Cleaner Production Letters最新文献

Several countries have revised their targets in recent years to reach net-zero CO₂ emissions across all sectors by 2050, and the transport sector is responsible for a significant share of these emissions. This study compares possible pathways to decarbonise the transport sector including passenger cars, light commercial vehicles and heavy commercial vehicles. To do so, we explore 125 scenarios by varying the share of battery and hydrogen-based fuel cell electric vehicles in each of the three categories above independently. We further model the decarbonisation of the industrial hydrogen demand using electrolysers with hydrogen storage. To explore the potential role of electric and hydrogen transport, as well as their trade-offs, we use GRIMSEL, an open-source sector coupling energy system model of Switzerland which includes the residential, commercial, industrial and transport sectors with four energy carriers, namely electricity, heat, hot water and hydrogen. The total costs are minimised from a social planner perspective. We find that the decarbonisation of the transport sector could lead, on average, to a 12% increase in costs by 2050 and 1.3 MtCO₂/year which represents a 90% CO₂ emissions reduction for the whole sector, compared to fossil-based transport. Second, the transport energy self-sufficiency (i.e. the share of domestic electricity generation in final transport demand) may reach up to 50% for the scenarios with the largest share of battery electric vehicles, mainly due to a smaller energy demand than with hydrogen vehicles. Third, more than three quarters of the industrial hydrogen production is met by local photovoltaic electricity coupled with battery at minimum costs, i.e. green hydrogen. Finally, the use of hydrogen as an energy carrier to store electricity over a long period is not cost-optimal.

Protecting natural forests such as those identified as high conservation value (HCV) areas may facilitate crop production due to the benefit from ecosystem services provided by biodiversity spill-over from adjacent forests. To investigate the effect of protecting contiguous and isolated forests adjacent to oil palm plantations on crop health, we measured the distance between oil palm plots and the continuous forest and forest patch boundaries. We surveyed 715 oil palm sample plots comprising 613 plots in large-scale oil palm plantation and 102 plots in smallholdings that were at least 300 m apart and had a radius of 100 m. Satellite imagery and ancillary spatial data from 2016, 2018, 2019 and 2020 of Negeri Sembilan, Malaysia were used to determine elevation and vegetation indices (VIs). The VIs derived were the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Normalized Difference Moisture Index (NDMI). Both NDVI and EVI are used to measure the vegetation greenness. The NDMI is used to determine the water content of plants. The VIs are crucial for a variety of applications, including vegetation monitoring, drought research, and agricultural operations. We then used generalized linear models (GLMs) to examine the relationship between VIs and stand-and landscape-level variables. Each VI was used as a response variable, with elevation, distance from continuous forest or forest patches, and oil palm management system (i.e., smallholding and industrial plantation) as explanatory variables. Our results revealed that the chlorophyll sensitive NDVI decreased with increasing distance from continuous forest, but increased away from the forest patches. In contrast, the dense vegetation sensitive EVI increased away from continuous forest, but decreased when distance from forest patches increased. Proximity to continuous forests or forest patches had no effect on the NDMI. All the vegetation indices were lower in smallholdings than industrial plantations. None of the vegetation indices were significantly influenced by elevation. Given that these indices predict palm health and yield, this pattern could result in greater ecosystem services that benefit oil palm growers in oil palm closer to some forest types through the spillover effects of forest biodiversity from continuous forests and forest patches. This study suggests that conservation and industry stakeholders should work together to strengthen the conservation of biodiverse continuous forests and forest patches in HCV standard to develop more-sustainable oil palm agriculture, because of their potential role in supporting ecosystem services.

Hydrogen is an energy carrier with potential applications in decarbonizing difficult-to-electrify energy and industrial systems. The environmental profile of hydrogen varies substantially with its inputs. Water consumption is a particular issue of interest as decisions are made about capital and other investments that will affect the scale and scope of hydrogen use. This study focuses on electrolytic hydrogen due to its path to greenhouse gas neutrality and irreducible water demand (though other pathways might be more water intensive). Specifically, it evaluates life cycle consumptive freshwater intensity of electrolytic hydrogen in the United States at volumes associated with 12 scenarios for a deeply decarbonized 2050 US energy system from two modeling efforts for which both electricity fuel mix and electrolytic hydrogen production were projected (America's Zero Carbon Action Plan and Net Zero America), in addition to volumes for a stylized energy storage project (500 MW hydrogen-fired turbine). Freshwater requirements for hydrogen could be large. Under a central estimate for 2050 US electrolytic hydrogen production, electrolytic freshwater demand for process and feedstock inputs alone (i.e., excluding water for electricity) would be about 7.5% of total 2014 US freshwater consumption for energy (1 billion cubic meters/year, 10⁹ m³/y; [0.2%, 15%] across scenarios, for 2050 electrolytic hydrogen production of [0.3, 18] exajoules, EJ). Including water associated with production of input electricity doubles this central estimate to 15% (2 × 10⁹ m³/y; [1%, 23%] across scenarios). Turbines using electrolytic hydrogen are estimated to be about as freshwater intensive as a coal or nuclear plant, assuming decarbonized, low-water electricity inputs. Although a decarbonized energy system is projected to require less water for resource capture and electricity conversion than the current, fossil-dominated energy system, additional conversion processes supporting decarbonization, like electrolysis, could offset water savings.

