Simulating the land use change effects on non-point source pollution in the Duliujian River Basin.

The uncertainty in the generation and formation of non-point source pollution makes it challenging to monitor and control this type of pollution. The SWAT model is frequently used to simulate non-point source pollution in watersheds and is mainly applied to natural watersheds that are less affected by human activities. This study focuses on the Duliujian River Basin (Xiqing section), which is characterized by a dense population and rapid urbanization. Based on the calibrated SWAT model, this study analyzed the effects of land use change on non-point source pollution both temporally and spatially. It was found that nitrogen and phosphorus non-point source pollution load losses were closely related to land use type, with agricultural land and high-density urban land (including rural settlements) being the main contributors to riverine nitrogen and phosphorus pollution. This indicates the necessity of analyzing the impact of land use changes on non-point source pollution loads by identifying critical source areas and altering the land use types that contribute heavily to pollution in these areas. The simulation results of land use type changes in these critical source areas showed that the reduction effect on non-point source pollution load is in the order of forest land > grassland > low-density residential area. To effectively curb surface source pollution in the study area, strategies such as modifying urban land use types, increasing vegetation cover and ground infiltration rate, and strictly controlling the discharge of domestic waste and sewage from urban areas can be implemented.

Prioritizing Non-Carbon Dioxide Removal Mitigation Strategies Could Reduce the Negative Impacts Associated with Large-Scale Reliance on Negative Emissions.

Carbon dioxide removal (CDR) is necessary for reaching net zero emissions, with studies showing potential deployment at multi-GtCO2 scale by 2050. However, excessive reliance on future CDR entails serious risks, including delayed emissions cuts, lock-in of fossil infrastructure, and threats to sustainability from increased resource competition. This study highlights an alternative pathway─prioritizing near-term non-CDR mitigation and minimizing CDR dependence. We impose a 1 GtCO2 limit on global novel CDR deployment by 2050, forcing aggressive early emissions reductions compared to 8-22 GtCO2 in higher CDR scenarios. Our results reveal that this low CDR pathway significantly decreases fossil fuel use, greenhouse gas (GHG) emissions, and air pollutants compared to higher CDR pathways. Driving rapid energy transitions eases pressures on land (including food cropland), water, and fertilizer resources required for energy and negative emissions. However, these sustainability gains come with higher mitigation costs from greater near-term low/zero-carbon technology deployment for decarbonization. Overall, this work provides strong evidence for maximizing non-CDR strategies such as renewables, electrification, carbon neutral/negative fuels, and efficiency now rather than betting on uncertain future CDR scaling. Ambitious near-term mitigation in this decade is essential to prevent lock-in and offer the best chance of successful deep decarbonization. Our constrained CDR scenario offers a robust pathway to achieving net zero emissions with limited sustainability impacts.

A review contribution to emission trading schemes and low carbon growth.

In this study, the researchers focus on policy instruments that employ a market-based strategy to promote emission reduction, find the key spots and recent changing aspects in the field of Eemission Trading Systems (ETS) and Low Carbon Growth, and make suggestions for future studies. Making use of the bibliometric analysis, the researchers examine a sample of 1,390 research from the ISI Web of Science database to find research activity on ETS and low carbon growth between 2005 and 2022. Also, the researchers visualized the knowledge domains in this field using software like CiteSpace and R-Biblioshiny. The research unravels the most influential published articles and authors on their citations and publications and their location and significance within the network. The researchers further examined the recent themes, identified the barriers to developing literature in this field, and made recommendations for future research. Research on ETS and low carbon growth globally lack cross-border collaborations between emerging and developed economies. The researchers concluded the study by recommending three future research directions.

Can the new energy vehicles (NEVs) and power battery industry help China to meet the carbon neutrality goal before 2060?

