic. This paper proposes a new problem, i.e., the resource constrained unrelated parallel machine green manufacturing scheduling problem (RCUPMGSP) with the criteria of minimizing the makespan and the total carbon emission. To solve the problem, a collaborative multiobjective fruit fly optimization algorithm (CMFOA) is proposed. First, a job-speed pair-based solution representation is presented, and an effective decoding method is designed. Second, a heuristic for initialization of the population is proposed. Third, three collaborative search operators are designed to handle three subproblems in the smell-based search phase, i.e., job-to-machine assignment, job sequence, and processing speed selection. The technique for order preference by similarity to an ideal solution and the fast nondominated sorting methods are both employed for multiobjective evaluation in the vision-based search phase. Moreover, a critical-path-based carbon saving technique is designed according to the problem analysis to further improve the nondominated solutions explored in the fruit fly optimization algorithm-based evolution. In addition, the effect of parameter setting is investigated and the suitable parameter values are recommended. Finally, numerical tests and comparisons are carried out using the randomly generated instances, which show that the CMFOA is able to obtain more and better nondominated solutions than other algorithms. The comparisons also demonstrate the effectiveness of the collaborative scheme and the carbon saving technique as well as the CMFOA in solving the RCUPMGSP. [ABSTRACT FROM AUTHOR]

This paper represents the prediction of the thermal interruption characteristics of a 72.5-kV CO2 circuit breaker (CB). An analysis method to simulate CO2 arc plasma was developed. The principle phenomena of CO2 arc plasma—nonideal gas behavior, radiative heat transfer (RHT), and nozzle ablation—were considered. In addition, the electric field analysis to compute ohmic heating in the arc region and the analysis of turbulent flows were conducted. The absorption coefficients used in RHT were simplified into mean values of 10 frequency bands to represent the entire absorption spectrum. The proposed method was verified through experimental tests of pressure rise and arc voltage. To predict the thermal interruption characteristics, post arc current (PAC) was computed. PAC is the minute current existing between the contacts of a CB after current zero, and has important value to comprehensively understanding thermal interruption. For comparison, a 72.5-kV CO2 CB was manufactured and tested, and the results were compared with the results of the thermal interruption tests. [ABSTRACT FROM AUTHOR]

The increasing penetration of electric vehicles (EVs) results in growing interdependency between power and transportation networks. This paper proposes a hybrid economic-emission dispatch model to coordinate the operation of both networks toward social optima. Specifically, carbon emission from gasoline vehicles (GVs) is quantified by the macroscopic emission model, while the emission from EVs is indirectly characterized by that emitted from fossil power plants. To enhance regulation efficiency and improve social welfare, a differentiated pricing scheme is proposed to independently regulate GV traffic flow, EV traffic flow, and EV charging flow. Logarithmic transformation, combined with an accuracy-aware adaptive piecewise linearization (AAPWL) approximation method, is developed to reformulate the original nonlinear model into a tractable mixed-integer quadratic constrained programming. Numerical results from two test systems demonstrate the relationship between economic dispatch and emission dispatch. Meanwhile, the effectiveness and superiority of the proposed pricing scheme and the AAPWL method are validated. [ABSTRACT FROM AUTHOR]

Carbon Capture and Storage (CCS), seen as a necessary technology to mitigate global greenhouse gas emissions, requires traceable fiscal metering technologies for large-scale deployment. The present work assesses ultrasonic measurement principles for CO2. Static tests with pure CO2 at pressure and temperature conditions relevant for CCS transport via ships and pipelines were undertaken; and the performance of the ultrasonic signals assessed. The effect that the CO2 attenuation has on the signal quality is evaluated over various densities. The speed of sound measurements are presented and compared to theoretical figures. The results demonstrate that acoustic coupling efficiency of the ultrasonic wave from the transducer into the liquid is strong at high densities, but it deteriorates at transport conditions above 293 K. Consequently, measurement perspectives for shipping and pipeline conditions below 280 K show superior performance for the ultrasonic system under test. This paper also explores the limitations of ultrasonic technology for speed of sound and inter-channel variations. [ABSTRACT FROM AUTHOR]

The COVID-19 has slowed down global economic growth. Meanwhile, it also significantly cuts the global carbon emission, which provides a golden opportunity for the whole world to combat the climate change together. While the former policies (e.g., the CAFE standards, renewable portfolio standards, etc.) have reduced certain level of fossil fuel consumption, the most effective measures (such as carbon tax, cap-and-trade programs) are still far from ready for global implementation. This paper investigates an alternative way to achieve a more carbon efficient power grid using the uplift payment scheme. Specifically, we propose an effective algorithm to guarantee carbon efficiency with minimal uplift payments. We also submit that this scheme provides more flexibility to realize carbon reduction than carbon tax, which is exemplified by thorough numerical studies. Furthermore, we show that the stability of the power grid can be ensured under our uplift payment scheme, both from theoretical analysis and numerical studies. The results strengthen our belief that our uplift payment scheme is practicable for carbon reduction in the electricity market. [ABSTRACT FROM AUTHOR]

Most existing carbon emission management strategies only control the total carbon emission without focusing on both the regional carbon emission and the stochastic properties of the system. Correlated regional loads and unpredictable renewable energies in the power system make regional carbon emission management (RCEM) increasingly challenging and necessary. A complex multi-objective RCEM model based on probabilistic power flow (PPF) considering correlated variables is contributed in this paper. The three objective functions to be minimized are 1) the cost of electricity generated, 2) the total carbon emission, and 3) the carbon emission difference among regions which reflects the regional carbon emission imbalance from the supply side. A new clonal selection algorithm (CSA) coupled with a fuzzy satisfying decision method and an extended 2 m +1 point estimate method (PEM) is proposed to solve this multi-objective RCEM model. The proposed method is illustrated through IEEE 30-bus, IEEE 118-bus and simplified Shanghai case studies. The proposed model can help reduce the total carbon emission, control regional carbon emission, prevent probabilistic congested lines from overloading, and choose the most suitable region for wind farms (WFs). [ABSTRACT FROM PUBLISHER]