Greenhouse Gas Reduction Policies Research Articles

Process Reduces Carbon Emissions From Natural Gas Compression and Production

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 214974,“New Technology Reduces Carbon Emissions From Natural Gas Compression and Production Facilities,” by John Guoynes, SPE, David Stiles, SPE, and Cory Vail, Axip Energy Services, et al. The paper has not been peer reviewed. _ A chemical-free process has been developed to capture exhaust from natural gas drive compressors and supporting gas-fueled production equipment while featuring a small footprint. The process separates CO2 and nitrogen from exhaust, allowing the CO2 to be discharged at high pressure for transport, sequestration, or enhanced oil recovery. Introduction Over 50,000 compressors move natural gas in North America. Most are driven by either internal combustion engines or turbines. These compressors produce am estimate of more than 30 million tonnes of CO2 equivalent yearly, according to the US Environmental Protection Agency’s Greenhouse Gas (GHG) Reporting Program. The significance of GHG reduction policies has heightened with the passing of the Inflation Reduction Act, which provides support for companies investing in future carbon capture use and storage, along with methane reduction. Process Modeling Modeling and analysis of an exhaust-gas carbon capture system, and the design and optimization of a supercritical CO2 (sCO2) waste-heat-recovery power cycle, was performed. This cycle was chosen for its high efficiency and relatively compact design compared with competitive waste-heat-recovery technologies. The preliminary process-flow diagram was provided based on conditions for 30,000-hp large reciprocating gas engines. Several process configurations were investigated; these iterations are detailed in the complete paper. A summary of this development shows that Iterations 1 through 3 showed improvements in power through improving the sCO2 power-cycle efficiency. However, this came at the increase in high-pressure sCO2 components. A simplification of components returned the sCO2 cycle to a single cascaded cycle in Iterations 4 through 5. Temperature selection in the sCO2 cycle also improved its efficiency. Moving to Iteration 4 improved the system power requirement by 20.7%. Iteration 5 showed moderately reduced performance over Iteration 4. This was the result of shifting more duty to the ammonia chillers and a moderate worsening of performance in the gas compressor. Iteration 5 did not improve the power requirement of the system. Ultimately, Iteration 4 was the most-efficient cycle evaluated with the overall lowest power requirement. Exhaust-Capture Decarbonization System The system developed captures exhaust from compression and other internal combustion equipment commonly used in gas transmission, oil and gas production, and midstream applications. The system works with a chemical-free, cryogenic design with a small modular footprint to capture large volumes of exhaust gas at atmospheric pressure. This technology separates CO2 and nitrogen, generates enough power from waste heat to run the equipment, and discharges captured CO2 under high pressure at supercritical conditions for compressor stations of 5,000 to 20,000 hp. The design is fully self-contained and mounts on a compact skid package capable of handling up to 70 million scf/D of exhaust while extracting liquid CO2 from rich-burn driven compressors, lean-burn driven compressors, or turbines.

Estimation of greenhouse gas emissions from ships registered in South Korea based on activity data using the bottom-up approach

The shipping sector is one of the major contributors to greenhouse gas (GHG) emissions. We aimed to calculate GHG emissions categorized by ship type for all vessels registered in South Korea. Hence, for the first time in South Korea, a bottom-up method based on ship activity data was employed, estimating energy consumption and emissions by ship type. Data from ships registered from 2019 to 2021 were collected and reclassified by ship type, and operational profiles were developed. Based on these profiles, the emissions of major GHGs, including CO2, CH4, and N2O, were estimated for the 3-year period. Cargo ships accounted for the highest percentage of annual fuel consumption, approximately 62.7%–64.7% of the total fuel consumption for all ships. The GHG emissions were calculated to be an average of 4.644 million tonCO2e, which is approximately 6.5 times higher than those from oil tankers (0.710 million tonCO2e), the second-highest emitter. This highlights the need for intensified GHG reduction measures specifically targeting cargo ships, providing clear evidence for prompt and enhanced implementation. The research findings are expected to be utilized as substantiated data for developing specific and systematic GHG reduction policies tailored to each ship type.

