This paper develops an innovative computational model for assessing the Carbon Emission Factor(CEF)of provincial power systems that incorporates inter-provincial electricity transfers and hybrid generation portfolios ...This paper develops an innovative computational model for assessing the Carbon Emission Factor(CEF)of provincial power systems that incorporates inter-provincial electricity transfers and hybrid generation portfolios combining conventional and renewable sources.A key contribution lies in evaluating how deep regulation of thermal power plants influence the carbon intensity of coal-fired generation and coal-fired generation together with high penetration renewables.Furthermore,the study quantitatively analyzes the role of renewable energy consumption and the prospective application of Carbon Capture and Storage(CCS)in reducing system-wide CEF.Based on this framework,the paper proposes phased carbon emission targets for Guangdong’s power system for key milestone years(2030,2045,2060),along with targeted implementation strategies.Results demonstrate that in renewable-dominant systems,deep regulation of thermal units,load peak-shaving,and deployment of flexible resources such as energy storage are effective in cutting carbon intensity.To achieve the defined targets—0.367 kg/kWh by 2030,0.231 kg/kWh by 2045,and 0.032 kg/kWh by 2060—the following innovation-focused policy is recommended:in early stage,mainly on expansion of renewable capacity and inter-provincial transmission infrastructure along with energy storage deployment;in mid-term,mainly on enhancement of electricity market mechanisms to promote green power trading and demand-side flexibility;and in late-stage,mainly on systematic retirement of conventional coal assets coupled with large-scale CCS adoption and carbon sink mechanisms.展开更多
An integral part of the effort to reduce greenhouse gas emissions is carbon footprint accounting.EPA categorizes facility carbon footprints in three scopes.Scope-2 emissions include electricity,heat or steam purchased...An integral part of the effort to reduce greenhouse gas emissions is carbon footprint accounting.EPA categorizes facility carbon footprints in three scopes.Scope-2 emissions include electricity,heat or steam purchased from a utility provider.This paper evaluates the existing calculation methods for scope-2 CO2 emissions for purchased electricity.The electricity grid in US is complex and is divided spatially into states,eGRID regions,balancing authorities(BAs),and utilities.Up to hourly temporal granularity can be obtained from available datasets.A matrix is developed that categorizes different datasets based on the complexity to calculate the carbon emission factors.Spatial and temporal variations are evaluated.There are significant spatial overlap between regions in different categories and emission factors within a region show sub-regional variation.An area analysis is done using zip-code polygons to determine whether a state or balancing authority is smaller for all the overlapping cases.Temporal variations in emission factors are significant depending on the balancing authority considered.A single method to calculate scope-2 emission factors may not be accurate and efficient in every case and a nuanced assessment of emission factors is warranted.An implementation pathway for a“smart carbon calculator”—one that gives accurate carbon footprint that is the spatially and temporally most granular is suggested.展开更多
Under the“dual carbon”goals,it is imperative to incorporate carbon emissions-related factors into research of power grid risk assessment to meet the green transformation needs of the power grid.Therefore,this paper ...Under the“dual carbon”goals,it is imperative to incorporate carbon emissions-related factors into research of power grid risk assessment to meet the green transformation needs of the power grid.Therefore,this paper conducts a study on the risk assessment of carbon emissions changes in regional power grids based on dynamic carbon emission factors,aiming to quantitatively analyze the impact of random disturbances such as equipment failures or fluctuations in renewable energy generation on the carbon emission intensity of regional power grids.First,carbon emission change risk indicators are constructed from three dimensions:the probability,frequency,and magnitude of carbon emission changes.Second,a dynamic carbon emission factor calculation model is proposed to reflect the spatiotemporal change of carbon emissions in the regional power grid,considering output of different types of generators and the components of inter-area power transmission.Finally,with the premise of ensuring safe and stable operation of power grid,a quantitative assessment model for carbon emission change risks is proposed under the objective of minimizing the electricity loss.The sampling convergence conditions of the model are also derived.The results from the MRTS79 case study demonstrate the proposed method can effectively quantify and analyze the risk of carbon emissions changes in regional power grids,validating the effectiveness of the proposed model.展开更多
Emission factors of particulate matter （PM）, element carbon （EC）, organic carbon （OC）, SO2, NOx, CO, CO2, and ten ions （Na^＋, NH4^＋, K^＋, Mg^2＋, Ca^2＋, Fˉ, Clˉ, NO2ˉ, NO3ˉ, SO42ˉ） were estimated from...Emission factors of particulate matter （PM）, element carbon （EC）, organic carbon （OC）, SO2, NOx, CO, CO2, and ten ions （Na^＋, NH4^＋, K^＋, Mg^2＋, Ca^2＋, Fˉ, Clˉ, NO2ˉ, NO3ˉ, SO42ˉ） were estimated from the domestic burning of four types of commonly produced crop residues in rural China： rice straw, wheat straw, corn stover, and cotton stalk, which were collected from the representative regions across China. A combustion tower was designed to simulate the cooking conditions under which the peasants burned their crop residues in rural China, to measure the emission factors. Results showed that wheat straw had the highest emission factor for the total PM （8.75 g/kg） among the four crop residues, whereas, corn stover and wheat straw have the highest emission factor for EC （0.95 g/kg） and OC （3.46 g/kg）, respectively. Corn stover also presents as having the highest emission factors of NO, NOx, and CO2, whereas, wheat straw, rice straw, and cotton stalk had the highest emission factors of NO2, SO2, and CO, respectively. The water-soluble ions, K^＋ and Clˉ, had the highest emission factors from all the crops. Wheat straw had a relatively higher emission factor of cation species and Fˉ, Clˉ, NO2ˉ than other residues.展开更多
Volatile organic compounds(VOCs)are the important precursors of the tropospheric ozone(O3)and secondary organic aerosols(SOA),both of which are known to harm human health and disrupt the earth’s climate system.In thi...Volatile organic compounds(VOCs)are the important precursors of the tropospheric ozone(O3)and secondary organic aerosols(SOA),both of which are known to harm human health and disrupt the earth’s climate system.In this study,VOC emission factors,O3 and SOA formation potentials were estimated for two types of industrial boilers:coal-fired boilers(n=3)and oil-fired boilers(n=3).Results showed that EVOCs concentrations were more than nine times higher for oil-fire d boilers compared to those for coal-fired boilers.Emission factors ofΣVOCs were found to be higher for oil-fired boilers(9.26-32.83 mg-VOC/kg)than for coal-fired boilers(1.57-4.13 mg-VOC/kg).Alkanes and aromatics were obtained as the most abundant groups in coal-fired boilers,while oxygenated organics and aromatics were the most contributing groups in oil-fired boilers.Benzene,n-hexane and o-ethyl toluene were the abundant VOC species in coal-fired boiler emissions,whereas toluene was the most abundant VOC species emitted from oil-fired boilers.O3 and SOA formation potentials were found 12 and 18 times,respectively,higher for oil-fired than for coal-fired boilers.Total OFP ranged from 3.99 to 11.39 mg-O3/kg for coal-fired boilers.For oil-fired boilers,total OFP ranged from 36.16 to 131.93 mg-O3/kg.Moreover,total secondary organic aerosol potential(SOAP)ranged from 65.4 to 122.5 mg-SOA/kg and 779.9 to 2252.5 mg-SOA/kg for the coal-fired and oil-fired boilers,respectively.展开更多