In the context of increasing pressure for sustainable production practices, this paper proposes a framework for how production companies could operationalise circular economy principles. The focus is on the production organisation, and how production operations could contribute to strategic circularity change. Prior research has used the Green kaizen methodology to identify environmental aspects and circularity related to the input-output flow of resources at the production shop floor. However, this paper finds that a more comprehensive approach is required, involving all levels of the production organisation. First, the paper defines circular production principles for production operations, showing that these principles vary across different company levels. Operations and shop floor level principles tend to be closer to the production input-output system, whereas factory management level principles are more focused on information sharing and internal and external relations. The circular production principles followed a hierarchical organisational structure with a bottom-up drive, where the allocation of organisational resources increased as the level of the hierarchy increased. The study reveals parallels with Likert's management system, where green kaizen activities are suitable for the shop floor level, but business development requires authority exploitation. Secondly, the paper identifies four circularity impact factors that apply to all company levels. These factors enhance the practical utility and implementation of circularity aspects, making them applicable to all levels of the company. The framework for bottom-up escalation of circular production principles can be used as a roadmap or support for managing a circularity bottom-up transition work. The findings presented in this paper fill a knowledge gap regarding the organisational and managerial work required for circular production. Specifically, this paper addresses challenges related to circular production management, including the gap between strategic targets and operational-driven work. By proposing a comprehensive framework for operationalising circular production principles, this paper offers practical guidance for production companies seeking to transition to circular economy practices.

At a time when the links that bind the oil industry – both corporate and state-owned - to finance and governments seemed inextricable and unquestionable, some major changes have occurred that have prompted major financial players and governments to seek a separation strategy. From the Paris Agreement to the change of administration in the United States, the wind suddenly seems to be blowing in the opposite direction, and many banks change course. The UN-convened Net-Zero Banking Alliance (NZBA) is one prominent example of this new trend. However, banks are only one part of this complex and varied landscape of global finance, which, among institutional investors, includes investment funds, hedge funds, mutual funds, insurance funds, pension plans and ETFs (exchange-traded funds). Despite the promise to divest or reduce investments, global finance still holds profound ties with the fossil fuel sector. The high energy prices due to the war in the Ukraine and concerns over energy security are seemingly strengthening these ties. We provide an insight of the complexity of these interlinkages and explain to what extent the domain of public governance is trying to exert (still insufficient) control over the financial sector under the scope of climate mitigation policies.

Much evidence suggests that the wealthiest individuals contribute disproportionally to climate change. Here we study the implications of a continued growth in the number of millionaires for emissions, and its impact on the depletion of the remaining carbon budget to limit global warming to 1.5 °C (about 400 Gt CO₂). To this end, we present a model that extrapolates observed growth in millionaire numbers (1990–2020) and associated changes in emissions to 2050. Our findings suggest that the share of US$₂₀₂₀-millionaires in the world population will grow from 0.7% today to 3.3% in 2050, and cause accumulated emissions of 286 Gt CO₂. This is equivalent to 72% of the remaining carbon budget, and significantly reduces the chance of stabilizing climate change at 1.5 °C. Continued growth in emissions at the top makes a low-carbon transition less likely, as the acceleration of energy consumption by the wealthiest is likely beyond the system's capacity to decarbonize. To this end, we question whether policy designs such as progressive taxes targeting the high emitters will be sufficient.