Optimal Hybrid Pulse Width Modulation for Three-Phase Inverters in Electric Propulsion Ships

Global interest in environmentally friendly ships has surged as a result of greenhouse gas reduction policies and the demand for carbon neutrality. Despite growing demand for electric propulsion systems, there is a lack of research and development on crucial components. Efficiency and stability are primarily influenced by the performance of inverters, which are essential for driving propulsion motors. Existing inverter control techniques can be of two types: continuous-PWM (pulse width modulation) methods for harmonic performance enhancement and discontinuous-PWM methods for efficiency improvement by reducing losses. However, there are limitations in that each PWM method exhibits substantial variations in inverter performance based on its operating conditions. To address these challenges, this study proposes the hybrid pulse-width-modulation (HPWM) method for optimal inverter operation. By analyzing the inverter’s operating conditions, the proposed HPWM method adopts various pulse-width-modulation (PWM) strategies based on a modulation index to achieve harmonic improvement and loss reduction. Our focus is on comparing and analyzing diverse PWM techniques under varying modulation indices and frequency conditions to attain the optimal operating conditions. Experimental validation of the proposed method was conducted using a 2.2 kW dynamometer. In comparison with existing PWM methods, the proposed method demonstrated superior performance.

도시열섬 완화로 시민건강권 확보

A core project of Busan’s healthy city policy is the community health center project. Community health centers are established at the donglevel, the smallest and nearest place to residents’ everyday lives, to address community health issues such as health counseling, support for resident-led health community activities, and revitalization of health networks.
 The climate response activities of the health guardians in the 74 community health centers in Busan were promoted as a key component of Busan Metropolitan Government’s climate response policy. In 2022, Busan’s climate response policy with the community health centers was awarded the Korea Health City Award.
 This case study aims to describe Busan’s efforts on climate change adaptation and greenhouse gas reduction that is organized by an intersectoral effort of Carbon Neutral Policy Division 24 departments that includes the Health Policy Division. Busan City made efforts to create a city that adapts to climate change created with citizens by improving the vulnerability of heat wave mitigation and responding to climate change through citizen participation policies. And greenhouse gas reduction policies for various sectors (building, public, transportation, waste, and absorption sources) were promoted, while data-based efficient responses were promoted with urban heat island monitoring systems.

The developmental state's legacy and corporate carbon emission performance: evidence from Taiwanese firms between 2014 and 2018

ABSTRACT Despite international efforts to address human-caused climate change, greenhouse gas emissions continue to rise. However, existing literature often overlooks the role of the state and social actors in exacerbating or mitigating emissions. This study adopts the political-economic embeddedness perspective to argue that the role of the state and social actors cannot be separated in the greenhouse gas economy. Specifically, we explore how the embeddedness within the Taiwanese state and private corporations enables resistance to greenhouse gas reduction policies. Through an analysis of greenhouse gas emissions data and examination of corporate characteristics among major emitters in Taiwan, we find that two key legacies of Taiwan's developmental state period, family-controlled firms and private corporations with more governmental directors, tend to have higher emissions levels. Importantly, these legacies persist even after neo-liberal reforms. This study's findings have implications for developing countries, particularly in Asia, that employ developmental state strategies. It underscores the need for countries to consider the potential negative impacts of state intervention and market dynamics on greenhouse gas emissions.

Unmasking mobility patterns: international travel behavior and emissions of scientists in a higher research institution

PurposeThis study aims to investigate patterns in international travel behavior of scientific staff depending on the categories of gender, scientific field and scientific seniority level. The learning from salient differences possibly revealed may inform measures for reducing travel greenhouse gas (GHG) emissions, especially for high-emitting staff groups, and help strengthen the equality between scientists of different categories concerning their travel behavior.Design/methodology/approachThe study collected and used novel empirical data on travel GHG emissions from University of Graz scientific staff for five consecutive years (2015–2019) and used statistical analysis and inference to test and answer three distinct research questions on patterns of travel behavior.FindingsThe travel footprint of scientific staff, in terms of annual GHG emissions per scientist, exhibits various highly significant differences across scientific fields, seniority and gender, such as male senior natural scientists showing ten times higher per-person emissions than female junior social scientists.Originality/valueThe five-year travel GHG emissions data set across all fields from natural sciences via social sciences to humanities at a large university (Uni Graz, Austria, about 2,000 scientific staff) and across seniority levels from predocs to professors, both for female and male scientists, enabled a robust empirical study revealing distinct differences in travel GHG footprints of academic staff. In this way, the study adds valuable insights for higher research institutions toward effective GHG reduction policies.