The dynamometer tests with different driving cycles and the real-world tests are presented. Results indicated the pollutants emission factors and fuel consumption factor with ECE15+EUDC driving cycle usually take the ...The dynamometer tests with different driving cycles and the real-world tests are presented. Results indicated the pollutants emission factors and fuel consumption factor with ECE15+EUDC driving cycle usually take the lowest value and with real world driving cycle occur the highest value, and different driving cycles will lead to significantly different vehicle emission factors with the same vehicle. Relative to the ECE15+EUDC driving cycle, the increasing rate of pollutant emission factors of CO, NOx and HC are -0.42—2.99, -0.32 —0.81 and -0.11—11 with FTP75 testing, 0.11—1.29, -0.77—0.64 and 0.47—10.50 with Beijing 1997 testing and 0.25—1.83, 0.09—0.75 and -0.58—1.50 with real world testing. Compared to the carburetor vehicles, the retrofit and MPI+TWC vehicles' pollution emission factors decrease with different degree. The retrofit vehicle(Santana) will reduce 4.44%—58.44% CO, -4.95%—36.79% NOx, -32.32%—33.89% HC, and -9.39%—14.29% fuel consumption, and especially that the MPI+TWC vehicle will decrease CO by 82.48%—91.76%, NOx by 44.87%—92.79%, HC by 90.00%—93.89% and fuel consumption by 5.44%—10.55%. Vehicles can cause pollution at a very high rate when operated in high power modes; however, they may not often operate in these high power modes. In analyzing vehicle emissions, it describes the fraction of time that vehicles operate in various power modes. In Beijing, vehicles spend 90% of their operation in low power modes or decelerating.展开更多
Copper smelting is a significant source of SO2 emission. It is important to quantify SO2 emissions from combustion sources for regulatory and control purposes in relation to air quality. The characteristics of SO2 emi...Copper smelting is a significant source of SO2 emission. It is important to quantify SO2 emissions from combustion sources for regulatory and control purposes in relation to air quality. The characteristics of SO2 emissions from copper smelting industry in Yurman Province, China, were examined. Analysis based on the present situation, material balance and measuring method were used to confirm SO2 emission factors of copper smelting industry. Results show that SO2 emission factors for Isa system, side blown-continuous converting system （SB-CC）, blast furnace-continuous converting systems （B-CC） and blast furnace-converter blowing （B-C） are 11.69-18.64, 62.44--101.4, 19.43-37.88 and 45.48-81.03 kg/t（blister copper）, respectively. The comprehensive emission factor based on all smelting plants is found to be in the range of 23-39.99 kg-SO2/t（blister copper） for Yunnan Province, China. The results are compared with those for discharge coefficients of industrial pollutants in the First National General Survey of Pollution Sources and the emission factor of the total amount of major pollutants. It is observed that there are some differences among emission factors.展开更多
A database of real-world diesel vehicle emission factors, based on type and technology, has been developed following tests on more than 300 diesel vehicles in China using a portable emission measurement system. The da...A database of real-world diesel vehicle emission factors, based on type and technology, has been developed following tests on more than 300 diesel vehicles in China using a portable emission measurement system. The database provides better understanding of diesel vehicle emissions under actual driving conditions. We found that although new regulations have reduced real-world emission levels of diesel trucks and buses significantly for most pollutants in China, NOx emissions have been inadequately controlled by the current standards, especially for diesel buses, because of bad driving conditions in the real world. We also compared the emission factors in the database with those calculated by emission factor models and used in inventory studies. The emission factors derived from COPERT（Computer Programmer to calculate Emissions from Road Transport） and MOBILE may both underestimate real emission factors, whereas the updated COPERT and PART5（Highway Vehicle Particulate Emission Modeling Software） models may overestimate emission factors in China. Real-world measurement results and emission factors used in recent emission inventory studies are inconsistent,which has led to inaccurate estimates of emissions from diesel trucks and buses over recent years. This suggests that emission factors derived from European or US-based models will not truly represent real-world emissions in China. Therefore, it is useful and necessary to conduct systematic real-world measurements of vehicle emissions in China in order to obtain the optimum inputs for emission inventory models.展开更多
Domestic coal stove is widely used in China, especially for countryside during heating period of winter, and polycyclic aromatic hydrocarbons （PAHs） are important in flue gas of the stove. By using dilution tunnel s...Domestic coal stove is widely used in China, especially for countryside during heating period of winter, and polycyclic aromatic hydrocarbons （PAHs） are important in flue gas of the stove. By using dilution tunnel system, samples of both gaseous and particulate phases from domestic coal combustion were collected and 18 PAH species were analyzed by GC-MS. The average emission factors of total 18 PAH species was 171.73 mg/kg, ranging from 140.75 to 229.11 mg/kg for bituminous coals, while was 93.98 mg/kg, ranging from 58.48 to 129.47 mg/kg for anthracite coals. PAHs in gaseous phases occupied 95% of the total of PAHs emission of coal combustion. In particulate phase, 3-ring and 4- ring PAHs were the main components, accounting for 80% of the total particulate PAHs. The total toxicity potency evaluated by benzo[a]pyrene-equivalent carcinogenic power, sum of 7 carcinogenic PAH components and 2,3,7,8-tetrachlorodibenzodioxin had a similar tendency. And as a result, the toxic potential of bituminous coal was higher than that of anthracite coal. Efficient emission control should be conducted to reduce PAH emissions in order to protect ecosystem and human health.展开更多