China is working to boost the manufacture, market share, sales, and use of NEVs to replace fuel vehicles in transportation sector to get carbon reduction target by 2060. In this research, using Simapro life cycle assessment software and Eco-invent database, the market share, carbon footprint, and life cycle analysis of fuel vehicles, NEVs, and batteries were calculated from the last five years to next 25 years, with a focus on the sustainable development. Results indicate globally, China had 293.98 m vehicles and 45.22% worldwide highest market share, followed by Germany with 224.97 m and 42.22% shares. Annually China's NEVs production rate is 50%, and sales account for 35%, while the carbon footprint will account for 5.2 E+07 to 4.89 E+07 kgCO2e by 2021-2035. The power battery production 219.7 GWh reaches 150%-163.4%, whereas carbon footprint values in production and use stage of 1 kWh of LFP 44.0 kgCO2eq, NCM-146.8 kgCO2eq, and NCA-370 kgCO2eq. The single carbon footprint of LFP is smallest at about 5.52 E+09, while NCM is highest at 1.84 E+10. Thus, using NEVs, and LFP batteries will reduce carbon emissions by 56.33%-103.14% and 56.33% or 0.64 Gt to 0.006 Gt by 2060. LCA analysis of NEVs and batteries at manufacturing and using stages quantified the environmental impact ranked from highest to lowest as ADP > AP > GWP > EP > POCP > ODP. ADP(e) and ADP(f) at manufacturing stage account for 14.7%, while other components account for 83.3% during the use stage. Conclusive findings are higher sales and use of NEVs, LFP, and reduction in coal-fired power generation from 70.92% to 50%, and increase in renewable energy sources in electricity generation expectedly will reduce carbon footprint by 31% and environmental impact on acid rain, ozone depletion, and photochemical smog. Finally, to achieve carbon neutrality in China, the NEVs industry must be supported by incentive policies, financial aid, technological improvements, and research and development. This would improve NEV's supply, demand, and environmental impact.

Patent mining on soil pollution remediation technology from the perspective of technological trajectory.

Recent years have seen a marked growth in soil environmental problems, however, the research & development (R&D) direction of soil pollution remediation technology (SPRT) for addressing related challenges to the global ecosystem is still unclear. Patent is the most effective carrier of technological information. Therefore, this study investigates the status and future direction of SPRT through the analysis and mining of 14,475 patents from 1971 to 2020. In 2006-2020, 14,435 SPRT patents (79% of the total) were published, which is in the development stage. By measuring the proportion of high-value patents, determined by the ratio of the number of patent families containing two or more patents (PF2) to that containing at least one patent (PF1), we found that United States (PF2/PF1 = 0.711), Japan (PF2/PF1 = 0.500), and South Korea (PF2/PF1 = 0.431) hold a monopoly. International patent organizations serve as a bridge for technology transfer. Patent CN101947539-A measured by structural hole index (Effective size = 98.194, Efficiency = 0.926) has the most significant technological influence. Therefore, in order to accomplish the technological transition and improve the soil remediation capacity, more attention should be paid to the microbial-assisted phytoremediation technology related to inorganic pollutants, hyperaccumulators and stabilizers. Additionally, patents CN102834190-A (Effective size = 23.930, Efficiency = 0.855, Constraint = 0.141, Hierarchy = 0.089) and CN105855289 (Effective size = 21.453, Efficiency = 0.795 Constraint = 0.149, Hierarchy = 0.086) are both at the location of structural holes. So, more research should be carried out on green and cost-effective solutions for reducing organic pollutants in soil remediation. The current study identifies opportunities for innovations and breakthroughs in SPRT and offers relevant information on technological development prospects.

Performance analysis and socio-enviro-economic feasibility study of a new hybrid energy system-based decarbonization approach for coal mine sites.

The mining sector contributes to 4-7 % of global GHG emissions, of which 1 % are from scope 1 and scope 2 emissions, caused by operations such as electricity consumption used for the mining process. China heavily relies on coal for power generation, and the energy demand for coal production in the country is primarily met by fossil-based electricity. In addition, the transportation of the mined coal to various destinations within the supply chain is achieved by fossil fuel-powered transport systems. These daily activities of the Chinese coal sector further compound foreign and domestic pressure on China to limit its carbon emissions. The current study attempts to provide a solution to the situation by investigating the feasibility of adopting renewable energy sources for the process of coal mining in Northern China. The selected coal mine is one out of 643 coal mines in Shanxi Province, with a combined production capacity of ∼1 billion tonnes of coal per annum. In addition, the excess electricity generated has been designated to produce hydrogen on-site as a refueling source for hydrogen fuelled-trucks to replace diesel fuelled-trucks in transporting coal. The analysis has been completed using HOMER Pro software, and the key contributions are summarized as follows. 4 different scenarios comprising of standalone solar photovoltaic, wind turbine, and diesel generator have been designed in the current study to serve a daily load of 215 MWh and 2.4 t of electricity for coal mining and hydrogen for transport of 100 % of the mined coal by road using hydrogen fuel cell trucks, respectively. A technical, economic, environmental, and social feasibility analysis have been investigated in the present work. A grid-tied system is subsequently added to the base scenario and the results are compared against the base system in an attempt to identify the more feasible option between the two systems. Also, a sensitivity analysis has been conducted to reveal the performance of the base system amidst future uncertainties. The findings in the current work could prove beneficial to China's quest to reach carbon peak by 2030 and achieve carbon neutrality by 2060.