RCP 시나리오를 활용한 이상기후에 따른 마늘 수급 영향 분석

Our study investigated the impact of the implementation of greenhouse gas reduction (GGR) policies on the garlic market. We set an abnormal climate scenario; (1) emitting greenhouse gases as the current trend, (2) the greenhouse gas reductioin policy. Then, we analyzed whether the GGR policy was implemented or not. When abnormal weather occurred in 2030, Scenario 1 showed a larger decrease in yields per garlic unit than Scenario 2. On the other hand, in the case of price increase, Scenario 2 was found to be smaller than scenario 1. The results imply that if the GGR policy is implemented in abnormal climate conditions, the decrease in garlic yield per unit is relatively small due to favorable climate conditions, and it will positively contribute to stabilizing garlic prices. The results of the study suggest the need to implement GGR policies in the agricultural sector at a time when abnormal climate phenomena are inevitable. Since voluntary participation in farmers is essential to achieve carbon neutrality in the agricultural sector, policies should be implemented to increase farmers' participation rate, such as providing economic incentives when reducing greenhouse gases in the agricultural process.

Economic analysis of the circular economy based on waste plastic pyrolysis oil: a case of the university campus.

Recently, the concept of a circular economy for carbon neutrality is emerging. In particular, waste plastics are one of the key wastes, and efforts are being made to recycle them as energy rather than dispose of them. Accordingly, the technology of producing and utilizing pyrolysis oil from waste plastics attracts attention. As it is an early stage of technology development, however, there are not many demonstrations and papers that analyze the technology broadly. The goal of this study is to propose building a circular economy on a university campus through waste plastic pyrolysis oil technology. To show its feasibility, waste plastic pyrolysis oil technology is analyzed comprehensively from economic, environmental, and policy perspectives using the scenario analysis technique on the university campus level. A methodology of the scenario analysis technique enables predicting the uncertainties. Since plastic pyrolysis oil technologies and carbon neutrality are accompanied by many uncertainties, this technique is expected to be an appropriate methodology for this study. First, the amount of pyrolysis oil production from waste plastics from the campus is estimated. Then, the cost and carbon emissions from waste plastics are estimated if the pyrolysis oil technology is used instead of the traditional waste disposal process. As a result, the total economic profits of up to 425,484,022 won/year (354,570.01 $/year) are expected when a circular economy is built using waste plastic pyrolysis oil. In addition, it is also confirmed that greenhouse gas (GHG) emissions can be reduced by up to 840,891 kgCO2eq/year. The waste plastic pyrolysis oil satisfies Korea's gas pollutant standards and is consistent with the GHG reduction policy. It can be concluded that building a circular economy at the university campus level using waste plastic pyrolysis oil technology is suitable from economic, environmental, and policy perspectives.