Climate change mitigation is at the core of the preoccupations of governments worldwide. The main research gap is that little is known about a powerful tool used by corporations to address climate change, namely carbon reduction and energy transition targets. In the official statistics, companies are designated as the biggest polluters. The purpose of this research is to investigate the targets set by the largest European companies and their achievement status regarding the carbon reduction and energy transition process. Target setting was analyzed by reference to the pressures hypothesized by the institutional theory. To answer the research question, the targets set by the companies included in the STOXX All Europe 100 Index were extracted from various sources. Hypothesis testing was conducted on the existence of mimetic, coercive, and normative isomorphism. A new scoring system was proposed to measure the level of corporate commitment regarding carbon reduction and energy transition targets. The findings suggest that most targets are established for the short and medium term and refer to absolute emissions, some of them already achieved. All forms of isomorphism apply to the selected sample. The research has implications for policy setting, as relaxed targets may lead to greenwashing and prevent countries from meeting international strategic goals.

Urban metabolism uses the idea that cities are resource consuming systems that are supported by flows of energy and materials, and they produce goods and wastes, which generate greenhouse gas emissions both directly and indirectly. This research builds on other recent applications of input-output and ecological network analyses to urban metabolism with added value of comparing in one study both approaches across Europe and China specifically at the city scale. We use input-output (IO) and ecological network analyses (ENA) in a study of the urban metabolism of four cities, Vienna, Austria, Malmö, Sweden, Beijing and Shanghai, China. Based on economic input-output tables and environmental weighting coefficients, we create a connected network of flows between 17 economic sectors that captures the carbon emissions from transactions in a producer orientation. Ecological network analysis is conducted to identify the main sectors contributing to the direct and indirect carbon emissions in the four cities. Our results reveal these to be Transportation, Manufacturing, and Electricity production. Furthermore, we show that final demand in terms of domestic export is the highest contributor in each city, indicating that each city is a producer overall in the countries’ economies generating carbon flows that are consumed elsewhere.

The International Maritime Organization (IMO) committed to reduce by 50% the annual greenhouse gas (GHG) emissions from international shipping by 2050 compared to 2008 levels. Future low-carbon fuels use in the maritime transport to curb GHG emissions can increase freight rates and affect trade, especially for commodities transported over long distances. This study performed a case study to evaluate lignocellulosic marine biofuels use in soybean trade routes from Brazil and U.S. to China, in terms of supply volumes, GHG emissions and potential increase on freight costs. This is the first attempt to assess biofuel use in a specific product trade. To this end, two scenarios and three technologies were developed for biofuels availability from 2020 to 2050. Findings reveal that Brazil benefits from higher biofuel supply and four Brazilian biofuel pathways meet total bunker fuel demand in 2050, while U.S. pathways supplied up to 24%. However, emission reduction come at significant cost increase with abatement costs reaching more than US$ 300/tCO₂e for some of the Brazilian and U.S. pathways. To reduce this cost gap, market instruments, such as carbon price of at least US$ 100/tCO₂e would be required. Nevertheless, fuel cost increase has not resulted in significant cost variation between Brazilian and U.S. vessel routes. Hence, Brazilian trade routes could keep lower freight costs than U.S. even with higher biofuel shares. This indicates that regions capable of supplying low-carbon fuels can become more competitive in their exports in a decarbonized maritime trade.

Material consumption has been increasing steadily since the beginning of the 20th century. The urban metabolism field of research is one of the fields that focuses on understanding and measuring this increase at the city level. Many studies have been carried out to calculate the material consumption at the domestic scale. But it is also important to include the non-domestic scale to account for the amount of materials extracted outside the city that were needed along the supply chains to produce the final products consumed in the city. This is referred as the material footprint, which provides a consumption-based indicator of resource use. The objective of this study was to develop a method to measure the material footprint of the cities of Nantes-Saint-Nazaire (France) and Gothenburg (Sweden), both port cities and pioneers in the implementation of urban policies targeting a circular economy. The methodology combines urban material flow analysis with multi-regional input-output database to extend the urban metabolism beyond the administrative boundaries of cities. We then calculated the absolute and per capita material footprints of the two cities and its material disaggregation. We compared these results with domestic material consumption. Further analysis of the urban material footprint was performed by spatializing the flows in the global economy to understand the extent of consumption due to cities. The results show that on average the material footprint is 2.4 times larger than the domestic material consumption in Gothenburg and 1.9 times larger in Nantes-Saint-Nazaire. A decoupling between material footprint and domestic material consumption can be observed, as the material footprints grew much faster than the domestic material consumption. Regarding the material disaggregation, the most significant category is non-metallic minerals, which weighs more than 50% on average of the total material footprint balance sheet and also increased the most. In conclusion, future work should thus better integrate material footprint, as there is a need to better understand the externalization of urban metabolism and to identify what aspects urban circular economy policies should focus on.