The uncertainty in emission estimation is strongly associated with the variation in emission factor （EF）,which could be influenced by a variety of factors such as fuel properties,stove type,fire management and even ...The uncertainty in emission estimation is strongly associated with the variation in emission factor （EF）,which could be influenced by a variety of factors such as fuel properties,stove type,fire management and even methods used in measurements.The impacts of these factors are complicated and often interact with each other.Controlled burning experiments were conducted to investigate the influences of fuel mass load,air supply and burning rate on the emissions and size distributions of carbonaceous particulate matter （PM） from indoor corn straw burning in a cooking stove.The results showed that the EFs of PM （EFPM）,organic carbon （EFOC） and elemental carbon （EFEC） were independent of the fuel mass load.The differences among them under different burning rates or air supply amounts were also found to be insignificant （p 〉 0.05） in the tested circumstances.PM from the indoor corn straw burning was dominated by fine PM with diameter less than 2.1 μm,contributing 86.4%±3.9% of the total.The size distribution of PM was influenced by the burning rate and air supply conditions.On average,EF PM,EF OC and EF EC for corn straw burned in a residential cooking stove were （3.84±1.02）,（0.846±0.895） and （0.391±0.350） g/kg,respectively.EF PM,EF OC and EF EC were found to be positively correlated with each other （p 〈 0.05）,but they were not significantly correlated with the EF of co-emitted CO,suggesting that special attention should be paid to the use of CO as a surrogate for other incomplete combustion pollutants.展开更多
The emission factors of nitrous oxide have been determined during the combustion of rice straws, maize stalks and wheat stalks in an enclosed combustion system. They equal to 84.4 ± 6.08g/t for rice straws,132...The emission factors of nitrous oxide have been determined during the combustion of rice straws, maize stalks and wheat stalks in an enclosed combustion system. They equal to 84.4 ± 6.08g/t for rice straws,132± 8.63g/t for maize stalks,and 27.3 ±1.79g/tfor wheat stalks,respectively. The uncertainties in the determination of nitrous oxide have been discussed. The N_2O-N(nitrogen in nitrous oxide emission)accounts for 0. 59% and 0. 87% of the total nitrogen in rice straws and maize stalks,respectively. An 1￣0 ×1￣0 grid map on the distribution of N_2O emission from biomass burning in China mainland was shown.展开更多
Developing countries as Mexico lack their own emission factors for thermoelectric power plants, so they have the need to develop them, considering specific operation conditions for each plant. This study develops spec...Developing countries as Mexico lack their own emission factors for thermoelectric power plants, so they have the need to develop them, considering specific operation conditions for each plant. This study develops specific emission factors in Mexico for： sulfur dioxide （SO2）, nitrogen oxides （NOx） and particles, for thermoelectric power plants that use fuel oil. This work was necessary due to the differences found between the measured and the calculated emissions, using emission factors of different agencies, such as, US-EPA （Environmental Protection Agency of the United States）, IPCC （Intergovernmental Panel on Climate Change）, and UK-NAEI （National Atmospheric Emissions Inventory of the United Kingdom）. The new emission factors were used to calculate the emissions of a thermoelectric power plant in Mexico. The comparisons between the measured and the calculated emissions （with the new emission factors） for 502, particles and NO2 were not significantly different （p 〉 0.05）.展开更多
Emission factors （EFs） of particulate matter （PM） derived from mono and co-firing of Thai lignite and agricultural residues have been investigated. Two sampling methods for PM, total filtration （TF） and electric...Emission factors （EFs） of particulate matter （PM） derived from mono and co-firing of Thai lignite and agricultural residues have been investigated. Two sampling methods for PM, total filtration （TF） and electrical low-pressure impactor （ELPI）, were used together. The study is focused on the influence of fuel mass fraction, and of secondary air to total air; SA：TA on EFs of PM. The results have shown that EFs of PM in mass-basis given by TF method are 8.9, 5.3 and 8.1 mg/kgfuel, while 3.3, 2.7 and 3.3 mg/kgfuel when using ELPI, for firing at constant SA：TA （30%） of lignite, rice husk and bagasse, respectively. For co-firing with 30%SA of coal/rice husk, higher EFs of PM is observed. They are 7.17 and 10.9 mg/kgfuel （TF） for 40 and 70% rice husk share, respectively, or 4.18 and 5.19 mg/kgfuel （ELPI）. However, lower PM emission; 1-3.3 mg/kgruel （TF） or 0.72-2.83 mg/kgfuel （ELPI） are obtained during co-firing of coal/rice husk with lower degree of air staging （i.e. 0-10% SA：TA）. For the influence of oxygenation state, increasing of SA： TA leads to a low formation of ultrafine particles （Dp 〈 0.1 μm）. Apart from PM, major gases （CO, NO, SO2） will be documented in this paper.展开更多
Activity data and emission factors are critical for estimating greenhouse gas emissions and devising effective climate change mitigation strategies. This study developed the activity data and emission factor in the Fo...Activity data and emission factors are critical for estimating greenhouse gas emissions and devising effective climate change mitigation strategies. This study developed the activity data and emission factor in the Forestry and Other Land Use Change (FOLU) subsector in Malawi. The results indicate that “forestland to cropland,” and “wetland to cropland,” were the major land use changes from the year 2000 to the year 2022. The forestland steadily declined at a rate of 13,591 ha (0.5%) per annum. Similarly, grassland declined at the rate of 1651 ha (0.5%) per annum. On the other hand, cropland, wetland, and settlements steadily increased at the rate of 8228 ha (0.14%);5257 ha (0.17%);and 1941 ha (8.1%) per annum, respectively. Furthermore, the results indicate that the “grassland to forestland” changes were higher than the “forestland to grassland” changes, suggesting that forest regrowth was occurring. On the emission factor, the results interestingly indicate that there was a significant increase in carbon sequestration in the FOLU subsector from the year 2011 to 2022. Carbon sequestration increased annually by 13.66 ± 0.17 tCO<sub>2</sub> e/ha/yr (4.6%), with an uncertainty of 2.44%. Therefore, it can be concluded that there is potential for a Carbon market in Malawi.展开更多
Nitric oxide(NO)emissions from alpine ecosystems conventionally being long-term cultivated with feed crops are not well quantified.The authors attempted to address this knowledge gap by performing a year-round experim...Nitric oxide(NO)emissions from alpine ecosystems conventionally being long-term cultivated with feed crops are not well quantified.The authors attempted to address this knowledge gap by performing a year-round experimental campaign in the northeastern Tibetan Plateau.Fertilized(F)and unfertilized(UF)treatments were established within a flat calcareous-soil site for the long-term cultivation of feed oats.NO fluxes and five soil variables were simultaneously measured.A single plow tillage accounted for approximately 54%–73%of the NO releases during the cropping period(CP);and the non-cropping period(NCP)contributed to 51%–58%of the annual emissions.The direct NO emissions factor(EFd)was 0.021%±0.021%.Significantly lower Q10 values(p<0.01)occurred in the F treatment during the CP(approximately 3.6)compared to those during the other period or in the other treatment(approximately 4.9?5.1),indicating a fertilizer-induced reduction in the temperature sensitivity.The selected soil variables jointly accounted for up to 72%(p<0.01)of the variance for all the fluxes across both treatments.This finding suggests that temporally and/or spatially distributed fluxes from alpine calcareous-soil ecosystems for feed crop production may be easily predicted if data on these soil variables are available.Further studies are needed to test the hypothesis that the EFd is larger in alpine feed-oat fields than those in this study if the soil moisture content is higher during the period following the basal application of ammoniumor urea-based fertilizer.展开更多