CO2 and CH4 Emission Factors from Light-Duty Vehicles by Fuel Types in Thailand

Correct emission factors are necessary for evaluating vehicle emissions and making proper decisions to manage air pollution in the transportation sector. In this study, using a chassis dynamometer at the Automotive Emission Laboratory, CO2 and CH4 emission factors of light-duty vehicles (LDVs) were developed by fuel types and driving speeds. The Bangkok driving cycle was used for the vehicle’s running and controlling under the standard procedure. Results present that the highest average CO2 and CH4 emission factors were emitted from LDG vehicles, at 232.25 g/km and 9.50 mg/km, respectively. The average CO2 emission factor of the LDD vehicles was higher than that of the LDG vehicles, at 182.53 g/km and 171.01 g/km, respectively. Nevertheless, the average CH4 emission factors of the LDD vehicles were lower than those of the LDG vehicles, at 2.21 mg/km and 3.02 mg/km, respectively. The result reveals that the lower driving speed emitted higher CO2 emission factors for LDVs. It reflects the higher fuel consumption rate (L/100 km) and the lower fuel economy rate (km/L). Moreover, the portion of CO2 emissions emitted from LDVs was 99.96% of total GHG emissions. The CO2 and CH4 emission factors developed through this study will be used to support the greenhouse gas reduction policies, especially concerning the CO2 and CH4 emitted from vehicles. Furthermore, it can be used as a database that encourages Thailand’s green transportation management system.

Integrating greenhouse gas reduction and waste policy targets to identify optimal waste treatment configurations via Carbon Emission Pinch Analysis

Municipal solid waste (MSW) is a persistent burden in many countries. The heterogeneous MSW characteristic requires a transition from the monotonous treatment strategy to a diversified low-carbon waste treatment configuration. Nevertheless, complex mathematical models hinder the policymakers from adopting scientific-based solutions in the decision-making process, and those models seldom link national greenhouse gas reduction targets to local waste policy targets. This study applies two approaches in constructing Carbon Emission Pinch Analysis to either optimize waste treatment system configurations while considering greenhouse gas reduction and waste policy targets or identify the maximum possible national greenhouse gas reduction based on a waste treatment system configuration. Among the seven types of waste treatment systems studied, the carbon emission factor of material recycling is the lowest (−0.19 t CO2-e/t MSW), whereas open landfill is the highest (0.72 t CO2-e/t MSW). The proposed ten waste treatment configurations indicate a 1.0–2.2% reduction of national greenhouse gas emissions, in which the best-case configuration (i.e., carbon sink scenario) contributes to 3.64% of the national electricity consumption in 2030. This study provides a compendious comparison of waste treatment systems integrated with greenhouse gas reduction and waste policy targets for a more circular MSW management in countries facing the waste disposal dilemma.

An Analysis of the Groundwater Flow s Characteristics Following CLIMATE CHANGES

Purpose: The purpose of this study is to estimate the groundwater volume available in the Gyeongju region and predict changes in the groundwater flow s characteristics based on the IPCC RCP climate scenario. Method: As for the method to carry out this study, the results of forecasting the weather conditions in the Gyeongju region based on the IPCC RCP climate change scenario were used. By using the predicted precipitation data, the groundwater volume available was analyzed by using the SWAT MODEL. To analyze the groundwater flow s characteristics, the future groundwater flow s characteristics were analyzed by using MODFLOW by using the observed water level related data. Results: When examining the content by scenario, and across all scenarios, it was analyzed that the M3 basin was the largest, followed by the M2 basin and the M1 basin, respectively. It was also analyzed to be inversely proportional to the size of the outflow hydrologic curve in the case of the M1 basin as the city area was greater than that of the M2 and M3 basins. It was analyzed that the scenario of RCP 2.6 had the lowest variation for the content by basin, and that RCP 4.5 had the largest variation by basin. In terms of the flow direction of the groundwater, the M3 basin flows from the mountainous terrain to the Deokdongcheon Stream along the Deokdong Lake, and the M2 basin flows from the south towards the direction of the Bomun Lake. The M1 basin was analyzed to be the Bukcheon basin and finally flows towards the west side of the Hyeongsan River, and the overall groundwater flow in the target basin was analyzed to flow along the river towards the west side of the Hyeongsan River. Conclusion: As a result of analyzing the groundwater volume available and flow’s characteristics in the Gyeongju region according to climate changes in this study, the amount of groundwater volume available in the future RCP scenario both increased in 2100 compared to the current precipitation. Yet, in the case of RCP 4.5, the duration of no precipitation decreased by 57.75% compared to 2020, and RCP 8.5 increased by 56.79%, and hence, it was analyzed that, as for the available volume in 2100, the RCP 4.5 scenario was calculated to be 6.93% higher than the present, and the RCP 8.5 scenario increased by 0.10% compared to the present. In 2100, when there was no precipitation for 40 or more days, it was analyzed that the groundwater level decreased for RCP 4.5 by 0.7 m on average, and as for RCP 8.5, it was analyzed to decrease by GL by 1.0 m, and hence, the water level’s decrease turned out to be very large for the RCP 8.5 scenario. As a result of the groundwater flow analysis, it was analyzed that it was advantageous for securing the groundwater because of the high groundwater volume available and the groundwater level in the RCP 4.5 scenario where the greenhouse gas reduction policy was significantly realized.