Research Progress, Trends, and Current State of Development on PEMFC-New Insights from a Bibliometric Analysis and Characteristics of Two Decades of Research Output.

The consumption of hydrogen could increase by sixfold in 2050 compared to 2020 levels, reaching about 530 Mt. Against this backdrop, the proton exchange membrane fuel cell (PEMFC) has been a major research area in the field of energy engineering. Several reviews have been provided in the existing corpus of literature on PEMFC, but questions related to their evolutionary nuances and research hotspots remain largely unanswered. To fill this gap, the current review uses bibliometric analysis to analyze PEMFC articles indexed in the Scopus database that were published between 2000-2021. It has been revealed that the research field is growing at an annual average growth rate of 19.35%, with publications from 2016 to 2012 alone making up 46% of the total articles available since 2000. As the two most energy-consuming economies in the world, the contributions made towards the progress of PEMFC research have largely been from China and the US. From the research trend found in this investigation, it is clear that the focus of the researchers in the field has largely been to improve the performance and efficiency of PEMFC and its components, which is evident from dominating keywords or phrases such as 'oxygen reduction reaction', 'electrocatalysis', 'proton exchange membrane', 'gas diffusion layer', 'water management', 'polybenzimidazole', 'durability', and 'bipolar plate'. We anticipate that the provision of the research themes that have emerged in the PEMFC field in the last two decades from the scientific mapping technique will guide existing and prospective researchers in the field going forward.

Integrated AHP-TOPSIS under a Fuzzy Environment for the Selection of Waste-To-Energy Technologies in Ghana: A Performance Analysis and Socio-Enviro-Economic Feasibility Study.

Energy recovery from waste presents a promising alternative for several countries, including Ghana, which has struggled with unsustainable waste treatment methods and an inadequate power supply for several decades. The current study adopts a comprehensive multi-criteria decision-making approach for the selection of an optimal waste-to-energy (WtE) technology for implementation in Ghana. Four WtE technologies are evaluated against twelve selection criteria. An integrated AHP-fuzzy TOPSIS method is applied to estimate the criteria's weights and rank the WtE alternatives. From the AHP results, technical criteria obtained the highest priority weight, while social criteria emerged as the least important in the selection process. The overall ranking order of WtE technologies obtained by fuzzy TOPSIS is as follows: anaerobic digestion > gasification > pyrolysis > plasma gasification. The sensitivity analysis indicates highly consistent and sturdy results regarding the optimal selection. This study recommends adopting a hybrid system of anaerobic digestion and gasification technologies, as this offers a well-balanced system under all of the evaluation criteria compared to the standalone systems. The results of the current study may help the government of Ghana and other prospective investors select a suitable WtE technology, and could serve as an index system for future WtE research in Ghana.

Progress and Recent Trends in the Application of Nanoparticles as Low Carbon Fuel Additives-A State of the Art Review.

The first part of the current review highlights the evolutionary nuances and research hotspots in the field of nanoparticles in low carbon fuels. Our findings reveal that contribution to the field is largely driven by researchers from Asia, mainly India. Of the three biofuels under review, biodiesel seems to be well studied and developed, whereas studies regarding vegetable oils and alcohols remain relatively scarce. The second part also reviews the application of nanoparticles in biodiesel/vegetable oil/alcohol-based fuels holistically, emphasizing fuel properties and engine characteristics. The current review reveals that the overall characteristics of the low carbon fuel-diesel blends improve under the influence of nanoparticles during combustion in diesel engines. The most important aspect of nanoparticles is that they act as an oxygen buffer that provides additional oxygen molecules in the combustion chamber, promoting complete combustion and lowering unburnt emissions. Moreover, the nanoparticles used for these purposes exhibit excellent catalytic behaviour as a result of their high surface area-to-volume ratio-this leads to a reduction in exhaust pollutants and ensures an efficient and complete combustion. Beyond energy-based indicators, the exergy, economic, environmental, and sustainability aspects of the blends in diesel engines are discussed. It is observed that the performance of the diesel engine fuelled with low carbon fuels according to the second law of efficiency improves under the influence of the nano-additives. Our final part shows that despite the benefits of nanoparticles, humans and animals are under serious threats from the highly toxic nature of nanoparticles.