With the development of distributed photovoltaic energy in mining areas,the increasing proportion of new energy integration will gradually drive the structural transformation of coal mine parks into industrial active ...With the development of distributed photovoltaic energy in mining areas,the increasing proportion of new energy integration will gradually drive the structural transformation of coal mine parks into industrial active distribution networks.This paper takes a coal mine in Shaanxi Province as an empirical research subject,employing a multi-spatial hierarchical analysis method to systematically analyze the electricity usage characteristics across different spatial levels.It innovatively proposes a power line loss correction method for multi-level electrical equipment,effectively balancing the metering deviations of line losses between levels.Based on two types of carbon emission factors,it achieves precise evaluation of indirect carbon emissions from electricity usage in different levels of equipment or energy units.When calculating indirect carbon emissions from electricity using static carbon emission factors,the measured values show a positive correlation with peak electricity load.As the proportion of renewable photovoltaic power integration in industrial active distribution networks increases,the system’s indirect carbon emission factors exhibit a periodic decreasing trend.After adopting dynamic indirect carbon emission factors for accounting,the indirect carbon emissions from electricity in the first consumption level can be reduced by 31%-55%,while the overall plant-wide indirect carbon emissions decrease by 29068.94 kgCO_(2)/d,a reduction of approximately 40%.For the second consumption level in industrial production areas,indirect carbon emissions from electricity can be reduced by 5%-83%,with overall industrial park-wide indirect carbon emissions decreasing by 7376.48 kgCO_(2)/d,a reduction of about 31%.It is recommended to use advanced equipment and energy-saving technologies to suppress technical line losses in coal mine power supply systems and improve energy efficiency.Promoting the coordinated application of renewable energy and energy storage technologies can expand the scale of stable and reliable renewable energy supply,effectively reducing indirect carbon emissions from electricity.展开更多
Lakes are emission hotpots of nitrous oxide(N_(2)O),however,this phenomenon remains poorly constrained.Eutrophication is widespread in lakes,yet its contribution to N_(2)O emissions is still not well understood.Here,w...Lakes are emission hotpots of nitrous oxide(N_(2)O),however,this phenomenon remains poorly constrained.Eutrophication is widespread in lakes,yet its contribution to N_(2)O emissions is still not well understood.Here,we investigate the spatiotemporal variations of N_(2)O concentrations,fluxes and indirect emission factors(EF5r)and their drivers in Ulansuhai lake,a shallow eutrophic lake located in a semi-arid region in northern China,during 2019–2020.The mean concentration of N_(2)O in water was 20.0±6.7 nmol/L,with a mean diffusive N_(2)O flux of 16.50±21.52μmol/(m2·day),indicating that this lake acted as a persistent source of atmospheric N_(2)O.Estimated indirect emission factors(EF5r)(mean value 0.0037±0.0060)were significantly higher than the default values(0.0026)used in Intergovernmental Panel on Climate Change(IPCC)emission inventories.The N_(2)O concentrations,fluxes and EF5r exhibited substantial seasonal variations and small spatial variations.N_(2)O concentrations and fluxes were positively correlated with the trophic status and EF5r increased with increasing nutrient concentrations in the water.These findings demonstrate the role of eutrophication in influencing the N_(2)O dynamics and confirm that eutrophication can exacerbate N_(2)O emissions.展开更多
Ammonia(NH3)has been widely recognized as a key precursor of atmospheric secondary aerosol formation.Vehicle emission is a major source of urban atmospheric NH3.With the tightening of emission standards and the growin...Ammonia(NH3)has been widely recognized as a key precursor of atmospheric secondary aerosol formation.Vehicle emission is a major source of urban atmospheric NH3.With the tightening of emission standards and the growing trend of vehicle fleet electrification,it is imperative to update the emission factors for NH3 from real-world on-road fleets.In this study,a tunnel measurement was conducted in the urban area of Tianjin,China.The fleet-average NH3 emission factor(EF)was 11.2 mg/(km·veh),significantly lower than those in previous studies,showing the benefit of emission standard updating.Through a multiple linear regression analysis,the EFs of light-duty gasoline vehicles,light-duty diesel vehicles,and heavy-duty diesel vehicles(HDDVs)were estimated to be 5.7±0.6 mg/(km·veh),40.8±5.1 mg/(km·veh),and 160.2±16.6 mg/(km·veh),respectively.Based on the results from this study,we found that HDDVs,which comprise<3%of the total vehicles may contribute approximately 22%of total NH3 emissions in Tianjin.Our results highlight NH3 emissions from HDDVs,a previously potentially overlooked source of NH3 emissions in urban areas.The actual on-road NH3 emissions from HDDVs may exceed current expectations,posing a growing concern for the future.展开更多
The cogeneration system of heat,power,and biogas(CHPB)driven by renewable energy provides an effective solution for carbon emission reduction in rural China.Starting from fully meeting the energy demand of 17 new rura...The cogeneration system of heat,power,and biogas(CHPB)driven by renewable energy provides an effective solution for carbon emission reduction in rural China.Starting from fully meeting the energy demand of 17 new rural residential households in Lanzhou,considering the annual dynamic local climate change,energy consump-tion characteristics,and environment parameters,a model of environmental benefit index for the CHPB system is constructed.The concept of emission factor is used to quantitatively analyze the environmental benefits of the system.The equivalent CO_(2)emission factor is defined to connect emissions with energy output,evaluating the environment-friendly potential of energy supply system.Compared with the conventional systems of indepen-dent power and thermal generation,the year-round characteristics of CO_(2)emission and emission structure chart of the proposed system are analyzed.The results show that the total CO_(2)emission and the average equivalent CO_(2)emission factors of the conventional and CHPB system are 85.45t,1.53 kg/kWh,and 308.46t,0.22 kg/kWh,respectively.The maximum CO_(2)emission reduction ratio of the CHPB system is 113.47%.Anaerobic digestion technology is employed to consume biomass feedstock,which reduced CH_(4)emission(equivalent to 86.36t of CO_(2)emission reduction).Five typical cities were selected to study the regional adaptability of the system and analyze environmental benefits.The results indicate that the CHPB system has the best environmental performance in Guangzhou,where the average CO_(2)emission reduction rate is 103.52%.展开更多
基金supported by Science and Technology Project of China Southern Power Grid Co.,Ltd.(GDKJXM20231259).