Major US electric utility climate pledges have the potential to collectively reduce power sector emissions by one-third

Major US electric utility climate pledges have the potential to collectively reduce power sector emissions by one-third

Economics of co-firing rice straw in coal power plants in Vietnam

As governments forced electricity producers to use more renewable energy sources, over a hundred thermal power plants in high-income countries turned to biomass as a partial or complete replacement for coal. Is the co-firing technology appropriate for Vietnam? To assess the technology we build an integrated model simulating the economics, environmental and social implications of blending 5% of rice straw in two existing coal power plants in Vietnam. The business value of co-firing is positive –straw is cheaper than coal– but not large enough to motivate the stakeholders. The external social benefit of co-firing –reduced air-borne pollution– are several times larger than the business value. Within that external benefit, the social value of avoided PM2.5 and NOx emissions dominates the social value of avoided CO2 emissions. The net job creation effect is positive: collecting straw creates more employment than using less coal destroys. This is the first technology assessment of co-firing biomass in coal power plants in Vietnam and one of the first for a subtropical middle-income country. The study only considers rice straw, and it does not address the role of government nor the biomass market functioning. The price of coal is the primary determinant of co-firing business value. There is an empirical economic justification for a public intervention to promote co-firing biomass in Vietnam, mainly as a way to reduce open-field straw burning. Local air quality goals, rather than greenhouse gas reduction policy, can justify such regulations.

The power and promise of improved climate data infrastructure

The announcement by the Biden Administration to reengage the Paris climate process and lower US greenhouse gas (GHG) emissions 50% by the end of this decade is an essential development in the global effort to avoid the worst impacts of climate change (1). However, promises to reduce US GHG emissions are not new and have thus far delivered little real and sustainable emissions reductions (2). The result? Climate change continues unabated, and we forgo the associated jobs and technological innovation that will fuel economic growth in climate friendly businesses. It must be different this time—pledges must lead to practical policy and quickly. To mitigate greenhouse gas emissions, we need accurate and transparent emissions data infrastructure that maps when emissions are happening and where they’re coming from. Image credit: Shutterstock/Tatiana Grozetskaya. To meet the US emission pledge, practical policies will need to reach broadly across the US economy and mobilize new technologies, behavioral change, and private capital. Regardless of policy specifics, actionable GHG reduction policies will fundamentally rest on critical climate data infrastructure that comprehensively and reliably quantifies and tracks GHG emissions in the United States from the local to the national scale. Ideally, all citizens should be able to see a daily map of detailed emissions across the US landscape, much like viewing daily weather. In other words, we need a “US Greenhouse Gas Information Service.” Such a service would provide local emission context to our daily lives and is essential to determine whether emission reduction claims are real, if they’re targeting the best opportunities from neighborhoods to the nation, and whether they’re establishing the trust necessary to mobilize and sustain reduction investment. Right now, however, US climate data collection and dissemination efforts are falling short. Measurement and tracking of GHG emissions reflect a collection of ad hoc mandates and … [↵][1]1To whom correspondence may be addressed. Email: kevin.gurney{at}nau.edu. [1]: #xref-corresp-1-1

Near-surface atmospheric concentrations of greenhouse gases (CO2 and CH4) in Florence urban area: Inferring emitting sources through carbon isotopic analysis