Investigating evolutionary trends and characteristics of renewable energy research in Africa: a bibliometric analysis from 1999 to 2021.

Several countries across the African continent have been challenged with energy crises for decades. A growing number of studies have identified renewable energy as a sustainable way for Africa to address its persisting energy situation while combating climate change, as the continent has in abundance some of the common renewable energy resources. Little has been reported in the body of literature to quantitatively and qualitatively map the knowledge domain of this growing research field. In the current study, we conduct a bibliometric analysis on research documents extracted from the Web of Science Core Collection to identify trends and characteristics of the knowledge domain related to renewable energy in Africa from 1999 to 2021. Using two different software (VOSviewer and ITgInsight), we report the contribution of journals, countries, institutions, and authors and their collaboration patterns. We also perform co-citation and keyword analysis to identify the intellectual base and central themes of this research field. The results from the study revealed a growing interest in Africa's renewable energy, with about 90% of the total publication from within the last decade. Renewable & Sustainable Energy Reviews was identified as the most productive as well as the most influential journal in this field. The most contributing countries in this field were South Africa, USA, and Algeria. Centre de Developpement Des Energies Renouvelables, a research institute in Algeria, emerged as the most productive and influential institution. The analysis of research hotspots under different categories revealed that "solar energy," "CO2 emissions," and "rural electrification" are the topics that have gained maximum attention over the years. Keyword evolution analysis also identified "economic growth" and "green hydrogen production" as emerging topics that will play a major role in future studies. We conclude our work by providing specific suggestions and strategies to help bridge the gap which exists in the quantity and quality of renewable energy research between Africa and the rest of the world.

Low-carbon alcohol fuels for decarbonizing the road transportation industry: a bibliometric analysis 2000-2021.

The application of low-carbon alcohols (LCA fuels) in internal combustion engines has become one of the most important topics in road transport decarbonization. This paper aims to identify the trends and characteristics of LCA combustion research for the period 2000-2021 through bibliometric analysis. Citation analysis is used to evaluate the influence of most productive journals, countries/regions, authors, institutions, and relevant literature, while collaborative network between various authors, countries/regions, institutions, and the co-occurrences among different keywords are discussed. A dataset of 2250 publications was extracted from the Web of Science Core database and analyzed with CiteSpace and Biblioshiny. The extracted documents involve 429 journals of publications by 4782 authors from 1434 institutions across 83 countries/regions. The results reveal that the research output in this field has undergone three main stages of development, i.e., initial development (2000-2007), slow development (2008-2015), and rapid development (2016-2021). Currently, the research field is growing at an annual growth rate of 9.24%, with most of the contributions by authors and institutions originating from China. The analysis from relevant keywords and literature suggests that the core of this research field centers on the combustion, performance, and emission characteristics of LCA-fueled engines. The current study helps keep the scientific community informed of the latest paradigms in the LCA combustion research field.

Visualization and analysis of mapping knowledge domains for the global transition towards clean cooking: a bibliometric review of research output from 1990 to 2020.

Current statistics report that 2.6 billion households across the globe rely on polluting and inefficient cooking fuels and technologies, posing death-threatening health risks to people mainly from developing countries/regions. Several studies on clean cooking have been conducted with the emergence of international organizations such as the Clean Cooking Alliance to raise awareness. In the current study, a bibliometric tool, CiteSpace, was employed to analyze the 877 documents retrieved from the SCI-EXPANDED, SSCI, and A&HCI databases on clean cooking research from 1990 to 2020. The results reveal that interest in clean cooking research took a sharp rise in the last decade, especially after 2016. The research field has become increasingly interdisciplinary but has mostly centered on environment, energy, and health. The most productive countries/regions in this field are the USA, India, England, and China. The keyword and citation analyses indicate that research in this field mostly focuses on adverse impacts of household air pollution from unclean cooking fuels and technologies on the environment and public health particularly, in developing countries/regions. Also, the drivers and barriers to the large-scale adoption of clean cooking fuels and technologies have become a topic of interest in recent years. The three most studied clean cooking fuels among various regions are LPG, biogas, and electricity. This study synthesizes global research on clean cooking and may be beneficial to other researchers in understanding current trends in this field and serve as a guide for concentrating on the most important topics.