文摘This paper develops an innovative computational model for assessing the Carbon Emission Factor(CEF)of provincial power systems that incorporates inter-provincial electricity transfers and hybrid generation portfolios combining conventional and renewable sources.A key contribution lies in evaluating how deep regulation of thermal power plants influence the carbon intensity of coal-fired generation and coal-fired generation together with high penetration renewables.Furthermore,the study quantitatively analyzes the role of renewable energy consumption and the prospective application of Carbon Capture and Storage(CCS)in reducing system-wide CEF.Based on this framework,the paper proposes phased carbon emission targets for Guangdong’s power system for key milestone years(2030,2045,2060),along with targeted implementation strategies.Results demonstrate that in renewable-dominant systems,deep regulation of thermal units,load peak-shaving,and deployment of flexible resources such as energy storage are effective in cutting carbon intensity.To achieve the defined targets—0.367 kg/kWh by 2030,0.231 kg/kWh by 2045,and 0.032 kg/kWh by 2060—the following innovation-focused policy is recommended:in early stage,mainly on expansion of renewable capacity and inter-provincial transmission infrastructure along with energy storage deployment;in mid-term,mainly on enhancement of electricity market mechanisms to promote green power trading and demand-side flexibility;and in late-stage,mainly on systematic retirement of conventional coal assets coupled with large-scale CCS adoption and carbon sink mechanisms.
文摘An integral part of the effort to reduce greenhouse gas emissions is carbon footprint accounting.EPA categorizes facility carbon footprints in three scopes.Scope-2 emissions include electricity,heat or steam purchased from a utility provider.This paper evaluates the existing calculation methods for scope-2 CO2 emissions for purchased electricity.The electricity grid in US is complex and is divided spatially into states,eGRID regions,balancing authorities(BAs),and utilities.Up to hourly temporal granularity can be obtained from available datasets.A matrix is developed that categorizes different datasets based on the complexity to calculate the carbon emission factors.Spatial and temporal variations are evaluated.There are significant spatial overlap between regions in different categories and emission factors within a region show sub-regional variation.An area analysis is done using zip-code polygons to determine whether a state or balancing authority is smaller for all the overlapping cases.Temporal variations in emission factors are significant depending on the balancing authority considered.A single method to calculate scope-2 emission factors may not be accurate and efficient in every case and a nuanced assessment of emission factors is warranted.An implementation pathway for a“smart carbon calculator”—one that gives accurate carbon footprint that is the spatially and temporally most granular is suggested.
基金supported by the Key R&D Program of Hubei Province(2023BAB002)the Science and technology project of State Grid Hubei Electric Power Co.,Ltd.(52153223000A)。
文摘Under the“dual carbon”goals,it is imperative to incorporate carbon emissions-related factors into research of power grid risk assessment to meet the green transformation needs of the power grid.Therefore,this paper conducts a study on the risk assessment of carbon emissions changes in regional power grids based on dynamic carbon emission factors,aiming to quantitatively analyze the impact of random disturbances such as equipment failures or fluctuations in renewable energy generation on the carbon emission intensity of regional power grids.First,carbon emission change risk indicators are constructed from three dimensions:the probability,frequency,and magnitude of carbon emission changes.Second,a dynamic carbon emission factor calculation model is proposed to reflect the spatiotemporal change of carbon emissions in the regional power grid,considering output of different types of generators and the components of inter-area power transmission.Finally,with the premise of ensuring safe and stable operation of power grid,a quantitative assessment model for carbon emission change risks is proposed under the objective of minimizing the electricity loss.The sampling convergence conditions of the model are also derived.The results from the MRTS79 case study demonstrate the proposed method can effectively quantify and analyze the risk of carbon emissions changes in regional power grids,validating the effectiveness of the proposed model.
文摘Emission factors of particulate matter （PM）, element carbon （EC）, organic carbon （OC）, SO2, NOx, CO, CO2, and ten ions （Na^＋, NH4^＋, K^＋, Mg^2＋, Ca^2＋, Fˉ, Clˉ, NO2ˉ, NO3ˉ, SO42ˉ） were estimated from the domestic burning of four types of commonly produced crop residues in rural China： rice straw, wheat straw, corn stover, and cotton stalk, which were collected from the representative regions across China. A combustion tower was designed to simulate the cooking conditions under which the peasants burned their crop residues in rural China, to measure the emission factors. Results showed that wheat straw had the highest emission factor for the total PM （8.75 g/kg） among the four crop residues, whereas, corn stover and wheat straw have the highest emission factor for EC （0.95 g/kg） and OC （3.46 g/kg）, respectively. Corn stover also presents as having the highest emission factors of NO, NOx, and CO2, whereas, wheat straw, rice straw, and cotton stalk had the highest emission factors of NO2, SO2, and CO, respectively. The water-soluble ions, K^＋ and Clˉ, had the highest emission factors from all the crops. Wheat straw had a relatively higher emission factor of cation species and Fˉ, Clˉ, NO2ˉ than other residues.
文摘Volatile organic compounds(VOCs)are the important precursors of the tropospheric ozone(O3)and secondary organic aerosols(SOA),both of which are known to harm human health and disrupt the earth’s climate system.In this study,VOC emission factors,O3 and SOA formation potentials were estimated for two types of industrial boilers:coal-fired boilers(n=3)and oil-fired boilers(n=3).Results showed that EVOCs concentrations were more than nine times higher for oil-fire d boilers compared to those for coal-fired boilers.Emission factors ofΣVOCs were found to be higher for oil-fired boilers(9.26-32.83 mg-VOC/kg)than for coal-fired boilers(1.57-4.13 mg-VOC/kg).Alkanes and aromatics were obtained as the most abundant groups in coal-fired boilers,while oxygenated organics and aromatics were the most contributing groups in oil-fired boilers.Benzene,n-hexane and o-ethyl toluene were the abundant VOC species in coal-fired boiler emissions,whereas toluene was the most abundant VOC species emitted from oil-fired boilers.O3 and SOA formation potentials were found 12 and 18 times,respectively,higher for oil-fired than for coal-fired boilers.Total OFP ranged from 3.99 to 11.39 mg-O3/kg for coal-fired boilers.For oil-fired boilers,total OFP ranged from 36.16 to 131.93 mg-O3/kg.Moreover,total secondary organic aerosol potential(SOAP)ranged from 65.4 to 122.5 mg-SOA/kg and 779.9 to 2252.5 mg-SOA/kg for the coal-fired and oil-fired boilers,respectively.