From February to April 2019, near-surface CO2 and CH4 concentrations and carbon isotopic compositions (δ13C-CO2 and δ13C-CH4) were monitored at four stations belonging to the local air quality surveillance network of Florence (central Italy), representing typical zones of suburban background (SB), urban traffic (UT) and urban background (UB). The GHGs (greenhouse gases) concentrations showed a high spatial variability likely related to variable contributions from distinct emitting sources in the urban landscape. The δ13C-CO2 and δ13C-CH4 values suggested that domestic heating is the dominant GHGs emitting source at the UB station. Conversely, traffic-related CO2 emissions (about 74%) largely overwhelmed those from natural gas combustion at the UT stations, where vehicular exhaust emissions also affected atmospheric CH4 levels. The SB and UB stations registered the presence of multiple CH4 sources, which included both leakage from underground pipeline network for natural gas supply and biogenic emissions from urban waterways. These results offer a pivotal background framework to improve the performance of GHGs reduction policies and refine the spatiotemporal resolution of bottom-up estimations of urban GHG emissions.

In‐situ biochar production associated with paddies: Direct involvement of farmers in greenhouse gases reduction policies besides increasing nutrients availability and rice production

AbstractTreating soils with pyrolyzed biomass, that is biochar, is proposed as a conditioner and a carbon geoengineering measure. Rice is known as a strategic crop and rice husk is a cheap and available feedstock material for biochar in particular in Asia. We conducted a field experiment with laboratory biochar (LB) and locally produced [in‐situ biochar (IB)] applied at rates of 10 and 20 t ha−1 using a randomized block design in three replicates to examine the efficiency of IB for improving soil condition for rice production, and to propose a cheap and in‐farm applicable measure to decrease greenhouse gases (GHGs) emissions from the agricultural sector. Grain yield significantly increased following biochar addition by 52.2%, 53.2%, 65.4%, and 67.2% in LB10, IB10, LB20, and IB20, respectively. Total biomass in all biochar treatments had a significant difference (p < 0.05) compared with our control and the highest biomass belonged to LB20 and IB20 with 12.2 and 15.7 t ha1, respectively. The highest grain nitrogen, phosphorus, and potassium was in IB20. Compared to the control, IB20 significantly decreased emissions of CH4 by 72.3%, N2O by 85.8%, and CO2 by 32.9%. IB is as effective as LB. IB production and application provide a sustainable management approach for dealing with crop residues, improves soil conditions (aeration and nutrients availability) for crop growth, and directly and in a practical way involves farmers in GHGs reduction policies.

Evaluating Landfill Diversion Strategies for Municipal Organic Waste Management Using Environmental and Economic Factors

Municipal organic waste (MOW) contributes to greenhouse gas (GHG) emissions leading to global climate change. Incentives that encourage consumers to adopt MOW disposal strategies that minimize environmental impacts are needed. Policymakers must ensure that incentive programs align with environmental objectives and are economically competitive. The MOW disposal infrastructure in the city of Milwaukee, WI, was evaluated using a coordinated market model capturing the inherent value of environmental indicators (estimated with partial life cycle assessment methods) in the context of the city’s MOW supply chain. Tax programs are identified that incentivize consumers to reduce emissions through MOW disposal patterns. Results indicate that the existing MOW management infrastructure in Milwaukee incentivizes residents to minimize MOW GHG emissions by sending MOW to composting and digestion sites that have lower tipping fees and are located closer to the city (have lower transport costs). Therefore, limitations associated with MOW collection likely decrease alternative landfill disposal options. GHG reduction policy prioritizes anaerobic digestion systems for MOW disposal, but the outcome can be altered depending upon the tipping fees and transport distances. Composting and digestion hold few opportunities for reducing ammonia emissions from landfills, but there is a need to expand ammonia emissions measurements from landfill systems to improve model predictions as ammonia losses can redeposit, resulting in environmental issues and indirect formation of N2O.