文摘The dynamometer tests with different driving cycles and the real-world tests are presented. Results indicated the pollutants emission factors and fuel consumption factor with ECE15+EUDC driving cycle usually take the lowest value and with real world driving cycle occur the highest value, and different driving cycles will lead to significantly different vehicle emission factors with the same vehicle. Relative to the ECE15+EUDC driving cycle, the increasing rate of pollutant emission factors of CO, NOx and HC are -0.42—2.99, -0.32 —0.81 and -0.11—11 with FTP75 testing, 0.11—1.29, -0.77—0.64 and 0.47—10.50 with Beijing 1997 testing and 0.25—1.83, 0.09—0.75 and -0.58—1.50 with real world testing. Compared to the carburetor vehicles, the retrofit and MPI+TWC vehicles' pollution emission factors decrease with different degree. The retrofit vehicle(Santana) will reduce 4.44%—58.44% CO, -4.95%—36.79% NOx, -32.32%—33.89% HC, and -9.39%—14.29% fuel consumption, and especially that the MPI+TWC vehicle will decrease CO by 82.48%—91.76%, NOx by 44.87%—92.79%, HC by 90.00%—93.89% and fuel consumption by 5.44%—10.55%. Vehicles can cause pollution at a very high rate when operated in high power modes; however, they may not often operate in these high power modes. In analyzing vehicle emissions, it describes the fraction of time that vehicles operate in various power modes. In Beijing, vehicles spend 90% of their operation in low power modes or decelerating.
基金Projects(KKK0201022137,KKK0201122183) supported by the Special Research Foundation of Yunnan Provincial Environmental Protection Bureau,China
文摘Copper smelting is a significant source of SO2 emission. It is important to quantify SO2 emissions from combustion sources for regulatory and control purposes in relation to air quality. The characteristics of SO2 emissions from copper smelting industry in Yurman Province, China, were examined. Analysis based on the present situation, material balance and measuring method were used to confirm SO2 emission factors of copper smelting industry. Results show that SO2 emission factors for Isa system, side blown-continuous converting system （SB-CC）, blast furnace-continuous converting systems （B-CC） and blast furnace-converter blowing （B-C） are 11.69-18.64, 62.44--101.4, 19.43-37.88 and 45.48-81.03 kg/t（blister copper）, respectively. The comprehensive emission factor based on all smelting plants is found to be in the range of 23-39.99 kg-SO2/t（blister copper） for Yunnan Province, China. The results are compared with those for discharge coefficients of industrial pollutants in the First National General Survey of Pollution Sources and the emission factor of the total amount of major pollutants. It is observed that there are some differences among emission factors.
基金supported by the National Science Foundation of China (Nos. 41275124, 51278272)the Beijing Natural Science Foundation (8142011)+1 种基金the Ministry of Environmental Protection of China (No. 201209007)the International Council on Clean Transportation (ICCT) research program
文摘A database of real-world diesel vehicle emission factors, based on type and technology, has been developed following tests on more than 300 diesel vehicles in China using a portable emission measurement system. The database provides better understanding of diesel vehicle emissions under actual driving conditions. We found that although new regulations have reduced real-world emission levels of diesel trucks and buses significantly for most pollutants in China, NOx emissions have been inadequately controlled by the current standards, especially for diesel buses, because of bad driving conditions in the real world. We also compared the emission factors in the database with those calculated by emission factor models and used in inventory studies. The emission factors derived from COPERT（Computer Programmer to calculate Emissions from Road Transport） and MOBILE may both underestimate real emission factors, whereas the updated COPERT and PART5（Highway Vehicle Particulate Emission Modeling Software） models may overestimate emission factors in China. Real-world measurement results and emission factors used in recent emission inventory studies are inconsistent,which has led to inaccurate estimates of emissions from diesel trucks and buses over recent years. This suggests that emission factors derived from European or US-based models will not truly represent real-world emissions in China. Therefore, it is useful and necessary to conduct systematic real-world measurements of vehicle emissions in China in order to obtain the optimum inputs for emission inventory models.
基金supported by the Natural Science Foundation of China(No.41275135,41105090)the National High Technology Research and Development Program(863)of China(No.2012AA063506)the Open Foundation of Environmental Simulation and Pollution Control State Key Laboratories(Peking University)
文摘Domestic coal stove is widely used in China, especially for countryside during heating period of winter, and polycyclic aromatic hydrocarbons （PAHs） are important in flue gas of the stove. By using dilution tunnel system, samples of both gaseous and particulate phases from domestic coal combustion were collected and 18 PAH species were analyzed by GC-MS. The average emission factors of total 18 PAH species was 171.73 mg/kg, ranging from 140.75 to 229.11 mg/kg for bituminous coals, while was 93.98 mg/kg, ranging from 58.48 to 129.47 mg/kg for anthracite coals. PAHs in gaseous phases occupied 95% of the total of PAHs emission of coal combustion. In particulate phase, 3-ring and 4- ring PAHs were the main components, accounting for 80% of the total particulate PAHs. The total toxicity potency evaluated by benzo[a]pyrene-equivalent carcinogenic power, sum of 7 carcinogenic PAH components and 2,3,7,8-tetrachlorodibenzodioxin had a similar tendency. And as a result, the toxic potential of bituminous coal was higher than that of anthracite coal. Efficient emission control should be conducted to reduce PAH emissions in order to protect ecosystem and human health.
基金supported by the National Natural Science Foundation of China(No.41130754,41001343,41001343)the Beijing Municipal Government(No.YB20101000101)+1 种基金the Ministry of Environmental Protection(No.201209018)NIEHS(No.P42ES016465)
文摘The uncertainty in emission estimation is strongly associated with the variation in emission factor （EF）,which could be influenced by a variety of factors such as fuel properties,stove type,fire management and even methods used in measurements.The impacts of these factors are complicated and often interact with each other.Controlled burning experiments were conducted to investigate the influences of fuel mass load,air supply and burning rate on the emissions and size distributions of carbonaceous particulate matter （PM） from indoor corn straw burning in a cooking stove.The results showed that the EFs of PM （EFPM）,organic carbon （EFOC） and elemental carbon （EFEC） were independent of the fuel mass load.The differences among them under different burning rates or air supply amounts were also found to be insignificant （p 〉 0.05） in the tested circumstances.PM from the indoor corn straw burning was dominated by fine PM with diameter less than 2.1 μm,contributing 86.4%±3.9% of the total.The size distribution of PM was influenced by the burning rate and air supply conditions.On average,EF PM,EF OC and EF EC for corn straw burned in a residential cooking stove were （3.84±1.02）,（0.846±0.895） and （0.391±0.350） g/kg,respectively.EF PM,EF OC and EF EC were found to be positively correlated with each other （p 〈 0.05）,but they were not significantly correlated with the EF of co-emitted CO,suggesting that special attention should be paid to the use of CO as a surrogate for other incomplete combustion pollutants.
文摘The emission factors of nitrous oxide have been determined during the combustion of rice straws, maize stalks and wheat stalks in an enclosed combustion system. They equal to 84.4 ± 6.08g/t for rice straws,132± 8.63g/t for maize stalks,and 27.3 ±1.79g/tfor wheat stalks,respectively. The uncertainties in the determination of nitrous oxide have been discussed. The N_2O-N(nitrogen in nitrous oxide emission)accounts for 0. 59% and 0. 87% of the total nitrogen in rice straws and maize stalks,respectively. An 1￣0 ×1￣0 grid map on the distribution of N_2O emission from biomass burning in China mainland was shown.
文摘Developing countries as Mexico lack their own emission factors for thermoelectric power plants, so they have the need to develop them, considering specific operation conditions for each plant. This study develops specific emission factors in Mexico for： sulfur dioxide （SO2）, nitrogen oxides （NOx） and particles, for thermoelectric power plants that use fuel oil. This work was necessary due to the differences found between the measured and the calculated emissions, using emission factors of different agencies, such as, US-EPA （Environmental Protection Agency of the United States）, IPCC （Intergovernmental Panel on Climate Change）, and UK-NAEI （National Atmospheric Emissions Inventory of the United Kingdom）. The new emission factors were used to calculate the emissions of a thermoelectric power plant in Mexico. The comparisons between the measured and the calculated emissions （with the new emission factors） for 502, particles and NO2 were not significantly different （p 〉 0.05）.
文摘Emission factors （EFs） of particulate matter （PM） derived from mono and co-firing of Thai lignite and agricultural residues have been investigated. Two sampling methods for PM, total filtration （TF） and electrical low-pressure impactor （ELPI）, were used together. The study is focused on the influence of fuel mass fraction, and of secondary air to total air; SA：TA on EFs of PM. The results have shown that EFs of PM in mass-basis given by TF method are 8.9, 5.3 and 8.1 mg/kgfuel, while 3.3, 2.7 and 3.3 mg/kgfuel when using ELPI, for firing at constant SA：TA （30%） of lignite, rice husk and bagasse, respectively. For co-firing with 30%SA of coal/rice husk, higher EFs of PM is observed. They are 7.17 and 10.9 mg/kgfuel （TF） for 40 and 70% rice husk share, respectively, or 4.18 and 5.19 mg/kgfuel （ELPI）. However, lower PM emission; 1-3.3 mg/kgruel （TF） or 0.72-2.83 mg/kgfuel （ELPI） are obtained during co-firing of coal/rice husk with lower degree of air staging （i.e. 0-10% SA：TA）. For the influence of oxygenation state, increasing of SA： TA leads to a low formation of ultrafine particles （Dp 〈 0.1 μm）. Apart from PM, major gases （CO, NO, SO2） will be documented in this paper.
文摘Activity data and emission factors are critical for estimating greenhouse gas emissions and devising effective climate change mitigation strategies. This study developed the activity data and emission factor in the Forestry and Other Land Use Change (FOLU) subsector in Malawi. The results indicate that “forestland to cropland,” and “wetland to cropland,” were the major land use changes from the year 2000 to the year 2022. The forestland steadily declined at a rate of 13,591 ha (0.5%) per annum. Similarly, grassland declined at the rate of 1651 ha (0.5%) per annum. On the other hand, cropland, wetland, and settlements steadily increased at the rate of 8228 ha (0.14%);5257 ha (0.17%);and 1941 ha (8.1%) per annum, respectively. Furthermore, the results indicate that the “grassland to forestland” changes were higher than the “forestland to grassland” changes, suggesting that forest regrowth was occurring. On the emission factor, the results interestingly indicate that there was a significant increase in carbon sequestration in the FOLU subsector from the year 2011 to 2022. Carbon sequestration increased annually by 13.66 ± 0.17 tCO<sub>2</sub> e/ha/yr (4.6%), with an uncertainty of 2.44%. Therefore, it can be concluded that there is potential for a Carbon market in Malawi.
基金jointly financed by the Ministry of Science and Technology of China(Grant No.2016YFA0602303)the National Natural Science Foundation of China(Grant Nos.41775141,41375152,and 41603075)
文摘Nitric oxide(NO)emissions from alpine ecosystems conventionally being long-term cultivated with feed crops are not well quantified.The authors attempted to address this knowledge gap by performing a year-round experimental campaign in the northeastern Tibetan Plateau.Fertilized(F)and unfertilized(UF)treatments were established within a flat calcareous-soil site for the long-term cultivation of feed oats.NO fluxes and five soil variables were simultaneously measured.A single plow tillage accounted for approximately 54%–73%of the NO releases during the cropping period(CP);and the non-cropping period(NCP)contributed to 51%–58%of the annual emissions.The direct NO emissions factor(EFd)was 0.021%±0.021%.Significantly lower Q10 values(p<0.01)occurred in the F treatment during the CP(approximately 3.6)compared to those during the other period or in the other treatment(approximately 4.9?5.1),indicating a fertilizer-induced reduction in the temperature sensitivity.The selected soil variables jointly accounted for up to 72%(p<0.01)of the variance for all the fluxes across both treatments.This finding suggests that temporally and/or spatially distributed fluxes from alpine calcareous-soil ecosystems for feed crop production may be easily predicted if data on these soil variables are available.Further studies are needed to test the hypothesis that the EFd is larger in alpine feed-oat fields than those in this study if the soil moisture content is higher during the period following the basal application of ammoniumor urea-based fertilizer.