Selecting Relevant Biological Variables Derived from Sentinel-2 Data for Mapping Changes from Grassland to Arable Land Using Random Forest Classifier

Permanent grassland is one of the monitored categories of land use, land use change, and forestry (LULUCF) within the climate concept and greenhouse gas reduction policy (Regulation (EU) 2018/841). Mapping the conditions and changes of permanent grasslands is thus very important. The area of permanent grassland is strongly influenced by agricultural subsidy policies. Over the course of history, it is possible to trace different shares of permanent grassland within agricultural land and areas with significant changes from grassland to arable land. The need for monitoring permanent grassland and arable land has been growing in recent years. New subsidy policies determining farm management are beginning to affect land use, especially in countries that have joined the EU in recent waves. The large amount of freely available satellite data enables this monitoring to take place, mainly owing to data products of the Copernicus program. There are a large number of parameters (predictors) that can be calculated from satellite data, but finding the right combination is very difficult. This study presents a methodical, systematic procedure using the random forest classifier and its internal metric of mean decrease accuracy (MDA) to select the most suitable predictors to detect changes from permanent grassland to arable land. The relevance of suitable predictors takes into account the date of the satellite image, the overall accuracy of change detection, and the time required for calculations. Biological predictors, such as leaf area index (LAI), fraction absorbed photosynthetically active radiation (FAPAR), normalized difference vegetation index (NDVI), etc. were tested in the form of a time series from the Sentinel-2 satellite, and the most suitable ones were selected. FAPAR, canopy water content (CWC), and LAI seemed to be the most suitable. The proposed change detection procedure achieved a very high accuracy of more than 95% within the study site with an area of 8766 km2.

Inter-provincial correlations of agricultural GHG emissions in China based on social network analysis methods

PurposeThe purpose of this paper is to explore the heterogeneity and correlations of agricultural greenhouse gas (GHG) emissions among provinces in China, and then policy implications are proposed.Design/methodology/approachAfter agricultural GHG accounting and a pre-analysis of inter-provincial heterogeneity, improved gravity model and the Social Network Analysis (SNA) methods are introduced to construct the network, being carried out from three aspects of the whole network, individual provincial characteristics and cluster analysis.Findings(1) There are significant regional variations in agricultural GHG scale among provinces owing to the layout of agricultural production, and the temporal trends show that the direction and speed of agricultural GHG scale change vary among provinces; (2) In terms of inter-provincial correlations, there exists a complex spatial network of agricultural GHG among provinces, which tends to be more complex, intensive and stable, while the status of the provinces in the network also has gradually become more balanced. All provinces played their respective roles in the four clusters of the network with agricultural layout and comparative advantages, and the distribution has continuously optimized.Practical implicationsThe inter-provincial network characteristics of agricultural GHG emissions and its evolution have practical implications for differentiated and coordinated agricultural GHG reduction policies at the provincial levels.Originality/valueThis paper innovatively study inter-provincial agricultural GHG correlations in China with the SNA methods used to study economic and social connections in the past. There is some originality in the introduction of network theory and application of the SNA methods, which can provide some reference for researches in similar fields.

Evaluating Japan’s national greenhouse gas reduction policy using a bottom-up residential end-use energy simulation model

The national policy in Japan for reducing greenhouse gas (GHG) emissions in the residential sector by 2030 is evaluated using a bottom-up-type simulation model called the Total Residential End-use Energy Simulation (TREES) model. According to the Japanese Plan for Global Warming Countermeasures (PGWC), the target GHG reduction in the residential sector is expected to be realized through the aggregated effect of various mitigation measures. In evaluating the impact of these measures, the following three factors must be considered: occupant behavior, differences in the effect among households, and secondary impacts. In this paper, to discuss the required specifications for supporting the policies related to GHG reduction, these factors are examined via the TREES model, considering the differences in the energy use among households due to occupant behavior, appliance/equipment ownership, and building energy efficiency. The simulation results of the end-use energy in the Japanese residential sector in 2013 show good agreement with available statistical values. The results of the TREES model applied to evaluate the proposed countermeasures suggest that 1) The Japanese government may be overestimating the effect of high-efficiency lighting installations, 2) The reduction in the total energy use varies by a factor of two depending on the combination of high-efficiency water heaters and household characteristics, 3) The relationship between the types of water heater and space heating system influences the effect of high-efficiency water heater installations, and 4) Energy demand reduction affects the electricity load curve and CO2 emission intensity of the electricity grid.