基金supported by CHN Energy Investment Group(GJNY-23-138)。
文摘With the development of distributed photovoltaic energy in mining areas,the increasing proportion of new energy integration will gradually drive the structural transformation of coal mine parks into industrial active distribution networks.This paper takes a coal mine in Shaanxi Province as an empirical research subject,employing a multi-spatial hierarchical analysis method to systematically analyze the electricity usage characteristics across different spatial levels.It innovatively proposes a power line loss correction method for multi-level electrical equipment,effectively balancing the metering deviations of line losses between levels.Based on two types of carbon emission factors,it achieves precise evaluation of indirect carbon emissions from electricity usage in different levels of equipment or energy units.When calculating indirect carbon emissions from electricity using static carbon emission factors,the measured values show a positive correlation with peak electricity load.As the proportion of renewable photovoltaic power integration in industrial active distribution networks increases,the system’s indirect carbon emission factors exhibit a periodic decreasing trend.After adopting dynamic indirect carbon emission factors for accounting,the indirect carbon emissions from electricity in the first consumption level can be reduced by 31%-55%,while the overall plant-wide indirect carbon emissions decrease by 29068.94 kgCO_(2)/d,a reduction of approximately 40%.For the second consumption level in industrial production areas,indirect carbon emissions from electricity can be reduced by 5%-83%,with overall industrial park-wide indirect carbon emissions decreasing by 7376.48 kgCO_(2)/d,a reduction of about 31%.It is recommended to use advanced equipment and energy-saving technologies to suppress technical line losses in coal mine power supply systems and improve energy efficiency.Promoting the coordinated application of renewable energy and energy storage technologies can expand the scale of stable and reliable renewable energy supply,effectively reducing indirect carbon emissions from electricity.
基金supported by the National Natural Science Foundation of China(No.52279067)the National Key R&D Program of China(No.2021YFC3201203)+1 种基金the Project of Key Laboratory of River and Lake in Inner Mongolia Autonomous Region(No.2022QZBZ0003)the Research Foundation for Young Scholars of Inner Mongolia University(No.10000-23112101/333).
文摘Lakes are emission hotpots of nitrous oxide(N_(2)O),however,this phenomenon remains poorly constrained.Eutrophication is widespread in lakes,yet its contribution to N_(2)O emissions is still not well understood.Here,we investigate the spatiotemporal variations of N_(2)O concentrations,fluxes and indirect emission factors(EF5r)and their drivers in Ulansuhai lake,a shallow eutrophic lake located in a semi-arid region in northern China,during 2019–2020.The mean concentration of N_(2)O in water was 20.0±6.7 nmol/L,with a mean diffusive N_(2)O flux of 16.50±21.52μmol/(m2·day),indicating that this lake acted as a persistent source of atmospheric N_(2)O.Estimated indirect emission factors(EF5r)(mean value 0.0037±0.0060)were significantly higher than the default values(0.0026)used in Intergovernmental Panel on Climate Change(IPCC)emission inventories.The N_(2)O concentrations,fluxes and EF5r exhibited substantial seasonal variations and small spatial variations.N_(2)O concentrations and fluxes were positively correlated with the trophic status and EF5r increased with increasing nutrient concentrations in the water.These findings demonstrate the role of eutrophication in influencing the N_(2)O dynamics and confirm that eutrophication can exacerbate N_(2)O emissions.
基金supported by the National key research and development program of China(No.2022YFE0135000)the National Natural Science Foundation of China(No.42175123)the Natural Science Foundation of Tianjin(No.23JCJQJC00170).
文摘Ammonia(NH3)has been widely recognized as a key precursor of atmospheric secondary aerosol formation.Vehicle emission is a major source of urban atmospheric NH3.With the tightening of emission standards and the growing trend of vehicle fleet electrification,it is imperative to update the emission factors for NH3 from real-world on-road fleets.In this study,a tunnel measurement was conducted in the urban area of Tianjin,China.The fleet-average NH3 emission factor(EF)was 11.2 mg/(km·veh),significantly lower than those in previous studies,showing the benefit of emission standard updating.Through a multiple linear regression analysis,the EFs of light-duty gasoline vehicles,light-duty diesel vehicles,and heavy-duty diesel vehicles(HDDVs)were estimated to be 5.7±0.6 mg/(km·veh),40.8±5.1 mg/(km·veh),and 160.2±16.6 mg/(km·veh),respectively.Based on the results from this study,we found that HDDVs,which comprise<3%of the total vehicles may contribute approximately 22%of total NH3 emissions in Tianjin.Our results highlight NH3 emissions from HDDVs,a previously potentially overlooked source of NH3 emissions in urban areas.The actual on-road NH3 emissions from HDDVs may exceed current expectations,posing a growing concern for the future.
基金This work was supported by the project of National Natural Sci-ence Foundation of China(51806093)Youth Doctor Foundation Project of Gansu Provincial Education Department(2021QB-046)+2 种基金In-dustrial Support Plan Project of Gansu Provincial Education Depart-ment(2021CYZC-27)Natural Science Foundation of Gansu Province(20JR10RA193)Red Willlow Excellent Youth Project of Lanzhou Uni-versity of Technology(201810).
文摘The cogeneration system of heat,power,and biogas(CHPB)driven by renewable energy provides an effective solution for carbon emission reduction in rural China.Starting from fully meeting the energy demand of 17 new rural residential households in Lanzhou,considering the annual dynamic local climate change,energy consump-tion characteristics,and environment parameters,a model of environmental benefit index for the CHPB system is constructed.The concept of emission factor is used to quantitatively analyze the environmental benefits of the system.The equivalent CO_(2)emission factor is defined to connect emissions with energy output,evaluating the environment-friendly potential of energy supply system.Compared with the conventional systems of indepen-dent power and thermal generation,the year-round characteristics of CO_(2)emission and emission structure chart of the proposed system are analyzed.The results show that the total CO_(2)emission and the average equivalent CO_(2)emission factors of the conventional and CHPB system are 85.45t,1.53 kg/kWh,and 308.46t,0.22 kg/kWh,respectively.The maximum CO_(2)emission reduction ratio of the CHPB system is 113.47%.Anaerobic digestion technology is employed to consume biomass feedstock,which reduced CH_(4)emission(equivalent to 86.36t of CO_(2)emission reduction).Five typical cities were selected to study the regional adaptability of the system and analyze environmental benefits.The results indicate that the CHPB system has the best environmental performance in Guangzhou,where the average CO_(2)emission reduction rate is 103.52%.
